big bore kits, is it worth the cost

from what it seems you lot all seem to have big bore kits. but from what i heard they wreck your engine in a couple of months. is this true or is it jst a load of crap. is their other mods you have to do in order to ride with damaging your engine with a big bore kit.



piaggio nrg power 50cc

 

Depends if you know how to fit them or not.


Change your avatar WAY TO BIG!

 

well im not gunna fit it . i'll get a bike mechcanic to do it for me. so it should be done properly

lol yer i no, jst relized........ its gone now

 

Also if the crank has a lot of miles on it then it might be worth changing.

 

If you run it in properly and get it set up correctly (Jetting, mixture etc.) then they last for 1000's of miles.

I can't really talk as mine seems to break down every 2 miles,


Don't let this put you off though It's cos I'm a dumb ass and not built it right, all good now though.

 

if you buy and fit properly something like a polini/malossi cast iron sports kit,

run it in properly...and use good 2 stroke oil...and dont rag it when its cold..

And of course the bottom end is healthy and has plenty of life left on it..

Then...it should be no less reliable than the std barrell and piston

problems occur with big bore kits when 1 or more of the above are not adhered to

 

How do you guys run it in?

 

Hey guys i worry the same as zumaman im wanting to buy/install a 70cc kt but worry that it will blow the engine or sumink:/ everything on my bike is stock except i have ligter rollers and a dopler S3R exhaust on it btw does the milage of the bike make a diffrence to how long it will last with a 70cc kit?

 

depends on milage of the bike.. a bike over 10,000 miles.. personally i would do the crank if ure doing a 70 kit..

but if u run it in right.. use good oil and use a GOOD 70 kit.. i.e malossi sport or polini sport u could get a good 20,000+ miles from it then its a simple piston ring change.. (so im told)

ofc its worth it...

ben.

 

My bikes done just over 5500 miles so its all good yer(Y)
Id want a kit that has good reliability any ideas???
and would ther be anything els that would need to be installed to get the best out of it?

 

a sport kit would be the best for reliability and for getting most out of it all depends on money like everything

decent pipe, bigger carb, porting

 

cheers for all the info. mines only done under 3k millage so it not really worn, and i found a page on this website telling you all the mods for a budget tuning so i will probably follow the cheapest one

seems i'll hav to get it in stages, buying an fitting the bore kit first shouldn't cause any damage to the engine?? ( if i wear it in and a mechanic fits it for me) bearing in mind their will be about a months gap between being able to get the rest of the stuff.

 

Im putting a 70cc kit on my scooter
Its an ebay cheapy but i am not worried i have measured up the porting and its a 180 degree exhaust with a 117 transfer cylinder
i will up the transfer port duration a small amount and run my genalli pipe
17.5 mm carb and carbon reed

I will also blend in the cases as they are shocking


If it all goes wrong in time to come i will put making a 133cc out of it anyway

the 45mm crank goes straiaght into my cases with no issues

Got to love the chinese copies

 

i wouldnt go for a cheap tuning setup because they can be lots of trouble, go for a polini sport 70cc kit there more reliable.

dont forget that its better to have a pipe which is useable with 70cc kits so the doppler s3r and yasuni etc. are the best to go for.

 

Its a next pipe
i am wondering where that fits in with the reverse if its a higher or lower rev pipe

 

My NRG had the 7 port MHR Race 70 Kit and I did 3500Km on it before it came off the road, I'd say there was still a good 1500km left in it before I rebored or stuck a new ring on it.

 

hay ime new to this but i no abit about peds.big bore kits will blow ur engine up in proper run in or just to much strain on the engine.

 

#1, you make no sense mate, read it back and retype it

#2, bore kits only blow our engine if incorrectly fitted or fitted to an already weak engine, there will always be a reliability tradeoff when power in involved, however, good workmanship and workshop practice can make this tradeoff a lot less aparrant.

i can make an iron 70 kit las just as long as a stock engine with the right parts.