Super Jet Big bore

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bondra131

Thaat's braptaastic!
Location
Coeur d'Alene, Idaho
I looked into groupk's 845cc mod using 62t or 64x cylinders. They said that you have to use an oem head... Oring heads wont work. But any big bore motors I've ever seen no one ever runs stock heads lol... So what are they talking about? Anyway... I have 61x cylinders, just wondering how big I can go with those cylinders if I bored them, over-size sleeved them and bored the sleeves to the max. I have an ADA girdled head
 
shepster

shepster

Living the dream!
Location
united kingdom, Jersey
HI, Group k's concern is with the sealing surface of the cylinder not being big enough to form a reliable seal with just an o ring. Using a head gasket would solve this but you would not have the ease of removal etc etc. Ive been running my 780cc big bore 61x cylinder for years using an ADA head with no problems. The sleeves Group k use have a bigger top sealing flange anyway compared to the standard Yamaha one.
 
B

bondra131

Thaat's braptaastic!
Location
Coeur d'Alene, Idaho
780 is big enough for me. Maybe I will try the xscream 771 mod.. It rips now as a 701 with no port work at all. I'm sure a ported 771 would satisfy.. No way am I using a stock head! Lol
 
B

bondra131

Thaat's braptaastic!
Location
Coeur d'Alene, Idaho
Not more than enough for meee ;) I'll at least have xscream or someone
port my 701 even if it stays 701... Better than stock port 701. I have type 4 dry pipe on it that made a lot of power
 
raytherace

raytherace

Canadian Brapp Dealer
Location
St-Ray Beach, QC
We used BB850 sleeve from blowsion. First bore is 89mm last is 91mm. Case and cylinder are ported for the best bottom end. The best setup we have tried was with BJ46 and Flame. Was very powerfull for the price. I have 2 of those in stock and ready to ship, pm me for more info !
 
raytherace

raytherace

Canadian Brapp Dealer
Location
St-Ray Beach, QC
I can only take the case and the cylinder as a core. 250$ for the case/bolt and 100$ for the cylinder, both 62T and must be in good shape as well. Those price are shipped to my place in Canada. BB850 shortblock with prox piston is 3100$CAN + shipping and with wiseco piston is 3200$CAN + shipping, so if you send me you your case/cylinder as a core you will save around 300$ on those price.

Here the 2 engine who are available. They are the 4th and 5th engine we built. The first one was built in April of this year, run still that time and we had 0 problem at all. Same for the 2th and 3th.

If you have any question feel free to call me or text at 418-265-3571

Thanks, Remi

photo (1).jpg
 
raytherace

raytherace

Canadian Brapp Dealer
Location
St-Ray Beach, QC
IMO yes. Ask Proformance, feartheride and marcgraham they have all ride my 850.

Im not 100% sure but i think the bore are limited with the 771cc. With the 850 we have bore from 89mm to 90.50mm in .25 size and a final bore at 91mm

91mm = 885cc we are close to 900 for AM legal
 
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raytherace

raytherace

Canadian Brapp Dealer
Location
St-Ray Beach, QC
steve-uk said:
hey Remi,

what porting is on these?

ported cases and cylinders?

whos doing the assembly and porting on these?
Click to expand...

Cylinder and case as well. My friends Dany Fiset from 911 racing engine is doing the job for me. The guy has top notch reputation by here around ATV and Subaru porting. He own a dyno, bench flow and all the tool to do the job and he do that since 15 years !! He probably know better than me about duration and timing !! And he own and ride a jet ski, like you probably know loll
 
R

River Rat

Squarenosed
Location
USA
raytherace said:
IMO yes. Ask Proformance, feartheride and marcgraham they have all ride my 850.

Im not 100% sure but i think the bore are limited with the 771cc. With the 850 we have bore from 89mm to 90.50mm in .25 size and a final bore at 91mm

91mm = 885cc we are close to 900 for AM legal
Click to expand...
thank you for the info! deff keepin this as my next idea for motor!
 
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