Author Topic: racing cb500 marching on (Read 10669 times)

turboguzzi · « **on:** February 21, 2007, 03:37:15 pm »

hi all

it's been a long and cold winter in the garage but finally things are starting to fall into place.

Frame is shortened, tab cleared and gusseted (some 8 all around) and starting to put it back together.

first race is in Vallelunga in 2nd of march but I doubt if I'll be ready on time. Cam and valve springs still need to arrive from the US.

turboguzzi · « **Reply #1 on:** February 21, 2007, 03:40:19 pm »

rear set are self made with CBR900 pegs and pedals, trying to keep it all honda....multiple holes are there to let me find the best peg position during shakedown testing, after that the two spars will be welded together
special triangular plates should let me use shocks with normal bottom eye + let me adjust rear ride height by swapping these simple plates

turboguzzi · « **Reply #2 on:** February 21, 2007, 03:44:00 pm »

using a 1992 750 gsxr rotor, pick up and coils
rotor fitted into the existing recess like a dream, modifiying the original timing plate to mount the pick uo took some time and planning though

turboguzzi · « **Reply #3 on:** February 21, 2007, 03:51:05 pm »

not having the budget for 29 mm smoothbore CR's, I think these 50$ autojumble 28mm mikunis of some kawasaki (650 or 750?) should do quite well. 29's sound too big for a 500 anyway. having a much bigger spacing betwen left and right banks means that inlet tracks are super straight now but also having to design & build a custom manifold.
clutch activator was cut from 3/8" ally plate with a jigsaw...

more to follow as I advance

thanks to all who gave me good advice a few months ago

cheers from milan
TG

bill440cars · « **Reply #4 on:** February 21, 2007, 04:49:30 pm »

Hey turbo,

You've definitely got my attention and I'm sure, quite a few others. Now, you're gonna have to keep us posted with facts and pictures.

That is a pretty cool idea on those rearsets and, as a matter as fact everything I've seen on this, is interesting.

Tell us more.

Later on, Bill

MRieck · « **Reply #5 on:** February 21, 2007, 07:23:25 pm »

What cam did you end up buying?

turboguzzi · « **Reply #6 on:** February 22, 2007, 02:36:21 am »

Sure, learned a lot from this forum so will be happy to give back by posting pics. Bill, will be nice to see better pictures of that racing cb you have as an avatar.

went for the 126-20 cam, most tracks this championship runs on are kind of medium-slow so with 5 speeds I thought it better to get some torque rather than go for the extreme 126-x6.

have a problem though with valve springs. Kibblewhite do not list springs for the cb500 four in their online catalog, only for the cb500T. The girl who answered the phone said they could do them but only after sending a sample and paying 100$ to setup for a run. (thats a after she kept telling me that they dont do springs for honda CIVIC cars....)

does anybody ever got cb500 four springs from kibblewhite? if yes, they they could re-track that order and get all the dimensions.

otherwise, webcam do list a set. didnt go with the megacycle set as someone quite knowledgeable said megacycle springs werent good enough for racing use. any other ideas / sources?

tnxs
TG

MRieck · « **Reply #7 on:** February 22, 2007, 04:38:01 am »

Quote from: turboguzzi on February 22, 2007, 02:36:21 am

Sure, learned a lot from this forum so will be happy to give back by posting pics. Bill, will be nice to see better pictures of that racing cb you have as an avatar.

went for the 126-20 cam, most tracks this championship runs on are kind of medium-slow so with 5 speeds I thought it better to get some torque rather than go for the extreme 126-x6.

have a problem though with valve springs. Kibblewhite do not list springs for the cb500 four in their online catalog, only for the cb500T. The girl who answered the phone said they could do them but only after sending a sample and paying 100$ to setup for a run. (thats a after she kept telling me that they dont do springs for honda CIVIC cars....)

does anybody ever got cb500 four springs from kibblewhite? if yes, they they could re-track that order and get all the dimensions.

