carbs and fuel pumps
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Molto Verboso
Vespa
Joined: 19 Jun 2007
Posts: 1183
Location: California
Thu Feb 27, 2020 9:51 pm quote
the 1.80 squish must be bad. Just looked at the head it has a 1.5mm drop. When I measured the squish must have rocked the piston with just one big solder log in there. As you were saying.
Molto Verboso
2007 Stella 150
Joined: 02 Nov 2019
Posts: 1114
Location: Rochester, Minnesota
Fri Feb 28, 2020 6:35 am quote
I'm not familiar with the head and it's orientation, when you were measuring squish did you try and measure above the gudgeon pin? I try to measure there to reduce rocking.
Jet Eye Master
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 2443
Location: London UK
Sat Feb 29, 2020 7:25 pm quote
With +0.50mm piston above deck the squish clearance should be 1.00mm.

Would give it all another measure before cutting anything.
Molto Verboso
Vespa
Joined: 19 Jun 2007
Posts: 1183
Location: California
Sat Feb 29, 2020 7:30 pm quote
Seems in 2018 must not have measured squish accurately. Looks like the head has a 1.5mm squish. If the piston is + 0.75 PBT squish could be around 0.75 as it sits.

If the numbers still look acceptable moving to a 2.0mm base gasket giving 0.5mm PBT above deck and 1.o squish raising exhaust to 32.5mm.

EX 185.22
TR 126.21
BD 29.59

This is what I was thinking for the exhaust port but an arc across the top center up to 32.5.

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Jet Eye Master
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 2443
Location: London UK
Sun Mar 01, 2020 2:50 am quote
Not as simple as the Bajaj with this port. Piston and capacity is quite a bit bigger, so cannot be so full straight along the whole top. The narrow sides will waste too much area. Essentially this port needs to be exactly the same shape as the original just wider. Keep the 8mm radius. The big challenge is not going through to the studs.
Molto Verboso
Vespa
Joined: 19 Jun 2007
Posts: 1183
Location: California
Sun Mar 01, 2020 12:27 pm quote
OK I failed math and art too. Made more room in the exhaust port today. Used a 1/2" coarse drum to start in the middle of the port and worked to the tape line as close I could trying to stay inside the cylinder on the working edge and not too far back into the duct. Once I got as far as I thought I could blended to the top and bottom with the 3/8" coarse drum. That was the max I could get with the tool perhaps with a longer bit could have had more reach. Also the exhaust does not come off the cylinder at 90 one side is more difficult to reach. Finished with files then 100, 180 and 220 grit emery paper. In retrospect it would have been more difficult making my suggested shape the dremel sanding drums seem to make the perfect shape safely. Port went from ~41mm to 48mm & 32.5mm.

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just beginning to work on the left side the right side is untouched by me.

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Molto Verboso
Vespa
Joined: 19 Jun 2007
Posts: 1183
Location: California
Sun Mar 01, 2020 5:40 pm quote
cleaned up with gasoline, water rinsed and blow dried. Scott Clough Racing lowered the transfers and exhaust when I went to the 60mm crank. Think he did a nice job. The damage to the cylinder happened 6,000 miles ago, no corresponding marks on current piston.

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Jet Eye Master
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 2443
Location: London UK
Sun Mar 01, 2020 7:24 pm quote
That's that done already. Looking exactly right. Size is ok 48mm will do. With the risk of going through its just not worth it. Port shape is good. Top edge nice. On the MHR they use smaller stud holes to get a bit more width. These old cylinders were not made to be so fast. You'll be doing exhaust ports for other guys before long.

Cylinder looking like done now. Transfers appear to be a good job. Not sure if he moved the angles but the old 210 was a bit tame, so hopefully he did.

