I need TECH HELP!!!

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brap337

Member

Apr 9, 2006

2

0

• Apr 9, 2006

• #1

I have a 2001 CR 125 with some mods to it. I have a Phat Heads Racing head on it, vforce reeds, FMF fatty pipe, flat top piston kit. Im having problems with keeping the top end intacted. It seems like I have to put a new top end in after every other weekend of either riding or racing. Im using the recommended 32:1 fuel to oil mixture and Im running premium gas with motul oil. Does anyone have any sugestions or has anyone delt with Phat Heads before.

 

robwbright

Member

Apr 8, 2005

2,283

0

• Apr 10, 2006

• #2

Does the cylinder measure within spec?

What symptoms are telling you that you have to put in a new top end?

 

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brap337

Member

Apr 9, 2006

2

0

• Apr 11, 2006

• Thread starter
• #3

I bought a OEM cylinder last year so i know that it is good.

The symtom that is telling me the top end is bad is not compression what so ever and when i take the top end out the ring is always stuck in the piston land. I emailed Phat Head Racing last night and they told me to run 100+ octane gas to cool the engine more.

I have another Question too.

What do flywheel weights do?

 

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NacNac250F

Member

Apr 15, 2003

154

0

• Apr 11, 2006

• #4

If your running pump gas in a race gas setup detonation could be your problem. Try running race gas with your next top-end and see what your cylinder walls look like, see if theres burn marks or if its scored.

 

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Chili

Lifetime Sponsor - Photog Moderator

Apr 9, 2002

8,062

17

• Apr 12, 2006

• #5

Those Phat Heads come with different domes for the head don't they? I thought that was their gimmick. If so run the lower compression one for pump fuel or run the pump gas with the high compression dome.