pedal start Tomos

frank stellagh /

I think I'm getting the hang of working on a "pedal starting" Tomos but would welcome a seasoned pro's advice.

I keep putting my Tomos together and everything seems to work for a little while but the claw collar keeps lurching forward enough for that infernal brake spring to be pushed out of its slot -- as well as the chain sprocket on the shaft -- for both to move about 1-1 1/2." Then, of course, nothing will turn when I check 1st/2nd gears and try to rotate the clutch by hand. The pedal shaft is not in working order. And any experimenting at this point will only damage the bike further.

If this description seems a bit wordy I can break it down to this:

I've been baffled by the "twist" of the pedal shaft when it turns clockwise. I ask myself why there isn't some kind of clip or other retainer on the other (left) side of the shaft to keep the entire assembly from throwing the sprocket and claw collar out of joint.

But I think what I've been missing is that the claw teeth on the starter chain sprocket and the claw collar REALLY have to mesh well enough so that the collar and sprocket aren't separated --thus keeping the brake spring in its slot. BY THEMSELVES, each piece is governed by the movement of gear on the pedal shaft. It sounds simple enough, anyway.

Maybe I've been blinded by the fact it's a new bike. And evidently it doesn't take much wear on the claw teeth for the entire assembly to lose its integrity.

So I'll be replacing the claw collar and spring, as well as the starter chain sprocket. [At least the claws on the mainshaft sprocket looks like they're in good enough shape.]

But maybe the best thing I can ask is: "what else could I be missing?"



Re: pedal start Tomos

Reeperette /

Hmm, I wonder if the bearing race on the LEFT side there might have popped out or something...

You might consider total dismantlement, if it comes to that.


Re: pedal start Tomos

frank stellagh /

by bearing race do you mean "needle" bearing, "ball" bearing on gearbox chain sprocket, or main shaft bearing ring?

Re: pedal start Tomos

Reeperette /

Dunno, all my experience is just that, experience, and so I don't know the "proper" names of many parts.

Anyhow, on the opposite side, that shaft fits into a ring of bearings, just like it does on the side you removed, see ?

Now if that ring's popped out on the other side, yeah, you gotta problem, but not really an insurmountable one.

Just a thought.

It's hard to visualise a lot of this without parts-in-hand, so bear with me, guy.


Re: pedal start Tomos

frank stellagh /


I now know what a bearing race is. It would be hard to believe that the mainshaft bearing race would be a possible source of the problem.

BUT...considering what's transpired up to now on this %^&@*$# fking bike...I ought to believe anything.

And, yes, there is an actual bearing race on the mainshaft. In ONE diagram. It's external to the mainshaft and it's found around the hub on the gear. In another diagram it's not present. All the 2nd drawing shows is the sprocket and the associated needle valves. At least the 2nd drawing "alludes" to a "seal ring" on the close end of the first needle cluster for holding the pedal shaft in place. So the first seal ring may be the part that failed.

And I can always buy a needle ring tool from Tomos -- just as soon as they start making one again. Or I can machine press the needles back into the cluster if my crude needle valve extractor tool knocks them loose.

So I'm left with little other to go on other than to tighten the brake spring on the claw collar so it won't be AS likely to pop out of the slot between the mainshaft and crankshaft. Of course, this spring will loosen again when in road use, and if it loosens something else on the pedal shaft in the process the bike will lock up.

Getting the spring to bend symmetrically is not as easy as I thought, either. So, if tensing the spring further doesn't work, I'm parting out the goddmn bike!

I don't have the ability to take the thing completely apart. Or the patience. I'm too distracted by the thought of 30 megaton warheads slamming into Slovenia.

One of the things that occurred to me while dreading a "complete dismantle" is the irony of taking the head apart, prying off the inner engine covers, which are machined on to the frame, removing the mainshaft and crankshaft, etc., JUST TO GET TO A PART THAT POPPED LOOSE WHILE MAKING A COUPLE OF HAND ROTATIONS OF THE REAR WHEEL. Evidently one locks the rear wheel down TIGHT once the engine cover is removed even if it's ONLY to get the pedal shaft to line up with the gear cluster!! That's right, THAT'S ALL IT CAN TAKE, and once the brake spring pops loose other parts under tension will be soon to follow. And evidently they did.

MEANWHILE, it's truly amazing how smug Tomos has been about the problem. I keep getting referred to their shop manual. That be-all and end-all of manuals. DEDICATED to the qualified mechanic! A qualified mechanic wouldn't wipe his or her ass on the damn thing.

Well, it's too late to cry now. But I'll have my revenge on Tomos if takes a lifetime!!

Kids...DO try this at home.


Re: pedal start Tomos

Reeperette /

Make it work, then laff at them, It's what I did.

Best revenge there is.

Depending on what you paid for the bike, you might consider finding out what shipping would be for sending the transmission to Ann Arbor-area Michigan and back.

For damn sure I could fix that puppy, so if it's worth the shipping back and forth (cause I wouldn't charge ya) you might think about it.

But then, I dunno what ya paid for the 'ped to begin with.


Re: pedal start Tomos

frank stellagh /

thanks Reeperette:

will consider offer. But may need to ship by hearse.


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