Correct.

 

But they can be made to fit

 

not trying to be wise

but

why bother when were getting 15.4 hp from a 57mm bolt on ported lifan head

 

ego

 

ego

You are correct

 

Just never had one. I was just doin it for the experience and to learn more about the head. My Lifan head does do well like you say. 16hp? baby stuff.

 

Dyno numbers are like a fingerprint,everyone has one and there all different. And most are like intestines full of sh!t.

 

just my 2 cents, but china has designed a twin cam head... Havent seen it released yet, but have seen the pictures, and have heard the name of the people most likely distributing....... Totally unsure of measurements, but I'm led to believe it'll fit lifan.

 

Ill keep an eye out for a dual cam head that would fit the studs. As far as dynos go... Big numbers dont mean everything in the dirt or on the street. And you notice, these guys always doing the dyno threads. They never make more than 20hp. There are motors that make over 20, and they are members of this site. They just dont get involved in all the kiddy crap and tell about it. Dynos dont win championships. Thanks for the info, keep me posted on what you find if you would.

 

There are also likely members of this forum that have video footage proving Bigfoot exists. I bet you can guess why they haven't posted that either...

 

Dynos are pieces of paper and the chinese motors do put out some bigger numbers but the bottom ends still have issues holding up to the power that needs to be solved first before you put a DOHC head on one.

 

Dynos are pieces of paper and the chinese motors do put out some bigger numbers but the bottom ends still have issues holding up to the power that needs to be solved first before you put a DOHC head on one.

really because cat5 in FL put one on and the thing is ripping, and holding up well so far.as well as others.

 

dont need dynos to prove our chinese builds make power, we win and the next issue of minmoto magazine will show just that.

 

Fair enough Hack, but some of us don't have raw skill and talent, so we need dynos for comparison 'cause our riding style doesn't let the motor show itself off.

 

Kurlon. If they post them ill look. But dont expect to see any from me.

Skin. I have had no problems with my bottoms. The shifting deal seems to be an easy fix.

 

Fair enough Hack, but some of us don't have raw skill and talent, so we need dynos for comparison 'cause our riding style doesn't let the motor show itself off.

dyno comparisons are like saying my mommy will beat your mommmy up.....

 

whys everyone bitching about dynos i think the gentlemen just wanted to know if it would work on the chinese stud spacing not how much power it will get

 

I think it would make more power though too. I dont see how the fuel and air could not mix better going through two smaller valves than one big one. The exhaust could escape better i think also.



Bottom line, there cool, there expersive, ive never had one, i want one, they have to be somewhat better.

 

well that depends on who you ask on power. alot of guys are pushing the 2 valves some still go with 4 valves. fuel and mix does mix better with a 4 valve setup. i myself pefer the dohc setups i have a takegawa 124 dohc and am currently trying to make it into a 143 or 146 dohc. but then you guys like rk finch thats makeing these monster hp 2 valve motors with 31mm 24 or 25mm valve setups. i have both the the take 124+r and i have a 124 take dohc i rode them both on the same tracks did lap times with both and i was faster alot faster on the dohc. each motor was set up with same pipe carb etc... only difference the dohc ports were mildly cleaned up but when i sent it to kenny he said the + r head still flowed a higher rate than the cleaned up dohc so that didn't even get it a flow advantage. i felt the + r was lacking alot of hp compared to the dohc it did feel a lil more torquey as the dohc. but on the same note i had a number of other guys put some time on both motors from some buddies i ride with to a couple i don't know. and they would all put better times on the +r. the dohc takes a different kind of rider than the other motors out they are high strung power comes on like a light switch. so it pretty muchs comes down to personally preference, riding style, and how deep are your pockets. if you have a big ego deep pockets and just like rev the cock out you motor by all means get a dohc you'll love it. but if your looking for lower rpm power and a wider power curve get a 2 valve motor. big hp can be had with both motors the 2 valve can be done alot cheaper is the difference. before i tore mine down mine pulled a 18.6hp with 8.8ft/lbs rkfinchs that he posted which i know he got more out the same more with getting it tuned in pulled a 17hp with 10ft/lbs hope this helps you out

 

A dohc can be put on a china motor easy just get a hold of a xtreme bottom through the dohc piston and head on and bore the china cylinder to 54mm and you got yourself a 131 DOHC. For dohc you will have to use the appropriate cam chain too. Guy Cooper runs that setup and has been for a couple years.

