RB 250

[AndyS]

This is this years project, I am a bit prone to building scooters and then selling them on but hopefully might keep this one for a bit
RB250, franspeed touer exhaust, 34mm Dellorto.
Has a 5 plate clutch in at the moment but am going to upgrade to a 6 plate soon.
I have done all the work , paint, engine and all the build.
I sprayed one last year with cans, but have tried this year with a compressor and spray gun and it turned out ok.

[CANbus]

Very nice Andy S, love the subtle vents for the carb. Is the seat bought as is or did you have it reupholstered. also is there a reason the front brake hose comes off at that angle?

[Toddy]

Looks lovely that mate done a good job there is it running ok ??

Toddy

[AndyS]

The seat was a slope back that I cut at the back. Tony Archer in Huddersfield reupholsterd it, £40, and a great job.
I think it is the angle of the picture that makes the pipe look to be coming out of the caliper at the wrong angle, its fine really.

As for running right, I have posted a question in the carb jetting section, I set it as per Af but it is very boggy low dow. They recomend running in for a few hundred miles up to 55 mph, at that speed the throttle is only about 1/4 open, and it 4 strokes badly, it clears if you get it up to 60mph,. The trouble is if you open the throttle to clear the bogging down it just keeps going faster, consiquently whilst going to Scarborough I spent all the time accelerating to 55ish and then letting the revs off to do it again. I dont know if it will ever clear up as it revs so low at that speed, ( sx 200 gearing 16 x 46 sporokets 4.5 ratio) might change to a mikuni

[Knowledge]

Very nice Andy.

I am sorry you are having problems with the carburation. Perhaps when you have run it in, you should try getting it set-up on a dyno. It might be cheaper than buying a new carb and new jets.

It might be a timing issue. If you have gone a bit conservative on the timing, you might be bogging down as a result. Are you using varitronic or the tradition 6 pole electronic?

As an experiment, try altering the timing to something mad like 24degrees (which is fine up to 5000rpm - plenty fast enough for this exercise) as see if it cures or improves the problem. It might lead you to go down the Agusto route if you are not already using one (or Varitronic).

Alter the timing back after the experiment.

And why the decision to move to a six plate clutch? Are you having clutch problems?

Martin

[Bilko]

That looks superb.

[AndyS]

The timing is set to 17 degrees, but I dont have a strobe, so it was with a timing disc. Would advancing this assist with its running?
Again on AF's spec sheet they recommended 17d btdc.
I do plan to fit an Augusto, when funds permit, I think this will help to clear up the bottom end.
Regarding the clutch, the only problem is that it has strong springs and a centre spring, which is unbeleivably hard to use, I fitted these due to only having a 5 plate kit.
I am just about to do the Yam clutch lever modification, this should help, I suppose I could try it without the center spring, but I think in the long run a 6 plate will be a better option

[lifes a drag]

i think a scooterotica dyno session is called for ,
try a foxhat cluch ,
do you go around with any club in hx ?
when is it for sale
i love it

[Knowledge]

The timing is set to 17 degrees, but I dont have a strobe, so it was with a timing disc. Would advancing this assist with its running?
Again on AF's spec sheet they recommended 17d btdc.

I am sure they do recommend 17 degrees, though this is very conservative. The last thing they need is a batch of RB25 pistons being returned with extra ventilation in the crown, but 17degrees sounds rather conservative and will adversely affect the bottom-end, which would be happy at 24degrees.

I do plan to fit an Augusto, when funds permit, I think this will help to clear up the bottom end.

Given the info above, the Agusto would be good for your engine. Starting, pick-up and fuel consumption will be improved (with correct jetting).

Regarding the clutch, the only problem is that it has strong springs and a centre spring, which is unbeleivably hard to use, I fitted these due to only having a 5 plate kit.
I am just about to do the Yam clutch lever modification, this should help, I suppose I could try it without the center spring, but I think in the long run a 6 plate will be a better option

The Yam clutch lever is a good conversion, and MB do the whole show for a very reasonable price (it's hardly worth doing it yourself). Combine this with a nylon cable, and things will only get better. I'd also thing that AF's insistence on the centre spring has more to do with mitigating clutch slip regardless of whether the scooter is rideable. I would definately try it without the centre spring. Afterall, clutch slip is as much to do with gearing as it is with power. It is not a one-size-fits-all solution kinda thing.

Good luck.

[M210]

Really nice scoot mate.
Superb paint job, excellent seat, sweet motor.
...- but - why such a brake?!? Cannot understand.

Use the same brake on my not-ridden custom scooter (parking inside the shed) but for my all day b*tch I love an anti dive variation nowadays....