Hi Group - new member here with a new-to-me 92 timberwolf 250 that's reasonably clean, but hasn't run in several years.
Seller had just put in a new battery. It cranks over, sounding ok (thup-thup-thup) - but no spark at the plug. Took off the engine cover, surprised half cup of oil came out - have read that oil there is normal) otherwise clean and shiny in there.
Tested the resistance of the trigger coil - varies between 0.8 and 4 ohms, way less than the 189-231 ohms it should be. So I've ordered a new one.
My question is what else should I look for? I can see it could go open-circuit if burned out - but what causes a trigger coil resistance to go low?
Thanks for reading. Arby

 

Wires can short together inside the coil, so your tester hasn't as much wire to go through to form a circuit, making for a lower resistance. If resistance on the power coil is OK, I would wait and see if the new trigger coil fixes the spark problem. Probably best to clean the fuel tank and carb out if it has old fuel in there too.

 

Thanks for your post - new pickup coil is on the way - DOH ! of course it makes sense if the coil is partially shorted inside it would go low. (I'm less stupid around mechanical stuff example here )

The fuel tank is dry but dirty inside from years of sitting - will clean it out and put a Shindy kit in the carb. Reverse shifter handle is seized too. And brakes are awol.

But on balance, less daunting project than splitting a tractor. Take care, Arby

 

Update - Replaced the pickup coil - it actually was open-circuit. Has nice spark now. Fixed the front brakes, freed up shifter, replaced rear brake drum (studs loose). Fuel system is next....should be running soon.

 

The Timberwolf is alive! Reinstated the fuel supply - cleaned tank, new T & C cables, new cheap carb, etc. It started right up after not running for years. Motored up and down my street smartly - engine sounding healthy with no smoke, clutch and gears all working fine. Above half-throttle the carb is still a little goofy. But I think its a jetting issue and this little rig has a new lease !

 

Good to hear it is up and running. Those Yams seem to be pretty reliable.

 

The new carb was crazy cheap - but it ran quite sputtery above half throttle - pretty sure I found a reason - its main jet is too big. When installing it I compared them feature-for-feature - I noticed that even to my inexperienced eye the new one's main jet has a much bigger hole than the original. So today I tried reinstalling the original main jet - it fits fine and seems to work great over the full range. I'll post back if with more time the miracle turns out to be bogus.

 

8 week update: Still running strong - but there was a new issue. One day it was only driving with one real wheel - jacked it up and the right side was floppy. Took the axle nut off and found the splines in the drum center hub were worn enough to stop driving - needed a new drum.

But before buying a new one ($125) I decide to try using epoxy to "repair" the splines. Loctite makes a product 660 quick metal intended for repair of shafts and drive keys that have loosened. Some of its ads say it works on worn splines. I bought a $21 tube to give it a try.

The small tube had just enough to coat the splines in both parts. After thorough cleaning with brake-cleaner the drum was fitted back on the axle and the nut was tightened. It cures by anaerobic action - keeping the air away from it for 24-72 hours, which the tightened nut accomplished nicely. I wrapped some paper towel around the inner end of the drum so any excess squeezing out would not get on the brake shoes - any hardened debris would just tumble around in there harmlessly. It was left for 3 days to allow for a full cure.

Both wheels drive fine now. If it remains strong, great. If it needs to come apart for any reason, heating the hub to 500 F supposedly releases it. Meanwhile I'm impressed and saved a few bucks.

 

Can't see it lasting, there is an awful lot of strain on rear axle splines when you do a turn on asphalt, as one wheel is traveling a lot further than the other and the tyres have to slip. I used that Loctite on a worn Yam star wheel in the gear selector mechanism, and it worked, but tried it to take up wear in the knuckle assemblies on Honda front hubs (wheel bearings turning round in knuckles) and this was a failure in the long term.

 

Thanks for your response. I agree its a tough application for the retaining compound. On the good side the machine only gets light use, and I've bought a cheap used drum to have on the shelf if needed.