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660 backfired and shutoff, eventually started, but now only runs full choke

4K views 5 replies 4 participants last post by  03LimitedEditionRaptor 
#1 · (Edited)
Hi! I'm a new forum user and new owner of a 2005 660, and I'm looking for some direction with a problem I encountered today.

Here's my situation:
We bought the quad last week. I put a new battery in it (gel battery, from a local yamaha dealer) and we've put about 8 hours onto the quad in the last few days without issue. Until today.

I rode for about 2 hours without issue and then was cruising down some farm roads when I had a laggy throttle response when I got on it for a hill. It righted itself after a second or two so I thought I was just a gear too high (new owner, inexperienced, just cruising, etc.) I downshifted going into the next hill (now 4th) and I got the same thing - except this time on the downhill under deceleration I got lots and lots of backfires. LOUD backfires. Alarmed, I pulled the clutch to pull over and it shut off and I coasted to a stop.

Then it wouldn't start. Sat for about 20 minutes trying to get it to start then ended up calling my father to come pick me up with his truck. So we hand loaded it on the truck and took it home.

Once in my garage (approx 45 mins later) we gave it a try and it fired right up. (yeah.) However - it would only start and only run with 100% choke.

At 100% choke it idles fine (maybe a touch high?), but is steady and smooth. No backfiring and not rough or anything. Throttling up with 100% choke has good response and seems to be perfect. Reducing the choke causes it to shut off immediately.


So now I'm looking for guidance:
Based on reading the stickies and searching previous threads, the fact that it starts/runs clean on choke but not without choke tells me it's fuel starved and most likely a carb issue.

With that being said, in my situation, does the community feel that my first step should be to remove and fully clean the carbs? Are there other items that I should be looking at instead/as well?


Disclaimer:
My existing mechanical skills are limited, but I'm a former software developer turned IT manager so I'm hoping my experience troubleshooting technical issues will lend itself to diagnosing this issue.


Thank you all in advance for taking the time to read this post and for your guidance, it will be appreciated.
 
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#2 ·
Was it just poping out the exhaust or where they carburetor back fires. Carburetor back fires can pop the carbs out of the rubber intake boots, which will cause a lean condition due to the air leak. 01 carb boots are more prone to this problem but it could happen on newer raptors if the carbs were not properly seated in the boots.
 
#4 ·
Your problem to me suggests either dirty carbs and jets or a leaking intake boot.................Cracked or popped out of place............If you do dismantle the carbs, Install #25 pilots..............
 
#5 ·
Spray starting fluid or carb cleaner around the front boots while idling... if idle speed changes you have a leak.
 
#6 ·
Slight popping from the exhaust on deceleration is normal. It needs to have a soft woofing or popping sound. If they are real sharp hard cracking in sound then your probably a little lean on the pilot mixture. The lean condition could be from the wrong size pilot jets and fuel screws, or the carbs could be dirty and blocking fuel flow.
 
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