Author Topic: racer weighted (Read 7403 times)

turboguzzi · « **on:** August 04, 2007, 06:18:42 PM »

Quite a few people asked for my cb500 racer's weight + I was quite curios too.

Got exactly 150 kg (that's 330 lbs) dry weight ( with oil & battery, but no gas in the tank)

Sounds nice compared to the original 190 kg / 420 lbs or so but bear in mind that those RD350's i am racing against must weight 30-40 lbs less still.....

At this point, losing more weight becomes tricky. Haven't removed the kickstarter shaft and gear yet but that will wait till the end of season engine tear down. With the engine open I'll check if the electric starter gear (which is not in use) can be removed too.

Got hold of some lighter fork tubes, have to work out if the original dampig mechanism will still work with them. An ally lower triple clamp and ally steering stem could shave some weight too. Might go for a smaller battery as the current one handles a whole weekend of practice and racing without problems, don't mind charging a smaller one between sessions.

All in all maybe I can shed 5-6 kg (10-12 lbs.) but after that it losing more weight becomes really tricky or swiss-cheesing time. Any other ideas?

Cheers
TG

Peter2 · « **Reply #1 on:** August 04, 2007, 06:39:32 PM »

What about a magneto? Then you can ditch the battery.

chrisf · « **Reply #2 on:** August 04, 2007, 07:04:58 PM »

Running a few miles a day will peel the total weight off--at least it does for me. Switching to Ti bolts will shave 10 lbs or so as well.

I'm not really familliar with your bike, but if your gutting the kicker mechanism, it soulds like you took care of the usual suspects.

--Chris

MRieck · « **Reply #3 on:** August 04, 2007, 08:03:55 PM »

I can't remember...does the 500/550 kickstart gear drive the oil pump?

paulages · « **Reply #4 on:** August 04, 2007, 08:42:12 PM »

Quote from: MRieck on August 04, 2007, 08:03:55 PM

I can't remember...does the 500/550 kickstart gear drive the oil pump?

no.

bwaller · « **Reply #5 on:** August 04, 2007, 09:20:10 PM »

Turbo,

I think you have done well at 330lbs. I just finished a 500/550 for my wife and pared off as much weight off it as was feasible. It made sense to keep the e-starter so I removed the kickstart shaft complete & lever. All that weighs 3lbs. I didn't mark down the weights for the e-start components but I think that was around 7lbs.

I'm sure you've done all the the other little things but in case not replacing axle spacers, rear engine spacers with aluminum add up to another 1/2 lb.

I thought about going to larger ID wheel bearings and replacing both axles with larger diameter Ti material, which although expensive, would save a great deal of weight and increase rigidity.

Keep up the good work!

oldbiker · « **Reply #6 on:** August 05, 2007, 01:27:08 AM »

Have you looked to see how many pounds you can shave off the jockey

Many years ago, I shared fastest lap with a close friend in the 250cc class. He weighed 120 lbs and I weighed 175 lbs.

peter c · « **Reply #7 on:** August 05, 2007, 01:46:04 AM »

Well done TG but keep at it and get that kick start out. We have managed 141kg with the 500 and maybe can save a little more.Lighten all those bolts and fastners,reduce the bolt head thickness and countersink the ends.
No doubt about the diet method for the rider,need to try harder in that dept. myself.

regards

peter c

turboguzzi · « **Reply #8 on:** August 05, 2007, 02:26:19 AM »

141 kg? Gee.... You managed to motivate me!
BTW peter, how did the Chimay race go?

