How do I de-tune a CR250 ???

[Bizerk]

Yes, most people want to get more and more power out of their bikes. Well I would like to know how to de-tune a bike for a little less snappy-ness. Long story short-this is my brothers bike, a 1996 CR250. He has been riding it for several months with no problems and then got into trouble this last weekend and crashed and broke his collarbone. What a tramatic event. Anyhow, the bike has gobs of power right off idle. IS there a way to slightly de-tune it to not be as snappy? I was thinking about adjusting the timing but not sure which way to go.

Help Please! :worship:

 

[mtk]

If I were you, as a first pass I'd head off to Steahly Offroad (it won't let me post a link, so the web link is the name with no spaces) and order up the heaviest flywheel weight they sell.

This won't cut down the power, but it will make the bike gain revs slower, which should fit that "not be as snappy" thing you were looking for. It's also cheap (~$100) and easily reversible.

 

[gwcrim]

1- Get the heaviest flywheel weight available.
2- Retard the timing.
3- Put the jetting a little on the rich side.

 

[DanAKAL]

Another vote for the flywheel weight. It will just smooth it out all of the way through.

 

[James]

Flywheel weight doesn't have a whole lot of taming effect in my opinion. Seems to help more with stalling. Jetting makes a much bigger difference to me.

Set the air screw at 1 turn out - try it. Put 1 size bigger pilot jet or raise the needle one notch (or both), try again. If that still isn't tame enough, put a 1 tooth bigger sprocket on the front. A jet and sprocket combined might cost around $25...cheaper than a flywheel weight.

I have a 12oz flywheel weight that I'd gladly sell to you, but I'd recommend trying that other stuff and see if that didn't tame it enough. I went through this whole taming ordeal a few years back and finally decided to just ride it a gear higher in most cases until I got used to the power.

 

[MXTex]

Spend $50 on a riding lesson. At 41 years of age, I had my first riding lesson several weeks ago. Best money I ever spent.

 

[pace]

In addition to what was suggested above, you could maybe pull the silencer and fit a spark arrestor. Also go down a couple of teeth on the rear sprocket will help to remove some of the hit.

-Pace

 

[Green Horn]

No need to de-tune, just learn how to ride it. I'm not trying to be a jerk either. Take a lesson or just spend more time on the bike. Throttle control is #1 when riding a bike with loads of "hit". I wouldn't spend a single dime on "de-tuning" a bike because eventually you'll want that power back. Just a waste of money in the long run.

I had an '89 YZ 250 and when I first started riding that thing, it would take me for a ride. I went off the back on a number of occassions. I then learned that having excellent control of your right wrist is a big help. You can also learn to ride the bike and keep it out of the peak of the powerband. ie... choose a gear higher than you'd normally use and keep the revs down low. Take your time time and just be patient. You'll soon love the power you have.

 

[yz138]

"how to de-tune a bike"
Thats what I wanted to do when I first got my RM250. Best thing to do is like someone mentioned above ' ride in a higher gear', use the power as needed. My RM was geared higher then stock which helped tame the bottom end but that sucker would rev to the moon if you wanted it to. I like the new gearing 14/50 stock was 13/49 and will stick with it. That may be an option for you as well. :aj:

 

[Bizerk]

Thanks guys!! Great advice! Ya, it's tuff getting older...my brother is 37 and I am 35. We have ridden for a number of years when we were younger and now after about 12 years have finally got back into it again at the beginning of this year. Go figure that my bro gets hurt right at the beginning of the summer. He wasn't even screwing around. He was just going up a hill and the back tire kicked up knocking him off. Thus he suffered a broken collar bone and some other injuries. He kept asking me to mellow out his bike a little for him...and now look what happened. I feel somewhat responsible but know it is not my fault. Anyhow...a little off topic here...I'm just upset about the whole thing and I'm reluctant to get back on my bike now! :(

Thanks again for the advice.

 

[blanc]

Beg to differ my 1996 Honda cr20 gained substantial amounts of controllable linear and smooth power. Way way easier to handle.

 

[Junkyard Dog]

While you are getting the flywheel weight, spend the 10 bucks and get the tool to screw down the spark plug hole to keep the engine from turning over. It's made out of derlon or some sort of plastic. Stealthy has that also.

I ride a 02 KX250 and it smooths out the power delivery (very linear) without any loss of power.
I use an 11oz. stealthy weight.

Money well spent.

 

[Rcannon]

James, I am with you on the flywheel weight. I bought a set that was intended for a YZ400f. They happen to fit the 97 YZ 250 like a glove.

The kit has a 6 oz, 8oz, and a 10 oz. There is little difference between them when mounted on the bike. none of them make the low end very manageable.

I think a guy would need to add 3 or 4 lbs to do this.

That Honda has an excellent engine in it. I would spend more time getting familiar with it, or trade it towards a KDX 200.

 

[darringer]

Rcannon, I beg to differ with you. I have a 12oz. weight on my 99cr250. This bike hits like a hammer right off the bottom. After installing the weight I noticed less wheelspin, smoother hit, and it became almost stall-proof. It made the bike easier to ride in traction-poor situations. However, it does NOT add any bottom end, it just makes it a bit smoother and somewhat easier to ride. I think the biggest difference made was seat time on the bike. Throttle control takes awhile to learn, because on a 250, things happen in a hurry.

 

[Rcannon]

I dont think we have a differenc ehere!

I love my flywheel weight . Heck, I bought the rest of the kit after I bought the 10 ox. I should have explained myself more clearly. Most folks I have talked to think the extra weight will turn their MX bike into a ttr 90 replica.

I know we both agree that is not true. The bikes are very fast, but easier to deal with. Even with a heavy weight , my bike is not as dosile or manageable as a KDX 200 .

 

[darringer]

Rcannon, we do then agree. The weight helps smooth out the power a bit, but doesn't change the original characteristics of the bike. In my instance I just needed a little help controlling the quick burst of power to control wheelspin. The 12oz. weight was just enough to accomplish that. It helped considerably for single-track woods and hillclimbing.

 

[Rcannon]

I think we do for the most part. The weight was honestly one of the best investments I made to my 97YZ 250. Most other products were just a waste of money.

I notice improved tire wear with the weight in place. Wheelspin was reduced without a doubt.

If I could start over on my motor again I would buy the weight kit first, then send the cylinder and head to Eric for a Mo' better power everywhere port job.

I bought one of every pipe I could find on ****. I bought stock, FMF fatty and Gnarly, Pro Circuit, Noleen, and SPES/ Doma. Out of all the pipes the Noleen is the most fun to play with. It honestly gave the bike more low end. Top end is nothing. Almost like hitting the kill switch. Still, the low end burst is fun.

The Pro Circuit pipe and silencer were a giant dissappointment. The fit was excellent. The performance was less than stock. Very booring power dilivery. Zero low end.

The FMF stuff was ok. No real improvement, but no decrease. Fit was lousy. I ended up returning the fatty as it offered nothing extra except exhaust leaks.

I am running the SPES stuff right now. It is well built, it fits , and offers a wider powerband than anything else. Good stuff.

The weight set, however, is much more valuable than any of the pipes. The YZ feels like it should have been supplied with the 8 oz weight from the factory.

 

[Bizerk]

Great advice guys. I think I've convinced my brother to get the flywheel weight. Now we just gotta wait 4=6 weeks for him to heal. Meanwhile...I'm out on my KDX 200 playing by myself! :aj: