Author Topic: HRC Clutch Basket (Read 18489 times)

Rod · « **on:** July 26, 2009, 03:08:20 am »

I have finally got round to getting my HRC CR gear cluster recond'd (by Nova UK - great job) for my race 500 and had forgotten that it comes with a special clutch basket. It carries an extra friction plate, but also runs a 78 tooth cog instead of the 64, does anyone have an idea why this might be? does it alter the torque values going through the clutch maybe? NB I was told when I bought the bike and trick parts many years ago that they were HRC but could be Yoshi for all I know.

bwaller · « **Reply #1 on:** July 26, 2009, 07:03:58 am »

Very cool Rod. There is a buzz these days about those gearboxes. Is yours a 5 or 6 speed? We have the ratios for the 6sp. but would dearly love to get a hold of info on the 5 speed if you care to share.

Jerry Rxman Griffin aka MuthaF'er · « **Reply #2 on:** July 26, 2009, 09:49:35 am »

No clutch basket listed in my Yoshi catalogue circa 1977.

Bill/BentON Racing · « **Reply #3 on:** July 26, 2009, 12:29:27 pm »

Not in earlier catalog either.If the CR750 trans was in Yoshs catalog under RSC parts why not for the 500s?Either they were RSC or Pops made them using RSC parts? Bill. I posted pic in Yoshimura secrets of catalog showing RSC parts for CB500.

Rod · « **Reply #4 on:** July 27, 2009, 06:37:32 am »

Quote from: bwaller on July 26, 2009, 07:03:58 am

Very cool Rod. There is a buzz these days about those gearboxes. Is yours a 5 or 6 speed? We have the ratios for the 6sp. but would dearly love to get a hold of info on the 5 speed if you care to share.

Hi bwaller - its a 5 speed. I've e-mailed the engine builder and asked him to make a note of ratios before putting the cases back together and I'll let you know. It's along time since I ran these ratios but do remember that they seemed well spaced for a track motor - although 1st was a little tall which along with 12.5/1 cr made dead-engine starts 'interesting'. I raced it in TTF2 along with the 350 stink wheels and regularly got ridden over whilst trying to push start off the grid.

bwaller · « **Reply #5 on:** July 27, 2009, 07:46:59 am »

Thanks Rod, that information will be interesting.

"350 stink wheels"........great description!

A four strokers nightmare. I've tasted that stink from their side of the fence though!

Rod · « **Reply #6 on:** August 24, 2009, 06:27:19 am »

Haven't got the ratios yet for the HRC cluster - engine builder is busy with the Manx GP at moment, but have received an explanation about different gearing of clutch basket.

"Comp clutch has greater primary reduction to reduce gearbox speeds and to allow sensible final drive ratios at higher engine speeds and reduces load on the crank - extra plate in the clutch copes with the higher torque multiplication. Torque at clutch equals torque at crank x gear ratio minus losses".

bwaller · « **Reply #7 on:** September 23, 2009, 05:18:04 pm »

Rod,

Are you able to give us that primary reduction fiqure?

Also have you been able to get the 5 spd ratios?

turboguzzi · « **Reply #8 on:** September 25, 2009, 04:05:59 am »

Hi rod

it'll be also nice to see an update picture.

Seen a 2yr old post of yours (bill relied ti it now :-) ) and you said that the engine was mounted semi stressed.

Can you explain?

TG

Rod · « **Reply #9 on:** September 28, 2009, 12:51:01 pm »

Bill - not got the cr and primary drive ratios yet (sorry) but am chasing the workshop for some answers.

TG - bike still in bits and waiting on the engine builder - this has been a really slow process, (mainly my fault). Dymags have gone back to the factory for crack test and re-coating. I need to decide what to do about front brakes, the TZ 48mm calipers are seized and there are limited options for pads (no race compounds). I could go lockheed but see you run brembos? what are your thoughts (it runs two 298mm rotors). Re the semi-stressed design, the frame was conventional duplex which has been cut, the down tubes remain and now bolt onto plates fixed to the front of the crankcase, and the rear engine mount bolts to the frame just in front of the swing arm pivot - I'm away from home but will take some pics when I get back. As a result, the weight distribution is a little too much on the front end I think, around 55/45% - that said, I don't know what the norm is for race bikes?

turboguzzi · « **Reply #10 on:** September 28, 2009, 03:22:32 pm »

hi rod

that's a pretty interesting mod. It was often done to guzzi's, i.e. running without the bottom tubes, never seen it on a sohc.

would you say that handling remained the same? better? you must have a handler for the TT.... Worth the 1-2 kilos saved?

Can definitely recommend the small brembos, really happy with how they work on my 275mm suzuki discs. Cant see why the wouldn't work well on 298's. You might want to play a bit with pad componds, the full sintered i tried first were too aggressive, running SBS "dual carbon" now

kos · « **Reply #11 on:** September 29, 2009, 09:17:37 am »

HRC vs RSC

Just to clear up this issue of Honda Racing Services vs Racing Services Corp or (Club)

RSC was in business making the Honda Roadracers and parts for customers up to 1979.
In early 1980's Honda changed the designation to HRC. I think it was about the time they went to water cooled bikes ie: VF750F

And from all the vast data that I have accumulated...I have never heard of a HRC clutch basket from Honda, Yoshimura or

?

