Stella 2T highway/performance upgrades
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Wed Jun 12, 2019 4:13 pm quote
Freak gasoline fight accident.

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Wed Jun 12, 2019 4:17 pm quote
charlieman22 wrote:
Freak gasoline fight accident.

That one specifically:

http://modernvespa.com/forum/post2323729#2323729
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Sat Jun 15, 2019 3:11 pm quote
I was finally able to set the ignition timing properly on my stella. Took grinding the stator plate in multiple spots to allow turning far enough to set at 18 degrees.

Once I got the timing set to 18 degrees, I reset the jetting to the malossi instructions for 18 degrees timing: 52/140 idle, 140/be4/115 main stack. This was way too rich all across the board as I fouled a plug and couldnt get it started from a rich idle, despite having the air mix screw set to half a turn out from closed.

I then made adjustments I thought I needed to do to get it running better. I went down to 48/140 idle jet and walked the main stack down slowly to 140/be4/108 with air mix screw 1.8 turns out. I think this is very close now. Waiting for a hundred miles to check plug again. I realize that my jetting is way leaner than what everyone is suggesting, but I listened to what the bike was telling me it needed and not what works for everyone else. I have not been riding it hard yet as I want to run another 100+ miles before I think it will be safe, and also want to check plugs a few times.

As far as the rattle, it got better with an 18 degree ignition timing, but there is still a slight rattle. It has to be either the wrist bearing, or just the way this cylinder sounds as a result of my honing, or just manufacturing tolerances.

It wants to go fast now. I am trying my best not to ride like i stole it!

EDIT: rattle seems lesser after only about 20 miles. I'm thinking it might hopefully work itself out with the run in and go away. Bike sounds strong great now, and feels like i'm riding a motorcycle instead of something under powered. It definitely sounds louder now to the point where everyone walking down the street turns around to look, and some guy yelled at me to do a wheelie. So I gave him a little rev and laughed!

IMG_20190614_113823.jpg
all 4 screw holes were doubled in length on the left side to allow further turning to right closer to TDC

IMG_20190614_124907.jpg
then I had to take a chunk out of the plate arm that sticks up above TDC and holds a magnet or sensor. this part was catching on the case opening for it.

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Sat Jun 15, 2019 6:43 pm quote
swiss1939 wrote:
I can be as loud as i want while jetting right here. Manhattan on the left, the Verrazano Bridge on the right.
Very cool photo!
Molto Verboso
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Sat Jun 15, 2019 6:58 pm quote
Well at least that's the timing done. Not easy with all those strange parts. Give it a while and then re-measure everything (especially TDC) and strobe again.

If 52/140 is really too rich for now then 48/140 is the correct way to go. Can you rev to at least 8000 wide open on the stand? If you can then 108 is not too big. If you can't then room to go down once run in.

Glad you're happy with it so far. And this is just bolt on. With the 60mm crank there could be 5bhp more to play with.
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Sat Jun 15, 2019 7:12 pm quote
that is awesome happy to see your progress.
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Sat Jun 15, 2019 7:59 pm quote
Jack221 wrote:
If 52/140 is really too rich for now then 48/140 is the correct way to go. Can you rev to at least 8000 wide open on the stand? If you can then 108 is not too big. If you can't then room to go down once run in.

Glad you're happy with it so far. And this is just bolt on. With the 60mm crank there could be 5bhp more to play with.
I did not chance revving it to 8000 or high at all on the stand. I did to about 6500 and cut it out so I wouldn't overtax it. I couldn't get it to rev while riding at 115 or 110 MJ higher than 4000 rpm. Now at 108 it wants to go way higher, but I am not pushing it.

Yeah I think long stroke crank with shaped ports it will be a beast (for me at least). I think its around 15-16 hp now. I don't think I really want the peakiest engine on earth, but would like a little more grunt, hopefully in the sub 5000rpm range. It is so funny how it runs normal, then a sharp line at 5000rpm and it just surges into power and feels like a completely different engine! Neither are bad, but so much more torque at 5000 than below.

I've also lost about 17 lbs from 230 down to 213 over the past month with so much time off from work. Video Editors working 60 hrs a week for 8 months leads to lots of weight gain during the season! So that is also helping with the power on this bike! If I can get below 200 lbs with my down time over the summer, I think this thing will be pretty fast for me.
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Sat Jun 15, 2019 10:25 pm quote
Well done with the weight. Is not easy to lose but the cheapest scooter tuning you will do.

Going to be entirely different with a 60mm crank and 24 carb. The power can be put wherever you need it and being an iron cylinder, easy to modify for even more.

You won't break it revving on the stand but will be run in soon anyway. On the rich side (but not a black plug) is best for running in.
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Sun Jun 16, 2019 6:42 am quote
It revs to 9400 on stand. I'm riding around all day to finish break in and check plug. I think it may be able to come down one size but I'll know later today.
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Sun Jun 16, 2019 8:34 am quote
Here is the plug at 108 mj. I think it's good, but from riding it, I think a big maybe could go down one point cause it's still slightly Rich in the lower to mid throttle. Either that or it's just the acceleration response of the top end. Sightly slower to take off with just a little four stroking until you get above half throttle.

I will leave it at this for a while because is safer and close.

IMG_20190616_122637.jpg

IMG_20190616_122645.jpg

IMG_20190616_122648.jpg

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Sun Jun 16, 2019 10:08 am quote
It may just need fine tuning with the air mix screw slightly leaner to fix the four stroking and not as rapid acceleration low to mid throttle.

Took it on the highway connector I use to test higher speeds out today for first time. Previously stock engine with stock clutch gear I could just barely get 59-60mph downhill with wind behind me. Once I upgeared the clutch on stock cylinder I got 62 on flat ground max. I just took it up to 67mph on slight incline and slowly climbing before I cut it out cause there was a cop speed trap at the end of that connector I knew was there. I think I might have been able to get it up to 70 with more room and on level ground. I definitely flew by a few cars that weren't expecting a scooter to be hauling that fast.

I'd say that's pretty damn good for a PNP cylinder upgrade. It is definitely doable on NYC highways now as most traffic is about 55-60mph, and 67 is just enough to overtake if needed. Case matching, long stroke and port timings would only be bonus at this point, and maybe giving that extra oomph at 65+ mph if you really needed to get out of the way of something with speed.
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Sun Jun 16, 2019 1:08 pm quote
Quote:
Awesome - first start.
Often anticlimactic - can feel like you stepped backwards - as completely out of tune.
By the end of next week - will feel like you have the fastest bike on the forum.
Looks like u r just about there.
Awesome!
Ballsy to take it on and figure out port timings - even if you went PNP. Will surely leave you better equipped/ more confident for next round.

Curious how much of your lighter low end/ above 6k punch is ports vs exhaust. Know you pondered that yourself.

Wonder if a box exhaust would boost rideability in the mid torque area.
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Sun Jun 16, 2019 1:11 pm quote
charlieman22 wrote:
Quote:
Awesome - first start.
Often anticlimactic - can feel like you stepped backwards - as completely out of tune.
By the end of next week - will feel like you have the fastest bike on the forum.
Looks like u r just about there.
Awesome!
Ballsy to take it on and figure out port timings - even if you went PNP. Will surely leave you better equipped/ more confident for next round.

Curious how much of your lighter low end/ above 6k punch is ports vs exhaust. Know you pondered that yourself.

Wonder if a box exhaust would boost rideability in the mid torque area.
I have a box exhaust designed for 20+ hp engines. Sip road xl
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Sun Jun 16, 2019 1:22 pm quote
My bad. Rings a bell now.

Same question tho - have u compared any Dino curves of it vs say SIP road II for torque/hp?

Am about to find out myself how the road II alters a lightly modified 150 with same carb as yours.
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Sun Jun 16, 2019 2:52 pm quote
charlieman22 wrote:
My bad. Rings a bell now.

Same question tho - have u compared any Dino curves of it vs say SIP road II for torque/hp?

