RB20 Build.

[10 inch Terror]

Good evening Gentlemen, I'm thinking about building an RB20 motor with a few bits I've got laying around. I have a nice Indian 150 case, an AF 58mm race crank with uprated rod and big end, Ducati light flywheel and BGM stator, a 30MM Dellorto VHSH with either a LI150 pacemaker box or Indian GP150 box to use. I'm going to match the transfers and just clean up the inlet and exhaust ports but nothing else. My question is what pipe and sprocket combination would you guys recommend? Has anyone used a certain combination with good results? I've got an RB250 for rallies and such but fancy a screamer for around town. Thanks in advance Pete.

[cgt75b]

What's the Rb 250 like

[10 inch Terror]

What's the Rb 250 like

Still running her in and it's a hell of a job not to give her any welly and as a bonus i've got a Cyclone in her too.

[sydduckett]

I have a rb20 with a vhsh, 58 crank, and Franspeed race and it goes well with power band in every gear if you want it. if your after a screamer though then go for the NK race which I also have. it really flies with this pipe but it's difficult to set up so it's not a bit lumpy downstairs. the Franspeed has a better spread of power and prob more tourqy but it's not as quick as the NK...... as a bonus the NK is a far cheaper.... oh and I have an 18 47 with an Indian GP 200 box, pulls in every gear although first is quite short.

[10 inch Terror]

I have a rb20 with a vhsh, 58 crank, and Franspeed race and it goes well with power band in every gear if you want it. if your after a screamer though then go for the NK race which I also have. it really flies with this pipe but it's difficult to set up so it's not a bit lumpy downstairs. the Franspeed has a better spread of power and prob more tourqy but it's not as quick as the NK...... as a bonus the NK is a far cheaper.... oh and I have an 18 47 with an Indian GP 200 box, pulls in every gear although first is quite short.

I forgot to say I've also got a brand new NK race to use. I'm on a pretty tight budget but could I stretch to a new 200 box. Also got both 18 and 47 sprockets knocking about. Cheers for the reply mate much appreciated.

[sydduckett]

If you do go for a 200 box try and get the Indian one as the Italian has quite a big jump between 3rd and fourth just where you don't want it and really have to be in the power to carry it. the Indian box seems to have the gap between second and third but it's not such an issue.

I'm thinking of building another RB as I have most parts apart from the barrel and reed block oh and carb..... I'm keeping my eyes peeled for a wrecked RB barrel that I can get welded up and ceramic lined. missed a tidy VHSH at Wicksteed that my mate beat me to. only £60 and in good nick....gutted...

[corrado]

I'd stick with the pacemaker box with 16 x 47 cogs, 81 link chain, 5.41 final drive, and the NK race, you might have difficulty keeping the front end on the ground, it'll do 80 because it'll rev way over 8 thou. Short gearing = revs = Fun, fun, fun.

[sydduckett]

I'd stick with the pacemaker box with 16 x 47 cogs, 81 link chain, 5.41 final drive, and the NK race, you might have difficulty keeping the front end on the ground, it'll do 80 because it'll rev way over 8 thou. Short gearing = revs = Fun, fun, fun.

that will work.... be full on though...

[10 inch Terror]

I'd stick with the pacemaker box with 16 x 47 cogs, 81 link chain, 5.41 final drive, and the NK race, you might have difficulty keeping the front end on the ground, it'll do 80 because it'll rev way over 8 thou. Short gearing = revs = Fun, fun, fun.

Exactly what I'm after