If you have the piston off, there are some issues that need a little grinding. Post some pictures and I'll draw on them.
Molto Verboso
Vespa
Joined: 19 Jun 2007
Posts: 1183
Location: California
Sun Mar 01, 2020 7:54 pm quote
The black stuff below the rings is a graphite coating I had applied when I rebuilt the engine in 2006. About 6,000 on this piston. Originally built the engine in 1994 with this cylinder and PM Tuning chamber. Around 1996 got the 60mm crank. 2006 new PM chamber, new piston and replaced all 4 gears.

Noticed some rotational play in the small end going to replace.

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1994 piston piece between rings broken floating like a ring luckily

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1994 piston seize

Jet Eye Master
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 2443
Location: London UK
Mon Mar 02, 2020 12:53 am quote
Piston is going to need some work. So lucky the skirt isn't touching the crank (although small end is worn....hmmm). Often the ASSO piston just touches the web on a 60mm crank. I usually cut off the whole thin bit at the bottom of the skirt and re-add the chamfer.

Most of these cuts are pre marked out by Malossi. Sort of 'cut here' in the casting. The line up of the side windows only need be done as marked for one area on each side.

Take the rings off and give it a good wash after. There are some lighter gudgeon pins available, if you are buying a new one.

Only really needs the top piston ring fitted when it goes back on. Keep the bottom 6000 mile ring in a drawer as a spare.

inside bottom.jpeg

outside top.jpeg

Boost.jpeg

Veni, Vidi, Posti
74 Super, 75 Super, PX project, LML off-roader and new to 2018, '66 Blue Badge Smallframe
Joined: 30 Nov 2011
Posts: 7954
Location: Victoria, Australia
Mon Mar 02, 2020 1:48 am quote
First one I put together, the skirt was just touching but I didn't know! I thought it was just the magnetism of the flywheel/stator... certainly felt like that. No real harm done even though I rode it a bit like that. The newer style of piston doesnt need to be adjusted.
Molto Verboso
Vespa
Joined: 19 Jun 2007
Posts: 1183
Location: California
Mon Mar 02, 2020 8:48 am quote
oh boy this is gonna be fun!
Molto Verboso
Vespa
Joined: 19 Jun 2007
Posts: 1183
Location: California
Mon Mar 02, 2020 4:55 pm quote
Made some Swiss cheese today. Super easy, fun and satisfying. Simple tools hammer, punch, belt sander, drill, hack saw and dremel. Will find out what I've been missing. Only had to widen one port, the clutch side piston was obstructing transfer port opening other side was OK.

Question about the two small windows on the piston skirt, how many mm should this be raised?

Question about the bottom. I used a belt sander to raise the bottom which worked out good. How much do I raise this? Took off maybe 0.5mm only the chamfer. I see inside the piston wall is thinner up another 2.5mm and then it steps up to thicker wall.

Tried to maintain some of the internal structure to hopefully maintain some integrity. Can't believe how much light can be seen through this now.

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tools of the day

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clutch side that was matched to port wow didn't even know this.

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clutch side that was matched to port wow didn't even know this.

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fly side

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crank web

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crank web

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inlet hole

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holes for balance?

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how much do I raise these?



Last edited by hibbert on Mon Mar 02, 2020 6:22 pm; edited 2 times in total
Molto Verboso
08 GTS 250, 79 P200E, 62 Allstate
Joined: 11 Jan 2006
Posts: 1753
Location: Florence, OR
Mon Mar 02, 2020 6:13 pm quote
Sweet Hibbert - Inspiration for future projects big time!
Jet Eye Master
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 2443
Location: London UK
Mon Mar 02, 2020 7:02 pm quote
Getting faster all the time.

That whole bottom of the piston can go. Just sand off the whole thin bit.

The flyside does need widening. Not as much but I can see the wear marks on the cylinder are blocking the secondary port (just like every other one I saw).

About 5mm up on the boost windows is enough.
No need to cut the cylinder skirt windows.

Will be more powerful with only the top piston ring. Leap of faith needed here.

Crank looks like someone had some fun with it. All good.

