Tuning a B1 China replica

hi guys i have a blate copy also & am thinking of putting a bi-zeta engine in it has any one ever done this b4 ?

my theory is: the bigger carby give's a better powerband aspecially in the mid range, therefor when the clutch grabbes it has better power to lift you off, so the clutch doesn't have to slip so much also with the bigger carby you can lower the rpm at the point the clutch grab's:stock 9/9.2k rpm carb upgrade 7.5/8.5k this alone could explain the clutch not wearing out so fast, like i said this assembly was designed like this by Blata, only the chinese desided to put a bean can for a carb and expected that theyre bad clutch material would be spared by the lesser power, but we al know that didn't work....

i wouldn't put so much dough in this replica, ride it upgrade it, learn youre lesson's and then go for a real polini/blata/grc whatever...my bike is 8.5/9 hp and still running fast and strong, i don't think it could handle more power and survive a week...

anyway does bi-zeta make blata style engine's or are you just refering to those polini type bi-zeta engine's?

Well, I went and ordered some PMT's and a new Bizeta end can before going to the race this weekend. Had a BLAST. The C1 did awesome. Came off the line with the same power and speed with 2 GRC RR's, then maintaned exact corner and straight speeds from begin to end (10 laps). Not only did it do this once but 2 times sunday. Coming out of every corner the bike pulls the front. I must say I am VERY impressed and pleased with the bike, for only having $703.00 invested in bike and parts. I was thinking of doing a 17.5mm carb swap, but I feel it would be an overkill and useless, meerly because it puts the bike in open class where your back to square 1, not enough hp.

Machine off the piston to make semi domed or flat and mod combustion chamber. The newer Blata Origamis come with 19mm carbs, this with a 21mm set length on the clutch spring length will give you good acceleration. The clutch needs to bite at around 9k revs.

Trevor, thank you for this and any other info / pics you could share with us.

let me say, if i am not mistaken i have herd of you a few times like the "B2" and others and i know that you are at the top of the game and i would love to hear whatever you have to say on the subject of the (B1/B2/C1) so once again thank you so very much!

Most of these threads deal with carburation and squish. The original B1's came with domed head pistons, that changed to flat top with corresponding combustion chamber inserts.

The squish as set at the factory for their team bikes is 0.63mm and they use 19mm PHVA carbs. I never liked these carbs and I always use a PHBG19mm carb with a 4 stroke atomiser set up. The 4 stroke set up allows a better rate of fuel/ air mix into the venturi before it enters the reed block this equals more power and you can run bigger jets.

I've worked with Scotty Finlay one of the best at setting bikes up and we found on a stock *****ie bike the best carb was the PHBG18MM with 266AN emulsion tube, W23 needle set at 2nd clip down and a 100 to 110 main jet, with 40 idle jet. All mounted on a B1 original manifold and DECENT FILTER.

The clutch was set to engage at just about 9k revs and the thing was a missile.

Robocop is corrct in that the water cooling of the *****ie bikes is not that clever. If you want extra power fit a full team spec stuffer crank as in the picture DEMTOOFAST has on his avtar. (I sold it to him).

Dont expect more than 10hp though unless you really spend some money on aligning all the transfer ports and boost port and making the exhaust port larger. Also the cases need to be dremmeled to allow the reeds to lift, at the moment the reed lift is crap, about 3mm at the most, this needs to be hugely enlarged to around 8mm. This work takes about 2 days to do and is expensive! but you will get 14.6hp at the end of it. I have the dyno sheet to prove it, or bore it out to a 46cc and get over 15hp at the rear wheel.

WOW! Trevor, I dont think i can thank you enough! thank you so much you really made my day!

