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Offline oppenheimer77us

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CR250 build
« Reply #15 on: August 01, 2012, 06:31:28 AM »
Will try to post a few before/during build pics, the throttle jockey graphics just came in and the bike looks as great as it runs.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline dogger315

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CR250 build
« Reply #16 on: August 01, 2012, 03:16:27 PM »
Sounds like a fun project.  I thought I would provide you with some additional information
to consider.

The case reed motors can be modified to make good power with a fairly decent powerband,
but it requires quite a few mods and a fair amount of money.  Some of the problems have
already been identified here:  Excess crankwell volume, heavy crankshaft, mild port timing,
recalcitrant power valve, Mikuni TMX, etc.

If you have your heart set on using the OE engine, I can recommend somebody that can turn
it into a match for anything out there today.  Of course, the catch is the cost.

As an alternative, you could do the same thing that Mike LaRocco and others did when the RC
valved engines first showed up by switching to a 00/01 engine.  Those engine drop right in to
the same engine mounts and swingarm pivot spacers.  The only change required is a different
head stay.  There is a company that markets a very inexpensive kit for this conversion.  The
gen 3 roller with the gen 2 engine is the ultimate Honda all CR250 and is the bike Honda should
have built and marketed from 02 to 07.

Of the two, the 00 is a better choice.  Eric Gorr comented in a book years ago that the 2001
engine was the best ever.  That drove the price of those bikes and engines up dramatically.
What EG didn't say, is that the 2000 engine is identical except for the port timing and it comes
with the superior Keihin PWK carburetor.  Additionally, both EG and Tom Morgan (probably the
two top Honda gurus still in the mix), prefer the 00 cylinder as the starting point for a race
motor - more potential.  A complete used 00 engine can be bought on EBay, rebuilt, ported
and race prepped for less than the cost required to bring an 02-07 engine up to speed.
 
It all boils down to what your goals are.  Do you want something that will match the latest SX
to the first turn, or do you just want a have some "fun" running mid pack.

Whatever you decide, good luck with it.

dogger

« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline oppenheimer77us

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« Reply #17 on: August 02, 2012, 04:43:39 AM »
Thanks for the info, I'm really not much of a racer (50+, old dude class) and was really just looking for a cleaner running CR. I'm going to bolt on a PWK and see how it goes. Not really looking to spend a bunch of money on either an 06 or a 00/01 motor. I like the simplicity of the 00/01 design and worry about all the electronics on the 06 taking a dump but until that happens I'm good with this motor and will save the money for suspension valving and springs.

I really have enjoyed this project, so much fun to get off a big thumper and back onto a 250 smoker. Haven't had this much fun in years.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline twosmoke595

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« Reply #18 on: August 02, 2012, 04:57:23 AM »


I really have enjoyed this project, so much fun to get off a big thumper and back onto a 250 smoker. Haven't had this much fun in years.
[/quote]


and that my friend is what its all about :)
grinning from ear to ear as you ring the SOB out  :P :P :P
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline travis.hudson.77

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« Reply #19 on: August 02, 2012, 03:12:34 PM »
I know that when Robbie Reynard was riding this bike his dad had his bike running so well that factory honda was taking notice.......does he still do motors? his website is down,....does anyone have his info? :<img src=" title="Roll Eyes" class="smiley">
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline travis.hudson.77

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« Reply #20 on: August 04, 2012, 05:52:32 AM »
Nobody Knows!? :P
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline luthier269

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« Reply #21 on: August 04, 2012, 08:22:26 PM »
Captmoto  what effect does it have on the motor not having the TPS hooked up with the new carb?
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
Motocross is a real sport all the rest are just games

Offline Swimr2DaResQ

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« Reply #22 on: August 04, 2012, 11:21:46 PM »
Best mod for that bike is to get a Keihin PWK carb from JD Jetting and get rid of the Mikuni TMX carb it came with! Just put a Keihin on my '02 and what a difference it made. JD setup the carb for my bike and area, it comes with an extra needle and two extra main jets! 245 bucks well spent!
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
"Technology frightens me to death. It's designed by engineers to impress other engineers, and they always come with instruction booklets that are written by engineers for other engineers - which is why almost no technology ever works."

Offline scotty dog

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« Reply #23 on: August 05, 2012, 11:01:41 PM »
Best mod for that bike is to get a Keihin PWK carb from JD Jetting and get rid of the Mikuni TMX carb it came with! Just put a Keihin on my '02 and what a difference it made. JD setup the carb for my bike and area, it comes with an extra needle and two extra main jets! 245 bucks well spent!
Thats not a bad price at all, i might have to look into that ;)
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
F**K THE WHALES......................SAVE THE 2 STROKE!!!!

The hardest part about riding a 4 stroke is telling your parents your Gay!!

05 CR 250

Offline kim wedding

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« Reply #24 on: August 12, 2012, 01:22:19 AM »
when people knock the case reed motor dont,  just look at the ktm sx250. its a monster. some one out there has to be able to build a motor and transmission for a fair price to fit in the stock frame and rip like the ktm does. i hope they do it for the honda cr125.  one comment does anyone think that the traction control on the cr250 adds to the flawed powerband. a friend of mine said the first ride he had on a traction controlled bike he didnt like it.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline _X_

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« Reply #25 on: August 12, 2012, 01:34:25 AM »
traction control? on a production honda? you sure about this cause i seem to be missing mine. Ha!
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline motoxr377

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« Reply #26 on: August 12, 2012, 04:23:04 AM »
Honda has used a form of traction control since the 1997 CR250.

Basically, it senses a abnormal spike in rpm and changes the timing slightly to compensate.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline TMKIWI

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« Reply #27 on: August 12, 2012, 06:41:44 AM »
I thought Hondas idea of traction control was to de-tune the engine after 2001 so it didn't have enough horsepower to lose traction. ;)
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
If you don't fall off you are not going hard enough

Offline gpnewhouse7

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« Reply #28 on: August 13, 2012, 08:52:28 PM »
I thought Hondas idea of traction control was to de-tune the engine after 2001 so it didn't have enough horsepower to lose traction. ;)

Haha, an I don't think the traction control worked very well on my old 99 cr 250, if it wasn't wheelspinning it was wheelying lol it was fun at first but somewhat tiring in a 5 hour enduro.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline oppenheimer77us

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« Reply #29 on: August 14, 2012, 02:34:44 AM »
I thought Hondas idea of traction control was to de-tune the engine after 2001 so it didn't have enough horsepower to lose traction. ;)

I think there is truth in this, this motor has so much power bottled up, the factory or other properly tuned CR's of the day had killer motors but were just screamers that were way hard to ride for the average joe. I really do think Honda did seriously de-tune this bike for public consumption.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »