Malossi 210 build thread - PWK30 tuning / perpetual torture
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Ossessionato
1976 Super (x 2), 1974 Primavera (x 2), 2006 Fly 150
Joined: 26 Sep 2013
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Location: So Cal
Tue Mar 19, 2019 7:27 pm quote
sdjohn wrote:
SoCalGuy wrote:
The not revving past 7200 doesnít make sense. Long shot, but is there a possibility the prior owner messed with the gearing? Did you ever actually count teeth?
My guess is once I lean up the mid range the thing will rev higher. I upped the main to fix 3/4 throttle temps but haven't cut the middle back down again via the clip or taper.

I messed with the gearing myself, it's stock P200 with a P125 4th. I've had it rev to 8000 when I had the jetting leaner (before I discovered the temperature issues). So I think jetting will get it back there or close enough.
IDK... even 8000 seems low for your port timings.
Molto Verboso
PX221 Malossi, O tuned PX200 and some motorbikes
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Tue Mar 19, 2019 7:38 pm quote
Is the timing still at 16 degrees?

Not looking lean at all. Black enough to lose at least a 1000 rpm. Have a go at jetting to rpm and not temperature. When really way too rich on a premix the compression runs higher with all the extra oil and can show up as over temperature.

The one to start with is half throttle. Once the clip is set to give a decent tan plug colour. Meaning needle atomiser and clip are all correct at that point, the main jet, pilot and taper decisions get a little easier. I often do this stage with no main jet fitted, as a too small main when rough setting the clip will waste a whole day.
Ossessionato
1980 P200E, 1974 Primavera, 04 Ninja 250
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Tue Mar 19, 2019 7:58 pm quote
Yes timing still at 16. Will have a go at the clip, it makes sense to me.

Socal I hit mid-ish 8000s earlier but even I donít feel like searching my 40 pages for the exact number
Ossessionato
1980 P200E, 1974 Primavera, 04 Ninja 250
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Mon Mar 25, 2019 6:44 am quote
clip to 3.5 instead of 4

8300 RPM at 1/2 throttle, 8800 down hill I'm sure the morning temps help out as well.

7300 RPM at 3/4+ throttle - looks like main should come down

No temp troubles yet, will watch it later today again.

I'm thinking to drop the main 1 jet size/ride and watch the middle throttle temps - it might need to go back to clip 4 if the main comes down too much.
Molto Verboso
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Mon Mar 25, 2019 6:59 pm quote
Well that's more like normal. Good job.

Aim for 1/2 to get over 8000 and hold a steady 280F or less on the plug.

3/4 is the hardest to get right

Keep WOT where you know it is close to rich (like will barely make 8000 rpm and no more) until the other throttle points are done and you'll be less likely to have an incident.
Enthusiast
PX 200
Joined: 25 May 2016
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Tue Mar 26, 2019 5:33 am quote
sdjohn wrote:
clip to 3.5 instead of 4

8300 RPM at 1/2 throttle, 8800 down hill I'm sure the morning temps help out as well.

7300 RPM at 3/4+ throttle - looks like main should come down

No temp troubles yet, will watch it later today again.

I'm thinking to drop the main 1 jet size/ride and watch the middle throttle temps - it might need to go back to clip 4 if the main comes down too much.
Sorry Iím going through the thread, whatís your setup of the valve and crank?

What jets have you ended up at now?
Ossessionato
1980 P200E, 1974 Primavera, 04 Ninja 250
Joined: 04 Apr 2013
Posts: 3677
Location: San Diego, CA
Tue Mar 26, 2019 8:10 am quote
Jack221 wrote:
Well that's more like normal. Good job.

Aim for 1/2 to get over 8000 and hold a steady 280F or less on the plug.

