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The Plvis

CRF250F how its made

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265 pounds???  Almost as heavy as an old XR400???  CRF230F was too heavy to begin with...

What in the world is Honda doing these days?

Any dyno curves yet?

Edited by VortecCPI
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No end to jokes about new crf250. One gear less then 80s Xr250r  same or more weight useless. Honda should stop production quick remember twin carb Xr200/Xr250. Two years no more. Guys this is almost 2019 no excuse for heavy short travel 5 sp bike. They only give it 5sp to cut down weight JAAAA FAIL 

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Looks like a “pork chop” crankshaft
Rear shock is made to be disassembled/serviced.

Cylinder can accept a much larger sleeve.

Steering stem is steel, probably lower tree is also.

Head gasket appears to be multiple layered steel?

Hard to tell for sure but rear suspension “Dog bone” rocker appears to be aluminum?

Any one notice anything else?

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1 hour ago, bajatrailrider said:

No end to jokes about new crf250. One gear less then 80s Xr250r  same or more weight useless. Honda should stop production quick remember twin carb Xr200/Xr250. Two years no more. Guys this is almost 2019 no excuse for heavy short travel 5 sp bike. They only give it 5sp to cut down weight JAAAA FAIL 

True but Al Baker got them figured out for us (we had two 1984 Al Baker XR265Rs) and they were NOT 265 pounds.

Oh...  And they were fast...  Very fast...

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Personally I would take a 96 and up XR250....

Make it higher compression and a 280....

Put a pumper carb on it .. port it.. cam it ... Pipe it...

There is good about the new one... But a lot to deal with too..

I would take the $$ difference and throw it into a sweet XR build....  I have already had 2 in the past... Awesome bikes with zero problems..

 

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Personally I would take a 96 and up XR250....
Make it higher compression and a 280....
Put a pumper carb on it .. port it.. cam it ... Pipe it...
There is good about the new one... But a lot to deal with too..
I would take the $$ difference and throw it into a sweet XR build....  I have already had 2 in the past... Awesome bikes with zero problems..
 
Me too but 300cc and 305 stroke late xr250s
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I'm a big fan of 4 valve motors because they produce a broader power band with milder cam timing than a 2 valve.
I've owned XR250Rs and they are porkers, a 95 is 255lbs wo gas so about 270 wet.

A CRF250X engine weighs 58lbs, the same as a XR200 engine, a crf230 engine has been reported at 68.8 lbs, a XR250R engine at 78 lbs.  And I've got mine to have a smooth bottom end almost like a XR250R so the 250F has possibilities.
My X is a 5 speed with less spread than my 6 speed XR but because of the broad power band of the X engine it is not a problem, just less gear shifting.:banana:

I would like to know component weights to know where the pork is,  that would indicate possible mods to reduce weight.

Edited by Chuck.
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Hijack in progress...

I had a big bore awesomely modded crf250/270r for woods work....

Power was strong and a mile wide with no fall off at rev limit...

Never should have sold that bike... Regret it to this day...

But.... I have to tell you about a Yamaha 5 valve engine... And how everyone mods them wrong...

5 valve advantage comes from the large periferal available at low to mid lift... Like the 4 valve can make wider band with less valve lift than a 2 valver... Only moreso...

But they suffer from more potential reverse flow before the intakes close at lower rpm.. when their is low intake velocity...

Longer duration cams kick the knees out of their power bands... 

Soooooooo...

You don't go big cams big valves big ports....

You reduce intake port volume and increase velocity..  and make a much better short side radius to get flow to the backside of the 3 intake valves to make max use of the 3 intake periferal flow advantage...

Brutally strong and early torque curves... Mid-range of the Gods...

Anyways , I had built 2 for friends/customers in the past...

YZ250 with the 290 big bore kit... Nobody would believe the wide band mini brute these become unless they rode one... That 3 intake head set for velocity and flow.... Feeding a +40cc bore kit to 290cc... Is a beautiful thing to behold...

So.... If I'm doing air-cooled for simplicity and reliability.... I'm doing an XR280.. .

If I'm going max light and max powerful with liquid cooling...

I'm going with a YZ290 big bore...

