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Harry Lilli replica CNC head
- Thread starter 270YAM
- Start date
Yes they are and as far as using the appropriate pistons(which cost $300 A POP) with the Lilly head to take full advantage of the special Squish chamber then "NO" there is no one on this site that I know of.If you have very deep pockets and plan on racing the XS go for it but for daily street operations the XS head with a little attention to detail will flow better in the lower lift spectrum where's it's need for street use for a lot less money. If you can get a hold of the early XS head "70's" they have better uniformed intake and exhaust ports to work with. The flow curve of the XS has the inherited tendency to spike early then diminish rapidly off causing the port to stall at higher lifts and this is where the Lilly shines allowing increased breathing at higher RPM's over a street ported head( but with some good old JBWeld the stock head can be reworked to bring that XS alive) ,never port for maximum gains,port to the cam if possible.
racerdave
^ Gone not forgotten ^
Do a search for Harry Lilli replica CNC head, and Harry Lilli yamaha. A lot of interesting info comes up.
Your welcome
some info you'll never be able to search
dwyatt
XS650 Addict
I have one on my roadracer and am very pleased, but I agree with Jack. For a street bike, it's overkill, but for a racer, a great way to go. Get the modification guide from MMM, it goes into all of the details, including piston, valve, exhaust and carb options and explains their different affects.
racerdave
^ Gone not forgotten ^
dwyatt, I just went to MMM site and seen the page about that guide. Can you tell me, is it photocopied loose leaf style in a binder, or bound like a shop manual?
dwyatt
XS650 Addict
It's a downloaded PDF file that you can print out. Great info and explanations for both race and street motors. Well worth the money even if you don't decide to get the head work. Since I was building a race motor, I studied this thing for hours.
650performance
XS650 Addict
We've shipped at least five CNC heads to racers in Australia and New Zealand. If you ask around I'm sure you'll be able to get first hand info about whether they feel they obtained sufficient bang for their buck.
In reference to Jack's previous comments, I agree the head is overkill for a street bike (although Tony Guest's tracker is very cool with 68 RWHP and great "streetability"), however I don't agree that the Lillie porting is substandard at less than upper RPMs. I offer as proof both the street user-friendliness of the Guest bike and the fact that Steve Eklund won the Peoria TT - a race where only a very small percentage is spent at high RPM and wide open throttle - with this porting and 34mm carbs against the best AMA pro-level bikes and riders.
dwyatt, send me an email and tell me about how China is going.
Craig
In reference to Jack's previous comments, I agree the head is overkill for a street bike (although Tony Guest's tracker is very cool with 68 RWHP and great "streetability"), however I don't agree that the Lillie porting is substandard at less than upper RPMs. I offer as proof both the street user-friendliness of the Guest bike and the fact that Steve Eklund won the Peoria TT - a race where only a very small percentage is spent at high RPM and wide open throttle - with this porting and 34mm carbs against the best AMA pro-level bikes and riders.
dwyatt, send me an email and tell me about how China is going.
Craig
Craig
Glad to see your still hanging around the sites,did you get my email? And please re-read my post to get the facts straight as no one mentioned anything about the Lillie head be substandard in the lower spectrum except for you
,that's the problem with the internet most misinterpret whats actually being said.Jack
650performance
XS650 Addict
Jack, I did get your email but the only address was the forwarding address, not your individual email. Plz email me directly. I do have the info for you.
Thanks,
Craig
Thanks,
Craig
Craig, problem is I have misplaced your email,please Pm me. Been in touch with 270AM via email and he's placed a Lillie order and he's got one wild trenching combination in the works
here's a shot of the dual catching some air
here's a shot of the dual catching some air
650performance
XS650 Addict
Thanks I'll be in touch soon.
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