3/4 is the hardest to get right

Keep WOT where you know it is close to rich (like will barely make 8000 rpm and no more) until the other throttle points are done and you'll be less likely to have an incident.
I'm pretty sure I'll have to put the clip back as I cut the main down. 3/8 was at 330F yesterday. I'm willing to push it a bit but I don't want to see it much higher than where it was. The only reason I don't move it back now is I'm not 100% that it's lean side. With the small main reduction (1 size) I will have another crack at measuring that again. It does feel pretty crisp at 3/8, this is why I'm thinking we'll end up on clip 4 with a smaller main, something in the low 150's, which is where I keep ending up anyway. But 1 change at a time and a full long ride to evaluate and we will get there. Probably my biggest time waster to date has been trying to evaluate changes with short drives.
Ossessionato
1980 P200E, 1974 Primavera, 04 Ninja 250
Joined: 04 Apr 2013
Posts: 3677
Location: San Diego, CA
Tue Mar 26, 2019 8:19 am quote
108 wrote:
sdjohn wrote:
clip to 3.5 instead of 4

8300 RPM at 1/2 throttle, 8800 down hill I'm sure the morning temps help out as well.

7300 RPM at 3/4+ throttle - looks like main should come down

No temp troubles yet, will watch it later today again.

I'm thinking to drop the main 1 jet size/ride and watch the middle throttle temps - it might need to go back to clip 4 if the main comes down too much.
Sorry Iím going through the thread, whatís your setup of the valve and crank?

What jets have you ended up at now?
Malossi sport 210. It's a 60mm crank with 1.5mm packer below the cylinder. I've got the Scooter and Service low compression head. It's a PM20 evolution pipe. You can see the porting work earlier in the thread. I'm running a standard stator with 16degree timing. This is a PWK 30mm carb. 18 hole atomizer, 42 pilot, HKJ needle, 3.5 clip, 160 main as of the last test configuration. I tried running atomizers with more holes but had too much trouble setting a rich enough needle diameter and balancing that with a reasonable size pilot. When you have some time to read my novel, check the previous 40 pages . Port timings:

Molto Verboso
PX221 Malossi, O tuned PX200 and some motorbikes
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Wed Mar 27, 2019 8:02 pm quote
If your temperature gauge is reading 50F over then its all good. Check the plug after a very long run at half throttle. This will show either way. If the temperature won't stay down then you know its lean.
Molto Verboso
One or two fun scoots....nothing too precious
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Thu Mar 28, 2019 12:02 am quote
John, your transfer timings seem low at 124.6 with the cylinder raised by a full 1.5mm. My [basic] understanding of the Sport was that it's got the same port setup as the MHR, but with a smaller exhaust port and lower exhaust duration. If I put a 1.5mm packer under my MHR, the transfer duration would be north of 130. I've settled at ~129 with a 1.0mm base packer.

Have I got this wrong (wouldn't be the first time!)?
Ossessionato
1980 P200E, 1974 Primavera, 04 Ninja 250
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Thu Mar 28, 2019 6:56 am quote
swa45 wrote:
John, your transfer timings seem low at 124.6 with the cylinder raised by a full 1.5mm. My [basic] understanding of the Sport was that it's got the same port setup as the MHR, but with a smaller exhaust port and lower exhaust duration. If I put a 1.5mm packer under my MHR, the transfer duration would be north of 130. I've settled at ~129 with a 1.0mm base packer.