otherwise, webcam do list a set. didnt go with the megacycle set as someone quite knowledgeable said megacycle springs werent good enough for racing use. any other ideas / sources?

tnxs
TG

I just purchased a set of 500/550/650 springs from Kibblewhite. They have them but forgot to post them in the latest catalog. Part # 30-4045. Assembled height is 1.380 to 1.400

turboguzzi · « **Reply #8 on:** February 22, 2007, 11:31:26 am »

wow mrieck! that's really valuable info, made my day

does this number include also the spring retainers? Ti or Ally?

if not, think you might have their number too?

ciao
TG

peter c · « **Reply #9 on:** February 23, 2007, 02:20:15 am »

:)Hi I've been following your thread and like what i see.
We run a 500 here in the Uk and after three seasons have it really sorted. We have converted to 520 chain and this saves wieght and hp. Have you installed a close ratio box? If not watch out for that first gear on a slow corner. We used modified F1 carbs which have screw in jets and adjustable needles. We keep it tuned on our local honda friendly dyno and it now shows a healthy 63bhp at the wheel. Like the carbs too.
Good luck,

Peter c

turboguzzi · « **Reply #10 on:** February 23, 2007, 02:39:25 am »

hi peter

nice to hear about your project. 63 hp from 500 sounds very good! hope to get there! easily comparable to 95 from a 750.... Dont know what F1 carbs are. can you detail or send photos? in fact, will be nice to see some pics of the whole bike. like your idea about the 520 chain too. did you find a suitable spocket to go over the stock countershaft off the shelf? + would be interesting to know what kind of gearing you are running. The stock 17:34 (if i remeber right) is surely way too tall. regretfully, dont have the resources for a close ration nova transmission right now.

Thanks for the info

Yossef

peter c · « **Reply #11 on:** February 23, 2007, 05:32:32 am »

Hi yossef,
Sure I'll send some pics when i get a moment to take some. On our short circuits we run 16/34/35/35/37. and on fast circuits like Chimay in Belgium 17/36 is the norm.We don't use nova in the 500.The 250/350 K4 gearbox fit straight in. In the Uk these cost about £800 and use some of the existing gears,works well at half the cost of a nova. To do this you must have an engine with the clutch operating arm on the sprocket side and not on the clutch cover on the right like the very late 500s or on a 550.The F1 carbs are 28mm and have an accelerator jet which we remove although it does work well on early acceleration it does richen the mix at top end and we gained 1hp by removing. What have you used for pistons?We are in the process of constructing a cr750 and should have out by the end of april all being well.

Regards

Peter c

MRieck · « **Reply #12 on:** February 23, 2007, 05:40:17 am »

Quote from: turboguzzi on February 22, 2007, 11:31:26 am

wow mrieck! that's really valuable info, made my day

does this number include also the spring retainers? Ti or Ally?

if not, think you might have their number too?

ciao
TG

Unfortunately Kibblewhite doesn't list Ti retainers for the 500/550. The stock ones are pretty good.

turboguzzi · « **Reply #13 on:** February 23, 2007, 09:59:00 am »

Hi peter
all very valuable info, tnxs. I am keeping the actuating arm on the sprocket side so will check tomorrow for 250/350 G/B parts in the big autojumble they are holding here.
+may I ask you what cam, valve springs and retainers are you running? Mrieck says that stock are quite OK, are you using these too?
Curious also about braking. have twin stock discs and calipers at the moment but these weight a ton! havent drilled them yet though. was thinking instead of laser cut some similar sized out of 5 mm SS steel. the serious guys run here double piston brembos like those of big guzzis but you need the right Ceriani or ex-guzzi fork to use these.
Got a huge list of stuff to get tomorrow, lets see how my parts hunting goes.
have a nice weekend
TG

ttr400 · « **Reply #14 on:** February 23, 2007, 10:04:06 am »

The Honda part # for the stock retainers is 14771-107-020, which is the same for the CB350F, CB400F, CB500, CB550K/F

Kevin

turboguzzi · « **Reply #15 on:** February 23, 2007, 11:36:18 am »

hei ttr

some really nice stuff you have there in the site! I'm jealous!

