Big Bore Kit Question By crazieness (Read 2,168 times)

[crazieness]

Hello again
A little advice please
I'm looking into fitting a Lextek 180cc Scooter Cylinder Kit for 152QMI GY6 to my Pulse Rage 125, just curious is there anything else I need to do such as rejetting the carb etc??

Any input is appreciated.

Thanks

Crazie

[Alleyoop]

Yes, you will have to re-jet your carb, Also putting in a 180cc kit you will have to have the Cases bored out to fit the bigger jug.
Alleyoop

[crazieness]

Can you tune it up with what its already got to give it more umphhh ?

Or is the Big bore the only way??

[Alleyoop]

Nov 14, 2013 14:18:14 GMT -6 crazieness said:

Can you tune it up with what its already got to give it more umphhh ?

Or is the Big bore the only way??

Sure to some degree but let me ask how does it currently run:
Top end speed at Wide Open Throttle and the RPMS it registers if it has a Tach on it. Were do you use it HILLY, FLAT or mix of the two and what is your complaint.

So explain how you would like it run from its current capabilities.
Then we can maybe get a little more of what you want out of it with some minor mods and not require a BBK and have to tear the motor down.
Alleyoop

[crazieness]

Hello again Alleyoop

As you probably are aware the bike is quite heavy and has only 7bhp approx, so when it comes to hills (which we are surrounded by where I live) it struggles like hell, to the point where my partner leaves me miles behind and has to wait around ( he has a yamaha rxs100) whilst i catch up.

On the flat and slight down hill it goes well there's no complaints there.

[Alleyoop]

Oh, ok so what you need is more RPMS out of that puppy to keep it in the powerband going up a hill and not loose rpms just speed due to the weight it is pulling. Very common problem because most tune the CVTs for FLATs and the most top end speed.

I hope you have a tach on it which helps tune the motor and cvt.
If not I recommend you get one and it can be used on any scoot if you happen to get another one without a tach.
I recommend this one it is not expensive and it registers quickly and works great.





From what you said going up the hill the motor slows down is that correct?
Alleyoop




INSTALL takes five minutes:

[crazieness]

Yes, when going up hill it slows down from around 50 to 35-30

and yes I have a tach .

[Alleyoop]

Great, so what does the tach say when it slows down to 30-35 mph?
Alleyoop

P.S. what does the tach say when doing 50?

[crazieness]

Revs are reading quite high , 6500rpm approx at 50, stays the same going uphill , just the speed drops off .

[Alleyoop]

Those are some low RPMS for a 125cc motor. No wonder it is a dog going up a hill.
RPMs should be around 7500 so something is not right. You may want to check the Grams on the weights in your Variator they are probably to heavy and you need lighter weights to bring up the RPMS if nothing else is wrong.
Alleyoop

[Alleyoop]

Max Speed :
80 kph
Max Power :
6.7bhp @ 7,000rpm

Not a very strong motor for the weight but you probably can get a little more out of it.
Alleyoop

[crazieness]

My partner says he will have a run on it tomorrow to confirm the rpm , but i'm sure its not going into the red which is at 7000rpm.

(My partner typing now )
Its really not a lot of bhp , my first ever bike 35 years ago ! lol ! was a yamaha FS1E 49cc moped and that had 5bhp almost and was probably half the weight , be nice if we could get it up to about 10bhp which is still on the low side but give it a bit more grunt. Would a performance air filter do any good and rejet the carb?? The bike is actually running really well now since the new coil was fitted so I wouldn't say its actually got any faults.

Paul

[Alleyoop]

But you may need to bump up the displacement on it and get a nother hp or so. Since it is a 125 you can probably boost it up to 149 or so ccs from the 126 is current is without boreing the case. But to make sure someone would have to measure the case opening, unless someone has already put a BBK on one of those. Your current piston is a 52mm I would think you could slap in a 55.5 piston hopefully without boring along with a Stroker Crank and bump up your displacement nicely.
Alleyoop

[Alleyoop]

I would try 1 and 2 gram lighter weights in there cost you maybe $20.00 for two sets and see if that helps any. If not it will be BBK time, that motor just does not have enough horses to pull all that weight up a hill.
Alleyoop

[crazieness]

Thanks alleyoop, will check it out tomorrow and post with more accurate reading.