Have I got this wrong (wouldn't be the first time!)?
I can't say for sure. There's a portion of this thread back 30 or so pages from here where we struggled to understand exactly what I had because I started with eyeball measurements and a degree wheel. But eventually we settled on calipers and the crowd was satisfied that I'd measured correctly and thus it was declared good. This is my first time around the rodeo on port measurements, setting up a tuned cylinder, etc. I defer to the experts.
Ossessionato
1980 P200E, 1974 Primavera, 04 Ninja 250
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Location: San Diego, CA
Mon Apr 01, 2019 6:52 am quote
158 main revs to almost 9000 at 1/2 throttle but 7500ish at 3/4 throttle. Progress. Will go 156 next. Still will have an eye on the 3/8 temps on the way home today. I'm near positive now that the clip will go back to 4 as I cut the main down enough to get the 3/4 to full correct, but will wait until I see some rise in 3/8 temps from where it has been running. The main isn't moving 3/8 much but eventually it will.
Ossessionato
1980 P200E, 1974 Primavera, 04 Ninja 250
Joined: 04 Apr 2013
Posts: 3677
Location: San Diego, CA
Mon Apr 01, 2019 4:13 pm quote
3/8 temps up to 350, but 1/2 throttle is routinely hitting upper 8000s. Will go clip 3.5 -> 4 and drop the main to 156 next.
Molto Verboso
PX221 Malossi, O tuned PX200 and some motorbikes
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Location: London UK
Mon Apr 01, 2019 6:43 pm quote
Do you not have a needle with a leaner taper and maybe a smaller diameter?

Cilp 4 and still way to rich at 3/4 is more of a needle issue.

Nice to see you up in the correct rpm range. Must be feeling like it has potential now.
Ossessionato
1980 P200E, 1974 Primavera, 04 Ninja 250
Joined: 04 Apr 2013
Posts: 3677
Location: San Diego, CA
Mon Apr 01, 2019 7:02 pm quote
Yes it is feeling much better. I have a GJK and a GJH, so it means the diameter would have to increase or decrease, and of course the length moves too then. This offsets some of the whole purpose of going there - the 3/8 comes down with the 3/4 because of it. What do you think would work here?

860177EC-CD17-4A2C-8DC2-7DCB20154ABD.png

Ossessionato
1980 P200E, 1974 Primavera, 04 Ninja 250
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Posts: 3677
Location: San Diego, CA
Mon Apr 01, 2019 7:04 pm quote
In addition, forgot to add that Iím not sure the 1/8 will like the lean out but it might be ok. Unfortunately there is no GJJ available.
Molto Verboso
PX221 Malossi, O tuned PX200 and some motorbikes
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Location: London UK
Mon Apr 01, 2019 7:27 pm quote
If the diameter has to get leaner the pilot jet can go bigger to fill the gap.

Your main jet is ballpark ok. Should be 150+ The main should only be set at WOT. Dropping a size to get the taper in maybe ok but weakening the main is losing power and that's not the idea.

The richer a needle is at the top, the leaner it will be at the bottom. This is what happens with a single taper needle. Your needle is over rich at 1/2 up and too lean below 1/2, needing a richer clip. If on H taper now, it needs to go probably down 2 to F taper. Go longer on length when reducing the taper.
Ossessionato
1980 P200E, 1974 Primavera, 04 Ninja 250
Joined: 04 Apr 2013
Posts: 3677
Location: San Diego, CA
Mon Apr 01, 2019 8:00 pm quote
There's the rub - you can only go to G taper, and the next needle down for length from the GJK is much longer (GFK). It's so fat because of the length that compared with the HKJ the 3/4 and up isn't even leaner with clip 3. I am game to try GJK but it doesn't seem to give us what we want either.

The only other way is mucking about with atomizers again. I'm on 18 hole. The 30 led to a situation where the required diameter was so big that I couldn't get a lean enough taper. That's when I moved back to 18 hole. I have 8 hole, which would have to use a much smaller main for sure. Directionally, I know with more RPM it will lean out more but I'm not really sure that it will do what we want throttle-wise, which would be to clean up the high throttles much more than the low ones. Looking at the chart again, if the 8 hole makes me use a smaller diameter, I'm screwed - the taper availability goes to nothing after L diameter.



Last edited by sdjohn on Mon Apr 01, 2019 8:05 pm; edited 3 times in total
Ossessionato
1980 P200E, 1974 Primavera, 04 Ninja 250
Joined: 04 Apr 2013
Posts: 3677
Location: San Diego, CA
Mon Apr 01, 2019 8:01 pm quote
See? For now I think I will chase the main downward a bit more with the clip 4 but I'm listening for all ideas. (this one is using setup #2 for comparison - it's why it is red)

749458AF-766C-4F77-865B-EF4A4D71762F.png

Molto Verboso
PX221 Malossi, O tuned PX200 and some motorbikes
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Posts: 1209
Location: London UK
Tue Apr 02, 2019 12:03 am quote
Need to correct myself first When I said go longer length when reducing taper, I actually meant go shorter. In Dellorto the length is the length of the taper, in Keihin the length is the length of the not taper. So not taper should be shorter.

What are the F taper options? From the G options, GFH does all the right things but I think you're going to need an F taper.
Ossessionato
1980 P200E, 1974 Primavera, 04 Ninja 250
Joined: 04 Apr 2013
Posts: 3677
Location: San Diego, CA
Tue Apr 02, 2019 1:15 pm quote
I can seem to find any f taper needles...
Molto Verboso
PX221 Malossi, O tuned PX200 and some motorbikes
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Tue Apr 02, 2019 6:53 pm quote
Having a look for your needles too. Seems like most of the needles available are in the C D and E range. Going outside of what is normally available and what most use would indicate going off at a tangent.
Might need less than F...maybe E?
Ossessionato
1980 P200E, 1974 Primavera, 04 Ninja 250
Joined: 04 Apr 2013
Posts: 3677
Location: San Diego, CA
Tue Apr 02, 2019 7:04 pm quote
They need to be the N427-46 type, usually associated with PWK26. The ones with richer tapers that you see are usually for the bigger carbs. I've yet to find a chart like I showed above with taper leaner than G yet.

The below chart would have you believe that something leaner must be available, but I can't find any, and not all combinations are available.

Molto Verboso
PX221 Malossi, O tuned PX200 and some motorbikes
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Tue Apr 02, 2019 7:13 pm quote
Yeah, I was not looking for 26/28mm carb needles. Thought it was the next size up (which seems way more popular).
Still need less taper or many more holes in the atomiser
Molto Verboso
PX221 Malossi, O tuned PX200 and some motorbikes
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Tue Apr 02, 2019 7:35 pm quote
Looks like Jetsrus will sell you a GFH needle
https://www.jetsrus.com/a_jets_by_carburetor_type/needle_keihin_N427-46.html

I think before buying more needles you should carefully check to see how small the main jet has to be to get WOT over 8000 rpm

Last edited by Jack221 on Tue Apr 02, 2019 7:39 pm; edited 1 time in total
Ossessionato
1980 P200E, 1974 Primavera, 04 Ninja 250
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Tue Apr 02, 2019 7:36 pm quote
With the 30 hole atomizer I was stuck on diameter D or E and then there are no choices but J taper which was way too rich.

Looking at it, there's really nothing wrong with trying to ride the main down while taking the clip to 4 or even 4.5. The baseline of clip 3 isn't quite right but kyajet only does whole steps on clip position. The G taper is barely better than HKJ and introduces leanness at 1/8 compared to my existing setup because you have to drop down on diameter. The F length makes things just brutal, forcing you down to a 1 clip position just to keep it close in the 3/8 throttle area.

Screen Shot 2019-04-02 at 8.32.58 PM.png

Molto Verboso
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Tue Apr 02, 2019 8:00 pm quote
Not an easy carb to work. So more holes is not an option.

We both said it so reducing the main jet is the next plan. Ending up on a high clip is not the worst thing. Might be a length available to fix that. Any resulting problems at 1/8 can be fixed with the pilot jet, you have room to go up.
Ossessionato
1980 P200E, 1974 Primavera, 04 Ninja 250
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Tue Apr 02, 2019 8:09 pm quote
Ha we were both typing at the same time. Yeah I think letís see what it takes to get close on 3/4 and wot and take it from there like you say. Stay tuned!
Ossessionato
1980 P200E, 1974 Primavera, 04 Ninja 250
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Mon Apr 08, 2019 9:23 am quote
Clip 4, main 156

3/8-1/2 still revs to mid 8000's, bit less crisp, temps seem lower but still hit 320's, will check again this afternoon.

