I've been sitting on this one for a bit but finally was able to start putting some time in on it. This will be a bit a project over the next few months to get finished, hopefully we can get a few rides on it before seasons end and figure out what bugs need to be addressed over the summer. The objectives here were to show my nephew some experience and mechanical skills as he's shown an interest in this type of stuff, build a lightweight sled that won't be a handful and isn't going to break the bank, keeping the power reasonable for him on his first project, and also turn out something unique that's a bit of tribute to the old skool cool mod hillclimbers that broke trail for the mountain sleds of today.
History - I picked this sled up for $200. It had been sitting for about 8 years and the owner was a good guy and was totally honest about its condition. He said it had lost a cylinder, and he never spent much time looking at it, it was easier to buy a new sled so he did. So we brought it home and cleaned it up well enough to get it running for dianostic, had compression, had spark - so this gets you scratching your head.....Cleaned all the carbs, gave her new plugs and fired it up - it ran........but clearly not well. Showed the nephew how to start diagnosing what could be the problem and it was pretty evident as we started spraying ether down the PTO side what was going on.
The phenolic (plastic) bearing cage puked itself into the PTO crank seal, but lulckily it did enough major damage instantly to the seal that it wouldn't let the PTO side fire, which likely saved it from slowly failing, air leaking and leaning out and then burning up. So, checked the crank run out and surprisingly it was good. So the motor came out, checked all the other components and they were in good shape. Appears that the top end had been done shortly before and although some light marks on the pistons are present, nothing else major. Measured all the motor tolerances etc and built a plan. The rest of the crank bearings seemed OK, so we re-used it as the intention is this motor may be replaced in a few months anyway.
We stuffed the crank in the freezer overnight, cooked up a batch of new crank bearings on the PTO and Mag ends and dropped them on. She got soda blasted, tanked and cleaned, all new seals and chased all the threads. She got some love in the porting dept and the head is getting a shaving.
She's almost all back together, just waiting on the new carb boots (old ones were cracked). I've got a track and skid that we will use but its going to need a different track eventually. Eventually it will probably get a drop and roll but not likely before the end of this season.
Up next the chassis work will start in a week in or, and I'll post some pics as things progress. Stay Tuned.....
History - I picked this sled up for $200. It had been sitting for about 8 years and the owner was a good guy and was totally honest about its condition. He said it had lost a cylinder, and he never spent much time looking at it, it was easier to buy a new sled so he did. So we brought it home and cleaned it up well enough to get it running for dianostic, had compression, had spark - so this gets you scratching your head.....Cleaned all the carbs, gave her new plugs and fired it up - it ran........but clearly not well. Showed the nephew how to start diagnosing what could be the problem and it was pretty evident as we started spraying ether down the PTO side what was going on.
The phenolic (plastic) bearing cage puked itself into the PTO crank seal, but lulckily it did enough major damage instantly to the seal that it wouldn't let the PTO side fire, which likely saved it from slowly failing, air leaking and leaning out and then burning up. So, checked the crank run out and surprisingly it was good. So the motor came out, checked all the other components and they were in good shape. Appears that the top end had been done shortly before and although some light marks on the pistons are present, nothing else major. Measured all the motor tolerances etc and built a plan. The rest of the crank bearings seemed OK, so we re-used it as the intention is this motor may be replaced in a few months anyway.
We stuffed the crank in the freezer overnight, cooked up a batch of new crank bearings on the PTO and Mag ends and dropped them on. She got soda blasted, tanked and cleaned, all new seals and chased all the threads. She got some love in the porting dept and the head is getting a shaving.
She's almost all back together, just waiting on the new carb boots (old ones were cracked). I've got a track and skid that we will use but its going to need a different track eventually. Eventually it will probably get a drop and roll but not likely before the end of this season.
Up next the chassis work will start in a week in or, and I'll post some pics as things progress. Stay Tuned.....