Every part of the piston should be smooth and chamfered. The only edge should be on the crown.
Molto Verboso
Vespa
Joined: 19 Jun 2007
Posts: 1183
Location: California
Mon Mar 02, 2020 7:27 pm quote
Thanks Jack need a little clarification. I'm adding a photo of the fly side that I did not include in the previous post. Can you draw on this picture and piston picture where it needs work.

On the skirt windows raise them 5mm but not really necessary?

Why only one top ring.

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Jet Eye Master
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 2443
Location: London UK
Mon Mar 02, 2020 7:52 pm quote
Its not at the base its up the cylinder. You can see on this picture.

One ring is better for many reasons. With all the set up of this engine the second ring is just being dragged around and stopping the oil from getting to the bottom edge of the top ring. Its faster. And its why the MHR only has one ring.

Edit: I think your cylinder has the area under the transfers reduced. Wouldn't be surprised if the second ring is popping into the base transfer window at BDC. No second ring, no issue.

Piston skirt boost port windows do need the 5mm. 60mm crank puts the windows 3mm lower at BDC. Upping 5mm corrects the loss and some. Some of the Germans up them 15mm, now that is pointless.

flyside.jpeg
Blocked here

Ossessionato
76 Sprint V, 63 GL, 62 VBB, 05 Stella
Joined: 16 Jun 2011
Posts: 2853
Location: Nashville
Tue Mar 03, 2020 6:37 am quote
I went through similar adventures when I was setting up my SprintV's Polini 177. I was, frankly, amazed at how much wasted potential even that cylinder and piston had in their factory construction.

Jack was a great help to me on that project, too.
Molto Verboso
Vespa
Joined: 19 Jun 2007
Posts: 1183
Location: California
Wed Mar 04, 2020 6:39 pm quote
Have to say seems like the case porting is only half way a fair amount of work and hopefully performance to be gained with the piston work. Gave the clutch lever the SaFiS double o-ring treatment.

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scribing piston

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5mm up

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3mm sanded from bottom

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is bottom chamfer enough?

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Jet Eye Master
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 2443
Location: London UK
Wed Mar 04, 2020 7:28 pm quote
Piston now looking done. You'll feel like its had a turbo fitted once the carb is set up.

Few more things to think about; What are the exhaust choices? Whats the ignition timing set at? Have you checked the float height? Condition of the reeds? Clutch?
bodgemaster
63 GL, 76 Super (x 2), 74 Primavera (x 2), 06 Fly 150
Joined: 26 Sep 2013
Posts: 5477
Location: So Cal
Wed Mar 04, 2020 10:22 pm quote
Thats mighty nice dremel work, hibbert.
Hooked
1984 PX(BGM187)EFL
Joined: 14 Apr 2017
Posts: 384
Location: Cornwall UK
Thu Mar 05, 2020 12:02 am quote
Nice work on the piston, Hibbert. Look after it!
Molto Verboso
Vespa
Joined: 19 Jun 2007
Posts: 1183
Location: California
Sun Mar 08, 2020 3:14 pm quote
Great I'm excited to get this engine performing better. Took the front wheel off to replace the tire which turned into a front brake closet roller upgrade, new brake shoes, new speedo drive gear, painted anti dive, painted wheel, repacked the front bearing with fresh grease and adding a Pinasco hub cap. Had Tim 'the machinist' trim M8 distance nuts to 22mm to fit hubcaps. Going old school.

Taking the time to fix a few things for 2020. Choke cable connected this will be such a luxury! No more lifting the panel for cold starts.

Going with a Polini Box and giving the PM a rest. Hope it's OK. Welded on spring clip and sent out for ceramic.

Timing is at 17 I think but will confirm when it's running. What is recommended? Standard P200 ignition PK flywheel.

Clutch looks to be in decent condition. Think it's a standard cork clutch with Pinasco springs in a banded basket. Will upgrade when needed.

The reeds were in good condition when inspected in 2018. Have 2 new pair on hand, can you suggest what is the recommended thickness for the Malossi petals? Think we got a package with 3 thickness.

