1998 vmax 700 missfireing

Y

yamaha06

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Joined
Feb 1, 2009
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28
Age
36
Location
Canada
Alright well this sleds been giving me some trouble this year, iv never had a problem with it at all until the start of this year, first time i go to take it out it wont idle unless choked so we ended up taking it in to the dealers and they cleaned the carbs and changed the seals in them and set them back up, it ran perfect for an hour and now when im riding il get it up to 60 km/h and it will be very hesitant and just start back firing out of the exhaust and it doesnt have much power, but if i stop and turn the sled off then restart it, it runs perfect again so i took the center coil off and the dealer tested it and it was shot so i got another one put in on and the sled ran amazing for like 3 hours and now its doing the same damn thing, could it be one of the other coils gone now? or does anyone have any other ideas, im not sure if i could be that TORS switch or whatever because its hesitant but if i put it the the bar it will move. . . so thanks for any help
 
my buddy has the same sled and the plug he was running were br9es he changes to br9eya and didnt do the back firing again
 
Ya im running br9es plugs in it right now, maybe il have to change them and try that, and the tors, i think iv bypassed it right just unhooked the the connecters from the carb and connected them to eachother.
 
well i havent got around to taking the coils into the dealer to get them checked out yet, but i might try a different plug first and see how that goes, im not sure if anyone had anymore ideas? thanks
 
Its a long shot, but if your toasting coils...could be a problem with the voltage regulator/rectifier. Thats a problem on some motorcycles as extreme temp changes can damage them causing a fluctuation of voltage coming out. Just adding my two cents, but I you will have to do some troubleshooting to narrow down.
 
Oh and disconnect the TORS...I had to on my 97 and it fixed the fouling issues. If the dealership didnt reset it after cleaning them, they wont work...and from what I hear they are a pain on these year yamahas to get dialed in
 
Ya i disabled the tors last night and went to put some new plugs in it, and noticed that the plugs looked a little milky, so im probably going to have to replace the head gasket now, and maybe that will solve my problem?
 
Yeah, dont run it again until you find where the coolant is leaking in. Could be a head gasket, or base gasket. If those check out it could be a leaky pump seal in the case. Coolant will seize your engine fast though if its leaking in...I would go as far as tearing it down to the cases to make sure there is no coolant still hiding in there. You dont have to split the cases, but if you see evidence of coolant flush them out thoroughly.
 
alright well iv got an update, i took my coils to the dealer and they are all shot so im going to need all new coils which pisses me off since i just spent $90 on a brand new one 3 days ago so now i need 3 new ones a 90 a piece then to make matters worse they figure my cdi box could be junk causing them to burn out which is 500 to replace and for my head gaskets those were about 50 a piece and i need three and for my other gaskets that come out to about another 50, so its not a good situation to be in since im a college student who doesnt have that kind of money to blow after iv already but 500 into it this year. Iv never had any problems with this machine and have had it tuned every year so this is like a blow to the nuts lol, im not sure if anyone knows a cheaper place to buy any parts?
 
You can find a lot of the parts you mentioned on E-bay for a lot less than what you mentioned. Just need to keep in mind that most are not new.
 
Help has arrived.

I have a 01 700 sxr. This year many of the same problems. Check this 1st. Have they really cleaned the carbs. Pull carbs, pull floats and needle. Under the needle valve is a small screem. Mine were all plugged not allowing full fuel flow. Problem solved.

I have three new coils. It wasn't my coils. I ordered a stator and will not pick it up but may need to pay return charge.
 
ya the carbs are cleaned good the dealers did them, they said the coils could be shot if you checked the spark and didnt have them ground out good, but they put them on there coil tester and said there junk, is there anyway to test your cdi box to see if theres anything wrong with it? Another thing is about the gaskets, whats an easy way of telling which ones you should replace if your plugs are milky, i havent worked on a sled much but iv got alot of experience with quads
 
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what do you guys think would cause all three of my coils to be junk just like that, im not sure what would cause them all to go at once like that, the weird thing is the dealer says there junk with no spark but the sled runs perfect for a little bit before it starts acting up and missfireing like that
 
Thats really strange...Ive never seen 3 coils fail at once...and only a couple CDIs fail. I know you can find junkyards that have a lot of that stuff at a fraction of the cost. But I would get a second opinion on the coils if possible. Test your stator and Voltage regulator with a multimeter to start.
 
Who Knows ?????

:homework: I'll give you guys' some insight on something interesting.This sight is great for anybody with sled problems, but it does not say anything about personal problems!!,meaning that if you read threads about sled problems a lot lead to the owners not diognosting the problem properly! I just had an incedent with my 600 on a spark issue also.I noticed that a lot of guys get there coils,stators, etc. checked if by a dealer or the person himself and they turn out bad and a guy goes out and buys expensive parts to replace and finds out later he doesn't have to replace a lot of the stuff.If a mechanic doesn't know how to read or work testers or the owner himself how can you test parts?My 600 had an issue with the pto plug bieng damp with gas,I had very weak and no spark on the plugs(3)when I checked them.I did all the test myself for resistance,then got my mechanics at work to do the same,two different ohm meters acted different giving simular readings.Now the catch here was that all tested well but my BLOODY caps.I don't know how this engine ran because there was no current flow through them!!The insides were not allowing contact to the plug,I had very weak spark and wondered why the exhaust popped once in awhile on the trail,also why the exhaust was rich smelling.For $20.00 she runs like new again and all 3 cyl. are firing properly.Plugs are dry and colored buetiful.Again go to the weakest link in your systems,start from the plugs work back to the stator etc. it's cheaper this way!! Sorry for the long thread but it might help out......
 
alright il give it a try, do you think you could give me a brief description on how to check the stator and voltage regulator and what kind of readings i should have ? thanks
 
KAPUSTA said:
:homework: I'll give you guys' some insight on something interesting.This sight is great for anybody with sled problems, but it does not say anything about personal problems!!,meaning that if you read threads about sled problems a lot lead to the owners not diognosting the problem properly! I just had an incedent with my 600 on a spark issue also.I noticed that a lot of guys get there coils,stators, etc. checked if by a dealer or the person himself and they turn out bad and a guy goes out and buys expensive parts to replace and finds out later he doesn't have to replace a lot of the stuff.If a mechanic doesn't know how to read or work testers or the owner himself how can you test parts?My 600 had an issue with the pto plug bieng damp with gas,I had very weak and no spark on the plugs(3)when I checked them.I did all the test myself for resistance,then got my mechanics at work to do the same,two different ohm meters acted different giving simular readings.Now the catch here was that all tested well but my BLOODY caps.I don't know how this engine ran because there was no current flow through them!!The insides were not allowing contact to the plug,I had very weak spark and wondered why the exhaust popped once in awhile on the trail,also why the exhaust was rich smelling.For $20.00 she runs like new again and all 3 cyl. are firing properly.Plugs are dry and colored buetiful.Again go to the weakest link in your systems,start from the plugs work back to the stator etc. it's cheaper this way!! Sorry for the long thread but it might help out......
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Ya i have already checked all the weakest links in the system
 
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