I have a 99 Banshee that is idling really rough. I had a motion pro twist throttle installed by 2 shops (the second shop did it correctly) The 1st shop did not drill the carbs and put the air screws in, and did not put the new caps on. When I got the quad back to my house I started it up and it back fired quite a bit because it was getting to much gas. So then I brought it to the second shop to get it done properly. (which they did by drilling the carbs and putting the new caps on). They started it up and it back fired again, and running really rough. They have been working on it for 3 days now trying to figure out why its doing that. So far the electrical, carbs, reeds, and viewing the pistons by taking the pipes off, all check out ok. Anyone here know what the problem might be.

 

I'm not sure this info will help but a rider I know had a twister put on His new Blaster by a bone head dealer and he had a similar sounding situation. It would idle but stalled when he twisted the throttle. I called another dealer right from the track we were at and the parts man said that some sort of by pass adaptor kit should have been installed with the twister. As near as I can remember, it had something electrically to do with it. Possibly that is your problem also. I ride a 97 Warrior and I've had a twister since the git-go & no problem, of course, it's a 4 stroke! Anyway you might check with some knowledgible dealer.

Cal, the Az hard packer

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[This message has been edited by hot_shoe_cv (edited 07-20-1999).]

 

I have a 93 banshee with a twist throttle and had the same problem as you.I then checked the throttle cable adjusters on top of the carbs and the locking nut on one side was loose and the cable had about a 1/16th inch of slack in it.Then I adjusted it and it ran great with no backfiring and hesitations. You should check to make sure the carbs are syncronized.If they are not the banshee will not run very well at all.I hope this helps you out.

 

Well it turns out the piston and rings where badly worn out. The funny thing is the motor has only about 40 hours on it. The mechanic told me it was a manufactures defect, and that the new pistons and rings should be here by friday. I'm just glad that it was still under warranty (3 month warranty only).

I was wondering to anyone who has bought a new Banshee, how long their warranty was?

 

When I bought my Banshee, I got an extended warranty. It was a few dollars more a month but I figured it was worth it. It is for 3 years if I remember correctly. That includes everything except new pistons, rings, etc. Things you need for a rebuild.

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Jayson Blough '99 Banshee, '97 Warrior, '96 Blaster Yes I like Yamaha

 

Well the shop thats doing the work on my Banshee, bored out the cylinders and installed new pistons and rings, after only about 40 hrs on the motor! Anyway. After putting everything back together it still ran rich on the 1 clylider. The Banshee has been in the shop for about a month now with this problem. Plus Yamaha sent the wrongs rings the 1st time out.

Can the crank be causing this problem? because everything else checks out ok.

 

One possiblilty you may suggest to the shop working on your machinbe is to check the Crankshaft seals. If the crank seals are leaking it will not run smoothly. If it is your right hand cylinder running too rich this may be the cause.

See if they will perform the six minute test on your machine. Basically what this test does is to pressurize your crankcase to 6 PSI and then time how long it take to leak down. If it takes less than six minutes to leakdown then you have a sealing problem. Then just use a soapy water solution to find where the air is escaping.

Not sure if this may be your problem but it is worth a try.

<A HREF="http://www.geocities.com/Baja/Cliffs/3856/index.html">The Wrecking Crew Quadz Page</A>

 

It's the left cylinder that is running rich. But I'm pretty sure the crank is causing this problem.

 

Well it turns out the problem wasn't with the crank at all...it checked out perfectly. They discovered that when they switched the carbs around, it started running rich on the other cylinder as well. Its been there a month now, and I'm wondering why they didn't do this test in the first place.

 

well samson...it could be a little thing like the plugs or something and the factory is falling behind on mone and they said it was something that would cost u alot...i wouldn't have brought it to the dealership.