86 G1 complete rebuild, frame off

[daveswaves]

Update on the rebuild. Manufactured a cluch puller pic to follow. Pulled the clutch and the mag side apart to look at the seals. I expected to see damaged seals, but in fact, both looked new. As a test, I filled the crankcase with varsol and rotated the crankshaft. The varsol literally poured out of both sides. Granted, the clutch side was worse but the flywheel side was leaking too. Both seals will be replaced. The bearings appear to be in excellent shape but I will know more when I get the case halves separated.

[daveswaves]

Heres a pic of the clutch side seal and a pic of the clutch removal tool. The tool was made from a 14mm spark plug, drilled out to fit the shaft in. Then the shaft was sized lengthwise for the depth of the clutch housing and then welded onto the spark plug top. Pulled the clutch handily. Cost, old parts from the shop and a coffee for my friendly welder.

The seals on both sides were separated from their lip. The lip was intact and still on the crankshaft. The outside of the seals showed no visible signs. The varsol proved them wrong.

[daveswaves]

Originally Posted by sho305

I could hardly get advance on the plate I worked on that for a while. I also worked on the exhaust port tried to make it 0.5mm higher approx. I sanded on it for around a week every time I walked by it lol. I doubt it cut much out but that cart ran really well. Lots of powerslides/donuts with it.

Why the trouble with the advance, slots not long enough or could not loosen the phillips screws??

[daveswaves]

Any body have the info on the attached, eg exhaust open in degrees, intake open in degrees. I should have put a degree wheel on it before I dismantled

[sho305]

Originally Posted by daveswaves

Why the trouble with the advance, slots not long enough or could not loosen the phillips screws??

Could not turn plate far enough, I hogged out the slots or whatever hit and got it moved just enough to help. It was a little doggy in reverse after that but it helped in forward, reverse still moved cart fine it was not that big a difference. I don't recall how/if I measured it, guessing I had a timing gun on it but forget.

I got the screws out ok.

I don't know how one could have detonation in good running condition, the compression is so low and the porting so mild.

Wow, great clutch puller now that is serious DIY Good job on that one. I had a machinist lathe me one out.

Some have used one of the pipes off a banshee quad. You can buy a yami bravo sled its a 250cc and adapt the ignition plate to it. With the sled pipe it makes good power compared to stock G1 and it fits right in there except the pipe needs mods to fit.

[daveswaves]

Originally Posted by sho305

Could not turn plate far enough, I hogged out the slots or whatever hit and got it moved just enough to help. It was a little doggy in reverse after that but it helped in forward, reverse still moved cart fine it was not that big a difference. I don't recall how/if I measured it, guessing I had a timing gun on it but forget.

I got the screws out ok.

I don't know how one could have detonation in good running condition, the compression is so low and the porting so mild.

Wow, great clutch puller now that is serious DIY Good job on that one. I had a machinist lathe me one out.

Some have used one of the pipes off a banshee quad. You can buy a yami bravo sled its a 250cc and adapt the ignition plate to it. With the sled pipe it makes good power compared to stock G1 and it fits right in there except the pipe needs mods to fit.

The detonation can happen with an extremely lean engine at high speed. This engine was not a good running engine. I suspect it was held at WOT till it finally died. The crank seals would be sucking air. It also got hot judging by the TAR in the intake . The oil pump was bypassed, lots of things could have happened, straight gas no oil, last run with a case of beer in the farmers field
As far as the pipes go I have design software to make a pipe and tweak the dimensions to fit the cart space. The software creates templates for cutting the pipe pieces then its weld em up.

If I can find a Yammie 250 engine I may go that route and rebuild it instead of the 215.

[sho305]

These things are a million years old too with little to no service, certainly built like a brick.

[daveswaves]

Originally Posted by sho305

These things are a million years old too with little to no service, certainly built like a brick.

And I found a Yammie 250, new seals, new gaskets, crappy crank. Let the switch out begin

[daveswaves]

The crank from the G1 stock engine is going into the 250 snowmobile engine. Mine is in pristine condition while the 250,s crank needs serious work. Honed the 250 today, new rings are on order. Other differences with the sled engine, it is a piston ported engine, not a reed block engine. The 250 did not come with a carb, most recommendations from the sled guys are for a 34 mm minkuni replacement. Apparently the originals were finicky on a good day.

[sho305]

Most sleds don't move until you hit 3K rpm likely why they don't have reeds. I have a 440 I could use in a cart just not sure I'd want to build one.