BIG bore, how far can you go?

[Smellybumlove]

so my little rattler is in need of a rebuild as its losing pressure

so while its stripped im thinking i might go to town on it and maybe increase the 10bhp to something a bit more respectable for a 106cc 2 stroke!.

ok i have been told i can go another 2mm on the piston and have around 114cc but that counds a bit rubbish to me, any piston kits availible which push it even further?

the gileras have kits that go 125-172!

[nissanman]

Rumor has it scooterworks has been working on one... just a rumor though.

[lou76]

isn't the buckten basically already kitted?

[DarbyWalters]

Don't HAVE to go bigger...porting and jetting can get you plenty of more power.

[BGK]

so my little rattler is in need of a rebuild as its losing pressure

so while its stripped im thinking i might go to town on it and maybe increase the 10bhp to something a bit more respectable for a 106cc 2 stroke!.

ok i have been told i can go another 2mm on the piston and have around 114cc but that counds a bit rubbish to me, any piston kits availible which push it even further?

the gileras have kits that go 125-172!

They made Gilera 800cc bikes so I can't see why not! But when you run out of metal on the motor, the big hole you have to machine to get the larger and extra cylinders to fit will make it hard to get good compression...

The nice thing is that when you are done you can re-use your hand grips and mirrors from the original bike and maybe the gas that was in your tank.

[Smellybumlove]

well the answer is 115cc

getting done right now along with a port polishing and port enlarging and other stuff i forgot about!.
you can get it to 123cc BUT it requires a larger carb and exhaust, i dont have either at the moment so i didnt bother, also the reliability goes out the window.
oh and my engine was wrecked, it was getting blow-by on the piston!

[Smellybumlove]

ok correction, its 112cc with a 53.5 piston, to compensate the compresion was raised to 7.2 from 6.8.

intial impressions are WOW, its like night and day, its got the same mental take off from 0-20 then it dips down for a second and picks up even faster from 20ish-90+, i cant go much further as its still being run in.
im supposed to be using 95ron but its full of 92 at the moment.

one annoying thing is that they switched to a 2000rpm spring set on the clutch without my say so, originally it was 1000rpm so im thinking it could be EVEN faster at take off.

exhaust is coming next week, with that i can increase the compression to 8 and enlarge the carb........

[nissanman]

Takeoff would be faster with the 2000rpm spring since the motor is making more power by then, the dip in power is most likely roller weights that a a bit too heavy.

[Smellybumlove]

hmm, not the clutch springs then.........
they messed with the carb settings as well, what could they have done in order for it to change so much?

[nissanman]

Wait until it breaks in a bit before judging it's performance. Then it'll be easier to decide what to do next. I'd do the pipe before the weights or you'll be tuning your variator for the stock exhaust not the performance pipe. Have faith, you'll get it to where you want it

[Smellybumlove]

really hard to break in as its geared quite low and it stays at high rpm all the time no matter what speed i go!.

i have been tol dits fine to give it a blast for a few seconds every now and then and to try and mantain 2/3 throttle for about 120kms, by then it will be running nicely.

its 95ron unleaded and semi-synthetic from now on though, problem is i have a full tank of 92 inside at present!.

got the exhaust coming soon


still not sure about the carb, if its really worth it i will do it, but i dont wanna bother if its only a 5% improvment!.

pics coming soon

[Smellybumlove]

posted some of this over in the yahoo group but thought i would put it here too.

i am just about finished in my performance mods for the rattler, i cant honestly see much point in doing anymore as i cant keep the front wheel down from 0-30kph top end is well over 100kph i havent dared try to go further as the engine is still technacially running in so can only do short bursts.

the exhaust i ended up getting was from a bws or zuma as its called in the states, it required some fabrication but im pleased to say it didnt require using the old restrictive exahaust in order to fit.

heres a picture of it, its rather odd looking and has a small expansion chamber inside the can and is very very loud, sounds like a MX racer.

i have had to change the oil injector pump for a higher flowing one, so i dont need to do silly 50:1 calculations at the pump every 2 days!.
the compression has been raised to 8.8, a more powerful spark plug thing (dont know the name but gives 4x more power to the spark plug) and some of the drive train has been lightened and modified, i cant say what was done as i dont speak chinese and they dont speak english, i just know they spent a few hours with my transmission and machining tools!.

the problem i have is that 2000-4000rpm its stuttering and not reving cleanly, my clutch was engaging at that exact point and causing a rather horrible on/off flip over start, to counter this some race spec clutch springs have been installed, the clutch doesnt engage until around 3000rpm, which doesnt cure it but helps alot and also annoys everybody as i scream before going anywhere!.

the reason for the stuttering is the carb and exhaust combo, the exhaust is designed for high rpm, the engine is designed for high rpm......the carb is not, now this is what im told by them so if you might know a different reason for this please tell me!.

so im either gonna bore out the carb another 2-3mm or buy a new bigger one maybe 24mm.


wow long post, you would think with all the mods i have done i would be facing a HUGE bill!.

so far i have spent less than $200!
exhaust cost less than $45! -EDIT- sorry was wrong i meant $90 but its brand new!

[lou76]

well, as looks go, it is SICK!!!