I have a yamaha blaster i put a motor together for and its detonating like a s.o.b. The motor has vitos big bore kit,vitos 3mm stroker crank,mild port work,carbon fiber reeds,ricky stator adjustable timing plate and im running the stock carb and also running a fmf fatty pipe.I want to run pump gas also but i need a baseline for jetting and how much do i retard or advance the timing should i also go with a colder plug?any input will help please i dont want to destroy a brand new motor.it has 190psi of compression is it too much for pump gas should i mill the chamber in the head and lower the compression but will i lose alot of power or should i just run race fuel...helppp
blaster detonating issues please helppp
- Thread starter fastblasters200
- Start date
Is this a stock vito's BBK head you're running with the stroker? Did you install a stroker plate under the cylinder?
it is the head that comes with the vitos cylinder kit..its not the sleeve job bbk...its the real deal bbk that comes from vitos and when i installed the crank and put the cylinder on i used the spacer kit
If you have the pocket for race fuel, a 190PSI big bore stroker blaster is one HELLOVA wild ride. I have mine setup on pump and it's insane. I personally don't have the want, need, or funding for race gas but you can if you want to....
i really dont have the funding for race fuel myself so thats why i was thinking about milling the head chamber and lower the heads cc's i know that with race fuel it would be retarded fast but i dont wanna spend 70 to 150 bucks in race fuel just to enjoy my weekend on my bike. so being they dont sell thicker head gaskets ill just have to take some metal out of the chamber so i can drop the compression
yea im using the 1.5mm spacer and the two gaskets but i think my problem is the head.I think if i took the stoker crank it wouldnt detonate cause it would drop the piston 3mm in the hole so the compression wouldnt be so high than but im not changing cranks now id rather just change the dome in the head and mill or spin it in the lathe and open the chamber up some.not unless i can get a head gasket made for it
also i think the head has been milled cause they're is barely a ridge from the dome of the head and to where the head seals to the gasket
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head rechambering sounds like your best bet. timeing should be set to stock till you figure this out. its best to tune that in later with the jetting. if its a bone stock head design then i can see why shes detonating.
planned stock heads = detonation
planned stock heads = detonation
it is the vitos head and not a stock chamber it is alot bigger and more aggresivie. i just think someone milled the head.so im just gonna sink the chamber and bring the compression down some
I see no mention of what jets you are using.
You asked for a base line on jets, what do you have in there at present.
Is it getting enough gas?
You asked for a base line on jets, what do you have in there at present.
Is it getting enough gas?
k i see the bbk vito heads and most of the time they arnt rechambered. they are opened up some to line up with the 240 cylinder but i havnt seen any with anysort of chamber. sometimes you see them with the swerl effect that gos around the chamber but thats not even a great design.
i did some testing with my stock head when i had it in and i hit detination quick after shavin like .20. i rechambered it up to 28cc's and never had a problem since. aswell as didnt loose any noticeable power. i have mine milled down to .50 from the piston and its at around 22cc's and i still have no problem. i dont think i have 190 psi tho that should be fun.
i also think the stroker crank didnt help any being the piston is further up on tdc so im just gonna mill the chamber but does anyone know how much should i take out of the chamber like 10,20,or 30 thousands or should i cut it and cc the head for every cut?
for jets i have a 37.5 pilot,needle is set one clip down from stock and it has a 360 main jet. i also have the airbox lid off,the plug is black and the porcelin is a little tan
so a 30cc dome should be plenty enough to drop compression.what do you think? i did notice that on a stock blaster motor the piston is 20 thousands in the hole when at tdc but with the stroker crank i am all the way up on the cylinder at tdc
360 main sounds abit big im sapprised the motor seems lean. After assembling the motor did you leak test it?
28cc dome for the head should be enough most perfer less then that but the squish and such are impprtant aswell. Sicivicdude has a tread on this
28cc dome for the head should be enough most perfer less then that but the squish and such are impprtant aswell. Sicivicdude has a tread on this
its not that lean it is rich but until i get the head rechambed im not messing with it anymore.Im also gonna send it out and check prices and get info from companies before i send the head out to get rechambered
so i cc'ed my heads just for haha's the vito's bbk head was 21.5 cc's thats way too much for my application and i also cc'ed a stock head which was 25 cc's which is more ideal for my application.I just need to send the head out to someone who knows with my mods how much to cut for squish measurements and all
all one word........... kenoconnorracing.com
LOL
lots of experience with the set-up your dealing with
call him anytime between 8/9am. and 6pm.
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