Now, if rider WEIGHT was the only problem..... in my case it's also rider LENGTH! at 6'4" I surely add some air drag too!
At least, I am lean at "only" 180 lbs, but surely not the jockey body type. have learned to accept myself through the years :-)

Thanks for the ideas. Cant believe a magneto will save weight against my current total loss setup, it will surely add rotating mass = less acceleration.

already got hold of a hollow rear axle off a GSXR, the original one weights a ton! Might change also to a 20mm front axle and hollow it big time. Indeed, most of the obvious stuff has been done: ally wheel spacers, CB350 rear hub. On the other hand, I am trying to keep this sensible, cant see myself parting with silly money for Ti stuff. A racing 35mm Ceriani fork would be nice but would require also new brake calipers, etc, so it's really out of my budget now.

thanks and cheers
TG

peter c · « **Reply #9 on:** August 05, 2007, 03:24:36 AM »

We still use boyer with a small battery and can't see us changing as it is reliable. Does the gsx spindle fit straight in? We use lightweight alloy clipons which make a big differenceand a light fairin too.

Chimay went well,I hadn't raced since October so was a little nervous too say the least. I qualified 12th out of 40 with a lap near a second quicker than last year. Finished both races in 9th with a lap 1.4 seconds faster than 06 but I finished 5th then.We all enjoyed the racing and intend to do the Belgium classic championship next year with both the 750 and 500. Not raced the 750 yet as we only got it running a week ago. CR Sam cam to Croft circuit last Saturday and gave his approval.

Keep up the good work and above all enjoy the racing.

Regards

peter c

bwaller · « **Reply #10 on:** August 05, 2007, 06:13:53 AM »

141kg.= well done.

peter c · « **Reply #11 on:** August 05, 2007, 11:32:04 AM »

Hey Bwaller, what's that pipe below the ignition cover,looks like an oil pipe or is some secret rocket fuel?

Peter c

bwaller · « **Reply #12 on:** August 05, 2007, 01:01:40 PM »

No secret fuel, just the oil feed to the top end.

paulages · « **Reply #13 on:** August 05, 2007, 02:07:34 PM »

Quote from: bwaller on August 05, 2007, 01:01:40 PM

No secret fuel, just the oil feed to the top end.

doing the same thing on mine, as the overbore comes pretty close to the oil passages. why did you reroute yours?

peter c · « **Reply #14 on:** August 05, 2007, 03:15:18 PM »

Tell me about it guys,I need to know.

Peter c

bwaller · « **Reply #15 on:** August 05, 2007, 04:17:26 PM »

The biggest reason is I hate oil leaks (not that they all leak mind you) and since I was building this one stem to stern I decided to feed the top end externally and avoid the potential for a leak in the future. In the case of this engine the job is quite simple also.

LoopsAndLogic · « **Reply #16 on:** August 05, 2007, 06:50:55 PM »

I wonder if this can be done on a CB400F?

LL

paulages · « **Reply #17 on:** August 05, 2007, 07:21:17 PM »

Quote from: bwaller on August 05, 2007, 04:17:26 PM

The biggest reason is I hate oil leaks (not that they all leak mind you) and since I was building this one stem to stern I decided to feed the top end externally and avoid the potential for a leak in the future. In the case of this engine the job is quite simple also.

yeah, i was also happy about the prospect of losing the potential o-ring leaks at the head gasket. i was going to tap into the main oil galley just before the filter for my lines, but seeing yours makes me think i'll go back to that idea for routing. i bought blank fittings to drill out for the restrictors. what did you do?

didn't mean to hijack the thread--bwaller, PM me if you want to...

bwaller · « **Reply #18 on:** August 05, 2007, 07:29:56 PM »

Loops, the 400F head would be difficult to feed externally because of the two oil pipes that supply the lubrication for the cam. They fit directly into the oil passage so I think it would be dangerous to attempt.

edbikerii · « **Reply #19 on:** August 05, 2007, 08:06:53 PM »

bwaller,

Could you elaborate on the parts and work required for that oil line mod? It bothers me that those o-rings have such a short life. I'd rather not have to tear into my engine again when it starts to leak, knowing that it will only leak again in a few thousand miles!

