Page 1 of 2

Are high compression pistons worth it?

PostPosted: Mon Feb 28, 2011 8:13 am
by Wyvern971
And are they a complete pain to fit?

I was toying with the idea, if I can somehow stop the girlfriend finding out, but I'm not sure if it's worth the effort and expense.

So if any of you have fitted them, is the difference noticable, and was it worth it?

Cheers

George

Re: Are high compression pistons worth it?

PostPosted: Mon Feb 28, 2011 7:21 pm
by tonto sp1
Wyvern971 wrote:And are they a complete pain to fit?

I was toying with the idea, if I can somehow stop the girlfriend finding out, but I'm not sure if it's worth the effort and expense.

So if any of you have fitted them, is the difference noticable, and was it worth it?

Cheers

George


Hi mate,not got hi comp pistons myself but had a good conversation with a guy from another forum who had them and loads more work done eg carbon rce airbox, head work,cams etc...He said he wishes he,d not bothered :( ...Its made the bike awfull to ride and cost a fortune.
In my oppinion and this guy as well..suspension and weight saving is the way to go :thumbup: ..get the bike well set up and shed a few kilos where you can will make a big difference..possibly lighter wheels (make a huge difference apparently)..After quizzing him on power gains he said it made a few more bhp but not a big gain for the outlay...I,m toying with the idea of a lightweight lipo battery at the mo 900 grammes :shock: ..3.5kg saving.. ;) but costs £200 ...hmmmmm :D .

Re: Are high compression pistons worth it?

PostPosted: Tue Mar 01, 2011 12:30 pm
by Wyvern971
Cheers, I think I won't bother then :)

As to lightening I've yet to do the PAIR or Flapper mod to the track bike.

As far as weight saving goes I think they'd be of reasonable benifit.

I'd love to get some lightweight wheels, but can't justify the expense (unless I can get a decent set 2nd hand) as I am trying to save a bit to get a flat at the moment.

Re: Are high compression pistons worth it?

PostPosted: Tue Mar 01, 2011 12:44 pm
by Sppete
Add a larger sprocket to the rear +2 teeth should do it ;) It'll feel like another 20bhp and only for £20
Should work especially nicely on the track bike, how often are you above 160? it's all about how quick you can get there :D

Pete

Re: Are high compression pistons worth it?

PostPosted: Tue Mar 01, 2011 9:08 pm
by spiv
Sppete wrote:Add a larger sprocket to the rear +2 teeth should do it ;) It'll feel like another 20bhp and only for £20
Should work especially nicely on the track bike, how often are you above 160? it's all about how quick you can get there :D

Pete

Way to go :thumbup: Cheap & can be easily reversed :thumbup: (& I dont mean going backwards :lol: :lol: )

Re: Are high compression pistons worth it?

PostPosted: Wed Mar 02, 2011 7:04 pm
by tonto sp1
Also one of the best mods i fitted to my bike was a power commander..made a huge difference to throttle control and fuelling :thumbup: ..
First loaded a map from dynojet site but wasnt over impressed...So had it set up on dyno and a custom map set up for my bike spec and it was a revelation :D :D ..Would definately recomend it if you havent already got one :thumbup: .

Re: Are high compression pistons worth it?

PostPosted: Wed Mar 02, 2011 9:09 pm
by spiv
tonto sp1 wrote:Also one of the best mods i fitted to my bike was a power commander..made a huge difference to throttle control and fuelling :thumbup: ..
First loaded a map from dynojet site but wasnt over impressed...So had it set up on dyno and a custom map set up for my bike spec and it was a revelation :D :D ..Would definately recomend it if you havent already got one :thumbup: .

Putting mine on a dyno next week .. first time (for me ) Will let ye know !! (no pc 111 standard bike ) Will make sure chain is tight Etc . :o

Re: Are high compression pistons worth it?

PostPosted: Wed Mar 02, 2011 9:40 pm
by Wyvern971
tonto sp1 wrote:Also one of the best mods i fitted to my bike was a power commander..made a huge difference to throttle control and fuelling :thumbup: ..
First loaded a map from dynojet site but wasnt over impressed...So had it set up on dyno and a custom map set up for my bike spec and it was a revelation :D :D ..Would definately recomend it if you havent already got one :thumbup: .


I've got one fitted to the SP2 with a custom map, but if I'm honest it doesn't make much difference to how it feels. 129BHP can't remember the nm

I've got one for the track SP1, but not fitted or mapped it yet.

Re: Are high compression pistons worth it?

PostPosted: Fri Mar 04, 2011 12:27 pm
by Sppete
Wyvern971 wrote:
tonto sp1 wrote:Also one of the best mods i fitted to my bike was a power commander..made a huge difference to throttle control and fuelling :thumbup: ..
First loaded a map from dynojet site but wasnt over impressed...So had it set up on dyno and a custom map set up for my bike spec and it was a revelation :D :D ..Would definately recomend it if you havent already got one :thumbup: .


I've got one fitted to the SP2 with a custom map, but if I'm honest it doesn't make much difference to how it feels. 129BHP can't remember the nm

I've got one for the track SP1, but not fitted or mapped it yet.


Not Much difference??? :shock:
George, I'd take it somewhere else :shock: Mine jumped up to the mid 130s but it revs sooo nicely and the pickup is sooo crisp. A custom map was definately the way to go for me. :P

Pete

Re: Are high compression pistons worth it?

PostPosted: Wed Sep 14, 2011 6:16 am
by steve p
tonto sp1 wrote:
Wyvern971 wrote:And are they a complete pain to fit?

I was toying with the idea, if I can somehow stop the girlfriend finding out, but I'm not sure if it's worth the effort and expense.

So if any of you have fitted them, is the difference noticable, and was it worth it?

Cheers

George


Hi mate,not got hi comp pistons myself but had a good conversation with a guy from another forum who had them and loads more work done eg carbon rce airbox, head work,cams etc...He said he wishes he,d not bothered :( ...Its made the bike awfull to ride and cost a fortune.
In my oppinion and this guy as well..suspension and weight saving is the way to go :thumbup: ..get the bike well set up and shed a few kilos where you can will make a big difference..possibly lighter wheels (make a huge difference apparently)..After quizzing him on power gains he said it made a few more bhp but not a big gain for the outlay...I,m toying with the idea of a lightweight lipo battery at the mo 900 grammes :shock: ..3.5kg saving.. ;) but costs £200 ...hmmmmm :D .

I do believe it was me you are refering to Tonto :D at one point i was very disillusioned about high comp. pistons but mainly as i had cocked up myself :thumbup: Being as fitting these is an engine out and crankcase split job it is major work for non competent mechanics (me) and so will cost for pro help. Also the choice of piston manufacturer is critical allong with oversize of bore and piston size. If you are going to split the engine anyway, maybe for gearbox problems etc. then you could fit HC pistons quite happily. I was recommended the 11.5 JE pistons rather than the 12.5 Wiseco which i had allready fitted, but again you would need to accurately measure the bore size for JE to make oversize pistons to fit, and they will only make specials in batches, therefore its a job best left to the professionals! There is no doubt that HC pistons do increase both HP and torque throughout the rev range but i doubt that the gains are worth the financial outlay to specifically strip the engine for this one reason.
sorry for digging up an old post but i do like nosing through what everyones been up to :lol: