whats the bore size?

[eotrx400ex]

I'm looking to rebuild the top end.just was gonna deglaze the cylinder and instale new piston/rings. so while lookin at different piston manafactures Wiseco, JE, Namura, PRO X all shows 85mm as standerd while Vertex shows 84.95, Athena shows a 84.94, 84.95, 84.96..so will i need to bore if i go with Wiseco, JE, Namura, PRO X??? guess i'm bit confused

[togup]

your wanting to just drop a new piston and rings in right, maybe a compression bump? I know stock bore is 85.000-85.010 the stock piston is 84.960-84.985, the main thing on a do-it-yourself job is to carefully measure the jug bore/new piston relationship. first make sure the jug is not egg shaped(use telescoping gauges) buy a good piston measure it for manufacturers clearance and drop it in.Sorry i cant answer the question about the differences in pistons but their website may have info or call them

[eotrx400ex]

Originally posted by togup
your wanting to just drop a new piston and rings in right, maybe a compression bump? I know stock bore is 85.000-85.010 the stock piston is 84.960-84.985, the main thing on a do-it-yourself job is to carefully measure the jug bore/new piston relationship. first make sure the jug is not egg shaped(use telescoping gauges) buy a good piston measure it for manufacturers clearance and drop it in.Sorry i cant answer the question about the differences in pistons but their website may have info or call them
thats exactly what i want to do...ahh i see so the few manufacturers are giving the piston size and wiseco, JE ect. are saying its for the standard bore(85mm). HAHA i'm such an idiot for not seeing that.thanks for clearing that up.
i did check it with a telescoping gauge and a dial caliper i think the cylinder might be little out of round..so might just go with 87mm an make it a 416.wanted to save some $$ but don't want to half *** it either...

[togup]

I hear good things about the 416 and 11.5or 12-1 comp but it sucks that you cant do a drop in ,you should talk to your machine shop to see if your jug is in an acceptable amount of egg shape for new piston and rings ,you might be alright never hurts to ask

[TRXRacer1]

Originally posted by togup
I hear good things about the 416 and 11.5or 12-1 comp but it sucks that you cant do a drop in ,you should talk to your machine shop to see if your jug is in an acceptable amount of egg shape for new piston and rings ,you might be alright never hurts to ask Bore jobs are cheap. Might as well go fresh if you're thinking piston.

[togup]

Originally posted by TRXRacer1
Bore jobs are cheap. Might as well go fresh if you're thinking piston.
yes they are cheap and I would rather it be done correctly the first time then be pissed that I cut corners when failure occurs but I also think you should know exactly what you have before jumping in,a machine shop will do exactly what you pay for no matter if you do or do not need it, so go knowing what you need so you dont pay for what you dont.

[eotrx400ex]

Originally posted by togup
I hear good things about the 416 and 11.5or 12-1 comp but it sucks that you cant do a drop in ,you should talk to your machine shop to see if your jug is in an acceptable amount of egg shape for new piston and rings ,you might be alright never hurts to ask
the bore could be "square" using a telescoping gauge isn't the most accurate way to check, compared to a bore gauge any how..in my opinion.but I'm sure in the hands of skilled machinist....i've herd some good things as well about the 416. thinking more along a 11:1 piston though and a stage 2 cam. would like to find a HRC cam but new ones sound to spendy and don't want to go with that XR copy.

[eotrx400ex]

Originally posted by TRXRacer1
Bore jobs are cheap. Might as well go fresh if you're thinking piston.
good point..but do you concider as "cheap". the yamaha shop want $80 to bore the cylinder. still need to call a couple other machine shops but they are more automotive. don't think that will matter though.

[Dathon Lawler]

yes that's a little spendy. i currently have my top end at a machine shop and asked for an idea of what kind of money this is going to run me on...checking the head for good valve sealing through a leak down test, check the flatness of the head, checking the flatness of cylinder, swapping my bolts from old cylinder to the new cylinder and adjusting their heights, and boring out to a 416. all for 50-60 dollars. and he even told me he would mill the head a few thousands if i wanted for i think he said 20 or 30 more. this was at a machine shop in indianapolis, indiana. if you want a follow up report? ask me and stay tuned for when i pick it up. btw. other machine shops advertise boring at 45 dollars all the time.

[TRXRacer1]

Anything over $60 and you're getting over charged. During a build that's a relatively small expense.

[eotrx400ex]

Originally posted by Dathon Lawler
yes that's a little spendy. i currently have my top end at a machine shop and asked for an idea of what kind of money this is going to run me on...checking the head for good valve sealing through a leak down test, check the flatness of the head, checking the flatness of cylinder, swapping my bolts from old cylinder to the new cylinder and adjusting their heights, and boring out to a 416. all for 50-60 dollars. and he even told me he would mill the head a few thousands if i wanted for i think he said 20 or 30 more. this was at a machine shop in indianapolis, indiana. if you want a follow up report? ask me and stay tuned for when i pick it up. btw. other machine shops advertise boring at 45 dollars all the time.
holy crap!! what a great deal! i called one other machine shop but there only able to do 4" bore and up. have. i though $80 sounded high.

[TRXRacer1]

The first guy I ever regularly used years ago was a Harley specialist. I had to talk him into touching a jap product but they typically are equipped and know what they are doing. Maybe search that route too.

[eotrx400ex]

i agree, an figured thats around what it would cost.. maybe since its at a dealer they mark the price up