Am about to find out myself how the road II alters a lightly modified 150 with same carb as yours.
Ive looked at other peoples dyno curves of them. My Road XL exhaust definitely has a bump in power at 5000 and up so some of it is from the exhaust. I'll keep this exhaust for now and once I rebuild engine and do the rest of the upgrades, if it is still lacking in the lower end then I may replace the exhaust. I'm really curious how this exhaust performs on a 20+ hp engine since that's what they designed it for. But, I hear the new Road 3 beta exhausts are supposed to be great. Same amt of horsepower as my current exhaust, but with more torque and lower on the rpm curve.

https://scooterlab.uk/vespa-big-box-exhaust-shootout-feature-2/
Molto Verboso
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Sun Jun 16, 2019 7:31 pm quote
Plug is looking not dangerous. Definitely will go down one more jet to 105. Be aware, as the main jet gets lower the pilot my need to go up.

Sounds like its performing well. If you are talking GPS speeds then there is no reason it won't make the low 70's mph every time, when the 60mm crank is in. As it is it will probably still slow down quite a bit uphill.

A little early to be fine tuning the exhaust but SIP Road II is a solid choice for this.
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Mon Jun 17, 2019 4:32 am quote
Jack221 wrote:
Plug is looking not dangerous. Definitely will go down one more jet to 105. Be aware, as the main jet gets lower the pilot my need to go up.
I am at 108 and have 107, 106 and 105. So I will walk it down to each of those hopefully finding the perfect one.
Jack221 wrote:
Sounds like its performing well. If you are talking GPS speeds then there is no reason it won't make the low 70's mph every time, when the 60mm crank is in. As it is it will probably still slow down quite a bit uphill..
Yes I am talking about GPS speeds and it feels good, but I bet with a point or two lower main and fine tuning the air mix, it will run that much better, hopefully at lower throttle. In third gear it will scream up to really high rpms.
In fourth gear it loses a bit of acceleration above 6500 and seems to slowly take its time to accelerate higher but it keeps going at least up to 67mph, possibly more. It doesn't scream to max speed like before, so that point or two lower on main jet might bring back some of that acceleration up top. Torque isn't bad now all over, but I do need to be about 3500-4000 rpm when starting up a hill. It seems to have slightly better low end torque on hills than before because it will accelerate at those rpms uphill slowly, whereas before I needed to be about 5000 rpm before it would accelerate uphill.

With all that, I wouldn't say there are dead spots anywhere, just a little less acceleration at low (four stroking) and max throttle (no four stroking) than ideal.
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Mon Jun 17, 2019 8:37 am quote
I'll be fiddling with the jetting on this from now on with minimal posts in this thread until the fall or winter when I rebuild engine and do the rest of the upgrades. Time to finally move onto my p200 project with it's own thread! Thanks everyone for help so far with this bike.

First full restoration project.. 1980 P200E
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Mon Jun 17, 2019 7:31 pm quote
swiss1939 wrote:
In third gear it will scream up to really high rpms.
In fourth gear it loses a bit of acceleration above 6500 and seems to slowly take its time to accelerate higher but it keeps going at least up to 67mph, possibly more. It doesn't scream to max speed like before, so that point or two lower on main jet might bring back some of that acceleration up top. Torque isn't bad now all over, but I do need to be about 3500-4000 rpm when starting up a hill. It seems to have slightly better low end torque on hills than before because it will accelerate at those rpms uphill slowly, whereas before I needed to be about 5000 rpm before it would accelerate uphill.
What you are describing is exactly what I would expect from the port timing that you have. Always nice to have confirmation that the mathematics work.

What you are experiencing is what low transfer ports do. As its max power is approx 6000. When you get to 6500 you are already past max power because the transfers struggle to keep up. As there is plenty of blowdown on this kit, the rpm will continue past max into a long overrun. The power is falling away so 4th gear goes flat. Great for high speed downhill with the wind behind, might make 75mph if you're lucky.
With the 60mm crank and some grinding, the port timing can be changed to move the power band higher and bigger, so you can overtake on the uphill too.

