Full Tilt CR250 Build - MXA Two Stroke Hall of Fame

blackdiamond
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blackdiamond 12/30/2015 11:03am
12/30/2015 11:03am
Here are a few of the carbon fiber parts I just finished fabricating. The case saver I made from scratch from a sheet of 5mm carbon plate. The silencer is custom as well, made to OEM specs in regards to the core diameter and length. I actually cut the brackets out of a spare PC silencer I had laying around and modified them to be riveted to the carbon/kevlar tube before having them black anodized. Turned out pretty sweet. The chain guide is a slightly modified Lightspeed piece.











Camp332
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Camp332 12/30/2015 11:23am
12/30/2015 11:23am
Black Diamond, you're killing this build! That silencer looks like it might be not so quiet. Which is all good!

Thanks for all the cool photos and detailed info.
blackdiamond
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blackdiamond 12/30/2015 12:06pm
12/30/2015 12:06pm
Camp332 wrote:
Black Diamond, you're killing this build! That silencer looks like it might be not so quiet. Which is all good! Thanks for all the cool photos...
Black Diamond, you're killing this build! That silencer looks like it might be not so quiet. Which is all good!

Thanks for all the cool photos and detailed info.
Should be fairly quiet actually. It's the same length as stock, and the same diameter as a PC silencer with a much higher quality packing than stock. I think it will be fine but I will find out soon enough.
blackdiamond
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blackdiamond 12/30/2015 12:08pm
12/30/2015 12:08pm
Here is another pic of the fuel tank, these things are a work of art.



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Camp332
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Camp332 12/30/2015 12:21pm
12/30/2015 12:21pm
Camp332 wrote:
Black Diamond, you're killing this build! That silencer looks like it might be not so quiet. Which is all good! Thanks for all the cool photos...
Black Diamond, you're killing this build! That silencer looks like it might be not so quiet. Which is all good!

Thanks for all the cool photos and detailed info.
blackdiamond wrote:
Should be fairly quiet actually. It's the same length as stock, and the same diameter as a PC silencer with a much higher quality packing than...
Should be fairly quiet actually. It's the same length as stock, and the same diameter as a PC silencer with a much higher quality packing than stock. I think it will be fine but I will find out soon enough.
oh nice! The picture makes it look pretty slim.
blackdiamond
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blackdiamond 12/30/2015 12:32pm
12/30/2015 12:32pm
I agree it does look thin in the pics but I think it's just because its full length and not a shorty? Not sure.
Awesome Johnson 12/30/2015 12:36pm
12/30/2015 12:36pm
Holy shit batman! That's a nice tank. How does one come across one of them? Weight compared to stock? Badass!
Xeno
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Xeno 12/30/2015 12:58pm
12/30/2015 12:58pm
Hard core dirt bike porn
blackdiamond
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blackdiamond 12/30/2015 1:02pm
12/30/2015 1:02pm
Awesome Johnson wrote:
Holy shit batman! That's a nice tank. How does one come across one of them? Weight compared to stock? Badass!
I import them from Italy, they are about 1/2-3/4 of a pound vs stock depending on the model.
MxKing809
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MxKing809 12/30/2015 1:15pm
12/30/2015 1:15pm
Awesome Johnson wrote:
Holy shit batman! That's a nice tank. How does one come across one of them? Weight compared to stock? Badass!
blackdiamond wrote:
I import them from Italy, they are about 1/2-3/4 of a pound vs stock depending on the model.
What's one of them run, if you don't mind me asking.....?
bvm111
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bvm111 12/30/2015 4:02pm
12/30/2015 4:02pm
Travis_Hudson wrote:
Unreal. ........Woohoo
Travis... Your CR was bad ass when I met you at Hangtown awhile back, but, black diamonds is to another level isn't it?

Both sweet rides!
Olson
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Olson 12/30/2015 4:22pm
12/30/2015 4:22pm
Me too Newmann, me too.... Drool all over my keyboard.
Travis_Hudson
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Travis_Hudson 12/30/2015 4:35pm
12/30/2015 4:35pm
Travis_Hudson wrote:
Unreal. ........Woohoo
bvm111 wrote:
Travis... Your CR was bad ass when I met you at Hangtown awhile back, but, black diamonds is to another level isn't it?

