Hey guys!!!

I was just wondering how much power there is to be had by going with one of the big bore kits on the market.

I have a friend who has a high compression stock bore grizz with a ported head, webcam and HMF exhaust. The thing just flies!!! I am getting ready to do mine and was wondering if it was worth the extra money to go with the big bore.

Also, for the guys that have them whos makes the most power?? Sparks?? Trinity?? FST?? Powroll??


Thanks!!!


Chris Rowe
trborowe@mounet.com

 

Call around and see who does the most for the least money. Every person in here swears by their own personal builder, kinda like brand loyalty. Bigger bore dosent add that much power all by its self but it makes all your other power adders add more than they would normaly. If you and your friend do all the same things to both of em but you have big more you should have a good bit more oopmh.

BTW most big bore kits come with other hop ups included, cams, pistsons, etc....

 

SIZE DOENS'T MATTER


smaller motors have to ref higher to make the power a bigger motor can make at lower RPMS. all engine builders should be fairly close to one another. its all in the parts you buy them to put in.

 

Almost completley true. The only thing I have heard of that a big bore would help on the 660 motor is the ability to unshrowd(sp?) the valves. This would be the benefit of a larger bore on the 660. IMHO

 

If size dosent matter why did you buy a 650 instead of a 350 or 400? [img]i/expressions/face-icon-small-tongue.gif[/img] ? [img]i/expressions/face-icon-small-tongue.gif[/img]

 

Adding too Ward's post, the big bore has the valves unshrouded. Now when proper porting is introduced (along with an engine package that compliments the porting) the engine responds extremely well. THis is apparantly crucial on the Rap and I would asume the Griz as well. Proper 686's are advertised at around mid 60's on the dyno.

 

i wanted to play with the rotax motor. a 350 or 400 doesn't have a very good head on it to produce much HP.


everything starts with the head, then you have to have enough motor under it.