07 ported head


28 replies to this topic
  • jjgixxer

Posted February 28, 2007 - 10:37 AM

#21

RHC
Are you doing any work on the YZ 250f? If so, what kind of performance gains?


My thoughts also... :applause: I have heard of 44 hp yami 250f's with hugelift and 14:8:1. I would like to see one built with less lift and less compression.

  • TexN343

Posted February 28, 2007 - 11:23 AM

#22

There is no excessive wear on the motor? Is the bike as reliable as stock? Do valves last as long? Where can I go to find more information on getting this type of work done.

  • YZ_Abuser

Posted February 28, 2007 - 11:34 AM

#23

In a previous conversation with Ron he didn't seem big on blue bikes. My impression was he'd rather spend his time on a head configuration that would yield better results. If the head configuration changed on the 450 maybe it did on the 250 as well?

  • grayracer513

Posted February 28, 2007 - 12:11 PM

#24

There is no excessive wear on the motor? Is the bike as reliable as stock? Do valves last as long? Where can I go to find more information on getting this type of work done.

Contact Ron Hamp Cycles. Other companies do this stuff as well.

ANYTHING you do to create more power puts more stress on the engine simply by virtue of transmitting that extra force. Additionally, the gains of which he speaks were not achieved by porting alone, and the more aggressive cams, etc., that are usually involved do come at a cost to overall reliability compared with the stock engine. But the question is, "how much more prone to failure will it really be?", and whether it becomes impractically unreliable or not. No one is going to deliberately build a racing engine that isn't going to finish races, although they might build them that need frequent rebuilding.

Ron's a good guy, and you'll get straight answers from him.

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  • Ron Hamp

Posted February 28, 2007 - 12:39 PM

#25

as far as building 250s goes i have always built what the customer wanted no special porting or larger valves always there specifyed cams and we still nearly acheived 40 hp I think if the time and money were put into the 250 head that was put into the 450 that i just did that pro level hps could also be acheived with a very strong midrange which some of the pro 250s are lacking in because there getting there power from the cams mainly and not better head desighns .

  • Eddie Sisneros

Posted March 01, 2007 - 09:27 AM

#26

our 40hp yzf 250 has been stone reliable.

the only failure weve ever had was a shim bucket that exploded after about 200hrs.

  • jjgixxer

Posted March 01, 2007 - 10:59 AM

#27

our 40hp yzf 250 has been stone reliable.

the only failure weve ever had was a shim bucket that exploded after about 200hrs.



Are you running the 450 carb ?

  • Eddie Sisneros

Posted March 01, 2007 - 06:31 PM

#28

RHC modded carb.

  • swatdoc

Posted April 01, 2007 - 12:29 PM

#29

Ron - any update on these Yamaha 450 heads? And are you using stock or oversize valves? What cams are recommended with this setup for supermoto use? I'm using your 187 cams in my DRZ SM - would that profile work well in the Yamaha as well?
Thanks





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