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No compression


Budd

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Well my bike has been sitting for a year or so and when i went to fire it up there was no compression. Pulled the head off and checked the cylinders, they feel smooth, rings must have taken a shit. My question is, while I have it apart should I just throw a set of rings in it or do a big bore of some sort? I dont want to spend more than 1k or so. Its already got Trinity stage 3 porting, trinity head with 20cc domes, toomey t 5 pipes, and v force 3 reeds and cages. Let me know how I should proceed.

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Well my bike has been sitting for a year or so and when i went to fire it up there was no compression. Pulled the head off and checked the cylinders, they feel smooth, rings must have taken a shit. My question is, while I have it apart should I just throw a set of rings in it or do a big bore of some sort? I dont want to spend more than 1k or so. Its already got Trinity stage 3 porting, trinity head with 20cc domes, toomey t 5 pipes, and v force 3 reeds and cages. Let me know how I should proceed.

 

 

So it had compression before you parked it? Now all the sudden it doesnt?

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So it had compression before you parked it? Now all the sudden it doesnt?

 

Yea. Super weird. It poped a few times like it was goin to start then i noticed i could kick it over by hand. My guess is the rings collapsed or one cracked or something. Ill have to check them out when i get the jugs off.

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Yea. Super weird. It poped a few times like it was goin to start then i noticed i could kick it over by hand. My guess is the rings collapsed or one cracked or something. Ill have to check them out when i get the jugs off.

 

Well in that case rings are cheap. Slap a pair of rings in and maybe run a hone thru alil. Check your end gap and see if you got comp. Thats what I would do first.

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Well since you already took it apart a new topend is in order. Just spend the money and do new pistons and rings it is not worth the headache since you have it apart but I dont think that is your problem. I have never heard of a bike just loosing compression while kicking it over. To bad you didnt run a compression test before you tore it apart.

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Well since you already took it apart a new topend is in order. Just spend the money and do new pistons and rings it is not worth the headache since you have it apart but I dont think that is your problem. I have never heard of a bike just loosing compression while kicking it over. To bad you didnt run a compression test before you tore it apart.

 

I pulled the plugs 1 by 1 and put my thumb in the spark plug hole, the compression was weak. I out brand new top in 2 years ago and only have a few rides on it. Im goin to pull the jugs and pistons and take them to the machine shop. See what he has to say.

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If all was good when it was parked then I'd agree with the last two posters. The rings are stuck... When they sit around and the fuel dries off the oil glues them up good. That happens all the time to used pistons sitting on my bench. Bearigs will do the same thing. You'll be able to bring it back to pre storage condition without a rebuild etc.

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If all was good when it was parked then I'd agree with the last two posters. The rings are stuck... When they sit around and the fuel dries off the oil glues them up good. That happens all the time to used pistons sitting on my bench. Bearigs will do the same thing. You'll be able to bring it back to pre storage condition without a rebuild etc.

 

SO basically just remove the jugs and clean the rings on the pistons and re assemble? Your thinking th erings got glued to the pistion and thats why there is a loss of compression?

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SO basically just remove the jugs and clean the rings on the pistons and re assemble? Your thinking th erings got glued to the pistion and thats why there is a loss of compression?

 

 

Yes sir. They gum up. Pretty bad sometimes but it will clean off.

I'd spray and work the rod & wrist pin bearings while your there.

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Yes sir. They gum up. Pretty bad sometimes but it will clean off.

I'd spray and work the rod & wrist pin bearings while your there.

 

Ok cool. I figured it had to be something stupid. I did leave racegas/91 mix in there for almost a year. I might just take the jugs and pistons down as well just to get them checked before i re assemble. What would you recommend for carbs? Im thnkin abou gettin some 33's or 35's and a set of billet intakes

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Ok cool. I figured it had to be something stupid. I did leave racegas/91 mix in there for almost a year. I might just take the jugs and pistons down as well just to get them checked before i re assemble. What would you recommend for carbs? Im thnkin abou gettin some 33's or 35's and a set of billet intakes

 

Carbs need to be balanced to the rest of your setup and riding style. I'm a full out balls to the wall 1/4 mile asphalt racer. There are a bunch of good guys on the site that have similar setups to yours that can make recommendations.

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Removed the jugs and pistons. Rings are glued to the pistons. Guess the race gas gummed up from sitting. Im still goin to take them to the machine shop since its this far apart just to make sure all the clearances are up to spec and to see if the rings are good. Ill let you know how it turns out.

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