Tomos A35 transmission issues

Ok so I've just gotten my bike back together since tearing it down last October after a wrist pin clip killed my cylinder.

It's been completely rebuilt and I've slowly gone over everything over this past year. New crank bearing and seals as well as a new final drive gear bearing. New wiring harness. New everything.

So I finally start it yesterday and immediately the pedals start spinning backwards as I rev the engine. I assume that my claw collar spring isn't seated right. So I take it apart and try to reseat it and get the same results over and over again. I must have cracked open that transmission like 10 god damn times yesterday getting the same results each time.

The last time I did it I followed some advice I found in a post on here and took special care to keep pressure on the pedal shaft pressing it towards the drive gear while I put the clutch and cover back on as well as the outside pedal spring and arm. When I go to start it, it starts up great and the pedals didn't spin. You know what else didn't spin, the back wheel. As in I give it gas and nothing happens at all except a revving engine. Pedaling still moves the bike forward. So I pull over to take a look at it (only gone about 200' down the street) and while im doing this the pedals catch again spin backwards and hit me in the back of the leg. Fun stuff.

Anyway that was my last attempt before calling it a night since my leg now had a gnarly scrape and it was about 2 am.

I've tried placing the spring very carefully multiple times and I've searched the forums and read a lot of posts and all signs lead to that stupid ass claw collar spring at least from what I've read. I've tried 3 different pedal shafts and 3 different claw collars as the first one did have some wear on the teeth on one side. Also tried two different countershafts as well as a number of different shim combinations on the pedal shaft since the tomos manual says "shim as needed". I do have another clutch bell but I haven't tried it. The one that's in now is the same one that it had when it died about a year ago and never had any issues. Also I did check the one way bearing and it seems fine.

Im baffled. I've taken apart and reassembled an A35 transmission more times than I can count now and I have never had this happen. In fact this is at least the third time I've assembed this particular bottom end as it came to me as a box of parts and I've now rebuilt it twice since first receiving it.

What am I missing? Is there something else I can check? I've spent almost a year building this bike and meticulously going over everything since the cylinder took a shit last October. I just want to ride it again before winter comes.

I hope someone on here has an obvious solution that I'm just not seeing.

Here's a pic of the bike for your enjoyment.

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Re: Tomos A35 transmission issues

picts of questionable tranny pieces would help, anyways the claw that has the peanut spring on it has to have a certain amount of friction on it to work right. it just doesn't fit in the slot... its gotta grab the slot, not sure how u measure rotational friction but its like two fingers pressed onto a table and moving it. short answer, u need to compress the peanut.

Re: Tomos A35 transmission issues

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Well here's pics of the other two claw collars I tried. I haven't opened it back up today but im about to. The one on the left seems like the spring is compressed more. Maybe I'll try that one again once I open it up again if it looks better than the one inside currently. It's possible I didn't have it shimmed right when I tried it before.

A number of the times I put it together there was definitely some side to side play on the pedal shaft and I know that's not good. The last time I put it together last night it had zero play.

Re: Tomos A35 transmission issues

IMG_20180903_182827.jpg
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Here's the pedal shaft and claw collar that was in it on the last attempt. Also the final gear inside the case.

The clip on all there claw collars I have seems to be compressed pretty well. Maybe im not understanding what you meant.

Seems like when you pedal forwards the claw collar slides toward the final gear to pedal the bike. When you pedal backwards the claw slides towards the clutch cover engaging the chain attached to your countershaft and engaged the clutch.

So once you've started the bike, does the claw sit in a neutral position that keeps it from catching the chain gear that engages the clutch? Or does it go back to sitting pressed against the final gear?

Seems like if it got caught and was sticking to the chain gear thing that would maybe be what's causing the pedals to spin backwards and try to take my legs off when it starts.

I still don't quite understand why the last time it didn't do that at all but it wouldn't turn the back wheel either. Then after sitting idling for a minute, all of a sudden the the pedals catch and swing backwards again.

