Kiwi's 750 Sport race conversion

[Kiwi Rider]

I filled in the hole where the headlight had been with some aluminum/plastic composite sign board material that bends and holds shape quite nicely. Just siliconed it in and after paint put some yellow wrap on the front number board area then applied the black numbers. I've been #22 since I started racing in 2015.

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The finished product for now!

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I'm happy enough, looks a lot better than when I first got it and it's ready to race.

[Kiwi Rider]

Race Report:

Ive had a couple of race meetings on the Sport now and I can report favorably - mostly! There was always going to be a few teething issues. My first race was a DNF as it started cutting out down the main straight on the first lap. It felt like a fueling issue, so I started by removing the inline pressure regulator. That seemed to do the job and Ive had no bother like that since, but it is still a bit rough getting back on the gas after being on a maintenance throttle mid corner. My man at Weber specialists has suggested drilling out the pump jet to .60mm. I'm not even sure what the pump jet looks like but I'm sure I'll find it!
I got my gearing wrong - I was at redline by halfway down the main straight. I put the original 38T sprocket on for my 2nd meeting and it was pretty much bang on. Man 1st gear is tall on these things, takes a bit of clutch slipping to get it off the start line. The brakes are pretty good for the age of the bike with the brembo master cylinder upgrade. The least lever travel I have ever had on a bike. Theres a little bit of shudder there under real hard braking into slow corners so I think there may be some disc warpage. On the whole the bike feels pretty balanced front to rear and the handling is good and stable if not a little slow compared to what I'm used to.
I think the main thing slowing me down/holding me back was being on road tyres and not knowing how much grip I had under me and how warm the tyres actually were. I'm used to racing on heated slicks so I have decided to go ahead with the 17 inch wheel conversion. I have already secured a 4.5 inch wide Ducati rear rim but the bearings are the wrong inside diameter for my axle so will need to replace those. Just need to track down a front rim now.

I had fun racing the bike, its taking some adjusting too and I'm at the rear of the pack but I'll keep tweaking bits and pieces till I'm happy. Today I fit a Domino quick pull throttle as I found I was dropping my right arm too much when applying full gas. The throttle pull on the weber is quite heavy compared to modern bikes. I also have a man making me some F1 style fairings too. Going to turn it into a bit of F1 look a like. On the whole I'm happy with how things are progressing.

A few pics below. I made the local paper after my 2nd meeting last wkd.

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[Tamburinifan]

Very nice report!
Keep up the good work!

[paso750]

I wonder if the shudder is from warped discs, a slightly lose headstock bearing or worn fork bushes. As these are hard to find, forks are often rebuilt using the old ones.
I'd consider replacing the stock flywheel with a lighter one. Not only will throttle response be quicker but getting off the line is usually also easier.

G.

[Mc tool]

Im picking the discs . My theory is that if you do have a knackered bush or two the shudder has to be initiated by something .

[Kiwi Rider]

The discs will be getting replaced with bigger diameter ones when I do my 17" wheel conversion. I do need to check the steering bearing tightness though.
Felt OK on the standard push/pull test hanging on to the bottom of the forks with the bike pulled over on the side stand.