HELP! Problems in the gearbox

I just want to thank everyone for the messages throughout this process. I didn’t realize I picked up a complete beater of a bike but here I am digging deeper and deeper and deeper into it. Won’t stop now!

So here’s where I’m at.

I ordered the 70cc kit. Cylinder is off. Piston wasn’t moving. I pulled off the right side case to find the transmission in absolute disarray. Metal chunks everywhere, Gears chipped, worn out, out of place, and whatever that metal disk thing is that goes into the clutch bell was completely warped and looks to be the cause of it all. One of the 3 bolts looks to have popped out and hit the case every time it’s rotated, causing it to wear away the metal and throw everything else out of whack. I’ll attach some pics and videos because I don’t know what this part is or where I should go from here but as always, your guys’ advice is greatly appreciated and keeping me afloat here!!! What is the name of this part!?! I can’t figure it out but I think I definitely need a new one.


Re: HELP! Problems in the gearbox

You might want to mention what kind of bike this is.

Re: HELP! Problems in the gearbox

Nano Vujkovic /

It’s a Tomos

Re: HELP! Problems in the gearbox

The good news is that all the parts you need will be easily found. Get it all apart and see what needs replacing. Post up a WTB in the buy/sell for the needed parts or check out the various websites like

Re: HELP! Problems in the gearbox

This is a classic beater Tomos issue. The pads on the first gear clutch (in your pic) wore out (as they tend to do on Tomos) and the previous owner kept riding anyway. This caused the clutch shoes to wear out at the pivot pin, as you can see in your pic with the one popping out of place.

Personally I would replace the entire first gear clutch, either with an NOS one or a "Jammer" from Treats. You need to examine your second gear clutch too. They don't wear out as quickly as the first gear clutch tends to but looking at the state of the first gear clutch I wouldn't be surprised if the pads on the second were gone as well. (edited)

Re: HELP! Problems in the gearbox


Start around the 2 min mark. You will definitely need a new first speed clutch and a bearing for the cover. Fortunately and should have everything you need. Just those two parts will run you about $40, so not too bad....yet. You need to take all the transmission bits out for inspection.

Re: HELP! Problems in the gearbox

campeona del mundo /

wow. the clutch side crankshaft support bearing has completely failed and the inner race has separated and stayed on the crankshaft.

this is a really, really beat engine. I wouldn't think about doing anything until you fully disassemble the engine and properly clean and inspect every part. more likely than not, you'll need to replace most of the internals if it has been ran in this condition for any extended period of time.

honestly, you're better off just buying a good condition bottom end.

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