Tuning a B1 China replica

About the "bore up" talk...

I attached some more images with usefull mesures!

Cylinder could be opened (and coated) to 40mm with no problems.
There is about 10mm of metal to hold the piston...

Like Trevor said, domme as about 1mm for the o-ring...

I think i'll have to buy a Blata orange silicon O-ring soon!

You can cut back the lower section of the cases i.e. the part under the bottom reed by at least 10mm and reshape the end profile. This will allow more air/fuel mix to hit the big end and aid cooling the bearing. The top section above the top reed needs to be shaped to allow the air/fuel mix to be directed into the transfer ports without going around a corner.

Remember dont use a polini 50cc piston the ring keep is in the wrong place, use a bizeta flat top 50cc

10mm???
This means that the uper side of the case will loose lots of metal, and the shape!
I will take a picture, some more measures and the post again how it would look after such modification!

I notice that there are different 50cc bizeta flatop piston sizes.
O,OO,A,AA,B,BB
Wich one is best for using with a modified 40mm (nicasil) chinese cylinder?

badazz had some pics here:

http://badazztoyz.com/images/tech/c1/

Good stuff guy's!!! time to get my hand's dirty aggain..


Greetz A

hi arjen, good to see you..

look at cagaroni's pictures particularly photo ref: CL-3 WORK .JPEG He's nearly got it right except the length of the lower casing (under the bottom reed) needs cutting back and narrowing in cross section not just thinning out.

The size of piston to use is up to you. Get a piston, give it to the guy who is boring out your barrel and he will match it.

I have no idea of how to upload the photos I have so dfelix give me your E mail address and I'll send some over. perhaps you could upload my pictures of the exhaust ports and case mods. Easier than explaining in text format.

trevor sellars...can you send that images for me to...i´m a little confuse about the chamber mesarures...i want to put a 40mm piston..but i not certain i can do it...yet!!thanks..

great to be back, my computer crashed and i had a realy hard time getting it fixed aggain.... pffff...... ***ck Bill gates

This is how i would do it...the lower green line and the upper blue line...

hey thats my pic
http://badazztoyz.com/images/tech/c1/
lots more pics there guys to show you the flaws of b1 motor.. Look at the pics i took through inake with head on as well. Im making a head now that will fix it all

are you selling those crankstuffers yet????

no its expensive work..im getting quotes on new fc stroker cranks that will work on b1 rep and b1

i see you have done many mods & experimentation with the c1/hydra.. would you say you've noticed a nite & day difference in performance between the stock c1 and a modded, matched & de-bugged c1....

word is out Chris is also building a real B1 to see what kind of power he can get out of it.....will be interesting to see if the gains are comparable with the B1 as the C1 ~ So whats the word chris???

weve got 17hp out of a B52 Bored out to 52cc!

LOL...........Trevor that is insane!!!

dang trevor thats awesome..i wouldnt mind knowing what you did if you wouldnt mind pming me? also john your motor is apart. im trying to find a machine shop to make me some delrin stuffers for the crank cause i dont think my cranks will be done in time for your race season. man your bike was diiirty

badazz, let me know how much one of those stuffers will cost to make if you find somebody....