There was or is a company in UK that was called HRC, but I thought they went away?

I am a dealer for Nova and know owner Graham Dyson well, so I don't think he would label anything.... HRC.

KOS

Rod · « **Reply #12 on:** September 29, 2009, 10:10:22 am »

Quote from: kos on September 29, 2009, 09:17:37 am

HRC vs RSC

I am a dealer for Nova and know owner Graham Dyson well, so I don't think he would label anything.... HRC.

I've had this many years, long before Nova started business. I'll get some pics taken this w/e and post, it could be a special of course but I've no idea who would have made it in that case.

kos · « **Reply #13 on:** September 29, 2009, 02:15:13 pm »

Yes, by all means...please post this most interesting part.

KOS

Bill/BentON Racing · « **Reply #14 on:** September 29, 2009, 05:56:11 pm »

I agree,never saw one listed,would like to know more.Also want to see pics of frame mods.Good Luck with build.,Bill

Rod · « **Reply #15 on:** October 01, 2009, 04:35:08 am »

Quote from: turboguzzi on September 28, 2009, 03:22:32 pm

would you say that handling remained the same? better? you must have a handler for the TT.... Worth the 1-2 kilos saved?

Can definitely recommend the small brembos, really happy with how they work on my 275mm suzuki discs.

Hi TG
The frame mods were made before I bought the bike, it was a special built and raced at the TT by a guy called Tony Dunnell who was a very quick privateer in his day (he now builds the most beautiful Manx Nortons that are raced in the IHRO series and in the UK). It ran in the TT F2 category (1980 & 81 I think) with a big bore top end (600cc ish) and went bang both times, the frame is Yamaha TZe 350 monoshock. I bought it in 82 with several boxes of parts which included the yoshi inlet manifolds, cr cluster and 'special' clutch basket with modded primary gearing).

I like the sound of the Brembos, when you say you have the small caliper do you mean the F08?

turboguzzi · « **Reply #16 on:** October 01, 2009, 05:20:55 am »

the frame is Yamaha TZe 350 monoshock

tz frame? getting confused by now , I thought it was a cut CB500 frame....

By small brembo's I mean the F05 , the ones with a single pin to retain the pads.

Rod · « **Reply #17 on:** October 01, 2009, 05:27:35 am »

Quote from: turboguzzi on October 01, 2009, 05:20:55 am

the frame is Yamaha TZe 350 monoshock

tz frame? getting confused by now , I thought it was a cut CB500 frame....

By small brembo's I mean the F05 , the ones with a single pin to retain the pads.

Hi TG - no its a yam frame, weighs in at about 140kgs (wet engine but no fuel).

turboguzzi · « **Reply #18 on:** October 01, 2009, 12:46:30 pm »

Hi rod,

so let me get this right:

Your bike is a CB500/600c.c. motor inside a Yamaha TZ frame? Sounds very cool, though my racing federation would have a hard time accepting it as true vintage..... never heard of such mongrel

Weight wise there's not much in it, my racer with a braced stock frame weights now 141 with liquids/no gas, but that yammie frame should be way stiffer.

Havent seen much pictures of your bike since the single one you posted some two years ago, mind posting some new ones?

Cheers

TG

Sam Green Racing · « **Reply #19 on:** October 01, 2009, 12:57:30 pm »

Here ya go TG, http://en.wikipedia.org/wiki/Formula_TT

Sam.

turboguzzi · « **Reply #20 on:** October 01, 2009, 01:54:38 pm »

Yep, I knew about formula II being 350 2stroke and 600 4storke, just never heard about such a mix

didnt remeber that string of wins by Alan Jackson jr.

coming to think of it, anybody's got a pic of Alan Jackson jr. 600cc honda winner of 1977-78-79?.

Sounds like the CB500 biggest sporting achievement ever?

Sam Green Racing · « **Reply #21 on:** October 01, 2009, 02:10:59 pm »

I will have one but It's at home in a book, it's called Honda, the winning years and shows pics of every TT winner.

Sam.

Sam Green Racing · « **Reply #22 on:** October 01, 2009, 02:23:52 pm »

Here ya go TG, full details of his TT career.

Sam.

http://www.iomtt.com/TT-Database/Events/Races.aspx?meet_code=ALL&ride_id=4528

turboguzzi · « **Reply #23 on:** October 01, 2009, 03:14:28 pm »

could be great to learn some details about that 500/600 sohc and see pics

was it an official Honda Britain effort?

now the whole mystery as why Pops called it an IOM cam starts to unfold

TG

Sam Green Racing · « **Reply #24 on:** October 01, 2009, 03:36:21 pm »

I'll take a look in the morning, see what the book turns up.

Sam.

News:

Author Topic: HRC Clutch Basket (Read 18489 times)