All Things CR250

[Erik Frank]

Here's some more crankshaft related information:

HotRods is now making a crank for the 2005 and on CR250:

http://www.hotrodsproducts.com/index.cfm?fuseaction=cNews.view&pressreleaseid=10

It look exactly like the OEM crank. What I call "billett" Each half machined from a solid chunk of steel with no sheetmetal covers. The sheetmetal covers are what fail, especially after you rebuild the crank once or twice.


Custom cranks and two piece cylinder heads are also available from:

www.vhm.nl

I've not got any experience with them, but they are going to be more $$$ for U.S. customers based on exchange and shipping. Their products look very nice.

I'm working with a two-piece head setup from Phathead Racing:
www.phatheadracing.com

Its ok, but the inserts are all wrong for roadracing. The price is reasonable.


I've also discovered an excellent source in the U.K. for many CR250 parts

http://www.viper-racinguk.co.uk/

Excellent "stock appearing" two piece head setups, the BEST offset engine sprockets around, and experienced CR250 wisdom. Oh and 11,200 rpms GUARANTEED


Ignitions:
You can adapt a PVL digital setup or (what I did) use a Speed Concepts CR125 Four Curve Programmable unit. You essentially just swap the CR125 stator plate (one small machine mod) and use the CR250 rotor and away you go. Even the rubber case grommet is the same.

I've custom made cylinder barrell spacer plates in thickenesses ranging from .005 on up to .5" precision water jet cut. I have extras.

Pistons - I've been using OEM stock flattop. There are many options out there. Haven't had any issues with the stockers yet. Just keep them fresh. Two rings.

Hope this is useful.

-erik
_________________
Member of the Fisher-Price Racing Team

[Roger Miller]

Some interesting sites with CR250 stuff:

Hyper Racing is a Micro/Mini Sprint outfit:
http://hyperracing.com/default.asp

Another Micro/Mini company:
http://www.rtschassis.com/catalog/subcatbrowse.php?cat_ID=6

Eddie Sanders Racing is fairly well known:
http://www.esr250.com/

For interesting bling and stuff, including those finned inline coolers for radiator hoses in different lengths and different colors:
http://modquad.com/store/storefront.asp?pgID=1

[Dan Davis]

RTS's "Econ220" forged piston for cyl. reed CR's is the one I have been having decent luck with...

[Ian Harrison]

Hi Erik

Nice set of links!!

That Wiseco (Hot Rods) 2005 on crank looks ok, but a couple of questions (I presume you have experience)??

We did (once) use a Wiseco 2001 crank. We were a bit dissapointed when the crank arrived in it's nice bright Box only to see "Made in Taiwan" on the box.

Perhaps against our better judgement we used it in a race motor, only for one of the tin shrouds to disintegrate after 6 meetings. (We've never had this happen in less than 2 years on an O/E crank.

Do you know the spec of the steel used in casting the crank halves and is it still made in Taiwan??

I would always use O/E now especially as it's available cheaper than the Wiseco!!

Regards

Ian
_________________
Ian Harrison
Viper Racing UK
www.viper-racinguk.co.uk
sales@viper-racinguk.co.uk
+44 7984 225 564
+44 161 343 2009
Championship winning Superkart race team 1997-2012

[Erik Frank]

Ian

The 2005 spec cranks I've used are all OEM Honda. This Hotrods link above is a new item.

-erik
_________________
Member of the Fisher-Price Racing Team

[Ian Harrison]

Thanks Erik

I'll try and find out for future info, and post if I do.

Regards

Ian
_________________
Ian Harrison
Viper Racing UK
www.viper-racinguk.co.uk
sales@viper-racinguk.co.uk
+44 7984 225 564
+44 161 343 2009
Championship winning Superkart race team 1997-2012

[Ian Harrison]

I have been asked about our soon to be produced 6-speed Honda CR250 gearbox in other threads, so here are a few answers.

Gear Ratios
The gearbox spread i.e. percentage change from 1st to 6th is the same as our current 5 speed close-ratio box.

This of course means that the gap between ratios, is closed up, so less rev drop.

