Modern Vespa

Have you ever had a spark knock issue on your 2t Vespa? what was the fix for you?

Last edited by Tradspa on Thu Jun 27, 2019 2:47 pm; edited 1 time in total

Higher octane gas or adjust your stator/points to 18 deg ignition timing.

Gas has always been 93 octane non ethanol
stack is 160/BE3/116

pull the choke out this far when spark knock is heard and it goes away

Strobe flashes right here. I havent verified the black mark on the flywheel yet so I dont know what that is. I assume its 23 degrees https://www.scooterhelp.com/tips/timing/electric.timing.html





Last edited by Tradspa on Mon Jun 24, 2019 10:46 am; edited 1 time in total

Check your timing manually by finding tdc and measuring 23 degrees before that. Make your new marks on the case and check again. Does this have a stock cylinder or did you upgrade it? Upgraded cylinders need 18 degrees instead. Instructions for the kit tell you what to set it at.

100% stock with stock exhaust

Check it to make sure it's correctly set for stock whatever that is for your scooter. I assume 23 degrees.

Used a piston stop to find TDC today then marked 23 degrees on the flywheel with a reference point... my plug is still firing at about 30 degrees BTDC with the stator jammed all the way clockwise as far as it will go. Must have been 32 or more before I moved it. The 3 mounting holes in the stator need to be elongated to get it to 23 degrees? how can a stock P200E engine with supposedly the original "rebuilt"stator be so far off?

Is this a common problem?

Only thing I can think of its not the original stator as I was told.

Its been spark knocking the entire time (700 miles since rebuild) and I didnt realize what the noise was until a few days ago.

So back to elongating the 3 mounting holes....is this common need on a supposedly all original parts stock motor?

went and took the stator off and looked at the back, its marked Ducati with the Piaggio double P logo. Flywheel is marked the same.

P200e is supposed to be the easy timing "line the marks up and forget it" motor, so how can it be so far off?

As far as I know (limited experience) nothing is set it and forget it unless you want to set it and "pray" as I hear a few people saying here. Don't trust marks. Make your own, but make sure yours are correct. 32 is pretty far off if it's supposed to be 23. You sure you measured tdc correctly?

As far as stator screw holes yes if they don't line up then you gotta extend then. I just did this on my Stella. Had to double the stator mounting hole lengths to get it to line up with 18 degrees properly.

Do the marks on the stator and case line up correctly as if they were set correctly? Ie.. sure the stator is mounted in the right position?

yes yes

Then extend the holes out enough for you to set it to the desired degree and see if it helps. Doesn't take more than 45 minutes.

Aftermarket stator? or....? what is the reason this had to be done? why so far off?

Stock stator for the lml Stella. Manufacturing tolerances probably. 18 degree mark was only about 21 degrees.

http://modernvespa.com/forum/post2327855#2327855

Okay.

I am thinking the center hub was replaced on my flywheel and it was put in one hole off which would move the crankshaft key away from the trigger on the flywheel thus throwing the stator position off. I can't see how it can be anything else. Very strange....

New flywheel hub was installed one hole off resulting in TDC in relation to the ignition trigger point on the flywheel being 10 degrees off? really had to go a long way to get timing around to 23 degrees.

The amount I had to go would line up perfectly if the flywheel hub was rotated one pin. Timing would then be 23 degrees instead of 33 degrees with the factory marks aligned.

Anyway, I elongated the stator plate holes to bring timing around to 23 degrees and spark knock is gone, runs better.

This might help someone else in the future.





Last edited by Tradspa on Thu Jun 27, 2019 8:24 pm; edited 4 times in total

Congrats.

I'm surprised it ran at 33 degrees, it didnt dawn on me that the sssssss tinny sound under load I was hearing was spark knock until the kickstarter started kicking back at me.

Thanks for your input.

No problem. I was just experiencing that myself last week and fixed it, so it was fresh in my mind. Now go ride it and enjoy it!

Wooohooo! Good Job in troubleshooting and getting it dialed in!

Well done. I bet it felt really strong at low rpm with 33 degrees.