I do not know how to check the float height. Is this as critical in pumped systems?

Can you recommend a starting point on the jetting. Going to need a lot of help on the jetting.

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fixed up front end new tire, brakes and speedo working again.

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new indicator lens thanks to whodat

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mickey mouse scooter tote

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bent nail for spring clip

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YSS to replaces blown Bitubo

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choke cable my favorite

Jet Eye Master
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 2443
Location: London UK
Sun Mar 08, 2020 7:30 pm quote
Looking like a scooter getting ready to run.

Float height. This is important. The pump just gets the fuel in the bowl. The height determines the delivery curve. On yours the float arm should be 24mm from the body when upside down.

The 0.35 reeds are the best place to start.

Clutch will need work. Probably soon but not today.

By all accounts Polini box will go fine. A modern fat expansion might not suit your riding but would make more power.

Jetting to start with. Pilot jet 45, X3 needle clip 2, AS266, 50 slide, no main jet. This is going to be quicker to set up than the SI. Focus on one bit at a time and its done in no time

Timing is a big subject. Yours not being variable means it needs to be as much as possible. With that old head, getting the squish tight is important. 1.0 mm or less will reduce detonation risk. Although, if the compression is too high with tight squish then detonation risk goes up again. So, hope the head is old school low compression (10:1), tight squish, correct jetting and it might take 19 degrees. Thats where to start.
Molto Verboso
Vespa
Joined: 19 Jun 2007
Posts: 1183
Location: California
Sun Mar 08, 2020 8:10 pm quote
ok sounds good will do some solder compressions when the 2mm base gasket arrives. Can you elaborate on the 24mm for the float arm when upside down? Do you have a photo or diagram? I do not know what this means.
Jet Eye Master
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 2443
Location: London UK
Sun Mar 08, 2020 10:26 pm quote
Lets hope the 2mm works. No big issue with using a pile of gaskets to make 2mm. The 0.5mm piston out of bore is what is needed here.

Slightly under 24mm on the float height is better than slightly over.

PHBH float.jpg
Found this on google. 24mm for your carb

Molto Verboso
Vespa
Joined: 19 Jun 2007
Posts: 1183
Location: California
Mon Mar 09, 2020 4:11 pm quote
Things I would not think to check or learn to know thanks to Modern Vespa and especially Jack221. Seems like the floats are in spec at 24mm. Also wanted to remove any suspicion they might leak put the floats in gasoline they floated for several hours.

Think we have the .35 petals in now as I have the old .35's a new .30 and .38.

Think I found a bad head temp sensor, gauge seems to function with ohm meter.

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flipped to test both sides

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Jet Eye Master
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 2443
Location: London UK
Mon Mar 09, 2020 7:32 pm quote
All helps make more speed. Nice it's not far off but the carb inlet should face down when you measure. Worth a check.

I use the KOSO temp sensors and they fail every few years. Always keep a spare in my ever growing stock of parts. Good you have a gauge. We'll get a bit more out of it with that working.

Next time the reeds fail use up the 0.38 ones.

Can't be long now before the fun begins.
Ossessionato
Joined: 26 Oct 2015
Posts: 2685

Mon Mar 09, 2020 9:36 pm quote
Im digging the hub caps! Now I kinda want to do the same thing? I have a silver PX 150 that they would look good on. And those red indicators tie in well with the red anti-dive linkage. Having a choke cable will be awesome to have now. No more of those removing the cowl dreaded early morning cold starts.

Cheers!
Molto Verboso
Vespa
Joined: 19 Jun 2007
Posts: 1183
Location: California
Tue Mar 10, 2020 5:52 pm quote
Thanks whodat had to wait a bit for the lens SIP were out of stock when I tried the 1st time. Been wanting them for a while they look great on black scooters.

Sometimes it feels there is a dimmer switch on the light bulb in my head. Also appreciate the way Jack leads us to the answers without giving them it helps with the internal learning process.