The cluster fits straight into the '02 onwards crankcases and we will have a conversion kit (no machining) to fit it into 2001 casings - if testing proves succesful, but it is tight!!

The kit comes with a new selector barrel (drum) and Centre Shift drum.

Regards

Ian
_________________
Ian Harrison
Viper Racing UK
www.viper-racinguk.co.uk
sales@viper-racinguk.co.uk
+44 7984 225 564
+44 161 343 2009
Championship winning Superkart race team 1997-2012

[Ian Harrison]

Hi Guys

All CR250's so I guess it belongs here.

Here is one of the best pictures on a rolling lap that I've ever seen

It pictures the UK 250 National field at Cadwell Park.

At the front of the field are Trevor Roberts (GP - Viper Racing UK) with Gavin Bennett (0 - GBR) alongside. On the second row are Dean Hawley (51 - Viper Racing UK) and Matthew Bett (hiding behind Gavin and a Viper Racing UK runner in 2008). On the third row are James O'Reilly (21 - Barker Racing in 2007, but Viper Racing UK in 2008) and Sam Moss (31 - running Viper power in 2007 and using his "prize" for being highest placed Viper privateer customer in 2007, of a fully prepared and maintained motor for 2008)



Enjoy

Regards

Ian
_________________
Ian Harrison
Viper Racing UK
www.viper-racinguk.co.uk
sales@viper-racinguk.co.uk
+44 7984 225 564
+44 161 343 2009
Championship winning Superkart race team 1997-2012

[Ian Harrison]

Hi Guys

A bit of technical for you on the crankcase induction Honda. Here's a couple of pictures from the Viper Racing tuning bench. 8 down, 8 to go!!

Here is a picture of the underside of 2 crankcase induction barrels. The one on the left is an '02 and on the right the '04. You can see the voids at the back of the barrel just inboard of the stud holes.

The voids are much smaller on the '04 (in fact on the '03 as well). We have never had a catastrophic failure of an '02 (as some of you have), but we did detect a crack in one before any harm was done.

My personal preferance is for the '02 in terms of the standard port configuration (less work!!). You pays your money and takes your chance.



Below is the front view of the same cylinders. As you can see the exhaust port profile and exit shape is quite different. Once we have finished with them they are exactly the same.



Incidentally the '04 barrel is destined for the US of A for one of your racers. Don't know if I'm allowed to spill the beans - - - - - so I won't

Regards

Ian
_________________
Ian Harrison
Viper Racing UK
www.viper-racinguk.co.uk
sales@viper-racinguk.co.uk
+44 7984 225 564
+44 161 343 2009
Championship winning Superkart race team 1997-2012

[Erik Frank]

Ian,

Thanks for the pics. The 2003 cylinder has the stronger lugs, with basically the same exahust port shape as the 2002. I've never seen a 2004 port, and I am surprised by how different the shape is as compared to the 2002/2003 port.


I have a 2005 cylinder I am prepping and (to me) that exhaust port looks like the the best shape yet.

-erik
_________________
Member of the Fisher-Price Racing Team

[Bernie Adamson]

[Dan Davis]

Bernie,
Who bought the Anderson Phish was driving.

[Bernie Adamson]

Larry Dobbs in Cali....
_________________
Bernie Adamson
WWW.USKGP.com

An excellent man; he has no enemies; and none of his friends like him.
Oscar Wilde

[Ian Harrison]

Hey Erik

Be careful playing with that cylinder, you don't want too much power on your latest ride, you gotta look after that passenger!!



Is the 2005 barrel the version with the "bolt-on" front, I haven't done anything with that as yet.

And no Bernie boy isn't the US customer - - - - - - not even close

Regards

Ian
_________________
Ian Harrison
Viper Racing UK
www.viper-racinguk.co.uk
sales@viper-racinguk.co.uk
+44 7984 225 564
+44 161 343 2009
Championship winning Superkart race team 1997-2012

[Chuck Bunnell]

Could someone please post the primary ratio and individual gear ratios for an '01 CR250? Thanks!