Both sweet rides!
Thanks buddy, I like to think it was pretty sweet for what I was working with but this kinda is.......some next level shit. Very cool project! I will stay tuned!
fulltime wrench 12/30/2015 5:02pm
12/30/2015 5:02pm
Hey blackdiamond!

When you say a component has been "slightly modified", can you elaborate on what you did to improve the part to your standard? I have been looking up these parts trying to find out what difference there is. First it was the rear brake disc and now the chain guide.

Excellent work and amazing attention to detail! I appreciate the updated title when you post new pics.

Looking forward to the next update!
avidchimp
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avidchimp 12/30/2015 5:08pm
12/30/2015 5:08pm
newmann wrote:
I'm still here.... [img]https://www.ohgizmo.com/wp-content/uploads/2013/02/Pop-corn-hoodie.jpg[/img]
I'm still here....

I'm sitting next to Newman.
mx836
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mx836 12/30/2015 6:28pm
12/30/2015 6:28pm
This is good stuff. Love how you aren't just slapping on the most expensive parts you can find and are actually modifying and making stuff. This is what we crave. Smile

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blackdiamond
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blackdiamond 12/30/2015 7:19pm
12/30/2015 7:19pm
Awesome Johnson wrote:
Holy shit batman! That's a nice tank. How does one come across one of them? Weight compared to stock? Badass!
blackdiamond wrote:
I import them from Italy, they are about 1/2-3/4 of a pound vs stock depending on the model.
MxKing809 wrote:
What's one of them run, if you don't mind me asking.....?
They retail for almost $1000 but I discount them somewhat, usually in the $875 range.
blackdiamond
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blackdiamond 12/30/2015 7:47pm
12/30/2015 7:47pm
fulltime wrench wrote:
Hey blackdiamond! When you say a component has been "slightly modified", can you elaborate on what you did to improve the part to your standard? I...
Hey blackdiamond!

When you say a component has been "slightly modified", can you elaborate on what you did to improve the part to your standard? I have been looking up these parts trying to find out what difference there is. First it was the rear brake disc and now the chain guide.

Excellent work and amazing attention to detail! I appreciate the updated title when you post new pics.

Looking forward to the next update!
The rear brake has the holes enlarged by approximately 1mm and then I had it Blanchard ground to make sure it was completely flat. In doing so I have .030" removed from the overall thickness of the disc. The combination of the oversized holes and the reduced thickness reduces the weight about 1/4 of a pound.

If you ever have a chance to look at the brake discs on factory bikes and check them out. They are much thinner than stock. Stainless steel is very dense and therefore heavy. It weighs approximately 20% more than steel so it is low hanging fruit for weight reduction at a reasonable cost.

In regards to the chainguide, I just changed the shape a bit to make it look like a modern one on the new Hondas. The 1996-2004 chainguides are old school looking but I think they actually work better because they are a bit stiffer and keep the mud out better. The later designs are lighter but expose more of the chain, sprocket etc. The pics below show the before and after. There are also two small drain holes in the bottom to allow the mud/water to drain easier from the void between the guide and the block when power washing.





1
Awesome Johnson 12/30/2015 7:51pm
12/30/2015 7:51pm
blackdiamond wrote:
I import them from Italy, they are about 1/2-3/4 of a pound vs stock depending on the model.
MxKing809 wrote:
What's one of them run, if you don't mind me asking.....?
blackdiamond wrote:
They retail for almost $1000 but I discount them somewhat, usually in the $875 range.
I'm not sure but I'd assume that a stock tank is 2-3 pounds. 1/2-3/4 pounds total is a major weight loss at the top of the bike. Very cool.

What are the plans for the seat foam? Guts racing, think or stock. I'm gonna reread from the start because I've already forgot what was mentioned in the beginning. To much cool shit going on every time I turn around. Its like watching a factory bike coming together.
blackdiamond
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blackdiamond 12/30/2015 8:26pm
12/30/2015 8:26pm
MxKing809 wrote:
What's one of them run, if you don't mind me asking.....?
blackdiamond wrote:
They retail for almost $1000 but I discount them somewhat, usually in the $875 range.
Awesome Johnson wrote:
I'm not sure but I'd assume that a stock tank is 2-3 pounds. 1/2-3/4 pounds total is a major weight loss at the top of the...
I'm not sure but I'd assume that a stock tank is 2-3 pounds. 1/2-3/4 pounds total is a major weight loss at the top of the bike. Very cool.

