All Things CR250

Darryl Bertram · Posted: Wed Sep 05, 2012 4:50 am Post subject:

Chris & Ian, thanks for the information. I'll check on the micrometer Very Happy

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Australian American Racing

Aussies in Texas

Andy Locuson · Posted: Mon Sep 10, 2012 11:17 am Post subject:

Anybody know if or where I can get a lightweight flywheel for a 01 ignition?

Ian Harrison · Posted: Tue Sep 11, 2012 3:22 pm Post subject:

Hi Andy

Apologies for not posting sooner, but I've been away at Laguna Seca.

I have a lightweight 2001 rotor which weighs in at 13 oz.

Here is a picture of it on the right against a 2002 rotor on the left.

It has a ceramic magnet with about 40% stronger magnetic field.

It is a direct bolt on for an '01

In practice we found that it overpowered our HPI CDI boxes (too high a voltage) and caused erratic timing and misfires, but great if you are rectifying/smoothing the output for battery charging or providing a feed for a DC CDI.

You'll see a similar rotor on a GasGas used in conjunction with the Kokusan ignition.

As I say, we use the standard '01 rotor on our own motors.

Best Regards

Ian Very Happy

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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

Andy Locuson · Posted: Tue Sep 11, 2012 5:46 pm Post subject:

Thanks for getting back to me Ian

What does a stock Honda flywheel weigh?
I'm using the stock cdi so I'm guessing that might be a issue

Ian Harrison · Posted: Wed Sep 12, 2012 3:24 pm Post subject:

Hi Andy

I'll weigh a stock '01 flywheel tomorrow, I can't remember exactly.

You can use it with the stock ignition, but you may well have the same issues as with the HPI box (i.e. over voltage). But really the problem with the stock ignition CDI box is the massive advance at 10,000rpm.

I have a customers dyno graph from a couple of weeks where we just substitited one of our programmed HPI ignition boxes for the stock '01. Nothing else was changed, just the box. You'll be amazed at the difference. I'll post that tomorrow as well.

So, forget the light flywheel . . . . . just replace the box!!

Best Regards

Ian Very Happy

_________________
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

Andy Locuson · Posted: Wed Sep 12, 2012 5:24 pm Post subject:

I would like to get more in on that box when you get a chance tomorrow thanks in advance

ted dale · Joined: 25 Oct 2004 Posts: 611

Ian is thet a kokasan or the other one you cant remember...twikysuky dinonassy cant think Laughing

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Anderson gas gas

Ian Harrison · Posted: Thu Sep 13, 2012 8:19 am Post subject:

Andy Locuson · Posted: Thu Sep 13, 2012 9:18 am Post subject:

The only thing i can say is WOW!

What the availability on one? Haha

Ian Harrison · Posted: Thu Sep 13, 2012 10:41 am Post subject:

John Michael Dillon · Joined: 26 Nov 2011 Posts: 62

Hi everyone. Been away having fun most of the summer. Bought another 80 shifter just to play with only got to race the 250 a few times.
Ian this question is towards you. I have both my 250's apart and getting parts as the budet allows. I orderd 6 prox pistons and the new ones are coated. Do I need any additional clearence???
Thanks so much
jmd

Ian Harrison · Posted: Tue Sep 18, 2012 4:57 pm Post subject:

Hi JMD

Yes the Prox piston for the '01 has changed recently.

It is still an ART piston, but it is a slightly different casting and as you say they have added a bi-sulphide coating.

We (and our customers) have run a few of them now using the same bore size as the previous piston. As yet no problems. All seems good.

But 6!! that's just plain greedy!!

Best Regards

Ian Very Happy

_________________
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

John Michael Dillon · Joined: 26 Nov 2011 Posts: 62

Andy Locuson · Posted: Sat Oct 06, 2012 7:40 am Post subject:

http://www.youtube.com/watch?v=NwjcIbRwen8

Came across this and thought it was really interesting seeing how the timing moves

Ian Harrison · Posted: Sun Oct 07, 2012 4:30 pm Post subject:

Hi Andy

Just so long as the guys realise that he has got the degree disc registered incorrectly and that's a very old Honda Ignition!!

Here is a screen shot of the '01 curve and a good basic Superkart CR250 curve alongside and a picture of the Viper rig below. I have posted before, but a while ago.

So basically with the standard Honda curve you will be losing out all the way up to 10,000rpm and after 10,250rpm there is a danger of melting due to the high advance particularly if you are using a fast burning race fuel.

Best Regards

Ian Very Happy

_________________
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