CR 85 Low End!!

[dojo]

Hello, Bought my boy a 04 CR 85, he came off a Suzuki 85. These bikes are like night and day on the low end, the CR has almost none, I'm afraid he is gonna burn the clutch up. I have heard getting a FMF Fatty pipe, I have heard going up 2 on the rear sprockett, and I have heard a lot about rejetting. I have rejetted his first mini a few years ago, I think I can do it again if need be. We are just weekend guy's but not much fun for him on his first ride. He wes a little tall for the RM so the CR is a big wheel. One guy suggested I sell the bike, I don't think I have to go to that extreme as know there are a ton of these bikes around and somebody knows how to make them run right. Any and all input from you guy's would help. So we can have fun again!!!

Thanks Again

 

[Chili]

Adding teeth to the rear will help as will getting the jetting spot on, although that will be a general improvement not so much for bottom end. For your usage I'd be tempted to see if I could move the CR85 Expert and find a KX100.

 

[Patman]

Yup completly different animals. I wanted to get my son on an RM but he HAD to have red so that's what we did. The FMF Fatty is a good addition to his '03 as was th Steahly flywheel weight. The weight doesn't add power but it does make the bike easier to ride without slipping the clutch as much and all the stalling. We had Eric Gorr go through the engine a couple months ago. He worked his magic and punched it out to a 102 and it is still no low end tractor but it does pull harder than stock down low no doubt!

 

[Philip]

Yep I,m there with ya. We have an 03 and it has a vforce 3 which cleaned up the jetting, more teeth and FMF fatty which gave a little more bottom. I think short of a port job to move the power band you can't get to much more out of it. It was designed to run wide open (all top end) which Josh does not do. He has been riding my 450 more than his bike. I can't wait until next year when I get him a 250 four stroke. Maybe the more mechanic minded can help more, but from experience with our bike I just don't think you can match the bikes with power valves on the low end.

 

[Patman]

I guess I should have added my son initially had problems but adapted really quickly to the power delivery and now is wringing the guts out of the modified engine given a little seat time your son might adapt to the power delivery and this will be a non-issue.

OR

http://www.servicehonda.com/junior.html

 

[gergetz]

i have a yz 85 and i did the sproket thing and pipe and know its runnin up hills just fine

 

[Holeshot Dad]

The Honda is a real mid to top end motor as it is among the 85cc biles that don't have a powervalve. The RM and KTM are the only ones that offer a power valve and this produce a more usable powerband for youngsters.

My son was an RM rider as well and we switched to Honda's but he didn't like the handling or the motor as well as he likes his new 06 KTM 85.

If your looking for more bottom end on the Honda go up a tooth on the back, no more and maybe a fatty pipe. Also you can check into the Vortech Ignition which may help a lot too.

Good luck

 

[husabutt]

Hello, Bought my boy a 04 CR 85, he came off a Suzuki 85. These bikes are like night and day on the low end, the CR has almost none, I'm afraid he is gonna burn the clutch up. I have heard getting a FMF Fatty pipe, I have heard going up 2 on the rear sprockett, and I have heard a lot about rejetting. I have rejetted his first mini a few years ago, I think I can do it again if need be. We are just weekend guy's but not much fun for him on his first ride. He wes a little tall for the RM so the CR is a big wheel. One guy suggested I sell the bike, I don't think I have to go to that extreme as know there are a ton of these bikes around and somebody knows how to make them run right. Any and all input from you guy's would help. So we can have fun again!!!

Thanks Again

In my opinion raising the compression and proper jetting will yield the biggest low end power gains ( think diesel motors and where does all that torque come from, high compression)

The Phathead Racing heads are great for this. On our YZ85 we are up two domes higher than stock. It completely changes the sound of the motor. The first time I installed it I didn't recognise the sound of my son's bike. And that was only on the first step up in dome size.

http://www.dirttek.com/phatheadracing/

 

[kawicam125]

ive heard going down a tooth on the front sproket is like adding three teeth to the rear. the kx has a ton of low end power. its got new reeds, reed cage, about to apply his new front sproket on, it has a fmf powercore 2 pipe and silencer, and much more. itll ride trails or tracks with great power all-round. :nod: :yeehaw:

 

[ncflattracker]

cr

E.g. Can Also Do Some Tricks With Epoxy And Such To Put That Cr At A Lower Power Band Give A Talk To E.g.

 

[kawicam125]

E.g. Can Also Do Some Tricks With Epoxy And Such To Put That Cr At A Lower Power Band Give A Talk To E.g.

( thanks Jamir) this is an english speaking site. :| :| :think:

 

[griffbones]

I have a 2007 KX100 engine in my son's 2005 KX85, and it has a ton of low end power.
BTW the Suzi's and KTM's aren't the only bikes with power valves, the Kawi's have them too.