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orwell84 wrote:
Thank you. I didn't find one for the Stelvio either.

I will just do the usual break in. The speed limit on the back roads is 45 mph with lots of hills. I will just enjoy them sensibly with rich jetting until I've run a few tanks through.

When I dropped my engine a few weeks back, I found that the coiled fuel hose had shrunk and it was even shorter yesterday. The blue hose I had was hard as a rock. It's like 6 months old!!

A hillbilly farm fix was in order. Had some 1/4 " brake line kicking around. I will sleeve it with some tubing to keep the clamps from rubbing on the frame. I'm keeping it like this. The brake line is pushed an inch and a half into the fuel hose going into the frame and almost an inch into the blue line. I warmed the ends up with a heat gun so the line is molded to the bit of brake line.

I'm starting with 140/BE5/128. 50-120 idle jet. I'm pretty comfortable setting up the main, but the idle circuit was impossible the last time through. It would run rich no matter what jet I put in and the mixture screw did not seem to do much until it was nearly closed.

When I put on the Si26, things seemed more promising. It would rev out at 1/4 throttle on the stand (it wouldn't before) and the mixture screw seemed to actually do something. Worst case scenario, I don't get quarter throttle any better than before. If that turns out to be the case, I can live with it.
Are you still on the 26/26?
If so, definitely AC120/BE4 to start with.
Iron cylinders take a lot more running in than alloy. Extra oil for the first few tanks too.
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Jack221 wrote:
Are you still on the 26/26?
If so, definitely AC120/BE4 to start with.
Iron cylinders take a lot more running in than alloy. Extra oil for the first few tanks too.
10-4 on that. Am I correct in thinking that the 26/26 will flow more air and fuel and that I will need to run it richer than the 20/20?

The 120AC hopefully will allow me to stay within the same range of main jets. I have a good range from 110-125, a 128 and that's it. I was also worried that the 26-26 would be too big, but I have come across other threads where you have said it won't and I think you were referring to a Stella reed.

Thanks.
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The 26 will run richer because the flow velocity will be slower. As long as the reeds are good now.
A 30mm carb on a 125 motorcycle is not uncommon. A 26mm on a 190 scooter is not too much.
Hopefully need the bigger pilot jets too.
Any filter on this?
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Jack221 wrote:
The 26 will run richer because the flow velocity will be slower. As long as the reeds are good now.
A 30mm carb on a 125 motorcycle is not uncommon. A 26mm on a 190 scooter is not too much.
Hopefully need the bigger pilot jets too.
Any filter on this?
I was planning on running without a filter.
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orwell84 wrote:
I was planning on running without a filter.
The 26 needs its own size filter. I suspect you don't have one and should neither buy one.
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Jack221 wrote:
The 26 needs its own size filter. I suspect you don't have one and should neither buy one.
I like the sound of that.

Engine startup was delayed due to ratty shift cables. Too frayed and chewed up to be worthwhile trying to make them work just one mo time. No fun to rev in neutral without a ride after.

Replaced the complete cables. A little fiddly getting them through the headset, but no tools were thrown. Bit by bit, is how an ok bike becomes a good one.
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Back to the 200 for a moment. Just checking that I have the right clutch side oil seal. The case has a groove for the lip on the rubber oil seal. The Malossi viton seal does not. The edge is metal. Can/should I use it?

Thanks

https://www.scootermercato.com/Scooter-Parts/Malossi-Seals-and-Bearings/M-6617310
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Finally started it up. Very short ride as I ran low on fuel and flooded it after switching to reserve. I couldn't start it again even after cleaning off the plug. No spark when I tested it. The spec sheet calls for a NGK B9ES. All I could find was a BR9ES. The one that ended up working was a used B7ES I had on hand. The headlight isn't working now either.

The good news is that I don't seem to be getting the low throttle 4 stroking anymore. Put in a 52/140 120/be4/125 just to get around the block.


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Actually, I couldn't have run out of fuel. I had 4 liters in the tank which is way above reserve. Maybe the 1% mix in the tank wasn't doing me any favors. I just wanted to have a backup until I was sure the autolube was working. It is.

Maybe the BR9ES is too cold. Either way, I could not get a spark out of it, even after cleaning.

