92 750 trouble

fixerman519

fixerman519

New member
My neighbour has a 92 that he bought last winter, runs like crap and fowls recoil side plugs all the time, ( 1 piston had a hole burnt through top , recoil side when he got it) new piston in it now .Carbs didnt seem to bad ,even stock jetting ( FAT), put in 135's, and it has 47.5 pilots, still fowls plugs and sounds lazy ( no snap anywhere in the trottle), pulled the exhaust off and found no restriction,we put all new fuel lines on (when carbs where off) ,still runs like garbage,changed pieces of my good running 94 750 to try to narrow down the issue, swapped coils,carbs,exhaust. Tryed pumping in some either through the pull rope hole to see if it was a crank seal but noticed no change ( ie assuming seal is not leaking, should of reved up )It idles not to bad but just doesnt sound right,If you happen to touch throttle with in the first min or 2 you foul plugs on the right side( recoil).check for crank spin issue and see nothing. does anyone have the stator testing info? Any Ideas,I would try a CDI but the plugs on my spare 94 and his 92 are not the same. He is ready to burn it and I am ready to hand him the match ! thanks in advance for any help.
 

So..you swapped the carbs (I asume the same jetting? in each set of carbs?)..Tried another set of coils...and the problem continues to be the right two plugs....that sure sounds like either a crank issue, or CDI to me??
(considering the compression is good on that side??)

AL P
 
Yes comp is equal across all 4, carb swap was done with carbs with the same jetting,worked on a ski poo FIII that wouldnt top 50 mph and found a bad stator , but I cant find spec for OHMing this one.I also think CDI but dont have one from a 92 to try,thanks for the feed back
 
Sounds like a turned crank to me. When they turn they will turn to "late" in respects to timing. Even the slightest turn to an "out of phaze" condition will cause the symptoms you describe. What did you do to check this possibility?

Phil (opsled)
 
we did it a little primatively, 2 pieces of steel same lenght in holes to see the total movement, then one in oposite firing holes to check that way , ( only by eye ) so there is room for error , when the cranks go out of phase I thought it needed abuse/ quad pipes,sinking under water etc, is it common to happen to a motor that has not been messed with or modified,,the sled was owned by a 50 year old that keep it TOTALLY STOCK,he did like to run the nuts off of it on the straight aways, but nothing to serious
 
Here is an old post of mine on the issue. If done with a little precision in mind it should answer the question.



Remove your plugs and recoil. Then find TDC on # 1 ( a dial indicator is best but a straw through the spark plug hole should get you close enough) and make a mark on the recoil cup with a corrisponding mark on the crankcase. Repeat the process with 2-3 and 4 cylinders each time making another mark on the recoil cup in line with the original crankcase mark. When you are done the marks on the recoil cup should be 90 degrees apart on a stock engine. If the engine has been 180'd the 1-4 marks should be together and the 2-3 should be together and at 180 degrees from 1-4.



Hopefully this is not your problem but it is an easy check and if it is will keep you from pulling your hair out looking for something else.

Good Luck, Phil (opsled)
 
opsled...he could also use the nut on the end of the stator in the center of the cover for the marks correct?

that way, he would`nt have to remove the recoil..

AL P
 
AL P said:
opsled...he could also use the nut on the end of the stator in the center of the cover for the marks correct?

that way, he would`nt have to remove the recoil..

AL P
Click to expand...


Yeah Baby, you can use your nut too. The only difference is diameter in relation to accuracy (the larger the degree wheel the more accurate it is). The cup is larger than the nut (almost sounds pornagraphic don't it and maybe nuts are bigger at your house Al) buuuut unless you have a larger nut than average your reference marks should be more accurate with the cup. All BS aside if the nut works for you it works for me:moon: :tease:.




Phil (opsled)
 
Crank spun, ,Ah needed something to do anyway !!! not enough snow here yet anyway. Thanks applecider, you sled sounds great !
 
Iantomasi will index and weld for @ $150 Canadian ( as long as bearings are good) thought that was a great price, expected $300-400
 
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