New from the UK

[Creamsodauk]

Hello ladies and gents

I'm Kris from the UK, very new too the scene so go easy on me!

I have been riding bikes on road for 10 years and after purchasing a Honda msx(grom) too the U.S. Guys I fell in love with little bikes haha

So a few days ago I purchased a new Welsh pit bike 125 with the intention of making it road legal

I have had a quick browse of the web and sadly the only UK pitbike forum is dead! So hopefully I will have more luck on here for info, ideas and General chat!

Are the Welsh pit bikes known overseas? It's a stomp crf70 basically just branded in the UK

 

[my67xr]

Welcome to Minirider's

Yeah we have seen the WPB's
there's a thread here on one currently too- http://www.miniriders.com/china-builds/41688-mikkhs-wpb-125-crf-70-framed-build.html

Pm sent too.

 

[mikkh]

The WPB 125 is actually 120cc. It´s weakest point is the clutch (crank mounted). I´ve had 3 clutch baskets explode and they have always taken the side covers with them too. First tip on a new bike is to change the engine oil (low quality shipping oil) to 10w40 mineral motorcycle oil (I´ve used car oil meant for older cars with success too because they don´t have friction modifiers in them which are bad for wet clutch). I highly recommend to take apart the rear shock and change the oil to 5w or 10w shock oil depending on your weight and have the shock piston rod nut replaced by locking on or have the old one welded, because in stock form they aren´t welded and I´ve seen them come apart many times. Front suspension is little trickier because you need to cut apart the cartridges and change the cast washers holding the piston shims to regular large m6 washers and use regular spacers. Use 15w fork oil in front forks. If you can have the frame swingarm mount welded because they are basically tacked together in stock form. If you can replace the stock bars with something better, I personally use handlebars from jap full size mx´ers. The swingarm bearings should be replaced with rubber sealed ones.

 

[Creamsodauk]

Wow much better response then the other forum I was on!

I will take on board what you say! The engine was purchased as I am on L plates so I needed the 125 engine number to register with the dvla

I haven't decided yet wether to run the 125 engine or simply just sell it on and purchase a 140, either way it will end up a 140

Could anyone tell me the rear bearing dimensions for the swim arm, as rubber shielded ones are far better, are the wheels also metal shielded or open?

 

[mikkh]

Secondary clutch version of the 125cc engine does exist. I am planning to convert my primary clutch engine to secondary. I am planning to use secondary clutch type mainshaft and fabricate oil spinner with custom gear or use the right crank half of the secondary clutch engine. The only drawback with my idea would that it will lose the ability to start in any gear.

If i remember correctly it is 6200 bearing for the swingarm, will check tomorrow for sure.

 

[Creamsodauk]

Thanks! I'm not too fussed about the 120 engine as I will be going too a 140

I just have to decide wether too use it at all or sell it new, it won't be thrashed maybe light trails and road use

 

[Cordogs]

Wow much better response then the other forum I was on!

That because Miniriders is owned and run by a guy who runs and owns Minibikes!

It doesn't get any better than here bud! :thumbup:

 

[my67xr]

What 125 engine is in your bike, the model number is on the engine case below your front sprocket
Something like 1p54fmi

 

[mikkh]

Mine was 120cc 1p52fmi. It is 52,4mm bore, same as 110cc but longer stroke. It has 27/23 big valve lifan engine. Crank mounterd clutch.

 

[Creamsodauk]

Ip52fmi is the start of my engine number

The blurb off the site states:

12hp Dyno & Race Tested Latest Generation Engine
22mm Mikuni Type Race Carb with 2 stage race foam filter
Big Valve High lift factory fitted Race camshaft
N1234 all up gearbox
Race CDI
High Capacity Race Ignition coil
Oil Cooler Bracket Provision

 

[my67xr]

Ok, yeah i know the engine.
Their horsepower estimate is a bit out though, it would have between 8 and 10 at the rear wheel

 

[Creamsodauk]

Haha yer everyone likes an unloaded dyno read out for big bhp figures