Modern Buddy

Hi all,

I have an issue with my 2012 Stella 4-stroke with 4,800 miles that I recently bought.

The clutch shudders extremely when taking off from a standstill and is very hard to dose. Sometimes it's even unpredictable and it will sometimes grab all of the sudden while I'm trying to dose. The latter happens especially when you are taking of quickly, which I need to do to get up the hills here in San Francisco.

The clutch is also noisy (loud clacks/rattles) in 1st and 2nd gear when it is fully engaged (meaning my hand isn't touching the clutch lever).

I already adjusted the clutch lever to make sure there is some play (around 2-3mm). And I also replaced the engine oil with motorcycle oil, just in case the previous owner put in an oil that doesn't work well with wet clutches.

Do you guys have any ideas what could be wrong? Is it a common issue? The first thing I would think of is a warped clutch plate or warped basket.

Thanks!
Martin

Happens to me on a regular basis. Especially when it's a difficult or hurried situation. The only solution would be to get a new aftermarket clutch. It's the same one as a PX, so any clutch built for that would fit.

[quote="martinvh"]Hi all,

I have an issue with my 2012 Stella 4-stroke with 4,800 miles that I recently bought.

The clutch shudders extremely when taking off from a standstill and is very hard to dose. Sometimes it's even unpredictable and it will sometimes grab all of the sudden while I'm trying to dose. The latter happens especially when you are taking of quickly, which I need to do to get up the hills here in San Francisco.


Hi Martin, being an old motorcycle guy, it sound like you have a glazed clutch. The clutch has heated up so much from slipping that the plates are warn smooth in some spots, this is why it chatters and shudders. It could be that the wrong oil did not allow for enough engagement or the oil burned off very quickly and reduced the effectiveness of the clutch from a start. You may be looking at a new clutch.

BigDaddy SnakeOiler wrote:Happens to me on a regular basis. Especially when it's a difficult or hurried situation. The only solution would be to get a new aftermarket clutch. It's the same one as a PX, so any clutch built for that would fit.

Thanks. Is literally everything about the clutch the same as on a PX (125/150) 2-stroke? Meaning that I could just order a PX (125/150) clutch, brass parts and inner lever? And even use the PX clutch tool to get the castle nut off?

martinvh wrote: Thanks. Is literally everything about the clutch the same as on a PX (125/150) 2-stroke? Meaning that I could just order a PX (125/150) clutch, brass parts and inner lever? And even use the PX clutch tool to get the castle nut off?

I'm not the expert, but I'm pretty sure yes. I think the 4 stroke uses the 7-spring clutch from the P200. I forget where I was just looking at an ad for a new aftermarket 8-spring one.
If you're on Facebook, look up the LML Club of Great Britain. Tons of experts there.

It is the larger, 7-spring clutch. Has a 21T drive gear, so a P200 clutch won't drop right in. Those are 23T and won't mesh with the 68T cush drive gear.

Go for a 7-spring with a 21T or 22T drive if you want a little upgearing.

Go for a Cosa clutch if you want a better-mannered clutch.

If you rebuild your stock clutch, use the Malossi plate set for a P200. Rebuild is relatively easy and the extra plate in the Malossi set is nice. Just don't use the Malossi springs unless you like snapping clutch cables.

Thanks all. The clutch problem is solved.

Since everyone dislikes a 'dead' thread without a fix for the posted problem:

I took the clutch apart. Found out that indeed EVERYTHING (but the clutch cover gasket) on the clutch is the same as the Vespa P200E clutch (108mm, 7 spring version, NOT the Cosa clutch).

Replaced the 5 clutch plates (3 cork, 2 metal total thickness: 11mm) with the Malossi 7 plate clutch for the P200 (4 cork, 3 metal total thickness: 11mm). I used new stock P200E clutch springs since the Malossi springs are extremely stiff, which is not needed for my stock 4-stroke. I used the Malossi plates because the additional plate will reduce heat build up per plate for all the hill starts I have (I live in San Francisco). I also replaced all the brass items, inner clutch lever etc. etc. The clutch works like a charm and is now actually a clutch instead of an on/off switch.

I do still have the rattling sound during 1st and 2nd gear though.... Does the 4-stroke have a cush drive?

martinvh wrote:Thanks all. The clutch problem is solved.

Since everyone dislikes a 'dead' thread without a fix for the posted problem:

I took the clutch apart. Found out that indeed EVERYTHING (but the clutch cover gasket) on the clutch is the same as the Vespa P200E clutch (108mm, 7 spring version, NOT the Cosa clutch).

Replaced the 5 clutch plates (3 cork, 2 metal total thickness: 11mm) with the Malossi 7 plate clutch for the P200 (4 cork, 3 metal total thickness: 11mm). I used new stock P200E clutch springs since the Malossi springs are extremely stiff, which is not needed for my stock 4-stroke. I used the Malossi plates because the additional plate will reduce heat build up per plate for all the hill starts I have (I live in San Francisco). I also replaced all the brass items, inner clutch lever etc. etc. The clutch works like a charm and is now actually a clutch instead of an on/off switch.

I do still have the rattling sound during 1st and 2nd gear though.... Does the 4-stroke have a cush drive?

Glad to hear that the clutch is doing its job now.

Yes, the 4T has a cush drive. It's built onto the 4th gear intermediate gear. Six single-springs instead of the double springs like P200s. I have more info on it in my transmission thread.

az_slynch wrote:

martinvh wrote:Thanks all. The clutch problem is solved.

Since everyone dislikes a 'dead' thread without a fix for the posted problem:

I took the clutch apart. Found out that indeed EVERYTHING (but the clutch cover gasket) on the clutch is the same as the Vespa P200E clutch (108mm, 7 spring version, NOT the Cosa clutch).

Replaced the 5 clutch plates (3 cork, 2 metal total thickness: 11mm) with the Malossi 7 plate clutch for the P200 (4 cork, 3 metal total thickness: 11mm). I used new stock P200E clutch springs since the Malossi springs are extremely stiff, which is not needed for my stock 4-stroke. I used the Malossi plates because the additional plate will reduce heat build up per plate for all the hill starts I have (I live in San Francisco). I also replaced all the brass items, inner clutch lever etc. etc. The clutch works like a charm and is now actually a clutch instead of an on/off switch.

I do still have the rattling sound during 1st and 2nd gear though.... Does the 4-stroke have a cush drive?

Glad to hear that the clutch is doing its job now.

Yes, the 4T has a cush drive. It's built onto the 4th gear intermediate gear. Six single-springs instead of the double springs like P200s. I have more info on it in my transmission thread.

Thanks! I posted further questions regarding the cush gear there.

Hi all,

My problems regarding the clutch were already fixed by replacing the original clutch kit for a Malossi plate set. But now also the very loud rattle under acceleration is solved.

I did split the engine cases and found out that the clutch-side crankshaft bearing was shot (5,000 miles). I replaced both bearings and it runs like a charm. I will do a write up on how to split the cases with pictures for future reference.

martinvh wrote:I did split the engine cases and found out that the clutch-side crankshaft bearing was shot (5,000 miles). I replaced both bearings and it runs like a charm. I will do a write up on how to split the cases with pictures for future reference.

Martin,

Glad to hear you got it all sorted. Looking forward to the write-up! You inspired me to go grab my block and get cracking on it. Replaced all the needle bearings with Torrington HK series bearings and replaced the small radial ball bearings with SKF Explorer-series. The crank got those NTN radial ball bearings too. Looking forward to getting it together, thanks for the motivation!