The VMC spec sheet recommends a B9ES, but I'm wondering if a hotter plug might be better.
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If the sheet says B9, you should go with a B9, IMO.

And the B9ES was the pre-resistor version of the plug. NGK discontinued them a couple years ago. I run resistor versions in all my bikes and they're fine.
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orwell84 wrote:
Actually, I couldn't have run out of fuel. I had 4 liters in the tank which is way above reserve. Maybe the 1% mix in the tank wasn't doing me any favors. I just wanted to have a backup until I was sure the autolube was working. It is.

Maybe the BR9ES is too cold. Either way, I could not get a spark out of it, even after cleaning.

The VMC spec sheet recommends a B9ES, but I'm wondering if a hotter plug might be better.
I've got no issues with the br9es in my VMC
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I will remember to carry a spare. I never have much luck cleaning a fouled plug. Switching them always seems to work though.
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FridayMatinee wrote:
I've got no issues with the br9es in my VMC
ditto for me
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Thanks! Got the headlight working again, the usual issues that happen when old electrics are disturbed. Stella electrics age in dog years.

Just a ride around the block today. Pulls hard in the range it used to make popcorn.
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Sounds much better than before. Is that the main jet done at 125? If it is swap the BE4 for a BE3. And see if it's any improvement.
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Jack221 wrote:
Sounds much better than before. Is that the main jet done at 125? If it is swap the BE4 for a BE3. And see if it's any improvement.
It does. Main is 125. Goes lean a little doesn't it?

Btw, I haven't done the WOT in 2nd splutter test to select the correct main yet. I just set it up to start the engine and get me around the block. I'm not sure if I should put some miles on it first before taking it to max revs.

So far, things look a lot more promising. The 26/26 was a good call. I'm sure the new reeds are helping too. I also spent a lot more time sealing up the intake and exhaust as well as setting up timings and squish. As with any engine, there usually isn't just one thing that determines whether it runs well or poorly.

A couple other things I've noticed with the VMC kit compared to the Polini. Compression seems higher, at least that's what my foot tells me. Might be due to a tighter squish. It also doesn't rattle when cold like the Polini kit. Anyway, I hope this is the one that works out for me.
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Once ridden for a tank of petrol, quickly do the 2nd gear WOT test. If the main jet is not enough, running in will be wearing it out.

It's going to be way faster than the polini. It's a modern kit with better ideas. As ever with 2 stroke tuning, one big mistake and it fails. Would say your doing fine. Keep the revs and temperature down but ride it harder after each tank.
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Jack221 wrote:
Once ridden for a tank of petrol, quickly do the 2nd gear WOT test. If the main jet is not enough, running in will be wearing it out.

It's going to be way faster than the polini. It's a modern kit with better ideas. As ever with 2 stroke tuning, one big mistake and it fails. Would say your doing fine. Keep the revs and temperature down but ride it harder after each tank.
10-4 on that. I'm going to finish the tankful of 1%, then do the WOT test for the main with just the autolube.

I was out for a short ride last night. Really pleased with how it goes. Revs pick up really quickly with the throttle just barely open and it cruises nicely at 1/4 throttle. Huge difference with how it was before. It's hard not to open it up and see what it's got.
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Jack221 wrote:
Once ridden for a tank of petrol, quickly do the 2nd gear WOT test. If the main jet is not enough, running in will be wearing it out.

It's going to be way faster than the polini. It's a modern kit with better ideas. As ever with 2 stroke tuning, one big mistake and it fails. Would say your doing fine. Keep the revs and temperature down but ride it harder after each tank.
Once youve established the jet that splutters at wot in 2nd how much smaller is the ideal jet? for example if a 135 splutters what jet should you come down to? 132? 130?
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andyx wrote:
Once youve established the jet that splutters at wot in 2nd how much smaller is the ideal jet? for example if a 135 splutters what jet should you come down to? 132? 130?
You would be trying the next smaller jet, so the 132. If you had a 134 or 133, you would try those first, though I don't know if they make jets that size.

I am hoping by going from a 140 to 120 air corrector that I will be able to stay in the high teens-low 20's. There are more available jets in that range, so easier to fine tune.
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I went for a 20 minute ride doing between 35-40 mph. My temps quickly got up to 310*F. I am thinking I should up the main and idle jet. I'm at 50-140, 120/be5/125.

