twinsted crank, or oddly failed MSD enhancer?

Big Kahuna

Administrator
Location
Tuscaloosa, AL
it doesnt "just happen" there has to be a reason



never heard about this happening to a yamaha twin....







now, a polaris triple...maybe..

It does "Just Happen". It can happen if you jump out of the water with the motor pinned and the re-entry can act like a brake. Rare for this to happen but possible. It can happen from sudden water injestion just to one cylinder. I have seen it happen on 550's before. You could even have a violent sudden seizure and the sudden stop could do it and have the piston unstick it self.
 

Mouthfulloflake

ISJWTA member #2
Location
NW Arkansas
I do not think the starter is bad.

and I have not had time to check BDC and TDC yet.

the engine turns over freely by hand with the plugs out, and the coupler disengaged.
no odd noises like that, and it feels as smooth as any other yamaha twin ive touched.
 

Matt_E

steals hub caps from cars
Site Supporter
Location
at peace
It was twisted about sixty degrees between the first and second rod. Perfect other than that, a real shame.
 

Mouthfulloflake

ISJWTA member #2
Location
NW Arkansas
60 degrees?! holy crap, yeah I think that would prevent a twin from running.

thats my bet at this point, I should know by this evening, leave work, grab beer, drive to lake, and play yamaha mechanic on the rocky shore!
 

Matt_E

steals hub caps from cars
Site Supporter
Location
at peace
You don't need to drive to the lake to do that check, but if it makes ya feel better....:biggrin:
 
It does "Just Happen". It can happen if you jump out of the water with the motor pinned and the re-entry can act like a brake. Rare for this to happen but possible. It can happen from sudden water injestion just to one cylinder. I have seen it happen on 550's before. You could even have a violent sudden seizure and the sudden stop could do it and have the piston unstick it self.

I think you just proved Idok correct... "just happen" would be riding along and it just happening, not jumping and landing wide open causing it to happen, right?

he he, sorry, but I could not resist.
 

Mouthfulloflake

ISJWTA member #2
Location
NW Arkansas
in2,

check Exhaust, its flowing, I held my hand on the starter and the output at rear of hull, its flowing alot of air to NOT be running..

Matt-E,

T handled allen wrench ( that I adjust b pipe screws with)
I bottomeed each one out, and the topped each one out, the look same, or very close by eye.. within a mm or so at least... ( given my old ass eyes)
 
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