And giving myself only the budget of a new crf250f...

Because I like to modify everything...

I will wait for a bigger aftermarket availability and a bigger supply of decently priced used crf250f's.. and then I would maybe look at it again....

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Hijack in progress...

  Pretty much like you said Mix, except I was building a CRF250 for the track. 05 model, 213 lbs w/o fuel, 290cc. Feels kinda like a really slow, super light CRF450. Just what the old man (me) wanted.  :thumbsup:

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On 11/24/2018 at 2:29 PM, scumbucket said:

It did look like it had a roller cam?

Yes, It's a roller cam. And roller valve rocker as well. I'm the brazilian Youtuber at the video. Hi everyone!

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On 11/24/2018 at 2:19 PM, adnohguy said:

Looks like a “pork chop” crankshaft
Rear shock is made to be disassembled/serviced.

Cylinder can accept a much larger sleeve.

Steering stem is steel, probably lower tree is also.

Head gasket appears to be multiple layered steel?

Hard to tell for sure but rear suspension “Dog bone” rocker appears to be aluminum?

Any one notice anything else?

Rear shock is locked like in the 230. I had to drill it to remove nitro and then dissasemble it. But the internal valve and shims stack is much better than 230

Head gasket is multiple layered steel

Dog bone not aluminum, only the swingarm is

 

WhatsApp Image 2018-11-17 at 13.36.32.jpeg

WhatsApp Image 2018-11-17 at 13.36.59.jpeg

WhatsApp Image 2018-11-17 at 13.38.37.jpeg

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7 hours ago, Chuck. said:

I'm a big fan of 4 valve motors because they produce a broader power band with milder cam timing than a 2 valve.
I've owned XR250Rs and they are porkers, a 95 is 255lbs wo gas so about 270 wet.

A CRF250X engine weighs 58lbs, the same as a XR200 engine, a crf230 engine has been reported at 68.8 lbs, a XR250R engine at 78 lbs.  And I've got mine to have a smooth bottom end almost like a XR250R so the 250F has possibilities.
My X is a 5 speed with less spread than my 6 speed XR but because of the broad power band of the X engine it is not a problem, just less gear shifting.:banana:

I would like to know component weights to know where the pork is,  that would indicate possible mods to reduce weight.

I could weight some of them: 250F steel chassis is 5.3 lbs heavier than 230 chassis. 250F engine is 6.6 lbs heavier than 230 engine. I was suprised to find out 250F steel gas tank (without gas pump) is 1.1 lighter than 230 plastic tank. I'm still weighting things.... 

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No issue for me, the old 73 XL250 I had weighed what 288 or something 'combat loaded'.  We stripped them for weekend racing, put them back together and commuted back and forth to work, stripped them down again Friday night and repeat.  The 230F reminds me of those days, and a few pounds here or there is not an break the deal' issue.

I got my 230 modded out, odds are Momma will not let me get the 250F.  She retires next year, and if you are here, you understand the Momma retirement concerns.

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2 hours ago, tatau said:

I could weight some of them: 250F steel chassis is 5.3 lbs heavier than 230 chassis. 250F engine is 6.6 lbs heavier than 230 engine. I was suprised to find out 250F steel gas tank (without gas pump) is 1.1 lighter than 230 plastic tank. I'm still weighting things.... 

figured that, they have to make the plastic thicker now for emissions, same with the old crfx vs the newer ones.  My 06 klx steel tank is lighter than 2 aftermarket plastics I have.

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  Mighty small ports in that shock piston.

4 hours ago, tatau said:

WhatsApp Image 2018-11-17 at 13.36.32.jpeg

 

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On 11/24/2018 at 10:44 AM, The Plvis said:

 

Now with English CC. Thanks for sharing!

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8 hours ago, tatau said:

Now with English CC. Thanks for sharing!

The 250F has a street bike engine in it, so it should be more reliable. I prefer the 230F engine.

Edited by The Plvis

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On 11/25/2018 at 11:20 PM, Doogee57 said:

  Mighty small ports in that shock piston.

 

I was thinking the same thing.  Looks the same as the stock 230, if my memory serves correct.  Bruce's custom billet one looks significantly different. 

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