In my defense the diagram for the float measure is not with inlet facing down. Measuring the pendulum resting point of the float was way off like 30mm. Then I discover the float limiting tab which allows one to set the float height. Discovering the adjusting tab sure eased the setting. On the other hand now that I've set the float at 24mm it has raised the float inside the bowl and reduced it's travel. The amount of travel from at the bottom to the upper most travel is only about 2-3mm WITH the needle installed the float/needle seat at 22mm when lifted to the stopping point. Is this acceptable? Wondering how much needle is open with this minimal travel?

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measuring the pendulum resting point of the float 30mm

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limiting tab float height adjustment

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adjusted limit tab to 24mm float drop

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float fully raised at 22mm

Jet Eye Master
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 2443
Location: London UK
Tue Mar 10, 2020 7:40 pm quote
Well this is not going well. Still upside down. The pivot (and inlet) should be at the bottom. And float needle must be installed. Seems like the wrong way to measure it but it isn't.

The float stop should be open wide, this helps when you forget to turn the fuel on.
Molto Verboso
Vespa
Joined: 19 Jun 2007
Posts: 1183
Location: California
Tue Mar 10, 2020 7:59 pm quote
OK simple but terms still confuse me one way or another. Turned carb around measurements remain the same. Had more time to observe it function. It has a springiness and naturally drops open and requires force to lift it. On table float spings to open position. The needle appears to be open but don't have the banjo on to test blow but it looks like maybe it's good. Just a little shocked at how much travel has been removed it was really dropping down in the bowl when it was at 30mm.
Jet Eye Master
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 2443
Location: London UK
Tue Mar 10, 2020 9:04 pm quote
Ok back on track. The float travel should be just the same as before. Only with the float a bit higher. range is still the same. Maybe the stop is in way too far now. Important this is right.
Molto Verboso
Vespa
Joined: 19 Jun 2007
Posts: 1183
Location: California
Fri Mar 13, 2020 10:34 pm quote
So it seems I messed up again with the figures but maybe not too bad. Think I see why I messed up. Looking at the photo measuring the PBT not realizing feeler gauge might be dropping into chamfer on cylinder so not actually on deck. Mostly was measuring side of piston but not PBT. Oh well new numbers don't look terrible.

Still don't know what the PBT is don't have a feeler gauge smaller than 0.30mm and gasket 0.25 both are larger than gap below deck. Think it's probably 0.10-0.20mm.

I do not have solder on hand larger than 1.0mm. Tried and failed squishing twisted solder but already know squish is +1.50mm.

IF the head squish is 1.5mm and PBT is 0.20mm below deck should have 1.70mm squish. Realize this was more than target. Will this be OK? Could this help alleviate the pinging we were having before?

At this point we have raised the cylinder/head/squish 0.25mm by moving up to the 2.0mm base packer.

Raised exhaust port to 32.5mm and widened to 48mm. These are the current numbers to the best of my ability, failing eyes and crude tools.

PBT -0.20 Ex 32.50 Tr 46.65 SQH ~1.70 St 60 Cr 110 Bg 2.0mm
Ex 187.09 Tr 128.28 BD 29.41

OK to bolt it up?

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hey batta batta batta swing - ya this was a swing and a miss on the measure

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new packer waiting to be packed

Jet Eye Master
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 2443
Location: London UK
Fri Mar 13, 2020 11:56 pm quote
Nope, will be lucky to pull 3rd gear with that timing on an old 210. Good you re-checked it and got the right number. Thought there was something up with the squish all along.
Where your PBT is, is exactly where any other old 210 would be, with the same packer. This makes me more comfortable with the measurements now. Yours is measuring the same all the others I ever saw.

Unfortunately that means you don't need the 2mm packer. However, the good news is the old 1.5mm packer on its own will put the PBT at 0.3mm poking out and squish at 1.2mm.......and everybody's nearly happy. Tighter squish would be nice. Fancy skimming the head 0.2mm?

