Pinned So what have you done to your bike today?

Yep, this is great site. Good site admins and plenty of friendly, helpful folks.

 

Did you make your own plenum chamber and plumbing?

 

Jeez Blokey, you're a talented man. Was it quicker with wire wheels or the lightweight alloys?

What was your best run? What're the records for ABF and ABG class?

 

That's beautiful. I think I have a front sprocket somewhere that has more teeth than the rear sprocket on your bike.

I contacted Hansen last night and their VP of R&D said they couldn't help me with a supercharger for my engine. Not to worry, there are plenty of options for me to investigate and I'd prefer a screw rather than roots style supercharger.

When was your last trip down the salt? Sounds like your bike might give the record a nudge with better gearing.

 

Turbo, You'll probably appreciate this. Wouldn't go as fast on the salt, but still ...

 

What about the small Japanese superchargers that the importers get in? They were used on 550cc cars like the Diahatsu and Suzuki cappachino. I have one on my historic open wheel racing car attached to a 950cc Morris Minor engine and fed by a 1 3/4" SU carby. It spins at twice crank speed and makes 8lb of boost (above atmospheric, 22lb absolute). They usually sell for around $100.
To buy a new Lysholm screw type will be a few thousands of $$$$.

 

Hey Murdo,

Yep, I need to make sure I can afford to do this. It would be great if someone had a bolt-on kit, but that's unlikely. Having seen plenty of drag racing trailblazers blow buckets of cash trying to make unusual combinations work, I'd prefer to spend a few extra up front and not blow anything up. You have to remember I'm not a mechanic and I'm drag racing for fun. I just think it would be cool to see how fast a 250cc 4-stroke motorcycle can get down the track.

What brand is the supercharger on your Morris Minor engine? Does anyone have any comments regarding running a single carb instead of the four that are normally on the standard 250/4 engine? I'm assuming the manufacturers used one carb for each cylinder for a reason (other than upsetting FZR owners!).

Frank

 

One carb per cylinder gives much better air flow than using a manifold with 90 deg bends.
The little blowers are 'Aisain' brand from Jap land. They are a two lobe roots type with self contained oiling and driven by a multi rib belt. About 300mm long, 150mm high and 100mm wide.
That is it behind the carb manifold under the silver plate. Only need one carb because only one intake hole in blower. Must always use a backfire valve (the triangular plate on top of pipe) to prevent blower damage in the case of engine backfire (the yanks call them 'sneeze valves' ).

 

Thanks Murdo. That might actually do the trick. I will do some investigation and see what I dig up. TURBO says a single 36mm carb so I'll need to see what's available there. I don't understand flow rates...if my bike has 4 x 30mm carbs, would a single 36mm carb be enough? I'm assuming I'll need to fiddle with my CDI to get everything working in sync? My head hurts.