I've successfully rebuilt a few of these engines now and I've never seen this happen. Ironically, I've actually taken my time more with this build than any of the others and it's the only time I've seen this happen.

Re: Tomos A35 transmission issues

After taking those last pictures. I put it back together and started it and the pedals weren't spinning backwards at all. However the back wheel wasn't either.

I realized that the back brake cable was so tight that the rear wheel would barely turn. So I undid the brake cable to adjust later once it's actually safe to take down the road.

After doing that I went ahead and filled up the transmission with oil because I assumed it was finally good and I wouldnt have to take it apart again. As soon as I crank it up again the pedals start spinning and the rear wheel doesn't. The only thing that turns when the engine is off is the damn pedals.

When it's off you can pedal it forward and it turns the wheel and when you pedal backwards you hear it trying to turn over.

As soon as the engine is running, sprocket doesn't seem to be turning and the pedals just try and murder me.

What the hell is going on here?

Re: Tomos A35 transmission issues

There's a shim that goes in between the claw collar and the finale gear. The pillow side faces inward towards the sprocket. Check all your shims make sure they are installed correctly.

check the clutch the cork shouldn't be touching the inside of the clutch drum you should have 1mm of space in between each shoe.

Check the first gear clutch make sure its not binding againts the clutch drum.Pull on the drum back and forth should have very little play the manual has the correct specs.(edited)

Re: Tomos A35 transmission issues

sadly i try not to understand how it all works, too many turny things for my brain to comprehend at once. alternately, I try to make sure each part works as it should and be in the right spot and hasn't been messed with.

everything looks normal in picts but.... why is there weld splatter in your tranny, i see it, its been messed with. all it takes is one of those little balls to fu any of those bearings.

from rt to left.

when turning motor 1st gear clutch spins freely, clutch bell dont move.

check one way bearing n cage, on intermediate shaft. sprag spring there?

last when u hold that peanut spring twist the claw collar, there should be resistance.is the ext pedal spring and washer installed, opposite side and is it the right one?

run a small magnet around to pick up all that weld splatter too.

Re: Tomos A35 transmission issues

> Tomos Forever Wrote:

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

> There's a shim that goes in between the claw collar and the finale gear.

> The pillow side faces inward towards the sprocket. Check all your shims

> make sure they are installed correctly.

>

> check the clutch the cork shouldn't be touching the inside of the clutch

> drum you should have 1mm of space in between each shoe.

>

> Check the first gear clutch make sure its not binding againts the clutch

> drum.Pull on the drum back and forth should have very little play the

> manual has the correct specs.

I've checked all of this EXCEPT there is definitely not a shim between the claw collar and final gear.

That has to be my problem. I've never seen a shim like that before when taking one of these apart but this is also the first time I've rebuilt one and actually replaced the final drive gear bearing on the stator side case. I'm guessing this shim got lost during the rebuild. Fortunately I have I think 3 more sets of cases in my shed that have the final gear attached to them. I'll check those when I get home and see if I can't track down one of those shims.

Pat, I'm not sure about the weld splatter. If you're talking about the silver that's showing on the raised section around the peanut shaped opening in the case I think that's actually just wear from getting hit by the claw collar spring or something. Can't say for sure though. This engine came from a friend who got it from one of the dam riders years ago. It could have been welded at one point but not since I've owned it.

I'm seriously hoping it's that shim that tomos forever mentioned because my clutches are all new and nothing is binding in the bell. All my shims are present except for the one under the claw collar. All the bearings and seals on the clutch cover are new.

Re: Tomos A35 transmission issues

Yep find that shim its supposed to be their

Re: Tomos A35 transmission issues

t5d-205-702_thumbnail.jpg

Is this the shim I'm missing?

I was looking at the exploded diagram of the pedal start assembly on mopedjunkyard and according to that it seems like this should be the shim between the claw collar and final gear.

A35transmission3.jpg

Seen here as part # 205-702

It's the only one from this diagram that I can't say I've laid eyes on while messing with it this past weekend.

