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Old 12-11-2018, 12:58 PM
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Default 2002 Raptor 660

     

Hi, y'all... I'm quickly remembering why I hate working on quads and could use a little help here:
Symptoms: I'm dealing with a 2002 Raptor 660. It starts great, has nice throttle response, but it absolutely falls flat on it's face at mid-RPM. It sputters, backfires, and makes no power. I also ran it with the carbs open (no filter, tubes, etc.) and noticed the vacuum operated slides are fluttering. I'm unsure if the fluttering is causing the misfire or if the misfire is causing a fluctuation in vacuum, therefore affecting the slide action. I suspect an electrical issue since no carb adjustments (running it with the choke on, needle adjustments) made any difference.

History: The quad was brought to me because the guy bought it running, took it out for a ride, and the bike died out on the ride. He brought it home and it wouldn't start and was pouring fuel all around the carbs. It has an aftermarket exhaust and a well-overdue-for-replacement K&N air filter.

What's been done: I cleaned out the carbs as best as possible. A few screws were stripped on them so I avoided them. However, upon reassembly, they were still dripping and I could tell it was from the pipe that connects both carbs together. I had to get a little aggressive with some vice-grips, but eventually was able to fully disassemble them. I installed new orings on that tube and found that the RIGHT carb's diaphragm had been pinched at some point. It did seem to seal up fine though, so I ran it.
I also looked over the connections at the CDI and noticed a few wires had rubbed through. I had to cut one and place a butt connector on it because there was little to nothing left on it (If I recall correctly it is a white wire with green tracer). The others didn't look quite as bad and just got a dab of liquid electrical tape to seal them up for the time being. This resulted in no change in the way the bike runs.

What's pending: I'm going to check the jetting and make sure I didn't mix up the main jets (they use a different size on the right and left carb) as well as blow through all the carb passages again. I'm going to check and set the valve clearances, but don't suspect that because the bike starts up very well and runs great at low rpm.

I've read almost every thread I could find on this issue (which seems to be quite common for this quad) but they rarely converge on a solution. Some are saying a replaced CDI did the trick, others a new spark plug, others eliminating some of the built-in rev limiters (parking brake and/or reverse).

Anyone willing to give me a fresh perspective on checking over this thing before giving up on it??
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Old 12-14-2018, 11:20 AM
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I messed with the diaphragms on the slides a bit and it improved. So, I tore into them in detail last night and found a pinhole in each one (on top of one having been pinched in the past). I sealed them up with a touch of silicone for testing purposes. I used quite a bit of grease to get them to hold in place during assembly too, and the quad seems to be running better. A light bit of hesitation at mid-rpm (most likely richer jetting is in order), but it manages to rev out and pull nicely. It did this once before and then when I reassembled the body work the symptoms came back... I hope it stays behaving now.
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Old 12-16-2018, 11:32 PM
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Hopefully that took care of it for you!
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Old 12-21-2018, 08:21 PM
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Nope :/
The symptoms came back, even replacing the diaphragms I'm going to go through the carbs one last time and run it without the airbox (since that's how I tested it when it ran fine) and if it still runs poorly I'll have to quit on it.
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