Motobecane 50V AV7 Clutch Problems!

I recently rebuilt my 1979 Motobecane 50v and it ran terribly. I got that fixed with some help of another thread I made.

All the specific history of the bike and it's problems can be found here .

The last problem that's keeping me from riding seems to be in the variator. I had the variator circlips in the wrong order somehow and the porting was totally keeping it from making any power. I fixed both issues and now the rear wheel spins on the stand, I can rev the engine, and the engine variates. I have another problem, though. Despite working on the stand, if I put any weight on the rear wheel, no power is made to it. The engine will rev, the inner bell will spin, but it won't grab the outer bell.

Of note: I believe the variator is making the squealing sound you hear in the video and I was only able to put 1 0.8 mm shim between the first (internal) and second (external) circlips. I attached a video.

Video:

Upon the recommendation of pat splat I filmed a video detailing the assembly of my variator on the engine. I dissembled my variator (once again!) and made this video:

The last item I took off is on the left, the first on the right. The worn side of the clutch pads have about 2.5mm of material left. The groove on the stem of the external clutch bell is from it grinding against the case the first time I screwed up reassembly by reversing the order of the circlips (who needs a manual when you have a memory!). I also have a 0.5mm shim that is not in the variator.

Help please!!!

Re: Motobecane 50V AV7 Clutch Problems!

I think a pictures would be better. I just took mine apart and I am sure your missing a shim. There should be two shims stacked together .

Re: Motobecane 50V AV7 Clutch Problems!

Two shims

IMG_20200513_172240~3.jpg

Re: Motobecane 50V AV7 Clutch Problems!

theres something cutting up your variator on the inside, did u do that? metal shaving all over.

Once the variator clips/shims are on you can spin it to double check that nothing is grinding before putting clutch on. Also belt alignment front to back pulley is important.

Re: Motobecane 50V AV7 Clutch Problems!

If you removed a thicker shim that should be between the two truarcs.

Assemble the cartridge, shim, int truarc, shims (thickness here is what adjusts runout), ext truarc in that order into the variator housing and slip on the variator to the drive shaft until you hear/feel CLICK of the int truarc finding its groove. Then check that there is not excessive runout.

Then introduce the drive portion of the clutch assembly (cover and PTO shaft).

Re: Motobecane 50V AV7 Clutch Problems!

The problem is that second truarc won't fit under it's retention lip with all 3 shims. It worked before I rebuilt the engine, I am dumbfounded as to how it won't go back together now.

Re: Motobecane 50V AV7 Clutch Problems!

If you are putting the variator onto the shaft then loading the components it will always be a chore. Assemble the guts into the variator, it will slide on and lock into place after.

> Jaden Stone Wrote:

> -------------------------------------------------------

> The problem is that second truarc won't fit under it's retention lip

> with all 3 shims. It worked before I rebuilt the engine, I am

> dumbfounded as to how it won't go back together now.

Re: Motobecane 50V AV7 Clutch Problems!

While I totally did this before, I have tried preassembling it a few times (cleaning everything, checking thicknesses/order) and the second clip will not engage.

On a separate note, how to I replace the drive clutch arms/pads. They come with rivets, but I there is no hole for them to go through on the inner bell because the starter clutch needs to ride somewhere.

Re: Motobecane 50V AV7 Clutch Problems!

After you drive and stake the rivets then you need to grind them flush to the friction surface of the clutch cover.

> Jaden Stone Wrote:

> -------------------------------------------------------

> While I totally did this before, I have tried preassembling it a few

> times (cleaning everything, checking thicknesses/order) and the second

> clip will not engage.

>

> On a separate note, how to I replace the drive clutch arms/pads. They

> come with rivets, but I there is no hole for them to go through on the

> inner bell because the starter clutch needs to ride somewhere.

Re: Motobecane 50V AV7 Clutch Problems!

No shit! I was expecting something with more finesse! Thanks!

Re: Motobecane 50V AV7 Clutch Problems!

Since my last post I have replaced the clutch pads. The moped moves now! The problem is that, despite revving well on the stand, it barely revs on the ground. Sometimes it will just die. It never goes above 5 mph. The pads were way to large to actually fit in the bell, so I had to sand them way down to even get the inner bell on the bike, and even more to make the clutch slip at idle. One pad is somehow bent and still rubs. I have considered just buying a Doppler ER3 with clutch and completely nipping the clutch-bug. I found one for $130 new. Any thoughts welcome! Thank you!

« Go to Topics — end of thread

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account