Start of the winter rebuild

[johnr]

just a thought re the plenum. is it essential that it be immediately next to the blower? reason i ask is, if it needs to be a certain volume but isnt taking massive pressure, couldnt you use the volume of, for example, the swingarm as a plenum? so, if it was an ally arm that was hollow, as long as there were no breather or drain holes in it, couldnt you use the swingarm as a plenum, or part of it?  just intrigued by this project and all the variables it throws up compared to a normally aspirated motor.

[JOOLZ]

A plenum could be fitted anywhere, a swinging arm could do or a large spine frame, the only problem would be, the more remote the plenum is the more chance for the fuel to fall out of suspension and condense on the walls, also there would be an increase of poor throttle response as the distance got larger between the carb and the intake valve

[JOOLZ]

Its a very short video, but here is the first start, the carb needs setting up and there are a few other jobs left to do but at least its a runner. By the way its very loud and I will have to do something about that 

[CrazyFrog]

It runs, fantastic - a great feeling after all that hard work. The finishing line is definitely in sight. 

[timbo]

Fantastic, and thanks for posting all your hard work on here. Its been really interesting, and educating 

[tommy]

great stuff joolz it sounds cool tommy

[JOOLZ]

Tucked away the oil pipes, looks lots neater. they were a right pain to fit there is literally no room left. Had a second start today tick over with the choke off, idles nicely at 1000 rpm. The revs hang after I open the throttle but thats the next job, set up the carb.
I didnt realise how much louder the bike would sound, its ear splitting, now sounds like a Manx Norton with a megaphone, I will need to quieten it down a little or Im going to be pulled by the police

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[Moto63]

Nice one Joolz, congrats on the start up. I imagine it was a good feeling eh? Bet you're itching to take it for it's maiden ride, best of luck with the rest of the "tidying up jobs"
Cheers..Michael

[JOOLZ]

Thank you all for the good wishes, I can finally see the light at the end of the tunnel.
I spoke to someone on facebook who runs a supercharged Jawa 500 land speed racer, he posted a video of his bike ticking over, and it had the same slightly obnoxous rattely burble in the exhaust note that mine now has, he tells me that it is the effect of having a supercharger fitted, so I think I will get myself a length of perforated tube and stick it in the silencer, maybe it will take the harsness out of the exhaust

[JOOLZ]

Still trying to jet the carb, but the rest is pretty much done

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[CrazyFrog]

That's a truly lovely bike Joolz. I find it strangely reminiscent of a round case Ducati...

[JOOLZ]

Progress continues, its looking likely that I will be on the road at the weekend. I have had fun and games jetting the carb, I now have a mixture of 4 stroke and 2 stroke jets plus an extra small air compensation jet.
I had 2 plenum explosions during testing, quite a loud bang about as big as a big banger or Chinese firecracker, I first explosion blew off the supercharger pipe, I adjusted the blow off valve spring pressure and the second time it happened it just lifted the valve.
It idles like a supercharged engine with the revs hunting up and down. Just waiting for some perforated stainless pipe to arrive to quieten down the exhaust.
I started my testing with the standard XBR cdi box but that has such advanced ignition timing at idle that my silencer was as hot as the downpipes used to get last year. I put on the XL600 cdi and thats a bit better, but I need to get a programmable ignition to retard the timing further. Ideally the timing should be around 10 - 15 degrees at idle ramping upto somewhere around 30 degrees at 3500rpm

[Moto63]

Keep at it Joolz, I'm sure once you swing a leg over it and feel that supercharge surge of power it'll av been worth all your efforts... good luck for the weekend and please let us know how it goes.
Cheers, Michael

[JOOLZ]

Sorry its been a while since my last update, Suzanne was ill again and back in hospital, so the bike went on hold again. However everything is back on course.
I was worried about how loud the bike was and how hot it was running, so I rechecked the cam timing, I must have been asleep that day as the timing was 1 tooth out. Retimed the cam and it sounds a lot better and is running cooler.
I encounterted a very unusual problem, I could get it to tick over but when reved, the revs stayed high and wouldnt come back down, the usual problem here is that it is running lean, after playing with the jetting I started to suspect they were not the fault, it turned out that the suction from the supercharger was holding the slide partially open. 2 throttle return springs cured that
The first video was before I realised the cam timing was out, the other 3 are the first test rides

[JOOLZ]

I took the bike out for a longer ride today, an interesting riding experience, out of town its pretty much like any motorcycle, but stop start riding is very tricky as these is a fair bit of blower surge between the 900-1100 idle, it pulls easily but obviously its a very jerky ride so I found it easier to get it rolling and feather the clutch to control low speed. There is more blower surge at 2200-2500 rpm as well but its not so much of a problem, I also have a flat spot at around half throttle that I will have to sort out.
Im happy Im back on the road but there is still a bit more to do