I've definitely never seen it before. I'm just trying to figure out what exactly I'm looking for before I get home and start digging through my parts.

Re: Tomos A35 transmission issues

Yes that is the shim.

Re: Tomos A35 transmission issues

turn your claw collar around and make sure your pedal shaft is all the way in check your pedal shaft c clips when its proper in your case will butt up with out force (there nothing wrong with your parts) its the location of claw collar and pedal shaft wiggle the shit out them

Re: Tomos A35 transmission issues

> fred sams Wrote:

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

> turn your claw collar around and make sure your pedal shaft is all the

> way in check your pedal shaft c clips when its proper in your case will

> butt up with out force (there nothing wrong with your parts) its the

> location of claw collar and pedal shaft wiggle the shit out them

Use punctuation . PLEASE . ;)(edited)

Re: Tomos A35 transmission issues

I dig through all my stuff. I can't seem to find one of those shims anywhere in four sets of cases with final gears. They all look the same.

However when going through all my shit I realized when I replaced the pedal shaft seal on my clutch cover I put it in backwards and pushed all the way down to the bottom of where it normally sits. I guess I forgot how it was oriented when I went to replace it.

I'm wondering if that has anything to do with my issues now. I don't really see how a seal would cause that especially since the pedal shaft doesn't actually butt up against it or anything. Either way. I've fixed that now. If that was my issues I'm going to to feel really stupid.

Honestly I hope it does but if not I guess the hunt continues for this shim. I was sure I'd have one in my bin full of cases but if I don't find one or find a different solution soon I guess my next step will be ordering that shim from moped junkyard.

Re: Tomos A35 transmission issues

i see weld splatter buggers on your final drive gear, claw/peanut area. maybe im seeing things.

away from tranny but is your back rear brake plate in its stop slot in swingarm?

Re: Tomos A35 transmission issues

> pat splat Wrote:

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

> i see weld splatter buggers on your final drive gear, claw/peanut area.

> maybe im seeing things.

>

> away from tranny but is your back rear brake plate in its stop slot in

> swingarm?

Yea it's possible for sure. I can't speak for this engine's history before it came to be. I will say it ran perfectly with all these same parts just fine up until my cylinder ate one of my wrist pin clips last October. That's when I broke it down for a fresh rebuild.

The brake plate slot is in its stop slot but it is a garelli rear wheel. So I am not using a tomos brake plate. That shouldn't matter.

I'm going to order that shim from moped junkyard since I didn't find one. In the meantime I just put a kickstart claw collar in and that fixed the pedal spinning issue as well as the rear wheel not spinning with the engine. I won't have functioning pedals for anything but kick-starting but who cares? Even if I brake down I'd be walking it as opposed to pedaling it. Engine is running strong anyway so that shouldn't be an issue anytime soon.

Re: Tomos A35 transmission issues

I recently had a Tomos start doing this and within the hour it ate both clutches... Same symptoms of the pedals spinning backwards and no forward motion. I'll admit I was a bit preoccupied.

I believe as others have said, either a thrust washer or other part is missing. I will write back once I have time to look into the situation and find a cause.

Have you had a chance to check further into yours or are you simply keeping the kickstart claw installed?

Re: Tomos A35 transmission issues

So I know I posted this a while ago but I wanted to post a follow up as i finally worked out the issue. Turns out it wasn't a problem with the transmission at all. I'd put a new parmakit CDI box on it and when I wired it up i had my ground and positive backwards on the box. So when the bike turned on the sprocket was spinning backward and the claw collar wasn't disengaging and therefore the the pedals were spinning backwards with the sprocket.

Either way i finally had a chance to work on it again yesterday and I figured I'd see what happened if I reversed the wires on the CDI. After I did that it turned over on the first kick and the problem was solved. I got to ride it again for the first time in over a year. God i missed that feeling. I'm just glad i can finally start turning it now and be able to ride again this season.

Re: Tomos A35 transmission issues

cograts, woulda never guessed.

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