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Chris Reinhardt
Joined: 29 Aug 2002
Posts: 2933
Location: United States, New York, Ossining
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 Posted: Mon Feb 04, 2013 6:02 pm Post subject: CRF450 vs CR250 Weight |
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OK so I was finishing up a CRF450 build and I was eye balling the barrel reed CR250 on the other bench. I picked up and moved the 250 from one bench to the other and thought: "Hmmm, that 250 isn't all that light".
I always wondered how much heavier the 450 was, I was happily surprised that it was A LOT less than I thought...
I removed the starter BS from the 450, but it's still in the 250, so lets call 10lbs different. That's also an earlier 450 with an aluminum left case cover, the 04 and up use a magnesium cover, that would make it even closer....
So all said and done, maybe we're talking 6 to 8 pounds, still a lot closer than I would have thought.
CR
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Chris Hegar
Joined: 25 Jun 2002
Posts: 3534
Location: United States, Oregon, Portland
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| Posted: Fri Feb 08, 2013 12:42 pm Post subject: |
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450-250=200 lbs difference duahhh 
450 apples in Billy's basket and 250 banana's in Suzie's basket, what's the difference in fruits?
200 nanna's and apples silly!
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Chris Reinhardt
Joined: 29 Aug 2002
Posts: 2933
Location: United States, New York, Ossining
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| Posted: Fri Feb 08, 2013 12:49 pm Post subject: |
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| Chris Hegar wrote: | 450-250=200 lbs difference duahhh
450 apples in Billy's basket and 250 banana's in Suzie's basket, what's the difference in fruits?
200 nanna's and apples silly! |
Don't you have 50mm sprags to build?
CR
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Chris Hegar
Joined: 25 Jun 2002
Posts: 3534
Location: United States, Oregon, Portland
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| Posted: Fri Feb 08, 2013 3:02 pm Post subject: |
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Naaa I ran without one last weekend I'm fine. It's just me and this intranet thing now, I gots nothing better to do. 
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Chris Reinhardt
Joined: 29 Aug 2002
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Location: United States, New York, Ossining
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marc walsh
Joined: 11 May 2011
Posts: 132
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| Posted: Mon Apr 08, 2013 2:33 pm Post subject: 450 |
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| My buddy runs a CR 250 in a Tony Kart and loves it. I wanted to put one in my 2011 Road Rebel for grins. I was told I would have to run a counterweight?? What do you guys think of this mod? |
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Ian Harrison
Joined: 23 Nov 2006
Posts: 1671
Location: United Kingdom (Great Britain), Manchester
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| Posted: Mon Apr 08, 2013 6:27 pm Post subject: Re: 450 |
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| marc walsh wrote: | | My buddy runs a CR 250 in a Tony Kart and loves it. I wanted to put one in my 2011 Road Rebel for grins. I was told I would have to run a counterweight?? What do you guys think of this mod? |
Hi Marc,
To one who has spent his life living, breathing and making a living from CR250 engines and karts/Superkarts . . . . . please could you define what you mean by a counterweight?
If it's to do with weight distribution then just move the biggest weight that's on the kart (commonly referred to as your "ar*e"). Last thing you want is extra weight provided you meet the class minimum.
If it's to to with the engine . . . . you got me lost!
Best Regards
Ian 
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Ian Harrison
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marc walsh
Joined: 11 May 2011
Posts: 132
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| Posted: Tue Apr 09, 2013 3:50 am Post subject: cr250 |
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Something about the engine being heavy so I was told to move my A** and seat more to the left. Ive got bids on a 99 cr250. Not sure what it will take to make it...KARTABLE  . Powervalves etc |
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Chris Reinhardt
Joined: 29 Aug 2002
Posts: 2933
Location: United States, New York, Ossining
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| Posted: Tue Apr 09, 2013 4:22 am Post subject: |
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OK, I was scratching my head also, I was thinking you were talking about a counter balancer in the motor, which I've never seen on the CR250.
The barrel reed cylinder power valves are easy to plug up the with the "kit". The next issues are the pipe and ignition. There aren't many choices for pipes, and as far as making it work together, there isn't many choices either.
Give Mr Harrison a call, he'll set you up....
CR
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Johnny West
Joined: 03 May 2002
Posts: 1182
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| Posted: Tue Apr 09, 2013 11:41 am Post subject: Cr250 |
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You can put a cr cylinder on a TRX bottom
End you need to modify it to accept the cylinder.
This has a balance shaft. I has been done before.
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Chris Reinhardt
Joined: 29 Aug 2002
Posts: 2933
Location: United States, New York, Ossining
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| Posted: Tue Apr 09, 2013 12:29 pm Post subject: |
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Yup, been there done that, but that's not a CR, it's a CR/TRX Hybrid...
In theory they have all the best parts, 6 speed, balance shaft and a powerful CR top end, in reality they weren't that great in a superkart....
CR
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East Coast Super Kart Series
"This is how we roll!"
www.eastcoastsuperkart.webs.com
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www.CR2MotorSports.webs.com |
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Ian Harrison
Joined: 23 Nov 2006
Posts: 1671
Location: United Kingdom (Great Britain), Manchester
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| Posted: Tue Apr 09, 2013 6:06 pm Post subject: Re: cr250 |
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| marc walsh wrote: | | Something about the engine being heavy so I was told to move my A** and seat more to the left. Ive got bids on a 99 cr250. Not sure what it will take to make it...KARTABLE . Powervalves etc |
Hi Marc, yes that's exactly it. Move your a*** but don't add any extra weight.
You want to end up with around 40 - 45 kg (88-99 lbs) evenly balanced on each front wheel and the balance on the backs as evenly split as you can. Ideally you don't really want to pre-load any twist into the chassis to achieve the front balance. In practice a couple of mm is OK.
If it's purely for "grins", then there is surprisingly little you need to do, but do the following all at once. they go hand-in-glove.
1. Have the head machined to reduce the squish clearance to about 1.3mm and increase the volume to 23cc.
2. Add a decent bespoke kart pipe/silencer that will allow the motor to rev-on.
3. Fit an ignition system with a decent curve.
From there you can spend a fair amount of money to get your motor to top racing spec.
| Chris Reinhardt wrote: | Yup, been there done that, but that's not a CR, it's a CR/TRX Hybrid...
In theory they have all the best parts, 6 speed, balance shaft and a powerful CR top end, in reality they weren't that great in a superkart....
CR |
And the shittiest set of gear ratios you've ever seen for a circuit racer! Very old school and not worth the effort.
Best Regards
Ian
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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 |
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Chris Reinhardt
Joined: 29 Aug 2002
Posts: 2933
Location: United States, New York, Ossining
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| Posted: Tue Apr 09, 2013 6:53 pm Post subject: Re: cr250 |
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| Ian Harrison wrote: |
| Chris Reinhardt wrote: | Yup, been there done that, but that's not a CR, it's a CR/TRX Hybrid...
In theory they have all the best parts, 6 speed, balance shaft and a powerful CR top end, in reality they weren't that great in a superkart....
CR |
And the shittiest set of gear ratios you've ever seen for a circuit racer! Very old school and not worth the effort. |
Exactly, like I said, they looked good on paper  I never did finish one for a kart, good thing.....
CR
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East Coast Super Kart Series
"This is how we roll!"
www.eastcoastsuperkart.webs.com
CR2 Motorsports
"Home of Cobalt Superkarts"
www.CR2MotorSports.webs.com |
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