KDXRIDER.NET

Jayson just got a YZ125....

Look out! When is his surfer-dude buddy getting one?!

He will be OWNED!

I just love how those guys drive each other... very cool to watch...

JC7622, My CR85 is very smooth, even without the flywheel weight.
Not much power down low, but a smooth transition from bog to BRAAP.
Would your son be interested in a cherry (NOT!) CR85 sw? I'm looking to replace mine with , ideally, a KDX/KX hybrid, a stock KDX, or, dare I say,
a KTM.

I got my head and carb back Saturday. Usuall quick turnaround and nice, clear paperwork.

I installed both and rode a bit Sat night. Sunday I had a bunch of guys over riding and put some of the kids on it. I couldn't get one of them off!

My seat of pants dyno says there is more pull in the 1/4 to 3/4 throttle range and the transition to WOT pull is cleaner and less abrupt. The throttle response and pull is MUCH better in the 1/8 to 1/2 throttle.

The real test is that a buddy of mine has a 12 year old daughter that has been riding a KX100 for a couple of years now. Listening to her bitch and moan to her daddy about any little thing on her bike, I get the impression she is pretty "sensitive".

It was definately money well spent. I don't think I'm going to put a FWW on until I get a bit more time on it, if at all.

Don't get a flywheel weight. They are a waste of money and do nothing to change the power characteristics. They only add inertia to "help" reduce stalling if your kid doesn't know how to ride. The rear tire is a MUCH bigger weight, and has a larger radius which gives it even more flywheel effect. g Go with a heavier tire next time if you want more flywheel effect while actually in motion (when it counts), but while still allowing the engine to rev freely if you need to rev it and drop the clutch to get over an obstacle.

I've never seen the point in flywheel weights, unless you don't like that crisp throttle response that took years of research and developement from the manufacturer.

MX500 wrote:Don't get a flywheel weight. They are a waste of money and do nothing to change the power characteristics. They only add inertia to "help" reduce stalling if your kid doesn't know how to ride. The rear tire is a MUCH bigger weight, and has a larger radius which gives it even more flywheel effect. g Go with a heavier tire next time if you want more flywheel effect while actually in motion (when it counts), but while still allowing the engine to rev freely if you need to rev it and drop the clutch to get over an obstacle.

I've never seen the point in flywheel weights, unless you don't like that crisp throttle response that took years of research and developement from the manufacturer.

I myself can't claim to know better by actual experience, but there's a WHOLE lotta' people that would disagree with your opinion on the flywheel weight. I don't need one for my KDX - it's GOT a decent amount of flywheel weight in my opinion - but there are some that have their KDXs rigged with one to suit their riding style and terrain.

Better yet, the mx bikes are designed to spin up really quickly and thus have a light FW which is why MANY add them to CHANGE the characteristics to, again, suit the characteristics to the terrain.

My point is a bike should be set to suit who's riding it and where they're riding it . . . so when you have a bike not quite set up for the riding terrain (a.k.a. mx bike for trails and such) a flywheel weight might be just the thing!

I do like your concept with the heavier tire though . . .

Rode a bit more last night and think I am going to lower the needle clip one slot. I've got it in slot number two, stock is four.

I was doing third gear pulls from idle to 1/4, 1/2, and 3/4 throttle. Real clean everywhere except for a little spot at mid revs in the 3/4 pulls. The advantage I have at 175 lb is that a little lagging spot will be apparent. For the bikes intended user I bet they'd zip right through it and never notice.

I rode one of the kids CRF150's this weekend. Very impressive motor, though I've got to say the bike felt significantly heavier than the KX100.
A third gear pull on that and it would fall flat on its face at anything over half throttle.

An object has to be moving to have inertia. The rear tire isn't moving much at low speeds thanks to a gear(reduction)box. The flywheel, however, is spinning along nicely. Extra wieght here will help a lot to reduce stalling, and tame town a pipey beast(rev slower). This is a personal preference thing not so much an engineering decision...MX riders like snappy power delivery and factory FWW is kept light. The flywheel effect of the rear tire is of course very prevelant pinned in 6th over a 120ft-er.

KX 85/100's have power valves. the little 85 makes 20 hp in a 143 lb. package. These are rockets, and maybe not the best trail bike unless ridden by someone willing to slide around corners and treat it like a jetski on dirt. My wife had a KDX 85 that would be an awesome trail bike for smaller riders. It had a decent amount of grunt for such a small motor after some boyeson reeds were added. I wish they still made it, and maybe a 150cc full sized version.

To the gentleman considering the KTM 65, think carefully. I would think your son will be moving into the 85 class shortly after you buy that thing. and the owners of the little KTMs were always bitching about costs at the races. Especially the 50's, which have a few reliability problems. In the 85 class at least in Colorado, you see very few KTMs, some Hondas, a few more Yammies, then a sea of lime green. The KX85 is very competitive and pretty reliable.