Author Topic: CB500/CB550 interchangeability (Read 1952 times)

peter400four · « **on:** November 18, 2018, 01:30:08 PM »

Hi again.
I hope this question isn't too "ho hum" for the technical experts here. I looked at the FAQs but didn't find an answer there. (Hope I didn't simply miss it).
Anyhow, could someone please tell me if I can drop my CB500 crankshaft straight into a CB550 crankcase and are the primary drive and cam chains interchangable? I have a 500/4 in an Historic Road Racing bike and would like to change to the 550 cases because I've heard that its clutch and gearbox are better suited to the rigours of road racing.
Thanks in advance.

bryanj · « **Reply #1 on:** November 18, 2018, 02:05:23 PM »

Crank and rods same as are chains. Primary drive gear to clutch basket different as is all gearbox and clutch. Heads cam and cam covers same. 550 bose can blow 2nd gear to bits.

peter400four · « **Reply #2 on:** November 18, 2018, 05:35:24 PM »

Thanks for your prompt reply bryanj. I thought they dropped in, but thanks for the confirmation.
I'm afraid you that you have raised a couple of new questions with this barely passable home mechanic.
1/- " ..... primary drive gear to clutch basket ..." Are you talking about the gearbox shaft and the clutch basket teeth there? Which would mean that as long as I use the 550 gearbox and clutch in the 550 cases, I can use my good 500 crankshaft, rods, pistons and barrels ... did I get that right?
2/- What is a "Bose" as in " ... 550 bose can blow 2nd gear to bits"?
Thanks.

dave500 · « **Reply #3 on:** November 18, 2018, 11:00:17 PM »

use the entire 550 transmission bottom end,its improved over the 550,youll need the clutch cable mount/right hand rear engine mount aswell.

754 · « **Reply #4 on:** November 18, 2018, 11:04:32 PM »

Bearings for the crank have to match the numbers on the case. They may he the same or close enough to run in some cases. New shell bearings will fix that issue.

Deltarider · « **Reply #5 on:** November 19, 2018, 12:20:24 AM »

Quote from: peter400four on November 18, 2018, 01:30:08 PM

Hi again.
I hope this question isn't too "ho hum" for the technical experts here. I looked at the FAQs but didn't find an answer there. (Hope I didn't simply miss it).
Anyhow, could someone please tell me if I can drop my CB500 crankshaft straight into a CB550 crankcase and are the primary drive and cam chains interchangable? I have a 500/4 in an Historic Road Racing bike and would like to change to the 550 cases because I've heard that its clutch and gearbox are better suited to the rigours of road racing.
Thanks in advance.

What's the problem right now? Would like to see some pics of your bike, if possible.

bryanj · « **Reply #6 on:** November 19, 2018, 01:10:28 AM »

Sorry damn dyslexic keyboard! Should have read 550 BOX(as in gearbox) and the primary gear i was talìng about is the one on the end of the primary shaft that mates with the clutch basket gear. Forgot about the LH rear mount being different and yes you will need to sort out shells as it is unlikely they will be the same.

peter400four · « **Reply #7 on:** November 20, 2018, 03:30:06 PM »

Quote from: 754 on November 18, 2018, 11:04:32 PM

Bearings for the crank have to match the numbers on the case. They may he the same or close enough to run in some cases. New shell bearings will fix that issue.

Thanks for your input 754,

I don't have the motor apart yet, but when I do, where do I look for the "matching" numbers. Also how close is "close enough"?

peter400four · « **Reply #8 on:** November 20, 2018, 03:34:07 PM »

Thanks to you for your advice too, dave500 and bryanj.
I know just what you mean about dyslectic keyboards Bryan, mine gets me nearly every time Want to write something.

peter400four · « **Reply #9 on:** November 20, 2018, 03:48:46 PM »

[/quote] What's the problem right now? Would like to see some pics of your bike, if possible.
[/quote]

It's not so much a problem Deltarider. It's more about finding out what fits which model in the continuing development of this project bike, an homage to the late John Blanchard TZ beater from the late 1970s, the Flying Dragon. My son started a thread on caferacer.met detailing the build and I was going to include a link here, but I can't seen to find it any more. I'll keep looking though. Will try to post a couple of pics. A couple of me on the track and the static shot features a poster of the original bike on top and mine underneath (still with straight megaphones at that early stage)

peter400four · « **Reply #10 on:** November 20, 2018, 08:45:09 PM »

