80' Trailfire 440 rebuild! Advice and opinons welcome

[DeereKid9]

They will come exactly like you need them. It might be a generic picture.

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[deerehunting]

ok thanks

[Matt]

You are correct, Trailfire should have two of the same - if you're looking at the photo it's probably not the correct photo for the set. Should be two OS1302R 30x62x10mm.

[deerehunting]

You are correct, Trailfire should have two of the same - if you're looking at the photo it's probably not the correct photo for the set. Should be two OS1302R 30x62x10mm.

Ok thanks Matt.

[deerehunting]

Ok so I've pulled the engine apart, I knew the pto cylinder, head, piston, etc. Were no good, but now that I've got it apart the mag side seems to be in pretty good shape, the cylinder is like new, piston is in good shape, so I'm ok there. Now my first question do you guys recommend replacing both pistons, or do you think I would be ok just getting rings for the good piston and reusing it? Next question is on the crank, the very center bearing on the crank (the one with the dowel pin to hold it in place) Is I supposed to have any play in it? Also how much if any play is allowed on the other bearings. Last question on the o-rings for the crank, how are you supposed to get them on the center bearings the last person to work on it cut them and put sealant on the cuts, is there a better way or is this ok. As I've said in new to this so I'm sorry if these are stupid questions, but I want to do it right. Thanks,
Matt

[JDT]

No stupid questions yet.

The o-rings stretch over the rods and journels.
Soaking them in hot water will make them more pilable.

If you had good compression on the mag side you may not even need rings. Close examination and checking end gap is important. Use your own discretion.

Bearings should not have much play. If they are all about the same you may be good to go. If one is worse or noisy or sticky than it may be time to renew them.
The bearings on the side that melted down need very close inspection as tiny pieces of your piston may have found there way inside the bearings and that is never a good deal.

After you have thoughly cleaned the crank assy turn each bearing slowly and in both directions several revolutions and base it's conditions one what you feel and hear.

If you have no gouges in the cylinder wall and only some aluminum deposits you can clean that off with some muratic acid followed by a good rinsing with water and than coak with light oil.

[deerehunting]

Ok it seems like the center bearing is way too sloppy the rest seem ok, I've already talked to dustin so if I have to I can get another crank, but I would like to reuse this one I'm gonna clean and check the crank over tonight. They center bearing seems different than the rest that's why I ask about it. I'm not sure about the compression as the bad piston was seized, I'll investigate the cylinder and piston specs tonight, it just seemed to me that old rings and new ones together would make a difference in compression between cylinders correct me if I'm wrong though.(still learning) Thanks Todd for the quick response.

[JDT]

Stop the presses guy....

[JDT]

A moment of clarification here.

There are two center bearings.
And between them is a seal. aka center seal or labyrinth seal.

This seal is suppose to wiggle a little.
The bearings on either side should not.

Your crank has 5 bearings, two outside seals and one center seal.

[JDT]

As for potential compresssion differences if the rings were worn it may have lower compression. But used rings don't always mean poor compression.

[JDT]

And be aware that new rings often test lower compression until they seat in with some run time logged up.

[deerehunting]

Ok thank you once again Todd, that makes me feel better the 5 bearings are good, the rod bearings are good, and I have new wrist pin bearings coming, it was just the Seal that I was questioning, it seemed odd as it had the pin to hold it and it seemed to be aluminum. Thanks again ,
Matt

[deerehunting]

Do the winderosa full gasket sets come with the crankshaft o-rings? It says o-rings if needed but not sure?

[DeereKid9]

No, but you can purchase those from newbreedparts.com too.

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[deerehunting]

Thanks that is what I figured.