I like the way you think this is finished but you do need to get the 200 running. If you think this 166 is quick imagine what a properly set up MHR is like.
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Tue Jun 18, 2019 2:26 am quote
Jack221 wrote:
What you are describing is exactly what I would expect from the port timing that you have. Always nice to have confirmation that the mathematics work.

What you are experiencing is what low transfer ports do. As its max power is approx 6000. When you get to 6500 you are already past max power because the transfers struggle to keep up. As there is plenty of blowdown on this kit, the rpm will continue past max into a long overrun. The power is falling away so 4th gear goes flat. Great for high speed downhill with the wind behind, might make 75mph if you're lucky.
With the 60mm crank and some grinding, the port timing can be changed to move the power band higher and bigger, so you can overtake on the uphill too.

I like the way you think this is finished but you do need to get the 200 running. If you think this 166 is quick imagine what a properly set up MHR is like.
That's good to know. I'm interested in how these different variables of Port timings, squish and blow down affect things so I appreciate that. Yes, it is done for now because I have gotten it to minimum required for my usage goals right now without taking it apart and doing extensive work. It currently will hold me over while I rebuild the p200 and go through the whole process to completely set up the 200 as you described with matching and timing of an mhr kit. Then once that 200 is fully set up and running I will revisit this engine for a rebuild with extensive timing work. My goal had always been to get this bike running sufficiently for my purposes while the other is being fully upgraded and then use that one while I completely rebuild and repaint this one. Then both will be optimally tuned for my needs, while never going fully without one. I hope to make the p200 a strong tourer with lots of torque and a solid highway cruising speed at lower rpm, while this Stella I'm more willing to go faster but hopefully not lose too much torque. This Stella has plans to become a theme bike with converting the headset to T5 and get a repaint as the pork chop express from big trouble in little China! One step at a time with lots of patience while still being able to commute with either one.

Last edited by swiss1939 on Tue Jun 18, 2019 2:13 pm; edited 1 time in total
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Tue Jun 18, 2019 1:54 pm quote
107 MJ that much better! Cleaner throughout. lots of acceleration down low now, still with the kick in the pants at 5000!
Still need to check plug though.
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Tue Jun 18, 2019 9:37 pm quote
Good feeling when the jetting starts to balance isn't it?

Give that 52/140 another go. And if it coughs/bogs at 1/4 take the main jet down another size.

Need to get a wot plug chop done soon. You'll be getting throttle happy and we know where that ends.
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Wed Jun 19, 2019 7:35 am quote
Jack221 wrote:
Good feeling when the jetting starts to balance isn't it?

Give that 52/140 another go. And if it coughs/bogs at 1/4 take the main jet down another size.

Need to get a wot plug chop done soon. You'll be getting throttle happy and we know where that ends.
Wot plug check. On the border of good and lean. Idle still a little rich cause it got damp and cold today then started bubbling low throttle so I turned mix screw in from almost 4 half turns to 3 half turns. Runs great again. Because I'm already rich in idle jet at the bottom range of air mix screw I ain't want to mess with the 52/140 right now.

Because I am just starting to get the chocolate tip turning whiter at wot, I ran the wot choke pull test at 3/4 throttle it throttled down with choke, at wot it didn't change throttle up or down at all which tells me I am either right on or slight lean. Im thinking i will go back up to 108 main just to be safe, then work on the air mix screw to get a clean low throttle

IMG_20190619_105500.jpg

IMG_20190619_105505.jpg

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Wed Jun 19, 2019 12:05 pm quote
I checked again at 107 mj riding normal (not wot) around with the leaner air mix setting 3 half turns out and it is dark chocolate. So i'm not sure if I should go down on the main one more or stay.
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Tue Jun 25, 2019 6:07 pm quote
I made some bigger revisions on Jack's suggestion which have helped a lot. I am very close now on nailing the jetting for this kit PNP. But, I have only had an hour after work each day to make one change and take a long enough ride to check plug before it gets dark and too late to be zipping around loudly pissing everyone off.