The biggest main I have is a 128. I will order some more in the130's.

Could the temps be break-in related?
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orwell84 wrote:
I went for a 20 minute ride doing between 35-40 mph. My temps quickly got up to 310*F. I am thinking I should up the main and idle jet. I'm at 50-140, 120/be5/125.

The biggest main I have is a 128. I will order some more in the130's.

Could the temps be break-in related?
At those speeds your not using much of the main jet. What is that 1/4 throttle? Anything to richen up mid or low end.
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orwell84 wrote:
The biggest main I have is a 128. I will order some more in the130's.

Could the temps be break-in related?
No. (That was easy Razz emoticon )

it's been a while since I ran a BGM on Stella cases, but that seems like a big main.

I think you should bump the mixer to a BE4 to start. What throttle positions were you mostly at? More mixer than main, I'd think.
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I was going to say BE4 also.
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chandlerman wrote:
No. (That was easy Razz emoticon )

it's been a while since I ran a BGM on Stella cases, but that seems like a big main.

I think you should bump the mixer to a BE4 to start. What throttle positions were you mostly at? More mixer than main, I'd think.
It runs so much better now, but it won't for long at those temps. CHT gauge was the best $25 I've ever spent.

It said STOP. Then, GO HOME.

At those speeds, I am often around 1/4 throttle and sometimes less. I have much richer idle jets that I could run. Before the carb and top end swap, this bike had nothing under 1/3 throttle.
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Didn't you buy a 50/100 pilot. I'd find out how rich that is first.
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Jack221 wrote:
Didn't you buy a 50/100 pilot. I'd find out how rich that is first.
Yes, I have one. I will try it. And actually I had a BE3 in there most recently. I guess I will go back to the BE4. I didn't ride with it long enough to get temps up. It ran well though.
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I haven't played with an SI carburetor in a few years now. Mark your throttle positions and keep track of where it's warm. That way you know what throttle position you need to work on. I had my main so big at one point, when it got warm I just cracked throttle to about 3/4 and mine cooled off. Ran like crap at that position but it was funny and a learning experience.
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orwell84 wrote:
I went for a 20 minute ride doing between 35-40 mph. My temps quickly got up to 310*F. I am thinking I should up the main and idle jet. I'm at 50-140, 120/be5/125.

The biggest main I have is a 128. I will order some more in the130's.

Could the temps be break-in related?
Hard to imagine a Runleader shooting like that with your current jetting, vs an "event" spike.
They may have changed since, but the older VMC nuts had coating inside the threads that provided a "false (thread friction vs nut face) torque."
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Ray8 wrote:
Hard to imagine a Runleader shooting like that with your current jetting, vs an "event" spike.
They may have changed since, but the older VMC nuts had coating inside the threads that provided a "false (thread friction vs nut face) torque."
I hadn't considered that it might be sensor related, but definitely something to consider. The temp went up gradually, but fairly quickly. Never saw that with the old kit even with way wrong jets. But it always ran rich at low throttle with the old carb even with a really lean idle jet.

It was 90* here yesterday. The plug is snugged up, not set to a specific torque, but it should do. I will check the plug sealing. When I was running the BE4, temps were way better, but they were very short rides.
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Switched to: 50/120 120, BE4, 125.

Temps got to 280 with the same kind of riding. Better, but still seems on the high side. I did check the plug and temp sensor, which looks like it was leaking. Put the plug back in and tightened it. Went from 180 to 280 in a 10 minute ride, 40-50 indicated, 5k rpm max.

One thing I noticed that temps stayed around 260 while it sat and idled. Usually CHT's fall off a cliff once the load is off the engine.

https://youtube.com/shorts/yiES4Q6Uy_Y?feature=share
Spoogey
Spoogey
Rich enough?
Rich enough?
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That plug looks super rich. Like practically fouled. Your temps still seem high for as gently as you're riding.

What gear and throttle position, rather than speed, are you riding at?
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chandlerman wrote:
That plug looks super rich. Like practically fouled. Your temps still seem high for as gently as you're riding.

What gear and throttle position, rather than speed, are you riding at?
I meant to post a longer video, but the camera shut off. I will try again soon.

