BannedCR500Riders.com

So i bought 01 cr5af. Yesterday i went out to a buddies private track. I have rode a lot of cr500's in the stock frames. But this is the first one ii rode that's in a 250 frame. Well let me tell ya that is the best handling bike with tons of power . I came home and decided i should do a compression test to see what it is it. Well unfortunately i was down to about 90psi. So now im tearing it all down so i can rebuild before the Hairscramble coming up. But i was so impressed on how it was on the track. Thanks to everyone on here guys.

Kevin

Compression ratings are overrated, if it starts and runs good and the piston has no cracks just run it

yea im getting ready to pull the motor out and pull the jug off of it and take a look at it. Why i have to cylinder off of it i think im going to do a little porting to it!!!!!! Why not hahaha.. But wow do i love that bike.

Just pull then intake manifold and reeds to check the intake side of the piston for cracks, if theres none then button her back up and ride

britincali wrote:Compression ratings are overrated, if it starts and runs good and the piston has no cracks just run it

yep. i never checked bone stock motor but i doubt its much over 100psi maybe 120 range. 90-100psi is more than plenty

britincali wrote:Just pull then intake manifold and reeds to check the intake side of the piston for cracks, if theres none then button her back up and ride

Yup....

8:1 is stock isent it

6.8:1 is stock but were talking about cylinder pressure

100hp honda wrote:

britincali wrote:Compression ratings are overrated, if it starts and runs good and the piston has no cracks just run it

yep. i never checked bone stock motor but i doubt its much over 100psi maybe 120 range. 90-100psi is more than plenty

mine blew 143 last time i check it, and my ring gap is huge.... 38 thousandths.

90 sounds pretty tired to me.

.008 gap ?


like i said i just guessed at 120 because i never checked stock motor before. mines at 100 and seems to run fine, i wanted it higher but i raised the exhaust port too much and miscalculated how much to mod the head. next time i take it apart ill pay more attention to what im doing. if the piston is slapping or cracked then obviously he should tear it down for new topend. but im thinking the same as brit, if nothing is cracked or slapping around then keep running it

i forgot to say everything is new in my topend. i raised the exhaust too high is why its at 100psi

south central hoon wrote:

100hp honda wrote:

britincali wrote:Compression ratings are overrated, if it starts and runs good and the piston has no cracks just run it

yep. i never checked bone stock motor but i doubt its much over 100psi maybe 120 range. 90-100psi is more than plenty

mine blew 143 last time i check it, and my ring gap is huge.... 8 thousandths.

90 sounds pretty tired to me.

It should be .004 per inch of bore yours is undersize Jeff

teemtrubble wrote:

south central hoon wrote:

100hp honda wrote: yep. i never checked bone stock motor but i doubt its much over 100psi maybe 120 range. 90-100psi is more than plenty

mine blew 143 last time i check it, and my ring gap is huge.... 38 thousandths.

90 sounds pretty tired to me.

It should be .004 per inch of bore yours is undersize Jeff

i fixed it mike...


that topend has about 50 hours on it.

Honda Service Manual:
Piston ring end gap: Standard -0.3-0.5 (.012-.020)
Service limit: .02 (0.02)
mine: (.038)

were they installed too large to begin with ? .038 is fuggin huge man, that would have me alittle nervous. you might have the wrong size rings on there maybe . i re-ringed mine not long ago, after getting the wrong rings the first time, i re-ordered the correct ones and put gap at .016

kevinp242 wrote:Why i have to cylinder off of it i think im going to do a little porting to it!!!!!! Why not hahaha..

I would NOT recommend this until you've had a chance to get to know the 500.

But don't listen to us. We don't know shit.

100hp honda wrote:were they installed too large to begin with ? .038 is fuggin huge man, that would have me alittle nervous. you might have the wrong size rings on there maybe . i re-ringed mine not long ago, after getting the wrong rings the first time, i re-ordered the correct ones and put gap at .016

yeah, it rattles around a bit, but i figure it will hold on a while longer, i am running a 2nd over OEM piston. the bike runs hard, i just pulled the top end to put that motor in my GEN 1, i wouldn't have even known otherwise.

MojoScojo wrote:

kevinp242 wrote:Why i have to cylinder off of it i think im going to do a little porting to it!!!!!! Why not hahaha..

I would NOT recommend this until you've had a chance to get to know the 500.

But don't listen to us. We don't know shit.

the dude wants to go faster. whats the harm in that ? not everyone is a old trail rider

alright so i got the motor out of the bike tonight and torn down. It is pretty torn up on the exhaust side. I believe it is on its last bore but im not sure. Does any one know how big wiseco goes on the pistons. Stock bore is 89mm i believe. So im dropping the top end off tomorrow at my machinist's shop. And he is also going to gasket match everything.... So here are a couple pics of it so far.

Kevin

90 psi= tired ass top end. that piston is scuffed fo sho. no lube holes...tell your machinist to relieve that exhaust bridge.

Wiseco Catalog page

south central hoon wrote:90 psi= tired ass top end. that piston is scuffed fo sho. no lube holes...tell your machinist to relieve that exhaust bridge.

lube holes?

the wiseco paper work shows to drill some holes in the piston for oiling where the exhaust bridge is.
no point in gasket matching, either port it or don't, but these things run great stock, as soon as you modify the porting, tuning becomes a nightmare.

yea i appreciate the help guys. I dropped the cylinder off at the machinist's house and it should be done by friday. So that means i need a case of red bull so i can get it together and tune it saturday. And the new piston i am going to relieve the exhaust side of the piston. Also why i have the motor out im going to replace main seals.

But one thing i do need to find is a Right side radiator for a '01 CR250. Any one know where i could find one?? So my roommate did not tell me but my bike fell off the stand and crushed the radiator.

Thanks

Kevin

Honda of Troy had them for $118 and I believe Bob has a hook up with someone. They go for more than that on Ebay used.

kevinp242 wrote: i am going to relieve the exhaust side of the piston. Kevin

Woah....don't go grinding on that piston!!!!!!! relieve the exhaust bridge in the cylinder and drill holes in the piston....