How about a set of titanium spring retainers for my CB500? you said they were the same size as the 400, no?

nice idea for the front wheel stand too.

Cheers

TG

ttr400 · « **Reply #16 on:** February 23, 2007, 11:13:24 pm »

Thanks.

I will be sending a shipment to my USA distributor within a couple of weeks, there will also be a few sets of the Ti retainers. His web site is www.400fourstore.com

Kevin

peter c · « **Reply #17 on:** February 24, 2007, 12:47:08 am »

yossef,
We use megacycle isle of man profile and springs from megacycle and we use stock retainers and four megaphones as the English classic rules dictate. We have the same situation with brakes and use the yamaha double sided drum from the early Tz with a few tweeks to improve it's performance.We have reduced the discs on our 750 to 5mm and drilled them too,saves a lot of weight. We are putting an 18 year old rider on the 500 this year and he only weighs 140 pounds so should be quicker than my 180 pounds. I'll still need to have a race on it ,I love riding so much.

regards

Peter

chrisf · « **Reply #18 on:** February 24, 2007, 05:26:50 am »

Quote

http://www.sohc4.us/forums/index.php?action=dlattach;topic=18579.0;id=18937;image

That is an interesting crossbrace. I used the following method

The copper things are clecos--temporary rivets--drilled every 3/4". When it's painted and time to mount it, I'll use Cherry Brand structural rivets.

--Chris

turboguzzi · « **Reply #19 on:** February 25, 2007, 02:28:33 am »

sure remeber them clecos form my days in the airforce designing mods for F-15's, F-16's and such!

nice idea but the engineering half of my brain says that you are simply moving on the flexing to the swingarm pivot - to - shock mount tubes. maybe you could cross brace these too the same way. paint it balck and you can say its a mudguard....

situation in the cb500 is diferent as there twin tubes raising up to the tank-seat junction. I am bracing those with an ally plate fixed to four wide spaced ears I wleded to the tubes. its going to serve also as battery mount. it doesnt appear inthe pics I posted yet.

you'll find a nice feature about frame bracing here:
http://www.tonyfoale.com/Articles/Frame.mod/KawaMods.htm

peter, thining the current discs to 5 mm sounds good too, but being that thin, didnt you run into any deformation problems when hot?

bwaller · « **Reply #20 on:** February 25, 2007, 04:49:02 am »

I'm using 5mm discs from a mid eighties Suzuki, several models used these. The are the same offset & diametre as the 500/550. The mounting hole pattern is just slightly smaller, need to drill these larger.

turboguzzi · « **Reply #21 on:** February 25, 2007, 09:21:34 am »

hei bwaller

looks suzook indeed. any chance you might remember what model was it from? thanks for the tip.

bwaller · « **Reply #22 on:** February 25, 2007, 04:13:01 pm »

I think Suzuki used those discs on GS 500's, 750's, Katanas from maybe 1982 to 86 or so. I had a friend who raced a GS750 and he never had a problem with rotor warpage at that 5mm thickness. He claims he didn't go fast enough! I believe that disc is two pounds lighter than that the original Honda disc.

turboguzzi · « **Reply #23 on:** February 26, 2007, 07:32:06 am »

dont like the idea of breaking my electronic ignition or bending the crank in a fall, so I thought these 4 mm thick castings might be useful.....

the RSC logo is there just to psyche out the competition, can't hurt to look a bit exotic...

TG

peter c · « **Reply #24 on:** February 26, 2007, 09:32:38 am »

Now I realy like the castings,they are excellent.

Peter c

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Author Topic: racing cb500 marching on (Read 10669 times)

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