
MBRS 100
Can't believe I'm doing this looking at the pictures.
Unfinished business. That’s what I figured I had with this bike. But with several other projects including a Bucket build for a mate, I’m just not getting onto it. Maybe it’s time for someone else to take the reins.
So, RS125 chassis with some (reversible) mods to make a normal size chap fit. MB100 engine converted to Full crankcase reed, watercooled and triple exhaust ports. 6 Speed gearbox. Extra plate clutch.
Ignitech ignition, high output CR250 Stator/Rotor, Intercooler waterpump, RS radiator. 32mm RGV carb. Optional 35mm bored out RGV carb fitted with home-made solenoid powerjet that I never had time to fully commission. Destroked crank and easily sourced KT100 kart piston. Fitted for quickshifter which is a boon on tight tracks. Needs the switch re-setup, but I have a spare.
It goes well, I’ve only faced one bike that could match it for straight line speed. It’s won bunches of races, sadly never a BoB although it has lead more than once (& I did win the CAMs trophy before) and held track record at Taumarunui. All with some fat old bloke on it.
I did have crank issues on the longer tracks but since machined the webs so a standard pin could be run rather than the stepped one that broke a couple of times. It’s been fine since. The stator & ignitech sorted out ignition problems I was having. Try find one.
Best dyno run on realistic dyno was 27.5hp. I lowered the transfer port floors to match piston @BDC and fitted inserts to make sweeping transfer inners. And lost 1hp. I’m pretty sure now that I’ve taken too much volume from the ports and grinding the easily reached outers would pay back this power and a bunch more.
The Pipe I now realise disobeys several rules of thumb and a better pipe should easily crest 30hp mark.
But I’ll never get around to it. While this is a push and go bike it needs someone who knows how to fettle 2 Strokes, feed it AvGas & decent oil, replace the occasional service part & ideally bring its potential above the weapon it is now. Last race I lent it out it got 2nd in the Wellington Enduro event. The tyres are somewhat old. Brakes & RS suspension are good.
I don’t want to be greedy, but this is prettied up FXR money $2800.
Oh yeah it could really do with a pretty up. I got some bright yellow paint, but you guessed it, - never got around to respraying it. Comes with full fairing as well.
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