Thanks

Quote from: bwaller on August 05, 2007, 04:17:26 PM

The biggest reason is I hate oil leaks (not that they all leak mind you) and since I was building this one stem to stern I decided to feed the top end externally and avoid the potential for a leak in the future. In the case of this engine the job is quite simple also.

bwaller · « **Reply #20 on:** August 05, 2007, 08:25:54 PM »

I apologize turboguzzi for getting off topic. My next winters project is to be a 500 roadrace project and I've been curious about what final weight to expect.

I wanted to start another topic with some pics of this 550 build anyway stand by on the oil line deal.

turboguzzi · « **Reply #21 on:** August 06, 2007, 01:48:11 AM »

Have the same mod in my racer and its working real good.
Really nice not to be bothered with those o-rings when you are closing the head + since I am using a thin custom cooper head gasket, The original o-rings wouldn't work anyway.
In case you do it, don't forget to put a restrictor in the oil line to the head or you'll lose all the pressure in the gallery. I simply put a carb jet at the end of the banjo that fits into the oil gallery. To feed both sides of the head I used a front brake line splitter.

Got to add that there's quite a lot of work involved, blanking all the original oil passages, machining adapters, pulling out the blanking plugs from the head, threading for the adapters there, finding all the right fittings and more. Be warned.
TG

edbikerii · « **Reply #22 on:** August 06, 2007, 04:21:39 AM »

Thanks for the info, and sorry for the hijack. I have a lot more questions about this mod, but I don't want to overrun your lightweight thread. Great work getting that weight down, by the way.

If I create a "500 / 550 oil passage bypass line" thread in "Tips and Tricks", would you mind if I quote your content, or would you discuss this mod further there?

Thank you

Quote from: turboguzzi on August 06, 2007, 01:48:11 AM

Have the same mod in my racer and its working real good.
Really nice not to be bothered with those o-rings when you are closing the head + since I am using a thin custom cooper head gasket, The original o-rings wouldn't work anyway.
In case you do it, don't forget to put a restrictor in the oil line to the head or you'll lose all the pressure in the gallery. I simply put a carb jet at the end of the banjo that fits into the oil gallery. To feed both sides of the head I used a front brake line splitter.

Got to add that there's quite a lot of work involved, blanking all the original oil passages, machining adapters, pulling out the blanking plugs from the head, threading for the adapters there, finding all the right fittings and more. Be warned.
TG

tsflstb · « **Reply #23 on:** August 06, 2007, 06:43:26 AM »

TTR400 sells a hollow front axle in Ti for the 400F - he could probably make one to work for you. He also has some nice alloy triple clamps, rearsets, etc. I'm still poking around scrapyards for a box section aluminum swingarm that could be adapted to work. There's probably 5 lbs. to be saved over the stock steel arm without losing any rigidity.

I imagine at 330 lbs. you've already got a minimal wiring harness. I haven't seen a picture, but I'd guess you have alloy rims. Buchanans now sells aluminum spoke nipples, said to reduce the weight by almost a pound per wheel vs. stainless steel. You could also switch from 40 spoke hubs to 36 spokes. It all adds up.

If you're still running a stock tachometer, there are small electronic units that are considerably lighter. You seem to be at the point where it's going to get expensive to lose a few ounces here and there, but there's nothing cooler than a vintage race bike. Nice work.

turboguzzi · « **Reply #24 on:** August 06, 2007, 09:29:36 AM »

Hei Tsf

Yep, been in contact with ttr at the time but classic racing rules here try to keep (rightfuly so IMHO) the classic looks and attitude, so no Ti allowed, no square section or aluminum or reinforced swingarms. Stuff has to be period, or at least period looking with 1975 as cut-off date. They are pretty stiff, wouldnt let me run with a remote reservoir master pump or regulable brake lever.

running already an electric tacho and alloy rims, so as you can see, I'm pretty much there with all the regular go-lighter stuff, now ineed to dig a bit deeper.

edbikerii
You are welcome to add a thread in tips and tricks. will add photos of my setup there.

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Author Topic: racer weighted (Read 7403 times)

Peter2

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peter c

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