Also the cases need to be dremmeled to allow the reeds to lift, at the moment the reed lift is crap, about 3mm at the most, this needs to be hugely enlarged to around 8mm. This work takes about 2 days to do and is expensive! but you will get 14.6hp at the end of it. I have the dyno sheet to prove it, or bore it out to a 46cc and get over 15hp at the rear wheel.[/quote] Thought I'd give this a try. I'll let you know how I get on.

i've already gone about half way with the intake and it made a big difference in low end, i'm going to try to go even bigger while i am finishing my port matching..

also i just made my boost port a little bigger where it meets the case and that also made a good deal more low end.

Dont forget to match & blend the air/fuel flow from the inlet port (reed block area) into the transfer ports. The fuel/air mix does not like to go around corners as in the current design!

p.s. Bike mad yank, you live about 40mins from my village!

hmm, i think i understand, after the mix comes through the intake port it has to take a hard turn, are we talking about right near the end of the intake port, or closer to transfer ports? i do see where it is a harsh bend compared to the smooth bend closer to the transfer ports.. i just wanted to make sure i am looking at the right place.

and once again, Thank You so much Trevor!

Cheers for that Trev. work is ongoing. Looking for some ceramic bearings at the moment.

Do they allow mini motos on the kart circuit at Little Rissington? I read that the kart track(Daytona) at Milton Keynes just opened for bikes. That track should be a real hoot on a water cooled! I wish they'd open Shennington. You'd see some seized engines on those long straights.

This could be another thread topic but I can see mini motos replacing karting as the next big fad in corporate events. Most of the kart circuits I go to make more from bikes than they do from karts. Lets face it, karts are a logistical nightmare (van/trailer, awning, tires, pit trolley, etc.)compared to throwing a couple of bikes and all your kit in the back of your car. I get both my bikes, spares, fuel, tires, workmate, leathers, helmet, and a passenger in my Renault Clio.

why you don´t put a bigger carburateor?!?!?

Can you recommend the type of carburator with experience of effectiveness.

William

Dellorto PHBG 18MM WORKS WELL with a standard B1 motor and tuned. Bigger carbs will give you more power but they are not too clever at top end revs. I used to run a 19mm all year with only a few jet changes to compensate for different weather conditions.

Standard set up. W23 Needle 2nd clip down, 266AN emulsion tube (4 stroke type) with correct atomizer! 40 degree slide, 40 idle jet, and 100 to 110 main jet. You will need a decent K&N style air filter - manifold and blata reeds (carbon).
The carb must have the choke extention lever usually supplied seperately which has to be cut down and filed to fit into subframe area..

Trev

This means that case should be dremeled about 2mm in both sides, right?
Yesterday i watched the case and it looks there is not much metal to be dremeled...
At first look It seems 2mm in some areas will maked the case too thin...

This means a new hand made domme, right?
The original domme o-ring has about 41mm diameter. To bore up from 39cc to 46cc, cylinder should be enlarged from 37mm to more than 40mm... and this will make original domme to short!
It will easly burn the o-ring in some minutes.

somebody should post pics of the work being done!!!!

dfelix, I am using the original Blata motor as an example. The clearance on the O ring was less than 1mm between the O ring and the combustion chamber, no probs as the Blata orange silicon O ring is temp rated to withstand this. I ran an engine for 2 years racing and no probs except when I leaned off the main jetting down to a 101, it burned the O ring.

Well... i took some measures from the reed place in case!
See pics attached!

The upper reeds open almost 1 milimeter more than te lower reeds.

The red line is how do I think that case could be dremeled.
If anyone with more experience could comment, it would be great!

The hole #1 is 2.64mm from the surface. The #2 is 4.32 and #3 is 3.26mm!

The upper side of the case could be opened up to 1.5mm near the hole #3 wich means that following the curve the end of reed will open about 3mm more than stock... (this means total >7mm of opening for the upper reeds)

The lower side looks more dificult.
Although there is more metal to dremel, the end is more thin!
If more than 1mm is cutted in #5, the case will loose that round shape where cylinder fits...

(An option could be rotating the reedcase... but this hard work!)