Over the weekend our 01 quad runner 500 4x4 started having a problem and I would like some opinions before I start ordering parts. The bike ran fine one day then the next day it wouldn't rev all the way, only to about half throttle. first I thought it was a gas issue so I drained the float bowl and cleaned it and added some sea foam and fresh gas to clean it out. After trying some other things the problem would come and go so I started looking at electrical connections. I had the throttle pinned in fifth gear and the engine ran like it had a rev limiter and wouldn't break 30 mph. Then I turned the ignition switch to the lights on position and it jumped up to 50 mph, like a switch I could hit the "rev limiter" by turning the key from run to run with lights on. Should I just buy a new ignition or could it be the coil or voltage regulator?

 

Sounds like the voltage regulator. It will fry your CDI and any other electronics if you don't get it fixed right away. Check by putting a voltmeter across the battery with the engine running. Start raising the revs, you should not get more than 14.5v. Over 15v and you need a new regulator.

 

Thanks for the info. I thought that the odds of the ignition switch going bad was unlikely. I can't test it right now cause it is in the garage at my parents cabin but I will post when I do to help others out if this happens

 

My dad just called after he was done testing it and he said the voltage would jump all over. He said at one time he saw over 17volts on his meter. Thanks merryman. I have a new one coming from amazon already.

 

I changed the rectifier and stator on my 500 Rubicon and it still doesn't charge, I've checked all the fuses and wires I don't know what to do now,??

 

Putting this in a post about overcharging Suzukis is not the best place.

Anyway, either one of your new parts is a dud or there is a wire with a high resistance between regulator and battery. I once did the changing stator because a new reg didn't fix it, on a Foreman 500, right pain with having to take the rear end off to get at the alt case, and still no charge. I had tested the red and green wires with a voltmeter first and got 12v but, after fitting the new stator and still no charge, checked the red and green at the regulator using a high wattage 12v test lamp, got a very dim light. Then found a hairline crack in the insulation on the red wire and, on pulling the wire, found about 1/8" of wire inside had turned completely to verdigris. Have always tested those wires with the test lamp since then, as you need to check you can get power through them, not just volts.

 

Ok so I got a 98 quadrunner 500 and it was doin the exact same thing; at first wouldn't take gas due to a vacuum issue in the petcock. So I replaced it, new lines, completely took apart the carb and cleaned it; and still the same problem. I put a brand new voltage regulator on it but I'm still having issues with backfire. When I first got it I didn't know the original regulator was shot and shorting out off the frame an I ran it for a few hours like that. All my fuses are still good. Do I need a new CDI box? An will that fix my backfiring issues?

 

Change the plug and clean the carb out. Once you have eliminated the obvious, you can start looking for more complex reasons why your machine doesn't run right. Backfiring can be caused by an air leak into the exhaust too.