3/4-full hits 7400RPM or so. I'm thinking to drop to 152 for next ride and skip the 154 jet step. But I might chicken out and just go to 154 .

Looks like we can keep going down on main as planned. I kind of figured that my drop from 158 to 156 would be washed out by the clip move and it was.

Pretty sure my filter loads up sometimes. Usually by the end of my 30-40 minute ride it is a lumpy idle and sometimes it wants to stall when clutch is in and coming down. Stalled it once coming up to a light today but popped it into 2nd and it came back to life. I can try to lean out the mix a bit and up the idle a bit but I know this is the compromise we make by using the foam filter.
Ossessionato
1980 P200E, 1974 Primavera, 04 Ninja 250
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Mon Apr 08, 2019 6:26 pm quote
Was a royal pain in the neck on the way home, flooding and burbling about. Had to pull over and clear a flood once. Sure it's warmer on the way home, but it seems hard to digest that moving the clip by 1/2 clip and dropping the main would result in this mess. Had to raise up the idle speed because the air screw is far enough out already on this pilot that opening it up more didn't seem to do much.

I will put it back to 3.5 clip and stay at 156 main - should have only changed one item at a time. I'm now convinced that we aren't on the threshold of too lean at 3/8 based on how it runs at 3/8 at 4 clip. Though I can't explain the 350F temps I saw last time.

The filter didn't look too loaded really once I pulled it off. I'm back to not liking this bike again.
Molto Verboso
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Mon Apr 08, 2019 9:14 pm quote
If it was a Dellorto it would need a smaller atomiser.

The main jet is getting small but does need to go smaller with that H taper. Drop to 152 main and see if you can get 8500 rpm. If not 150 main. Or less, see what it takes to get there.

Back to clip 3.5. As you're not talking about 'smells hot' or 'weak bogging' with the 350F at 3/8 its probably just a dud gauge. For this stage of jetting I aim for not more than 280F at 3/8, able to rev to maximum (8500 at least) and a dark tan coloured plug centre. If your plug is darker after long steady runs at 3/8 then the clip can go down some more. This will improve the 3/4 point too.
Ossessionato
1980 P200E, 1974 Primavera, 04 Ninja 250
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Posts: 3677
Location: San Diego, CA
Tue Apr 09, 2019 4:49 am quote
What does the Dellorto smaller atomizer comment mean? Is it the same as less holes or is it like smaller diameter?

I hear you on the gauge. Hot running has a very distinct feel/smell that Iíve encountered on my other bikes. We donít have it here yet.
Molto Verboso
PX221 Malossi, O tuned PX200 and some motorbikes
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Tue Apr 09, 2019 8:34 pm quote
If the gauge doesn't confirm the smell/feel/plug/rpm it must be dud.

On a Dellorto needle carb a 2 stroke atomiser has no holes. The variables are diameter and length. The diameter of the atomiser is adjusted at 3/16 throttle, whilst juggling clip and taper, not forgetting the interference from the pilot jet. More or less jetting the whole carb in at once. The first 20 years are the hardest
Ossessionato
1980 P200E, 1974 Primavera, 04 Ninja 250
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Mon Jun 10, 2019 2:00 pm quote
finally back on this

3.5 clip, 156 main = 7600 RPM - seems like about 200RPM for each 2 main points. may go to 152 next, we are getting close to a 3/4 and WOT rev out now.
Ossessionato
1980 P200E, 1974 Primavera, 04 Ninja 250
Joined: 04 Apr 2013
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Location: San Diego, CA
Mon Jun 10, 2019 4:57 pm quote
Well it turns out that was 154, looks like 152 is next anyhow. 8000 rpm at 3/4 at least is the goal.
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