What are the plans for the seat foam? Guts racing, think or stock. I'm gonna reread from the start because I've already forgot what was mentioned in the beginning. To much cool shit going on every time I turn around. Its like watching a factory bike coming together.
I meant 1/2 to 3/4 savings, not total weight. Sorry if I miscommunicated that. I will use one of the lightweight foams, not sure if it will be Guts or Think
Tokyo_Tiddler 12/30/2015 9:01pm
12/30/2015 9:01pm
Nice build, but I wondered why you went with stock suspension instead of an A-kit. I did the all the coatings on my CRF450 forks.. and they are good, but still not quite as good as my old works Showa's.
blackdiamond
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blackdiamond 12/30/2015 10:10pm
12/30/2015 10:10pm
Personally I think the KYB kit forks work better than the A Kit Showas, but that is just my opinion. I just sold a set of A Kit when I started this build and if I thought they were better I would have put them on the bike. The production forks nowadays are much closer to kit forks than they used to be. The coatings and the valving are the biggest difference (again my opinion)
Tokyo_Tiddler 12/30/2015 10:53pm
12/30/2015 10:53pm Edited Date/Time 12/30/2015 11:08pm
When you say "kit fork", since I believe you are using production CRF based upper and lower tubes, were you able to get a hold of KYB B kit dampening rods/ internals or something?

On my 450 I used the production 2012 CRF450 KYB fork, Kashima/DLC coatings, CNC lugs, CNC fork caps, changed the oil lock collars, pressure springs, spring perches, low friction seals, etc... just about everything you could do to a stock fork.. and they are better, but just could not get the same feel as the works Showa's on my CR250 which has regular seals and no coatings on the lowers. I compared the internals with the Showa stock ones and while they look identical with the exception of the kashima coating on the works dampening rod, the works dampening units were much smoother which made me feel that is where much of the meaningful difference is besides the valving.

Also, on the rear shock, I heard many people were replacing the rebound on the 2015 shock with the old style on the lower clevis, claiming it worked better. I see that you preferred the 2015 configuration.

Looking forward to seeing the final build! Cool ride!

mike
blackdiamond
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blackdiamond 12/30/2015 11:47pm
12/30/2015 11:47pm
Tokyo_Tiddler wrote:
When you say "kit fork", since I believe you are using production CRF based upper and lower tubes, were you able to get a hold of...
When you say "kit fork", since I believe you are using production CRF based upper and lower tubes, were you able to get a hold of KYB B kit dampening rods/ internals or something?

On my 450 I used the production 2012 CRF450 KYB fork, Kashima/DLC coatings, CNC lugs, CNC fork caps, changed the oil lock collars, pressure springs, spring perches, low friction seals, etc... just about everything you could do to a stock fork.. and they are better, but just could not get the same feel as the works Showa's on my CR250 which has regular seals and no coatings on the lowers. I compared the internals with the Showa stock ones and while they look identical with the exception of the kashima coating on the works dampening rod, the works dampening units were much smoother which made me feel that is where much of the meaningful difference is besides the valving.

Also, on the rear shock, I heard many people were replacing the rebound on the 2015 shock with the old style on the lower clevis, claiming it worked better. I see that you preferred the 2015 configuration.

Looking forward to seeing the final build! Cool ride!

mike
I am running the works free pistons, oil lock collars and spring perches in addition to the coatings.
cmotodad
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cmotodad 12/31/2015 12:56pm
12/31/2015 12:56pm
On the Lightspeed C/F chain guides built for Factory Honda, they are having him make them solid. He said they had a problem or 2 with rocks going in the holes. It is more weight, but interesting to note.
Jrewing
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Jrewing 12/31/2015 3:08pm
12/31/2015 3:08pm
As mentioned before TM 2 strokes run electronic power valves with tps/gear position sensors. They do have much experience in the kart game as well.

Love this build- best ever. I love machining stuff instead of bolt ons. Or even better machining the bolt-ons!

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