Hi, having problems with the tick over and running of our ty80. The bike won't tick over properly. The revs seem all over the place on tick over, itll start reving itself up or just die. When you twist the throttle and then let it go sometimes the revs take ages to drop back down. This also happens when riding it. When driving around the field, after 5 min it also bogs and then cuts out. It then wont start even with choke on. You have to wait for 5/10 min then for it start again!!! I've done all the normal things like cleaning the air filter, taken the carb apart and blown everything through and cleaned it. Also checked the float level and that's fine. The bike runs best with the pilot screw in fully, but trying to get a nice tick over with the other screw is impossible. The smallest adjustment either way either revs the nuts of it or kills it!!!! Just at a loss where to go from here. Any help would be brilliant.

by what you are describing it sounds like its pulling in air from somewhere,possibly crank seal does it run any better with the choke on whilst riding?

cheers ash

i think the same are there and splits or cracks in the inlet manifold

Ok, update on the bike!!! Went to start it this morning to tinker and see what happened leaving choke on and it wouldnt start. After kicking and kicking it it did start but proceded to run on revs but with massive amounts of smoke. Then oil out of exhaust and on floor under bike coming from left hand casing. I'm assuming crank oil seals gone, but can someone just confirm this? Also, how much work is it to rebuild the engine on one of these. I have never opened up a engine before!!!!! How much around about would I be looking for parts wise? Would I be better off ebaying it under spares and repairs!!!!!! Any info help would be appreciated.

Edited December 27, 201213 yr by bowellsyboy

Hi

crank oil seal isnt a big deal, but it needs some experience and tools.

The failure you describe could be the clutch side oil seal (is this the LH side?). This fits the air/oil leaks scenario.

The parts for this are probably around £10 plus some gaskets if you rip one (likely).

There is a TY series Haynes manual that covers the 80 (fairly sure). Do you have someone experienced that can help you?

Dom

you can verify a primary drive side crank seal failure by draining out the gearbox oil and measuring the oil quantity compared to what went in. I would say from your symptoms there is little doubt that it is the drive side crank seal failed. A motor mechanic would take about 30 minutes to an hour to change that seal. Parts required are the seal and a clutch cover gasket. If you don't know the bikes history I would buy the crank seal for the other side too while you are at it.

Thanks for the info guys. Just rang my local trials shop and spoke to them and they said they would do the crank seals and bearings if need doing. Hopefully that will be everything that's wrong with it. I assume that's why the bike has been running weak lately. Is there anything else I should get looked at while it is in?

When I just drained the oil it was quite thin and smelt like it had loads of petrol in it!!!!! Does that sound right? Cheers guys

Thanks for the info guys. Just rang my local trials shop and spoke to them and they said they would do the crank seals and bearings if need doing. Hopefully that will be everything that's wrong with it. I assume that's why the bike has been running weak lately. Is there anything else I should get looked at while it is in?

When I just drained the oil it was quite thin and smelt like it had loads of petrol in it!!!!! Does that sound right? Cheers guys

The fuel smell confirms the diagnosis.

be aware that crank bearings haven't always failed when crank seals themselves fail.

crank bearings are the next degree more complex to replace as this requires the engine out to split the crank-cases. failed crank bearings usually whine and slightly labour free revving.

worth checking before you commit to the extra spend.

Thanks for all your help guys. Ill let you know how it goes!!!!!

My son learned on a TY and still loves his, despite moving up to a Beta 80 (we still have the TY80 and a TY80 Whitehawk as well!) ...great bikes.

The only other thing I would advise is a carb rebuild kit, as the carbs are tempremental at the best of times. I'm sure I bought mine from 'Yambits' - off Ebay.

Keep an eye on electrics as well - points, condernser etc are cheap enough and worth replacing of you arent sure.

And I always carry a plug and plug spanner. Often its just a fouled plug if they dont start.

Persevere - well worth it !

cheers

John