I am now down 1 idle size leaner to 40/120 idle jet which I felt I needed to do because i was at 1.2 full turns on the idle mix screw and still bogging and rich at lower throttle, and conveniently it lines up with the other change I made, given overall consensus is to keep the air number for idle and mj stack same. I also changed to 120 air corrector from 140 and am now at 120/be4/105 for the main stack with 1 1/2 full turns out on air mix screw. The 105 jet is still rich as I am now slightly sluggish at WOT, but mostly clean throughout. there is still a little bit of four stroking at lower throttle which I believe will be solved once I go down to 104 or 103 on the main jet. This should also allow me to open up the air mix screw to 2-2.5 full turns out.

With my "overall richness" baseline number of the stock engine and jetting was at approx. 2.27, the new jetting should be 10% richer (between 2.07-2.08 "overall richness") to match the 10% increased volume of the kit, as nothing else has changed on my bike but that. This is lining up correctly with my current jetting on this 166 kit. With the 105 main jet, 120 AC and the new idle jet, I am currently at 2.071 "overall richness". 104 and 103 MJ would be slightly leaner at 2.77-2.81. This is reassuring to know that the math is lining up with my reality.

IMG_20190625_212914.jpg
40/120 Idle. 1.5 full turns air mix. 120/be4/105 MJ stack.

IMG_20190625_212909.jpg
40/120 Idle. 1.5 full turns air mix. 120/be4/105 MJ stack.

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Tue Jun 25, 2019 6:22 pm quote
My fuel economy when richer jetting on this new kit was also between 39-43 mpg, which seems out of whack. I am hoping once the jetting is locked in and a full tank runs through, it settles down to around 50-55mpg.
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Tue Jun 25, 2019 10:50 pm quote
Plug is looking good so far. That main jet is still way over. Save yourself time and put in a 100. If still rich go down another size.
Once the main jet is ok the pilot will suddenly go very weak, be ready for that.
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Wed Jun 26, 2019 6:35 pm quote
Here it is after 20 miles with 100 MJ, air mix screw turned out to 2.5 full turns.

It is just a little slow to take off the line now like its struggling to get off the ground, but very narrow window where that is the problem. Once you get past quarter throttle it takes off and is solid throughout. The behavior before where it would be normal until 5000 rpms then it would take off is no longer how it acts. It is solid and strong throughout with pretty good torque even down low now. The only thing is it has that sluggishness for first quarter throttle when starting from a stop after warmed up which goes away once you get up to about 5mph.

It settles to idle pretty normally even after warmed up and running fast for a little while, but I do notice that if sitting in idle for 30 sec or more it will dip from 1200rpm down to 1000 rpm and then back up. I will play with it more this weekend when I have all day to mess with it. I will check WOT plug then, which I am guessing maybe able to come down 1 size. air mix I will turn it out richer half a turn and see if the dip goes away, and if not I will turn it in half a turn from right now and see if it goes away.

I will say that it is running best yet with this jetting. So we are getting closer! It sounds great now, with minimal four stroking in the lower third.

IMG_20190626_213737.jpg
40/120 idle. 2.5 full turns air mix. 120/be4/100MJ

IMG_20190626_213726.jpg
40/120 idle. 2.5 full turns air mix. 120/be4/100MJ

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Wed Jun 26, 2019 7:48 pm quote
Sitting here for the past two hours going over my detailed notes on jetting changes and looking at the "overall richness" math I was using, I realized it was all wrong in that I was mixing overall richness or air/fuel ratio with the concept of volume. I believe regardless of volume of fuel and air flowing into the carb, the air fuel ratio should be the same in order to operate properly, and the combined jetting of both jets in the carb should tell you the air fuel ratio, not the volume. Whereas changes in richness of each individual jet should tell you the volume increase or decrease of gas flowing into the carb.

I rethought the math to compare the changes in jetting.. and now my overall richness shows a form of air fuel ratio based on the jetting sizes only. So with that concept, the combined average overall richness number taken from both jets I come out with should be the same regardless of size of bore. Once I go down to the 99 main jet they will basically be the same +/- fractions of a point.

