Has anybody been able to get one of these things to go real fast we have an 03 Honda cr125 Having problems with detonating which we have since cure, Head geasket blowing they burn away Jetting is spot on if any thing it is running rich std main is 430 we have fitted 450, Honda told us to run 490 which is far to rich. We have fitted a v-force reed block which help big time. Fitted a 2c pipe and muffler which makes a nice spread of power. Porting is STD just cleaned up. Bike has been to unreliable to do anything else at the moment. Any help will gratefully received. Nigel
Honda Cr125 Snail
- Thread starter fonz
- Start date
I have an 02 and my friebd an 03. He just got his back from Terry Varner ( Varner Motor Sports), port, polish, mill head, piston and rings, Pro Circuit Pipe and Silencer (standard length), this bike runs great from mid on up. He's got a 410 or 420 main jet with V-force 2.
- Thread starter
- #3
Thanks Jmeleel, do you have any problems with the head gasket burning from the exhaust side to the water jacket hole in the cyclinder head. My boy who races the Honda is quite a good rider he has race against Chad Reed and Micheal Byrne. He just holds this thing flat out most of the time around our sand tracks.
Yogurt
~SPONSOR~
- Dec 25, 1999
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I'm the owner of 00 CR125, and I got the Eric Gorr 133 kit, and i'm very pleased with it. Porting really isn't going to do much to a modern day 125, about at much gain as a pipe and silencer. Just gotta remember there is no replacement for displacement. And since my CR is only bored 2mm or .080in over, it's still AMA legal. Other worthy mods for the CR are, 1+ tooth larger rear sprocket, and V-Force reeds.
UKcr125rider
Member
- Apr 28, 2002
- 93
- 0
My '03 Cr125 burnt the coating off the head gasket at the exhaust side. Had very minor detonation problems, due to pump fuel quality we think. Now use a mixture of race/pump fuel. I've got a v-force and HGS exhaust system on mine. Run a 460 main on the long tracks and usually a 450 on everything else. Also, 1 tooth up on the rear sprocket helps low end acceleration that extra bit.
UKcr125rider
Member
- Apr 28, 2002
- 93
- 0
Fonz, heres a pic of the gasket that blew. It burnt on the cylinder side.
http://www.angelfire.com/theforce/nimxer/blown_gasket.jpg
http://www.angelfire.com/theforce/nimxer/blown_gasket.jpg
- Thread starter
- #12
Thanks UKcr125 rider This Honda is doing things It should not do where your gasket only burnt the paint off. Ours burnt through and hollowed out the head by the water jacket and stuffed it. Yes it is all fuel related problems. I have now sorted all my problems out but it is only a but it still does not go as fast as the YZ250F over here Australia we are not allowed to bore the thing out we have to stay as 125cc or go four stroke and have a bigger bank balance to repair the said bike. Any way what part of the UK are you from, I use to live in the Midlands and been a member of the Coventry Junior club.
Moto Squid
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- Jul 22, 2002
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that's expecting a lot :silly:
AJ Waggoner
Crash Test Dummy
- Nov 5, 1999
- 4,368
- 34
mod the head and run a suzuki piston ,(same size but different wrist pin location changes port timing ) Erics got the mods for that.
you are asking a bit much for it to run with a 250f
without spending the money you would on keeping the 250f in tune as well.
but the national riders here are still pretty evenly matched 125 2 stroke verse 250f 4 stroke..
excepting the starts and of course deep sand tracks as you mentioned.
???
you are asking a bit much for it to run with a 250f
without spending the money you would on keeping the 250f in tune as well.
but the national riders here are still pretty evenly matched 125 2 stroke verse 250f 4 stroke..
excepting the starts and of course deep sand tracks as you mentioned.
???
