Author Topic: Need help w/ cylinder head  (Read 828 times)

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Offline rotten ron

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Re: Need help w/ cylinder head
« Reply #15 on: July 11, 2018, 09:19:06 PM »
Years ago I built a 250 Rotax for a friend who raced a shifter cart ,the engine is a 2 cylinder ,2 stroke and is water cooled    I spent quite a few hours porting and welding , I don't know how much power it had but at a race at Mid Ohio he was clocked at 163 miles per hour and he said that was on a slow part of the track, there are 125 shifter carts too they only use half of this engine,each cylinder has its own crankshaft

Offline BIG AL 202

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Re: Need help w/ cylinder head
« Reply #16 on: Yesterday at 01:05:55 PM »
When building a flathead you need to remember compression is not as important as flow! when you port a flathead just clean up the ports, no need to make them bigger. If you go Way back in the flathead section you WILL learn a lot about the flathead. Just doing a good valve job and cleaning up the ports will make a big difference on how well it will run. B&S goes by cubic inches not horse power. The 28ci goes by 12, 12.5, and 13 horsepower. The 11hp or 25ci head will raise compression but folks will debate on whether or not it helps. Some depends on what else you do, cam, carb, ports, flywheel and so on. Yes the lighter aluminum  flywheel will add performance!  GOOD LUCK with your build!
ALWAYS VOTE FOR ED!   FONGS BROTHER FROM ANOTHER MOTHER!

Offline rotten ron

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Re: Need help w/ cylinder head
« Reply #17 on: Yesterday at 08:46:35 PM »
When Ryan Kerr raced with the Kohler he used no flywheel at all ,The only thing he had was a piece of quarter inch aluminum with magnets to trigger the ignition .When he raced in Delaware Ohio  2008 and won the finals I was talking to Bobby Clevland and he wanted me to show him Ryan's mower .When I told him about the no flywheel he wanted to see what it was about,I don't think he believed me.


Offline PJG56

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Re: Need help w/ cylinder head
« Reply #18 on: Today at 07:41:44 AM »
When Ryan Kerr raced with the Kohler he used no flywheel at all ,The only thing he had was a piece of quarter inch aluminum with magnets to trigger the ignition .When he raced in Delaware Ohio  2008 and won the finals I was talking to Bobby Clevland and he wanted me to show him Ryan's mower .When I told him about the no flywheel he wanted to see what it was about,I don't think he believed me.

Isn't this a little off topic :twocents:
Paul Guptill  (oppy) #238modX
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2014All American Champion FXT (engine builder)
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2016 OutlawTriple Crown FXT Champion (engine builder)

 

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