We finally are getting seriuos about the 150r Tuf has been supplying heads to mx world in england the results have been good so im in the prcess of developings a cam mx world has been doing the testing trial and error and has found the best components they sent over the best working cam and i have checked it and found comparable lobes just slightly more agressive while maintaining opening and closing times .Im also working on a much more agressive lobe desighn with comparable opening and closing events but as much as 12 degrees more dwell 2 the higher lifts its going to requier mods to the cam lobes width and the cam holder it will also require a more serious spring package and lighter valves .mybe with some time and devlopment we can have a package comparable to a super mini the 112s are going to be tough to beat .

I wonder what all JGR does to Cooper Webb's 150r? That thing rips!

Wandell said:

They could run a stock motor and with Cooper on it, it would still rip.  He's just fast.

I see your point, but that 150r is a long way from stock. A friend's son races against him and his KX100 screams so that 150r has to be a beast.

Wandell said:

His bike is good for sure - but they are fudging the rules a little too..

For instance the exhaust is a much larger core, huge outlet, and very short can coupled to a one off header.  

Not even close to sound rules (but no am nationals test).


I watched it at LL last summer and was very impressed by it - but it had no bottom for a four stroke - very two stroke like (needs to be to compete in HP with the 112s)

This year at oakhill a different 150 holeshot almost every moto in front of cooper....so whoever was doing it had what I presume to be a little more power (talking 8/10 holeshots - no fluke)


I think the 150 will not compete with a good super two stroke in peak but it should be close in avg power - as a good 112 can pump over 30 horses to the wheel. To get a 150 there - it would take an estimated 14lb/ft at 11k for  BMEP of over 230.  Factor in transmission losses - and actual BMEP would have to be even higher...making it somewhat unrealistic to achieve that...

But - I see 27-8 hp within reason - and that would certainly be impressive

Ron....

soon i will be tearing into the Venom CRF150.... i did all the baseline runs last season...

no mods yet.... you know my own engine building preference is to spend the least $$ for an endurance engine setup....  growing up dirt poor and fatherless made me focus on that early on... and i guess i'll never shake that sort of focus if i haven't by now...

anyways.... i would like the piston i develop to be part of your build if there is a place for it....stock bore ok?  big bore?

my own focus will be to go for as much compression as possible without compromising the efficiency of the combustion chamber.... 14+ comp range....

with as small and fast buring + detonation resistane as this combustion chamber is, i would love to be able to get 14.75:1 compression if possible

i already have a hot cam stg 2 for testing with.... but...i would be happy to do a comparo with a RHC cam too....

Nice to see some real development going on for an engine that Honda will probably redesign in the next year or two.  Not that there haven't been engine builders working hard on this engine since it hit the front door of the local shops!  If you look at Hondas history they change up engine designs typically every 4-6 years with their 4-stroke engines. In the past there have been a number of good engine builders who went all out for development and then within 1-2 years Honda up and came out with a new engine.  Most of it is marketing since whenever you build the same basic product year after year the buying public goes looking for something different and "NEW"/better!  The RFVC engines were their longest running design but they eventually changed them from dual carbs to single carbs and then to non-RFVC designs.  Love to see good Race engines developed, but watch out for a dying market due to design change!
Swiss

The pepole that we are working with in england have pretty much done all the testing all the cams. Im working on a cam simlar to what they found to work and then im having one made to my spec much more agressive in the cam velocities the cam holder will require work.of all the pistons they tested the procircut J&E and the costworth worked they said the cp sucked.there is a limit on compression  in theses engines the short stroke and bore make it dificult to get a high compression ratio with out sacrificing a good burn .TUF isnt really interested in building play bikes .most of the cam development will always transfer over into the new desighns it may require a diferent billet though .

part of the compression raise in mine will come from custom profiled flat faced titanium valves that kibblewhite is going to make for me....  flat faced valves make for a better combustion chamber than do bump pocket pistons....

becarfull on the ti valves on the exhaust side you have to pay atension to exhaust temps and keep track of hours the stem is quite small and they will fatige even faster with the rocker arm working @ them the only way i could keep a ti valve in the exhaust side was to go to 5.5 mm and use bronze alloy seats a nd bronze guides the seat width was also critical in pulling heat out of the valve the narrow seats may have flowed better on the bench but there was no measurable performance difference.you will eventually break an titanium exhaust valve on a honda

wonderful information Mr. Hamp.... thank you for taking the time to share it....!

Ron Hamp said:

I was planning on a CP 13:1 soon. Why did this piston not work well? Is it a bad piston in high output situations, like what you are talking about here, or will it work ok for a stock upgrade?

My engine is stock with about 12 hours, I am looking for a little bump in overall power/torque without changing pipes, cams, or jetting. I thought a 13:1 piston will do this.

If not CP, which piston is best for stock replacement?

I wonder if Honda will bump the compression on the 12s.

Ron, any follow up on this info?  Dyno chart and numbers?

Swiss

Ron,

Still no news?  Is development continuing with these engines or have you stopped?  You brought out some teaser informaiton and then dropped the ball in continuing to inform about what is happening?

With the release of these bikes again for 2012 there should be some new interest in building them.  Did the 5.5mm exhaust Ti valves work well and have an improved liftspan over the stock diameter valves?  No dyno reports or tech info available?

Swiss

I wonder why nobody makes super/turbo chargers for these bikes. You should make a kit for that. But it probably wouldn't be legal for real racing. ;(

Frist thing you run in to is dirttbike don't have room for this.
You have to run a low compression ratio below 9:1 idea you want 8:1
A strong forged crank and connecting rod is a must
A strong clutch
A better cooling system
A more powerful ignition system that progarmable
A free flowing exhaust.
The superchargers can be done but hard find ready made that small of packeage
The turbocharger can be done but there a one problem know as Turbo lag and look up IHI RHB31 turbo go to MBE Motorsports
Both will cost you a lot of time and money

They make one for a wr250....
http://www.mpfab.com/wr250/