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CMB .21 LS green head

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CMB .21 LS green head

Old 09-07-2007, 07:17 PM
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Sean Bowf
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Default CMB .21 LS green head

Trying to find some numbers on a CMB .21 LS (long stroke) green head, and not having much luck with google. Does anyone know a source??

TIA for your help,
Sean
Old 09-08-2007, 09:09 AM
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Default RE: CMB .21 LS green head

What numbers are you talkin about.
Old 09-08-2007, 09:30 AM
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Sean Bowf
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Default RE: CMB .21 LS green head

I think I got what I was looking for...but...

I was looking for HP and RPM numbers, and also, it seems like CMB builds certain engines for certain applications, and was wondering if the LS was built for a certain type of hull. If full size motor theory applies to these, then an longer stroke would mean lower RPM but more torque. But I don't know if the theory applies...

Sean
Old 09-08-2007, 09:57 AM
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Dan S
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Default RE: CMB .21 LS green head

Sean,

I would say you r probably right, if we compare the LS with the Valvola, they both have the same HP but the LS is @ a lower RPM, I just don't remember by how much.

I got my LS from a member on another site (Jason Jury) and he raced the LS in an Hydro. If my memory serves me right, I believe Jerry Dunlap raced or tested the LS with very good results.

My LS used to be on an Hydro 7 liter sport from Aeromarine and is now on a Sprint Cat and the Cat was faster with it than the Hydro, mainly because the Hydro was an older heavier hull. I say was because the conrod broke, so I will be ordering a new rod.

Dan.
Old 09-08-2007, 10:07 AM
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Default RE: CMB .21 LS green head

Sean are you looking at one on a websight to get??[&:] I know which one your looking at!!!
Old 09-08-2007, 10:50 AM
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Sean Bowf
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Default RE: CMB .21 LS green head

The problem I am having...is lack of knowledge and cost. The cost is going to be as much as, or more than a whole MV...so I would not want to wind up with an engine that does not suit the applications I am looking at. And no, I am not looking at putting it in a MV...at least, not yet...

MH, I am looking at two different ones...one new, one used. Dan knows more of the whole story...

Sean
Old 09-08-2007, 01:01 PM
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Default RE: CMB .21 LS green head

Sean,

if you can get a good use one at a decent price I would go for it, but if your looking at a brand new LS which is probably close to the price of a Valvola or an RS then I would go for the Valvo or the RS.

Dan.
Old 09-08-2007, 01:07 PM
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Default RE: CMB .21 LS green head

Sean,

have a read at this site, it might help you make a decision.

http://findarticles.com/p/articles/m...12/ai_n9018499

Dan.
Old 09-08-2007, 01:32 PM
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Ron Olson
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Default RE: CMB .21 LS green head

I forgot about this site until it was mentioned in the article: http://www.seaducerboats.com/motor.htm . Not a lot of info but better thqan nothing.
Old 09-13-2007, 03:46 AM
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yolanda
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Default RE: CMB .21 LS green head

can any one help where can i find parts for the .21LS green head cmb i am looking for a cranck. i am racing now a .21RS and this motor has got it all. power and torque.
Old 09-13-2007, 05:39 AM
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Default RE: CMB .21 LS green head

Check Ron's post just above yours, and use the link. you can give them a call or send them an email, thats where I got my Conrod for my LS.

Dan.
Old 09-13-2007, 06:35 AM
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Default RE: CMB .21 LS green head

ORIGINAL: yolanda

can any one help where can i find parts for the .21LS green head cmb i am looking for a cranck. i am racing now a .21RS and this motor has got it all. power and torque.
Are you saying the RS is a lot better than the LS? Or was the comment about power and torque made toward the LS?

Sean
Old 09-13-2007, 06:57 AM
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Default RE: CMB .21 LS green head

Sean, I think he was refering to the LS, but have a read at this post in reference to Long Stroke and Short Stroke.

http://www.intlwaters.com/index.php?showtopic=22538

Dan
Old 09-13-2007, 07:03 AM
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Default RE: CMB .21 LS green head

Long stroke engines will produce more torque and less rpm, remember also to stay a .21 the bore would be smaller , in the 2 stroke engine the fuel charge would be close to the same for each but the dwell of the con rod is longer creating more grunt on the long stroke, therfore long strokers can turn more of a prop at a slower rpm.
Old 09-13-2007, 09:03 PM
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Grimracer
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Default RE: CMB .21 LS green head

I have two CMB LS Green head motors one in my Ninja Sprint and one on my Nemesis (out board)... Both are VERY strong and run well.. The outboard has won some HUGE races for me as well as the IB..

some more info for ya..
The stroke is about .020" longer then the TT motor, the gold head 14mm and the red head 14mm motors.
Practical RPMs are around 28,000 to 30,000. I have heard one spin 34,000 but it could not do it all the time...

Also.. I have never been able to tell the difference between the SS and the LS motors regardless of who made them..


Rock On

Grim
Old 09-14-2007, 11:10 AM
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yolanda
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Default RE: CMB .21 LS green head

the conrod of the ls and of the rs is the same but the cranck is diffrent. i can turn a bigger prop with the .21rs

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