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Backfire!!

C
Jan 25, 2011
284
16
18
south lake tahoe
HELP! Frustration is setting in. :face-icon-small-fro I rebuilt the top end of my sled and took her out for a trial run. Ran great except for a pretty serious low end bog and some minor backfires. Figured jets were dirty, so I took carbs apart and cleaned em. One jet was dirty and the carb had some funk in the bowl. Put it back together and she starts, idles high(I have a PowerMadd extension that I think is the culprit of that). I can kick the choke on and the idle does drop though. But it does go right back up as soon as you turn choke off. But then I get a backfire every 30 seconds or so. If I mess with the throttle cable extension to drop the idle down it drops a little then just shuts off. I did notice that after it's warmed up, the idle issue seems to go away, but the low end bog and backfire doesn't. Haven't had a chance to take her back out today to see about the bog, but the backfires are there and almost seem to be not as violent, but more consistent. Spark plug wires? CDI? The throttle cables are brand new as well. Thanks.
 
C
Jan 25, 2011
284
16
18
south lake tahoe
would this be a sign of a clogged/dirty fuel filter or fuel intake in the gas tank? I cleaned it once, but I am seeing the same kind on stuff in the carbs. Not near as much but it's there. I've read to take tank off and dump carb cleaner in there overnight and shake a bunch of bolts around in there. Any other suggestions?
 
X

X2Freeride

Well-known member
Jan 25, 2009
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Sorry, Alot of us are into summer time mode, sled stuff kinda goes on hold for a little while.
 
C
Jan 25, 2011
284
16
18
south lake tahoe
No worries, just wanted to let everyone know what the fix was. I just can't get my spark plug wires to screw onto the damn CDI snugly.

As far as summer mode, we just got 20 inches of fresh powder!!
 

Scott

Scott Stiegler
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Nov 1, 1998
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38 pilots in stock Mikuni TM40 carbs?

I think I have 55 or 60 in my 800.
 
C
Jan 25, 2011
284
16
18
south lake tahoe
I've got Keihins with 38's. I have the air screws one full turn out. I think I finally got these wires on snug, gonna fire her up and see whats happening. I think it's gas in the PTO cylinder not burning, then blowing up cause of the spark plug problem. It's like a shotgun, I've seen the whole exhaust move from a couple of them. Last thing I want to do is blow up all the work I just did.
 

Hardass

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Troy Montana
The symptoms you describe are pointing to the pilot circuit having something in it i would clean all the jets again.Plugged pilot =low end bog you have to pump the throttle a bunch to get it going with backfiring happening soime time turning the choke on helps it?
 
C
Jan 25, 2011
284
16
18
south lake tahoe
Alright, I CLEANED the carbs, reset choke cables and sinced the carbs. Sincing carbs was weird, I had all this slack, adjusted them, then after trying to start I looked at them and they were half open. So I readjusted at that point to drop them down, and she fired right up. Spark plug wires on nice and firm, no backfire and pretty steady idle at 1600. HALLELUJAH!!! :kev:

I keep thinking we're going on our last rides, but it keeps snowing. Whenever summer does show up, I'll start in on clutches. That should be interesting.

Thanks again for the help, it is invaluable.
 

Scott

Scott Stiegler
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Yeah, they might have been stock on the 2000 700 SKS.



I am thinking that the only 700 that Mikunis in 2000 was the RMK. But, I could be wrong, it might have been 2001 that they went to Miks for the 700s though.
 
C
Jan 25, 2011
284
16
18
south lake tahoe
Cool. Well I just tried to load her up on the trailer and she wouldn't move. So I played with the secondary and that didn't help. Neighbor came over, looked at it for 5 seconds and said "Your Primary is BLOWN." So he happens to have one, replacing tomorrow and we'll go from there. It has a dark blue spring instead of white, he said I should notice more snap off the line. So, we'll see.
 

retiredpop

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Jul 3, 2001
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Calgary
Yeah, they might have been stock on the 2000 700 SKS.



I am thinking that the only 700 that Mikunis in 2000 was the RMK. But, I could be wrong, it might have been 2001 that they went to Miks for the 700s though.

They used the Keihins in 2000 on the RMK 700.
 

slash

Parts Moderator & Chat Box Cop
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Jul 22, 2008
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IDAHO FALLS 83404
ya and if you backfire them to much it will go way fat with no way to repair ,theres a seal in the jet well thats not aval from keihin !!
 
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