I'm an average C rider about 150lbs just trying to get a little more out of my bike both top and bottom end. It's completely stock I think I might need to replace the rings but I'm not sure how much that will help me. Any ideas?
04 cr250 help
Started by
Andrewb1298
, Jul 09 2012 07:51 AM
8 replies to this topic
Posted 09 July 2012 - 08:42 AM
Replace base gasket with a 05 -07 gasket. They are .010" thick and will lower the cylinder .014". Your squish clearance will be .054" This may require a 50/50 mix of pump and race gas. Not because the squish is to tight, but because compression was increased from lowering the cylinder. A higher octane fuel will burn slower and cooler which will help keep the motor from detonating. You could send the head to RB to had the head's combustion chanber enlarged to allow you to run 93 pump gas. This mod increases power form idle up thought the mid range. So top end might be lost. Buy a PWK from powersports pluse for 2000 cr 250 ($157), v force 3 reed cage, and a fmf fatty pipe and shorty silencer. These mods are aimed at increasing power from idle up though the mid range. The motor will pull much better and smoother and make it one of the best 250's you will ever ride.
Posted 09 July 2012 - 09:02 AM
Ok. By doing tht you said I might lose some top end. Can I do this and maybe change a few other things to get the top end back? Or am I between a rock and a hard place in trying to get the best of both? Also will doing this take away from the reliability of the bike?
Posted 09 July 2012 - 09:02 AM
Kirkes, on 09 July 2012 - 08:42 AM, said:
Replace base gasket with a 05 -07 gasket. They are .010" thick and will lower the cylinder .014". Your squish clearance will be .054" This may require a 50/50 mix of pump and race gas. Not because the squish is to tight, but because compression was increased from lowering the cylinder. A higher octane fuel will burn slower and cooler which will help keep the motor from detonating. You could send the head to RB to had the head's combustion chanber enlarged to allow you to run 93 pump gas. This mod increases power form idle up thought the mid range. So top end might be lost. Buy a PWK from powersports pluse for 2000 cr 250 ($157), v force 3 reed cage, and a fmf fatty pipe and shorty silencer. These mods are aimed at increasing power from idle up though the mid range. The motor will pull much better and smoother and make it one of the best 250's you will ever ride.
Good info!
Posted 09 July 2012 - 09:13 AM
You will have more than you need.
Maybe with porting the exhaust and transfers you can both. But that is out of my experience zone.
Maybe with porting the exhaust and transfers you can both. But that is out of my experience zone.
Posted 13 July 2012 - 05:25 AM
Is a .054" squish clearance efficient enough or can there still be more taken off? I've heard around .04" is where you want to be...is this right?
What is the correct squish clearance?
What is the correct squish clearance?
Posted 13 July 2012 - 08:27 AM
Conrad Murphy, on 13 July 2012 - 05:25 AM, said:
Is a .054" squish clearance efficient enough or can there still be more taken off? I've heard around .04" is where you want to be...is this right?
What is the correct squish clearance?
What is the correct squish clearance?
Most engine tuners recomend .050 for a good optimum squish band. I'm running at .035 on my CR with no issues.
Posted 13 July 2012 - 08:34 AM
Kirkes, on 09 July 2012 - 08:42 AM, said:
Replace base gasket with a 05 -07 gasket. They are .010" thick and will lower the cylinder .014". Your squish clearance will be .054" This may require a 50/50 mix of pump and race gas. Not because the squish is to tight, but because compression was increased from lowering the cylinder. A higher octane fuel will burn slower and cooler which will help keep the motor from detonating. You could send the head to RB to had the head's combustion chanber enlarged to allow you to run 93 pump gas. This mod increases power form idle up thought the mid range. So top end might be lost. Buy a PWK from powersports pluse for 2000 cr 250 ($157), v force 3 reed cage, and a fmf fatty pipe and shorty silencer. These mods are aimed at increasing power from idle up though the mid range. The motor will pull much better and smoother and make it one of the best 250's you will ever ride.
Good info except the fatty I ran one & felt the oem is a lot better.. I tried the thinner base gasket on an 01 & 03 motor & it did boost the lowend a little at the sacrfice of some overev.
Posted 13 July 2012 - 08:53 PM
Bell's book recommends .039-.055squish clearance. I will setting up my squish 05 cr 250 at .045". 100LL. UCCR 14:1. It started out at .084".
