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Discussion Starter · #1 ·
Hi guys, Not sure but maybe someone can help me.
I have a 81 el'tiger cat 6000 500cc liquid. The sled runs great when you first start it up and let it reach normal operating temp and then take it out. It has all the power in the world when you first start out. After about 15 mins of normal driving there is a noticeable loss of power. At the start full throttle would work and it would run great. After about the 15 mins it would decrease to about 3/4 throttle and the rest of the way it seems that it just floods or bog out. This continues to the point that the machine wont even move or idle and shut off. Some say it is compression, so I changed the rings and pistons. All new gas lines thinking air could be getting in somewhere.
Not sure if its possible that the jets are not set right? It seems to have something to do with the temperature. When its colder out side I can drive it for longer before it starts to loose power.
Some say its possible that the seals are gone on the crank case and that is causing it? Im running BR8 plugs.
Any help or idea would be great.
Thanks
steve
 

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theres a number of things you could try, first off you could try Br9 plugs, maybe it would help i don't know but maybe. Where do the carbs draw air from. maybe when the sled warms up they draw warmer air. check that out first.
 

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Did you try checking your fuel pump presssure, and the hose from the crankcase, it may have a crack in it. Also did you check the
vent in your fuel tank. If its blocked , it may be causing a vacuum
and starving the engine form getting fuel. Did you check the plugs
when it stops running. Are they wet or dry?
 

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Br8 plugs are to hot for that sled. Acrtic tells you to run 10's, I
wouldn't run anything under a 9, depending on your main jet.
My second sled is a 84, 6000, and I have 370 main jets, running
9's. Plugs look great. 10's are a little cold for it.
 

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Could be the crank seals. I have seen that before. How long does it have to sit before it starts and runs again? I have to go with the the gas tank vent too or maybe the fuel pump/impulse line. 81 had CDI ignition I think. Maybe the CDI box is breaking down. Does it have spark when it dies? Pull a plug and pull her over when it stops and see if it is firing. If it is, then fuel is the issue. If the plugs are dry and firing my next stop would be to pull a fuel line and see if there is any fuel in it. A dry plug can be either a bad pump/line or crank seals since the impulse for the pump is effected by the crank seals. The fact that it only does it after it warms up makes me lean toward the seals. The best of luck with her and keep us posted!
 

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Discussion Starter · #6 ·
Plugs are wet

Hi guys, Thanks for all these ideas.

Heres some more info
I got wet plugs and spark once and a while. i change plugs and seem to always get spark. Plugs get to hot and not fire? We have changed the diaphrams in the pumps. And all new lines from the pumps and crank and inbetween the filter. The lines to the tank appear to look good and hold preasure when you blow into them.
It Starts on the second pull with choke after sitting there for alittle while. Then it idels great.

The set of plugs i had in it wouldnt spark so i put in a brand new pair and they sparked but i still didnt have top performance. i cant quite tell if its flooding when im driving or not geting enough fuel or if the plugs aret geting any juice to spark?
Its been fairly warm out and im running 9's in it but i remember now that the guy I bought it from said he would run 10's on realy hot days. Thats something Im planing on trying out.

Im thinking it could be a mixture of bad plugs with some kind of carb problem.
We have changed the coils inside.CDI? i guess they would be the High and low? It wouldnt start before that at all so that seemed to change it, so i wouldnt think it would be the CDI now.

The fuel lines have bubbles in??? whats up with that. The bubbles are right before it goes into the vaccumes. so Im thinkin that its sucking air some where before that, in the tank area. Im suspecting the bubble are a bad thing. :)

I have been fighting with this sled for the last 4 or 5 years. Changing this and that trying to pin point the problem.

Plan to get some 10s today in town.
Its another great day out so happy sleding
Thanks
steve
 

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Discussion Starter · #7 ·
Plug Gap?

Hello all
Yeah, What should the correct plug gap be? on a 9 or 10 plug. 81 Cat 500cc 6000
Ive been just taking them out of the package and stuffing them in. I found a old pair of 10s from the previous owner and the gap is quite a bit smaller then the ones that I have been using
How much resistance should there be on a plug when you check it with a Multi-meter?

Took it out for a drive all morning after puting in a brand new pair of 9's and it seemed to run great other then there was still no top end like there should be.
All for now
thanks
steve
 

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in the manual for my 78 eltigre it says to run a plug gap of .020 for both the 440 and the 500, not sure if this applies to the 81 but i figured id let you know
 

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Discussion Starter · #9 ·
Gap was the Prob. :D

Man that sure made the world of difference. My gap was about .028ish before and I put it down to .22 and it sure changed every thing. Had full throttle power with no trouble geting there.
Only trouble is now ive somehow over heated it and blew all my antie freeze out. Could this because of to warm of plug runing to warm? its a Br9.

Also i managed to some how crack a peice on my clutch so ill be fixing that.
Is there a point on a clutch that u can push it to far to have it crack?
These things are a never ending nightmare.:mad:
Thanks for the Gap info
 
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