'97 700SX motor grenades @4,800mi. ..crankshaft

If the mechanic had the head off he would be able to see a lean burn down. So if he did't see that, that is why he is saying it is a crank failure. The 97s had utilized a crank bearing on the magneto side that often failed. That is why they redesigned it for the 98s. Mr. Viper is one of the best, go with his advice.


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Devilin AblueDress! said:
A piston seized from a lean burn down (other thread supports you were lean) would lock engine up. His conclusion you need a replacement crank based on he took the head of is a stretch in my opinion. Just pulling the head there is no way of knowing what is going on in the bottom of engine.
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dblshock said:
How should I mention this to him now that he's made a conclusion?
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He is possibly seeing no piston or cylinder damage, so is assuming that the crank is the problem- which may be true, but you need to at least see the crank and what is wrong with it (if anything), and just tell him that. Tell him you have been asking for advice and you would feel better about making a decision if you knew exactly what is wrong. The crankcase may be damaged and that needs to be known. At the minimum the cylinders need to come off and possibly you will see all that you have to then. If not, the crank may have to come out.

Another option if the crank is bad is to have it repaired.

Improper storage can cause rust, and crank bearing failure.
 
PZ 1 said:
He is possibly seeing no piston or cylinder damage, so is assuming that the crank is the problem- which may be true, but you need to at least see the crank and what is wrong with it (if anything), and just tell him that. Tell him you have been asking for advice and you would feel better about making a decision if you knew exactly what is wrong. The crankcase may be damaged and that needs to be known. At the minimum the cylinders need to come off and possibly you will see all that you have to then. If not, the crank may have to come out.

Another option if the crank is bad is to have it repaired.

Exactly my point. If crank is bad motor has to come out any way. Personally I like to look at it BIG PICTURE after stepping back and looking at the whole situation. Instead of thinking this, then that and then the other thing. If it were my sled my plan would be to look for an entire motor. If you find one from another single bulbed sled (dual bulb hotter electronics) try to get the whole motor (re-coil/flywheel/flywheel/stator....pretty much everything but the carbs) the few extra bucks you spend on these parts you don't exactly need at the moment will save you about the same bucks paying mech to swap your stuff over and you end up with spare parts. Plenty of threads here how to tear stuff apart.
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o.k. anyone, what years were the single bulbs and better bearings 98-XX?

That sounds like the best bet for me.
 
98-03 or whenever they stopped making the red heads, it doesnt matter if its the single bulb or dual bulb as all they changed was the flywheel for the 300watt dual bulb system, so you can use the dual bulb year engine and reuse your 175 watt stator and flywheel on it, the case interchanges as does the crankshaft, no problems.
 
What's left of the sled is in nice shape, just rebuilt the oem ski's with new skins, paint and Bergstrom triple skegs/ski savers..dealer has a guy offering $600..think I'll take it and soldier on.
 
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