Not sure if this is correct, but it feels like it makes sense to me. This is all half assed math as I went to art school, but I'm trying to find ways to understand these changes in a quantifiable way that makes sense to me. I could be dead wrong.

air fuel ratio of the whole carb jetting (avg richness of both the idle jet and MJ stack in the carb)
-stock cylinder jetting: 1.901984127
-malossi 166 PNP (at 99MJ): 1.904166667

The 10% increased volume can be worked out from average percentage of increased richness of individual jets. This seems to line up as well as follows:

stock setup Idle richness (140/45): 3.111111111
malossi 166 pnp idle richness (120/40): 3.0 (3.57% richer)
stock setup MJ stack richness (140/97): 1.443298969
malossi 166 pnp MJ stack richness (120/99): 1.237113402 (14.28% richer)

therefore:
malossi 166 cc jetting increased richness avg over stock 150cc: (14.28+3.57)/2 = 10.71% increased volume of gas to fill up that much larger cylinder bore, while remaining at approx. the same air/fuel ratio of 1.904166667
Molto Verboso
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Wed Jun 26, 2019 11:38 pm quote
All the low throttle issues are because you are now getting closer. The pilot jet is now too small. Probably dangerously small. This happens suddely as the main jet goes down.

Plug is still way too dark. Put is a 96MJ and the 52/140 pilot. Should be about right for another test.
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Thu Jun 27, 2019 5:51 pm quote
Jack221 wrote:
All the low throttle issues are because you are now getting closer. The pilot jet is now too small. Probably dangerously small. This happens suddely as the main jet goes down.

Plug is still way too dark. Put is a 96MJ and the 52/140 pilot. Should be about right for another test.
I had a 96 jet delivered two weeks ago and already lost it somewhere in my garage. Probably ended up in the trash accidentally. All I have are a 97 and a 95 MJ that small. I put the 97 jet in and changed back up two sizes richer on the idle jet to 52/140. It's back up to revving to 10500rpm on the center stand when it wouldnt go over 8000 at 100 MJ. As I say every time, the bike is running what I think is really great now, but again slight four stroking down in first third throttle. The air mix screw is barely a full turn out. Other than the minimal four stroking and barely turned out air mix screw, it runs great off the line and high speed. Plug looks almost exactly the same to me after 20 miles. Maybe more yellow/brown on the ceramic inside and tip, with a little less oil buildup on the outside edges.

Its surprising how much better this thing runs with almost correct jetting compared to the super rich jetting I have been running with for the past year. I keep experiencing performance hits from too rich jetting and thinking that is the natural characteristic of the bike. Now that I am at this jetting, the 5000 rpm wall where it takes off is no longer as pronounced. It takes off with tons of torque even around 2500-3000 rpm now, and when you hit 5000+ it only increases acceleration instead of surging forward like a turbo charge button was hit.

IMG_20190627_210810.jpg
52/140 idle. 3/4 full turns out air mix screw. 120/be4/97 MJ.

IMG_20190627_210837.jpg
52/140 idle. 3/4 full turns out air mix screw. 120/be4/97 MJ.

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Thu Jun 27, 2019 7:24 pm quote
Thank you Swiss for documenting your dialing in process, complete with pictures. It's helping me do the same but on a different engine (slightly ported P200 with a 20/20 carb). I appreciate it!
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Thu Jun 27, 2019 7:30 pm quote
qascooter wrote:
Thank you Swiss for documenting your dialing in process, complete with pictures. It's helping me do the same but on a different engine (slightly ported P200 with a 20/20 carb). I appreciate it!
No problem. Just when I think i'm getting it, I realize I don't fully get it and Jack tells me its way off! Seems jetting is an endless tweak. Can't wait till its locked in. Hopefully this weekend when I finally have more than an hour late at night to mess with it.
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1980 P200E project, 2005 Stella Malossi 166 MKIII
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Location: Staten Island, NY
Thu Jun 27, 2019 7:46 pm quote
I took it on my little test strip of 5 mile highway tonight with the current jetting and it is strong even at highway speeds, accelerating no problem from around 50mph to 64 enough for me to overtake slower cars and make lane changes without fearing for someone riding up into me for going too slow. I couldn't really open it up as rush hour there were too many cars on the highway and a few cops camping out at both ends (50mph speed limit), but I got it up to 64 with more room to go and it felt stronger than previously when I had it up to 67 max. I think it could top 67 with the current jetting, maybe make it to 70mph.
Molto Verboso
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 1419
Location: London UK
Thu Jun 27, 2019 11:42 pm quote
Better now for sure. Could still go a bit weaker but leave it until you get the pilot sorted out.