You might want to have a quick look at the top of the piston, just to be sure there is no damage.

looks like FreakMoped read this thread..perfect timing!

https://www.youtube.com/watch?v=KT9EtX0DMyo&feature=push-sd&attr_tag=XFQ8Z6Tq6pUYs1t4%3A6

Oh yes. I would but now i'm chasing a clutch noise. Always something with this motor.

Do you have a photo of what a spark knock damaged vespa piston looks like?

A bore scope would be nice right about now.

Was your flywheel re-rivited or did someone use a P125X flywheel. The center of those flywheels are rivited off from the others and have a cam shape where the points touch but the magnets still have the over lapping fingers to trigger the electronic ignition but will result in timing being 10 degrees off.

Interesting! The next time I have it off i'll look a bit closer to see if it has a points hub.

So now I am dealing with an internal rattling/knock noise, but only in neutral or in gear with no load. Under load the noise goes away. Pull the clutch in and the noise changes, it is not as loud. Its the loudest when the engine is turned off and its dropping rpms to zero

I started hearing it perhaps 100 miles or so ago. Total miles on this engine only 700 and as I said, it was spark knocking the entire time.

Has anyone ever heard of spark knock causing an internal seemingly clutch related knock?

Nope. Never heard of it causing clutch issues.

With sound issues, the best thing is to record it, put it on YouTube and link the video to your post.

maybe piston slap?

I dont know what that sounds like in a vespa but yeah its possible. Would it still run great with piston slap though? and would pulling the clutch in make piston slap noise change? and would piston slap totally disappear under load?

Piston slap in cars i've heard gets worse under load but those are 4t so idk.

Last edited by Tradspa on Wed Jul 03, 2019 11:06 am; edited 5 times in total

I dont have anything very good to record it with but i'll try.

I use my IPhone and upload through the YouTube app.

Sounds like gearing problems especially from a recently rebuilt engine and not wear. Upload a video with sound and maybe someone can recognize the issue. Being that Olympia put that together you can have anything in there like a mix of gears from a p150 and p200. They already put a p150 stator on there and no telling what what type of gearing it has. You already shimmed the selector box, which should not be required on a correctly built stock motor, and maybe a indication that something is wrong with the gear box. I've been through all of that and it boiled down to letting someone that can replace parts build my motor instead of an actual person that can identity the correct parts and tolerance for my engine.

Check your rear hub spindle for wear. You can also check to see if you have a 23 tooth p200 clutch. Having a p150 clutch will not cause the noise but will rev the motor higher than normal. I don't recall but I think you've already gone through the clutch but it may been that other motor you had.

You gonna prob have to open it up and if no indication of the problem have someone verify the parts in the gear box. Maybe you just need to shimmy the gears with a thicker washer. You can also just ride until the sound is unbearable or the entire gearbox goes bad. It's not going to get better as the miles increase and prob get worse.

It's a shame though as a proper stock motor should provide thousands and thousands of miles before any type of parts maintenance let alone having to open up to fix a problem. These motors did not have a bad reputation and was considered very reliable when new.

Good luck!

Yes this sounds more like my luck, and yes its already gotten worse from the time I first heard it to now. No I havent looked at the clutch on Olympia beer company $2000 mistakemotor yet, right now I dont want to look at the damn thing at all. 3 years worth of one headache after another.

I never intended to do this much work to it. My intention was to buy a motor and ride it. Finding a motor worth a damn has been elusive.

I dont have the tools to tear a vespa motor down, right now its a $2000 boat anchor built by a shop who now refuses to help me.

Bummer Tradspa. I'm selling the one I just rebuilt and have been riding it into town daily. Maybe you can do something with it, and have spare parts to boot. Here is the link to the rebuild: https://oregoncoast.craigslist.org/mcy/d/florence-reduced-price-vespa-p200e/6912348449.html

Good luck. I'm sorry you're having so much hassle!

I'm all spent out on this motor, no more money to buy another, plus i'm 2000 miles away. Thanks though.

continued at > http://modernvespa.com/forum/post2332070#2332070