125cc motorbike tuning questions
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Older 125's were awesome
My old tzr was 12 bhp when i bought it.
Remove pillion seatpad and connect 2 of the 3 wires under there(white blue and grey if memory serves).
This activated the servo for the powervalve, instant 25 bhp
It did need a little rejetting to stop her overheating, but it was fantastic
Older 125's were awesome
My old tzr was 12 bhp when i bought it.
Remove pillion seatpad and connect 2 of the 3 wires under there(white blue and grey if memory serves).
This activated the servo for the powervalve, instant 25 bhp
It did need a little rejetting to stop her overheating, but it was fantastic
One simple check to do edd is to make sure the carb slide is fully opening ,this is an easy restriction for a manufacturer. Take the carb off and see if the slide goes all the way up the carb body ,if it dosent then there might be a couple of hp there , machine the top of the slide so it fully opens
I wouldn't bother going too far on the gearing it will struggle at the moment with a head wind , pass your test and get a bigger bike ,aftr all as a wise man once said "if you want to build a fast bike strt off with a fast bike"
I wouldn't bother going too far on the gearing it will struggle at the moment with a head wind , pass your test and get a bigger bike ,aftr all as a wise man once said "if you want to build a fast bike strt off with a fast bike"
Bpool77
Senior Retro Guru
Bin talkin to my dad when me and my brother used to have 125cc road bikes
Kwak KDX,Yam DT
he was the tunein fella! cheap n chearfull he used to sort the filters, drill the box, look at the pipe, then carbs, reeds, then ratios sprockets, then depending on the bike mess with the "power valve" (it was the 90S)
Im pretty sure all this was legal as my Dad did it
He was a top class BAE fetlin fella.
(when we raced BMX he made us compact disc chain wheels and drilled my rims before it was even heard of)
Probably not worth a carrot to you but great memorys for me
Kwak KDX,Yam DT
he was the tunein fella! cheap n chearfull he used to sort the filters, drill the box, look at the pipe, then carbs, reeds, then ratios sprockets, then depending on the bike mess with the "power valve" (it was the 90S)
Im pretty sure all this was legal as my Dad did it
He was a top class BAE fetlin fella.
(when we raced BMX he made us compact disc chain wheels and drilled my rims before it was even heard of)
Probably not worth a carrot to you but great memorys for me
Baron von Trumpen Bottom
MacRetro Rider
orange71":3txm936j said:
Find a 150 barrel/piston for it and up-jet the carb the bikes will have 150cc barrels for O/S of Europe. Would see about 5mph increase in speed. Scooterist do it all the time very hard to prove it's not standard if your not in the know.
Rich Aitch
Retrobike Rider
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Ed, As it's got a two valve head there's probably not a massive amount of power in there anyway. If it's got a slide carb then they are pretty easy to have a look at but if it has a constant velocity a.k.a "Stromberg" type jobby they are a lot more complicated [Probably a slide carb on a small bike but it's hard to tell because your's is partly hidden by the frame tube]. On a slide carburetter the throttle slide goes up and down in this little tower- see arrows- you can unscrew the lid on top to see if there is a restriction.
Changing the final drive gearing will probably make the biggest difference and because chains and sprockets wear out you'll have to do it anyway sooner or later.
Saltyman
If you're after a CG125 best get one of the newer ones instead of one with drums...
Both of you
Mikee is right what you really need is an old school two stroke 125, like an RS125 or better still a Cagiva Mito. Ignore what people say about them not been reliable I got 28,000km's out of mine [Restricted] before I needed to do an engine rebuild to replace crankseals .
Changing the final drive gearing will probably make the biggest difference and because chains and sprockets wear out you'll have to do it anyway sooner or later.
Saltyman
If you're after a CG125 best get one of the newer ones instead of one with drums...
Both of you
Mikee is right what you really need is an old school two stroke 125, like an RS125 or better still a Cagiva Mito. Ignore what people say about them not been reliable I got 28,000km's out of mine [Restricted] before I needed to do an engine rebuild to replace crankseals .
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