Mixture screw is not always easy. On a 4 stroke the rpm behaves and just gets faster and levels off as the screw is wound in. Continue and cuts out. On a 2 stroke it goes up and down twice as its wound in. You are looking for the point where it gets fast for the first time. Always start with the screw right out like 6 turns. Then wind in until it speeds up for the first time and stop.
If the 52/140 is too big then try that 48/140 again.
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1980 P200E project, 2005 Stella Malossi 166 MKIII
Joined: 20 Jul 2018
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Location: Staten Island, NY
Fri Jun 28, 2019 6:23 am quote
Thanks again Jack. I'm gonna try your 6 half turns out tip on 55/160 idle. I think it will be either 55/160 or more likely 48/140. Doing all these changes with a broken temp sensor is nerve wracking so I've finally gotten in the practice of riding with two fingers always on the clutch lever, and shifting with just those two fingers. My default has always been to grab the lever fully when shifting and let it go when not. So that's a good thing to move away from and get practice with. It will become second nature by the end of this, just in time for my new temp sensor to arrive next week! Then I'll really put the jetting to the test.
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1980 P200E project, 2005 Stella Malossi 166 MKIII
Joined: 20 Jul 2018
Posts: 968
Location: Staten Island, NY
Fri Jun 28, 2019 5:44 pm quote
Looks like my previous idle jet before going down to 97 MJ was closer to correct.

Worked from 52/140 to 55/160 to 40/120 with 40/120 was best so far. plug looks much better with only slightly rich outer edge and nice tan tip and ceramic center. There is very very minimal four stroking only when warmed up in exactly the bottom quarter throttle. Unfortunately I am still at 1.75 full turns out air mix. Tomorrow will have all day to mess with this and other things.

I am going one more size down on idle to what my original idle jet was set to before the 166 kit... 45/140 so that I can finally get it into range of 2-3 full turns out, hopefully clear up that minimal four stroking, and am expecting I may need to go up 1-2 points on MJ to 98 or 99 if the WOT plug test looks lean.

IMG_20190628_211558.jpg
40/120 idle. 1.75 full turns air mix. 120/be4/97 MJ.

IMG_20190628_211602.jpg
40/120 idle. 1.75 full turns air mix. 120/be4/97 MJ.

Molto Verboso
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 1419
Location: London UK
Fri Jun 28, 2019 10:49 pm quote
Is that plug a B7 or B8? Looks like it needs to go up a number. Jetting looks fine where it is. Not keen on the 40/120 but if thats the one that works, then why not.
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1980 P200E project, 2005 Stella Malossi 166 MKIII
Joined: 20 Jul 2018
Posts: 968
Location: Staten Island, NY
Sat Jun 29, 2019 5:20 am quote
It's b8 as that was the suggested plug in instructions I think the camera washes out the color to look slightly more white. In person it looks brown yellow tan.
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1980 P200E project, 2005 Stella Malossi 166 MKIII
Joined: 20 Jul 2018
Posts: 968
Location: Staten Island, NY
Sat Jun 29, 2019 8:16 am quote
Went down to 45/140 to see if it would be any better. Yeah it ran faster and air mix screw was 2.25 full turns out but it seemed too lean cause the four stroking got worse and holding throttle at point of four stroking for 15 seconds then hitting gas hard caused a hiccup surge which 40/120 doesn't do. Also it would idle inconsistent at 45/140 which it doesn't at 40/120.

At 40/120 it is 1.75 full turns out. I will do a wot plug check for the 97 main in a few hours when the mid day heat cools down a bit.
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