878 kit

[steve speed]

i have just done a compression test,, ,, before i did the rebuild i got between 170-167 psi ,,now i get 215 psi and both pots are only 2 psi difference so that's quite big increase

[Kayla]

Cool! Are the 878 pistons listed as 'high compression', or could the increase simply be down to better sealing against the cylinder walls?

[steve speed]

i think they are 11 to 1 ,,, and the std are 10 to 1,,,,, i think

[Quan-Time]

standard is 10.5:1

[steve speed]

i have now done just over 300 miles since the rebuild and i can report that so far its using no oil,,, not a drop ,,and its the same color now as it was when it went in ,,,result,, BUT,, and there's always a but,, its cost about £800 for the rebuild of the motor,,it would have cost a lot more but i did all the engine strip and rebuild ,,and a big thank you to all who gave the tips and tricks,,( you know who you are)

[pwmotorsports]

just read this whole thing as im going to strip and rebuild the top end in a few months and im considoring the 878 or new rings on orginal, is it still going well ? when you did this were you running fcr's ? anyone done this with standerd carbs ?

[phuk72]

just read this whole thing as im going to strip and rebuild the top end in a few months and im considoring the 878 or new rings on orginal, is it still going well ? when you did this were you running fcr's ? anyone done this with standerd carbs ?

I can't actually remember when I did mine but I must have over 6,000 miles on the big bore kit now - including a big lump on the track.

And yes, I did it with standard carbs - makes a noticable difference to the mid range.

[pwmotorsports]

any other mods required to make it work right? not interested at all in top end just want grunt bike is allready downgeared for top speed of 110, cams in most cases seem to be about improving the top end on most bikes ? FCR's when ive got the spare cash and i find some ill have some but i cant bring myself to get some new reckon i mihgt one day find some for £3-400 does that sound right ?

[phuk72]

any other mods required to make it work right? not interested at all in top end just want grunt bike is allready downgeared for top speed of 110, cams in most cases seem to be about improving the top end on most bikes ? FCR's when ive got the spare cash and i find some ill have some but i cant bring myself to get some new reckon i mihgt one day find some for £3-400 does that sound right ?

This has been discussed a few times before but not sure if in one thread so ......

Without a doubt, FCRs are the way to go if you want bolt on power. In reality, you are now looking at nearer £500 for the carbs, filters, cables etc unless you get lucky.

if I was spending the money (again!), FCRs would be the first mod.

Closely followed by a big bore kit. I found that this worked best with almost standard jetting - and yes, you can big bore without any other mods.

Then cams and gas flowing (no point in doing seperatley IMHO). Not all cams are for top end power - Kent are specifically for mid range whereas V2 are for top end.

And then - stop. You can spend big on balancing cranks (there is some debate as to whether you need to do this with big bore pistons), polishing, knife edging etc but you'ld be better off sticking a Firestorm engine into a TRX frame.

NB - all of teh above is dependent upon having a free flowing exhaust for it to really work. You'll see gains with standard headers but .....

[steve speed]

i got her out today for a cleanup , i was going to sell , i had a quick go round the block and i will mot it tomorrow and tax it untill the end of the year , i am keeping it for now

[Mincehead]

You should keep her for EVER after the work and personalisation you`ve done Steve.

[Jak]

Yep ... glad to hear you've seen sense