Head Design

[Poulsen8r]

I'm not sure if this has been talked about before and i know it's old news but im trying to work out whats better about a 4 valve head on these mini's... i'm kinda looking for numbers or data to support your claims as well not just "4 valve is good"...

I read in this thread http://www.miniriders.com.au/tech-talk/17124-china-bike-122cc-dohc-4-valve-project.html that he is using 19.5mm intake and 16.5mm exhaust valves and i did some calculations and the total intake from the 2 valves is less than a 28mm single valve and the total exhaust flow is way less than a single 24.5mm exhaust valve. i know in that thread it was just a project to see if it would work, but i see dirtmax has a four valve head in their catalogue and i can't seem to find a reason why it would be good...

 

[Cactus Jack]

Multi-valve - Wikipedia, the free encyclopedia

 

[headsmess]

see? bigger diameter= mass= inertia=slow to change direction= valve bounce... and the smaller valves can cool down a tad quicker too... wwii fighter planes even went as far as having hollow valves full of SODIUM to help cooling.
and the smaller valves can have more lift and still clear the piston at tdc, etc etc etc...its a long list of reasons really...

 

[headsmess]

i was referring to that link bro. and damn...that is some work on that head tormented made far out. wish i was allowed to do foreign orders at work

 

[spoonta68]

i can get the four valve heads as of 4 weeks ago and i can beat dirtmax easily in price
also can get 3 valve head for yx engines aswell

im starting out small but all orders are welcome big and small and will try my absolute best to undercut any competitor

i can also get the new FULL cnc 57mm yx stroker cranks aswell

 

[themountain]

cool...what cams can you use in the3+ 4valve??

 

[themountain]

bumb!!!...whats now?? we get some info about that head or not...???

 

[motorman]

I'm pretty interested Spoonta.

What will fit/work well with a YX140? Some rough prices would be good as well. Cheers.

 

[themountain]

I'm pretty interested Spoonta.

What will fit/work well with a YX140? Some rough prices would be good as well. Cheers.

none of them...its for a klx studpattern...look at the pictures!

 

[themountain]

bump up an old thread...hey spoonta68, whats now with some specs on this head??...or was that only a wet dream you had selling them..??

 

[spoonta68]

the 3 valve works on all crf style stud pattern engines ie..yx140,lifan and jialing 140 and 125's
im waiting on specs of bore kits to suit with pistons
i know there is a 4 valve comming simler to taka head to suit the smaller head stud engines

when i get info and priceing ill post it up

sorry bout delay

also ive got a list of parts that u all might be interested in also comming just preparing the write up as we speak

cheers

 

[wogtaz ryder]

get as much Klx stuff as you can!!!! ;P

 

[tormentandglory]

I've got a 4 valve klx type head and 62mm cylinder for sale, check out the classified section

 

[sean01]

i can get the four valve heads as of 4 weeks ago and i can beat dirtmax easily in price
also can get 3 valve head for yx engines aswell

im starting out small but all orders are welcome big and small and will try my absolute best to undercut any competitor

i can also get the new FULL cnc 57mm yx stroker cranks aswell

whats the bolt spacing and head thickness of the 3 valve...all the chinamen tell there for 110 engines...