That will leave you at 185/126/29.7 and right on the money. Going to be a sporty ride. You'll like it.
Molto Verboso
Vespa
Joined: 19 Jun 2007
Posts: 1183
Location: California
Sat Mar 14, 2020 1:36 pm quote
Darn it did moving the exhaust to 32.5mm do any harm? Cleaned off the 0.25 gasket from the 1.5 gasket and set it under the cylinder. Using a jewelers loop and feelers the piston is poking out 0.35mm. This is challenging to measure accurately.

Can you say why 185/126/29.7 is better than 187/128/29.4? Thought larger exhaust and transfer degrees is better but notice blowdown decreases slightly.

Going to the 1.5 base and removing the 0.25 shim will tighten the squish. Is this going to help with the pinging?
Jet Eye Master
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 2443
Location: London UK
Sat Mar 14, 2020 7:18 pm quote
It's all fine. The 32.5mm for the exhaust port was calculated with PBT at +0.5. You're now +0.35, so this is nearly as planned.

128 degrees (and above) works well on some cylinders and not on others. On this old 210 they struggle with torque. 126 should be ok.

The tighter the squish the less gas volume in the squish band area and believe it or not CHT actually runs cooler. This older head will be ok with 1.0mm squish if it is a lower compression one, which a lot of the old ones were. The newer heads with the 13:1 type ratios are all fairly recent.

Bolted up already? Give it a pressure test.
Ossessionato
Joined: 26 Oct 2015
Posts: 2685

Sat Mar 14, 2020 7:46 pm quote
It looks like using the nail for holding the exhuast spring will work great. If you ever decide to go after the actual preshaped stainless steel weldable hooks, there's available on ebay for pretty cheap. I bought a couple packs of them last year on a whim and they are pretty legit. Even though they came from China, the shipping was pretty quick. The are a thick enough gauge that i don't see any quality issues either.

cheers!

https://www.ebay.com/itm/12pcs-U-Lug-Hook-Weldable-For-Motorcycle-Exhaust-Pipe-Muffler-Clasp-Springs-Weld/202470880185?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649
Molto Verboso
Vespa
Joined: 19 Jun 2007
Posts: 1183
Location: California
Sun Mar 15, 2020 7:05 am quote
Thank you for the reassurance will move forward with the 1.5 base gasket. Will also put the 2nd ring in my clown pocket for latter.

The nail was a quick idea to get what I wanted and seemed to work we'll see how it looks with ceramic next week.

What is a pressure test for? If something is funny should find out soon.
Molto Verboso
Vespa
Joined: 19 Jun 2007
Posts: 1183
Location: California
Wed Mar 18, 2020 6:42 pm quote
Got the P fired up and made a few vids. The plastic banjo for fuel line has deteriorated and leaking gas all over which prevented a test ride. Have a metal banjo for a 19mm primavera carb on it's way. Instead worked on adjusting the idle which may not be the correct 'smell of death' order of tuning but will wait for further instruction. Here's what I did.

Started with a 5o pilot jet AS266 atomizer X4 needle 2nd clip 50 slide NO main jet. Then jumped to a 55 pilot then to 58 pilot at 3 turns on AF. Took 2nd video. Then to 60 pilot and 2 1/2 turns. Idle seems better, pick up was better and drop to idle reduced with 3 nice pops. The pick up was very crisp and never seemed to break up opening to almost WOT.

Exhaust was leaking too excited to run before sealing. Sealed with goop and a SIP gasket for overnight always had trouble with the Malossi exhaust stub. Need spring exhaust was blown down 5mm during testing maybe because I didn't torque knowing it was coming off soon.

Video 1 21 kicks maybe due to Mikuni fuel pump. Video 2 58 pilot jet Video 3 60 pilot jet



63286DE9-CA0E-4775-B9DE-5EE7180B8168.jpeg
exhaust gasket

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gooped hopefully no more spooge

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Temp gauge working!

A955174F-D7B8-41A4-BFF8-C34736B44B25.jpeg
Why yess YSS for front too couldn't help it.

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