AlisoBob's Gen 4 A/F Conversion

[mxracr121]

Gen. three bikes were more of all of the above, and are considered by many to be the best handling two stroke Honda chassis of all time. Some think the turning became a little too sharp and lost some stability at high speeds.

Well that maybe true in some circles, I have found out from going to the track and races thats its commonly known that Gen III's have a turning problem. Needless to say I got tired of dumping mine. The fix is to spend the dough on 20mm offset triple clamps. Which I did and going to a 100 size front tire instead of the stock 90. Well that must be the ticket cause, knock on wood, I've only dumped it once this whole year, which was in one of Glen Helens finest ruts. Then there is having it resprung, revalved, correct sag and 12 psi in the front. Stability issues are from the forks set to high in the clamps and that will change when changing the clamp offset,/ or the springs to light for a riders weight.

AH the learning curve. Glad I'm over it. Now lets ride.

You are the only one I've ever heard of having handling problems with a Gen 3 CR 250. The 20mm offset clamps are the "hot" set-up on the '02-'04 CRF450, most who tried them on the CR250 said there was no benefit. The stock size front tire is the 80, the 90 is the bigger one.
My guess is Iggy, that your sag wasn't correct (maybe needed stiffer spring), and maybe didn't have the fork height correct. The '02-'07 CR250 chassis is pretty damn good stock (with correct spring rates and sag). I really feel only one bike is superior in handling. That being the RM250. Pick a year, all pretty good.

[iggys-amsoil]

Ya thats right 80-90.

Thats the first thing I did was resprung for my weight. I did the sag when I got them back. After words I added 3/4 turn more preload to the shock. But ya I should recheck the sag anyway.
But it comes down to my cornering skills just suck. Oh well, off to practice.........

[Rosco-Peeko]

Looks good Bob-a-rino.

[zorak-2]

Bob the bike sick sick as hell. When is it going to be done.

[AlisoBob]

Pretty friggin' soon!!

[Ported&Polished]

BRAAP!

[AlisoBob]

Heres the parts.. The airbox, flange, adapter, filter mount, boot, boot spacer.

I can't seem to find any info on the airbox and the template that was made and what it was for.

The key to the air box is the 3/8" thick, clear lexan spacer, seen at the bottom right.

It covers the face of the stock airbox, uses the inner airbox filter mount, and lets you mount the CR500 boot anywhere you wish to get carb alignment and clear the shock spring.

The first one was made from phenolic, but I made another one from Lexan, as its much easier to locate all the holes.

Does ths discription help you, Dog?

[Slomo]

What rate rear spring are you going to run Bob?

[AlisoBob]

5.8..... its a big mutha'

[hagendog]

She's a runner It was the 88 intake boot that had everything jacked up. Installed a 95 reed cage and boot and the 02 250 boot on the back and it's like butter. This was driving me crazy, but it's all good now. I have a 5.4 race tech on the back of mine, it might actually be a 6.0 but the numbers are gone so I can't tell the difference. Clearence was good with no mods or heat Thanks for the pics above and the conversation earlier Bob, I was ready to lose it. BRAPPPPPP going to see Bigworm in Truckee tomorrow. He said you can ride from his place to Reno damn near. First ride on the AF stock( not a hillclimber) since I built it. I am fuckin stoked. Makes me want to blare Def Leppard Well maybe some SLAYER YEAHHHHHHHHHHHHH

[AlisoBob]

... maybe some SLAYER YEAHHHHHHHHHHHHH

[youtube]http://youtube.com/watch?v=fn6gD5WYAD8[/youtube]

[hagendog]

Shit Bob, you climb a notch higher in my book . Now give me some Reign in Blood shit, that's the ticket. Old school SLAYER, Hell awaits with some 15's or .........well any SLAYER is good SLAYER FUCK YEEEEAHHHH

[dannygraves]

cool, I'm glad the boot fixed it for you.

[HrcRacing]

Lookin' good Bob. What did you use to radius the back of the cases?

[AlisoBob]

Lookin' good Bob. What did you use to radius the back of the cases?

A 4" grinder, with a fresh wheel, held "straight on" to the case. The radius of the cut is the same as that of the wheel.

[HrcRacing]

Lookin' good Bob. What did you use to radius the back of the cases?

A 4" grinder, with a fresh wheel, held "straight on" to the case. The radius of the cut is the same as that of the wheel.

Cool. I'll check the depth of my 250 engine before I sell it and match that.

Thanks Bob.

[AlisoBob]

Hold it straight on, and move it up and down at the same angle as the shock is installed at...

[HrcRacing]

Will do Bob. Thanks.

[100hp honda]

i hope you have it all writen down bob. im considering now using a aluminum frame for my race motor when it gets done. i would of already bought a roller but my cash is a little low. ill be calling soon as i can make it happen. something extended like Pstoffers machine is what ill be doing

[AlisoBob]

Write it down? Its all here !

[AlisoBob]

I'm currently moving the frame side of the head stay mount over, to be inline with the head lug, much like the OEM CR500 method.

S/H uses a one sided billet piece that while looking good, also looks like it isnt as stiff as it should be.




After moving the mount, the dual .250" 6061 T-6 plates will be very light and stiff.

[Ported&Polished]

I can see how to change the pictured design so that it has a double shear attachment on the frame as well as the head, pretty easy actually. And yes, using plate alloy makes alot of sense because the whole unit can be lighter and stronger. I would think that instead of two seperate plates, the stay could be two plates attached at the middle making a H shape which would be hella strong imo.

[Ported&Polished]

Something like this would work well.

[AlisoBob]

I'll order some from Zorak

( He manages 4 Wheel Supply)

[Ported&Polished]

Dork! You know what I mean, shaped like those shackles roughly. I didn't mean use leaf spring shackles as a head stay.