 

The disadvantage to current DOHC heads is the valve spacing. They are sized for 54mm bores, and are difficult to rework to take advantage of larger bore sizes. 2v heads are easier to rework to scale up, hence their popularity with the big displacement import motors right now.



Ducati has had the same handicap, their 4v heads for a long time (Up through the 996) were sized for a 748 bore, restricting how much they could increase the valve size without coming up with a new casting and reworking the desmo geometry. The 998/999 heads were built with a bigger bore in mind, and the motors scale better. The 1098 head should be even better as it's a new design.



On the flip side, when you compare valve area to bore, you'll find Ducs have been way down compared to the competition, yet have still been quite competitive. So valve size isn't everything.

 

Just like I said before the Chinese motor thing is exploding and you can get some serious Hp out of them. But now even Daytona is offering complete motors both 2 valve and 4 valve built on OEM honda cases and using OEM gears and the prices are very reasonable. A 2 valve 108 Daytona is under 1200 bucks and the others are very well priced too and these motors are being offered in Chinese built Chassis.



I have been around the Chinese thing for awhile now and I still say that if you want the most depedable motor stick with Honda parts unless you plan on spending tons of cash and time to make a Chinese motor durable. Yes it can be done yes you can do a all up shift pattern get rid of the false nuetral Yes you can build huge displacment motors but the kick back from the compression will destroy your kick start gears and crack your cases. Yes there are some people working on getting a compression release but we have not seen one for the mass market yet. I also know that there are many other parts that get tore up when these motors are built. Transmissions get tore up shift forks bend and wear out. The tolarances and materials in Chinese motors are just not up to par yet. But yes the Chinese are working on it but only because companies from outside China are helping them design them.



The Vegas race is a killer race but no Chinese motor has ever even come close to winning it and thats a fact even the Chinese bikes that did well were using Honda based power plants. example Guy Cooper with his Kitaco and Takagawa motors in his Extreme



Question if you were going to Vegas what would you feel more comfortable with Chinese or Honda?? its just a question not saying that the Chinese motors are junk because we have won many races with them they even beat the DOHC's at some races. But would you chance or take the risk of spending all that time packing up hitting the road to get to Vegas pay the prices to race and risk loosing because of engine failure?? I would wait for some more testing I would want to know for sure if they will hold up. All I'm saying is things take time to be proven and rushing head long into building these motors and risking the loss of a race and image of your company is not the wisest thing to do. I would stick with what is currently proven before putting my unproven motor into a national race with all eyes to see.

 

I hate to be the one to do this Skin but, so what? We all know we're dealing with ticking time bombs. That's half the fun for some of us. I agree, if I'm going to Vegas or a similar high profile event whatever I'm packing will be in matched pairs, and will be stress tested thoroughly before it ever sees competition. That said, builds to push the envelope and see how far you can go have their place as well. If we all wait for 'someone' to do this testing and refinement, it'll never happen.



This thread started as a discussion of the possibilities of a china bottom end with a 4v DOHC top end. No one brought up storming Vegas with such a setup yet. It's a back of a napkin note scratching session, why come crashing in with reliability concerns? : )



Now horde, if you've got any leads on the import 4v heads, share! : ) I've got my own cocktail napkin notes going for a build, and I'd love to fondle a chinese 4v head to see how it'd fit my nefarious plans.

 

I have also heard that Lifan has a new head with a 25/28 valve combo not sure what size motor it will be availible in but I'm going to try to get a sample or 2.



Yes Kurlon you are right but even loosing a local race because of failure sucks.

 

its about choices

and the simple fact is that some guys have no choice other than to run a china motor

and now we have the power to compete with the japan motors

so if your on a lower buget u can still race at a high level



an yes the cat 5 dohc 131cc factory thumpstar is for real !