Well you gain power when lightening engine components, and a quicker revving engine doesnt hurt either. Also you can gain about 10 lbs removing all that unnecessary stuff. That translates into free power. You just need to decide how much you like that starter. If i were doing it again I wouldnt hesitate to just do it all and be done with it.

 

I believe the rule is:


Remove 1lb of weight on non-moving parts = 1X return on HP
Remove 1lb of weight from moving wheel parts = 5x return on HP
Remove 1lb of weight from moving engine parts = 15x return on HP

So, you can see why the NASCAR boys spend so much time and $$ on Engine R&D. Shaving just a few ounces in the engine can gain a few HP.

 

you wont lose that much money, wiseco pistons are about 90.00 dollars and rick does bore jobs for 35.00 and shipping isnt that much. oh by the way can anyone write out the correct way of saying wiseco? thanks, scott

 

guys, im gonna chime in here, im afraid im a little behind you all, with the mods but here goes. i have gotten involved with the hillbillygp circuit here in the ozarks and have been doing well. yesterday was my first "open"course i have ran. and man was it fast. add to that a lap around a mx track mixed into the woods track. I got outpowered by everything. and im sick of it, so i started tonight and stripped the head off and am committed to milling it. how much can i go. i have heard .030 and its all good, is this true? i do not want to put this motor on the jagged edge or anything i just want to "slowly" start increasing power. i want to do this locally at a machine shop in town and need to know how much to go....
as for the shaving the flywheel, one of my biggest probs racing is the thing takes forever to wind up will the shaving of the flywheel help that, i can not sacrifce the starter, this series does dead engine starts and i would look stupid trying to pull start my bike after the board drops. i get enough razzing as it is for trying to race a t.b.
thanks for any help
james

 

So if you really want to open up a can of whoop-a$$ get a reed conversion
kit or aaen stage 5 upgrade. I have the flywheel in my TB 250 race lightened
and it made a big difference in throttle response. It starts pretty easy without
the starter, usually 1-2 pulls and it fires up.

 

talon,
i appreciate your input about the reed kit, wish i could, btw you got the 1000.00 price of admission you can loan me????lol. i want to go in small steps right now, im a little **** about this sort of stuff i must have it perfect and done right... so im convinced i just want to mill the head right now, i got two more races from now until feb. then after that i wiil pull the "jug"and do some port work on it, just in time for my april wynoka run. anyway, how much should i mill, im thinkin .030 can you or anyone confirm or deny that please.
(sorry to be a little pushy, but the head is in the truck and im wanting to take it to the machine shop today) thanks again guys

james

 

I have a .040" wiseco piston for a 250 I'll sell for $70.It's brand new in the box.

 

that sounds like a deal, but i think i would rather save my bore, until i need to, im under the impression that it wont make that much more power, and i looked at the cyl. wall last night and it looks brand new. thanks anyway, i read your sig. and i see that you post a .040 shaved head, is that a "safe" amount, or would you suggest a .030 mill?

thanks
james

 

i wouldnt really just shave the head because you wont feel any difference. i got .020 shaved but that was because i had the cylinder ported. the reason u shave the head is to create more compression which will give you more tourqe. i would say just wait to mill the head. mill it when u port it, it will work out better.

 

correct me if i'm wrong but the .040 over that is refered to is the cylinder and the head is shaved .020. i haven't heard of anyone going over .020 on the head or stock head i should say. from what i've seen on these forums and other sites, milling the head more than .020 would require something above 92 octane fuel.
well..... that's my addition
steve