With the richer idle jet and mixer, it was boggy at low throttle, but not awful like with the 20/20. I was more in the 1/3 throttle range because of this. I tried spinning it in 3rd and blahhhing along in 4th just to see if there was any difference for temps. When running the leaner idle jet and BE3 it took off with the throttle cracked.

Btw, timing is dead on. I'm running 1% in the tank. It did cut out at one point at about 40 mph and restarted right away. Not a soft seize, just rich and greasy.
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orwell84 wrote:
It did cut out at one point at about 40 mph and restarted right away. Not a soft seize, just rich and greasy.
Hmmm, I've never had a scooter cut out at 40, 30, 20, 10, or 5mph. I don't understand....
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qascooter wrote:
Hmmm, I've never had a scooter cut out at 40, 30, 20, 10, or 5mph. I don't understand....
I have only had that happen when close to reserve and then hitting a steep hill. But if the plug is running on the verge of fouling.

CHT sensors can be hard to seal and when they leak it can result in hot readings. Usually I keep the sealing washer on the plug because of this, but this time I didn't. I'm not sure if this is the problem though. I will try it different ways to see if it makes any difference.
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orwell84 wrote:
One thing I noticed that temps stayed around 260 while it sat and idled. Usually CHT's fall off a cliff once the load is off the engine.

That plug isn't seated. Dealing with a sensor there can be quite frustrating

Confirm torque on the cylinder nuts.

My wife's VMC leak tested on the bench, but not after the considerable vibration involved once riding. I ended up replacing those "optical tuning" nuts for standard nuts and Nordlock washers. Two years and no issues.
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Ray8 wrote:
That plug isn't seated. Dealing with a sensor there can be quite frustrating

Confirm torque on the cylinder nuts.

My wife's VMC leak tested on the bench, but not after the considerable vibration involved once riding. I ended up replacing those "optical tuning" nuts for standard nuts and Nordlock washers. Two years and no issues.
Thanks! I will retorque the nuts. Now that you mention it, the hardware that came with this kit was awful. Those spacer type nuts would not fit without retapping them. Not a quickie run the tap through, but really humping on it.

Ray8, I missed it when you said it the first time, but I get it.

There is a bronzey finish on the hardware that makes it feel tighter. I only tapped the cylinder/stud size of those spacer nuts. It passed the pressure test, but I can see how it could loosen up.

So a short list of logical possibilities to run down and no harm done.
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Looking back at my photos, it's really clear that the plug is leaking. There is carbon on all the sealing surfaces. That on its own can make CHT's read high.

I've never liked the thermocouple arrangement on CHT gauges. They don't seal that well when new and get worse every time you have the plug out, which can be quite often on a Vespa. Are there other ways to mount it or other sensors that avoid these problems.

Ray8: What hardware did you use to replace the VMC head spacer nuts and Allen bolts? It's kind of a strange arrangement.

Thanks.
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Get an M10x1.0 screw in sensor. You'll have to drill and tap the VMC head, but that's pretty do-able. FridayMatinee did an m4.5 on his and I feel like someone else has done an M10, but I can't recall who.

I did it on the Smallstate head and the BGM177 comes with that pre-drilled & tapped. That was actually a lot trickier, because it has an *angled* pad rather than just flat. Maybe it's Quattrini's way of making sure you've got actual builder chops to trick out their kits. Razz emoticon
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Posts: 3837
Location: northern New York
 
Ossessionato
@orwell84 avatar
Joined: UTC
Posts: 3837
Location: northern New York
UTC quote
chandlerman wrote:
Get an M10x1.0 screw in sensor. You'll have to drill and tap the VMC head, but that's pretty do-able. FridayMatinee did an m4.5 on his and I feel like someone else has done an M10, but I can't recall who.

I did it on the Smallstate head and the BGM177 comes with that pre-drilled & tapped. That was actually a lot trickier, because it has an *angled* pad rather than just flat. Maybe it's Quattrini's way of making sure you've got actual builder chops to trick out their kits. Razz emoticon
Thanks, that's exactly what I was looking for. I knew I had seen that somewhere and Ray8 fighting with the crap hardware…and uncle Henry and Auntie Em…everybody from back in Kansas.

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