CBX Racing

CBXs, new bikes, old bikes, cars, trucks, general chat, off topic, this is the place to post it.
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Syscrush
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Re: CBX Racing

Post by Syscrush »

Getting the CBX down to GSX-R weight is quite an accomplishment!

Thanks for the update.
Phil in Toronto
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Pics of Perry, my '79.

Warwick Biggs
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Re: CBX Racing

Post by Warwick Biggs »

Too much of everything. 2 lots of dohcams, 2 lots of 2 piston calipers, 2 banks of 3 carbies, 2 three into one exhausts and now, 2 crankcase breathers.

More puff so, let it breathe.

The tank is the biggest issue weight-wise in that I have to carry extra fuel so an up coming mod is a second pingel on the rhs so I can carry less fuel for typical short races. Longer term an alloy tank as previously mentioned. Another item that could be put on a diet is the barrels. The iron liners are probably contributing to that extra weight because the barrels are surprisingly heavy and if I were to take it out to the class limit of 1300 cc I would investigate alternatives to those liners.
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Warwick Biggs
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Re: CBX Racing

Post by Warwick Biggs »

To be painfully honest about the weight comparison Phil, I have not measured it for over a year and I'm estimating based upon a multitude of changes in that time. I'm also comparing half wet weight of the CBX (oil but no fuel) with the published weight of the GSXR road bike. My track bike by contrast is lighter with all road gear removed and race glass.

Power wise the de-catted, re-flashed and dyno tuned GSXR probably has a few horsepower more than the CBX but there is not much in it really and that could be reversed by the time I get the carbs percolating properly with the new motor. Today I pulled the needles out to rectify the hesitation off a closed throttle but the circlips were already at the bottom notch of the 9 positions. That means I have to go back up at least one size on the mains as it is running too lean. The carbs came with 120 mains but we ended up going to to 100's with the old motor.

Clearly the new motor is sucking harder and can handle a set of bigger mains. Or, I could be wrong. Doing it by trial and error without a sensor or gas analyser is a pain.

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Re: CBX Racing

Post by Warwick Biggs »

Roly reckons I'm wrong and the main jet size is correct and I should focus on the needles and perhaps go up a size in the slow jets.

I took the Lump out to the track yesterday to test a few things. I was not planning on doing too many laps which was just as well because every time the track started to dry out with a sunny break another heavy shower of rain would come thru'. I eventually got out for half a dozen laps but the track was still wet enuf' to throw spray and with slicks and open bell mouths not ideal test conditions.

The Brembo brake MC seemed to work OK altho' I was not using it as I would in a race. I've also been advised to try Castrol SPF brake fluid. Expensive but said to give superior performance and feel at race temperatures when the brakes get very hot indeed.

My new breather fixed the misting problem with the old breather but created it's own problems with oil escaping from it's bottle. I need to rationalise the 2 catch bottles and am planning to place a single larger catch tank higher up in the ducktail where I can vent it properly and where the oil can drain back into the engine without making an almighty mess.

The poor carburation off a closed throttle was also not good in the damp conditions because I would open the throttle thru' a turn only to have it hesitate, cough and then all 6 cylinders chime in with a bang causing the back end to step out. Disconcerting when over 100 hp are unleashed with no way to ride around it either other than be prepared.

Here is a pic I took of the trailer all loaded up and ready to go. I can usually hitch the trailer, load the bike and all my gear by myself in under 15 minutes and unload in similar time except at the track where I take a wee bit longer because I have to use ramps instead of my loading dock.
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Warwick Biggs
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Re: CBX Racing

Post by Warwick Biggs »

Why does this site put my pics on their ear sometimes. They are not that weird.

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Syscrush
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Re: CBX Racing

Post by Syscrush »

Warwick Biggs wrote:
Sun Jun 26, 2022 2:36 am
Why does this site put my pics on their ear sometimes. They are not that weird.
It's an issue with the forum software. It's not just your photos that have these issues when posted here.
Phil in Toronto
A cool guy deserves a cool bike, a dork needs a cool bike...
Pics of Perry, my '79.

Warwick Biggs
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Re: CBX Racing

Post by Warwick Biggs »

Hmm. Is there a programming fix in the works?

Stupid mistake of the w/e was attempting to start the Lump with the bell mouth covers still fitted. There I am thinking it wont start because it is a Honda and it is cold and wet and lean to boot when it was me rushing and not focusing on what I was doing. The result was that I flooded it and had to pull off the tank and seat to extract the plugs to dry them. Worse still is the difficulty quickly removing plugs #2 and #5 where the engine hangar plates have to be removed first to get them out. I just left them in and luckily managed to start it on the 4 dry plugs.

Just as well because I did not have any ether, the conventional solution to hard starting. My old mate Dennis who helped me with converting the Lump in the early days always decried the use of ether, also known as aero-start or Start'yabastard. He reckoned it stripped the oil off the bore and caused premature piston failure.

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