It's no wonder I have to post simple questions here about mechanical stuff, it took we ages to work out how to post more than one photo at a time.
As I said in the previous post, the one these photos didn't appear with, the pic with the straight pipes is the bike's first appearance, the curved megaphones, as per John Blanchard's original came a couple of years later.
Now p, having found a set of suitably sized Dymags, we're setting up the rear shock height and fitting the 550 crank cases for the better gearbox and clutch.
Still more to do, but little steps.

peter400four · « **Reply #11 on:** November 20, 2018, 11:18:38 PM »

Hi again Deltarider,
I thought I'd posted this link before, but obviously not.
It's the link to the caferacer.net thread my son posted about the build.

https://www.caferacer.net/forum/project-builds/22751-flying-dragon-honda-cb500f-repro.html

Thanks for your interest.

bryanj · « **Reply #12 on:** November 21, 2018, 02:25:55 AM »

If you look in the genuine Honda workshop manual it shows you where to look fot size codes on crank and case and has the table to work out what size you need.

peter400four · « **Reply #13 on:** November 21, 2018, 02:40:13 AM »

Thanks for that Bryanj.

Deltarider · « **Reply #14 on:** November 21, 2018, 06:03:07 AM »

Thanks for the pics, Peter. I just wondered if you aren't going to miss the mathematically stepped ratios the CB500 gearbox offers. To me it makes the impression of a more 'racy' gearbox than the CB550s but I could be wrong.

peter400four · « **Reply #15 on:** November 21, 2018, 12:25:53 PM »

Quote from: Deltarider on November 21, 2018, 06:03:07 AM

Thanks for the pics, Peter. I just wondered if you aren't going to miss the mathematically stepped ratios the CB500 gearbox offers. To me it makes the impression of a more 'racy' gearbox than the CB550s but I could be wrong.

I guess I'll just find out, Deltarider. The general wisdom appears to be that the 550 gearbox is "better". I don't know if that relates to smoothness of action, ruggedness or ratio options. I did read of a company that offered a couple of different gears for the intermediate ratios that when used in conjunction with a taller countershaft sprocket, give you a close-ratio gearbox. Unfortunately, I haven't been able to track down an address and one of those lovely six-speed gearbox sets from England are way above our budget. The clutch on the 550 has a different, lighter operation mechanism and I'm confident I'll be liking that as my poor old arthritic left wrist certainly feels it after a five-lap race. Oh to be young again.

dave500 · « **Reply #16 on:** November 21, 2018, 10:42:19 PM »

they have the same ratios in the transmission,the 550 has a faster primary reduction which is then geared back down with the larger 37 tooth rear sprocket.

RAFster122s · « **Reply #17 on:** November 22, 2018, 12:15:08 AM »

Peter,
PM Brent Waller, he races the 550 with his son doing the riding now. They have the 6 speed gearbox fitted...
They blew up a gear a couple years ago and had to have someone make them a replacement.

David

Quote from: peter400four on November 21, 2018, 12:25:53 PM

Quote from: Deltarider on November 21, 2018, 06:03:07 AM
Thanks for the pics, Peter. I just wondered if you aren't going to miss the mathematically stepped ratios the CB500 gearbox offers. To me it makes the impression of a more 'racy' gearbox than the CB550s but I could be wrong.

I guess I'll just find out, Deltarider. The general wisdom appears to be that the 550 gearbox is "better". I don't know if that relates to smoothness of action, ruggedness or ratio options. I did read of a company that offered a couple of different gears for the intermediate ratios that when used in conjunction with a taller countershaft sprocket, give you a close-ratio gearbox. Unfortunately, I haven't been able to track down an address and one of those lovely six-speed gearbox sets from England are way above our budget. The clutch on the 550 has a different, lighter operation mechanism and I'm confident I'll be liking that as my poor old arthritic left wrist certainly feels it after a five-lap race. Oh to be young again.

peter400four · « **Reply #18 on:** November 25, 2018, 01:10:15 PM »

Hi RAF122S,
Thanks for the tip.
I tried to PM Brett Weller, but couldn't find him in the members' list.
Once we get the new bottom end in and the bike running well, I may just open a new post asking if anyone knows about the conversion I mentioned. There's no real rush as these projects take time and are only restricted by my advancing years.

Quote from: RAF122S on November 22, 2018, 12:15:08 AM

Peter,
PM Brent Waller, he races the 550 with his son doing the riding now. They have the 6 speed gearbox fitted...
They blew up a gear a couple years ago and had to have someone make them a replacement.

David

Quote from: peter400four on November 21, 2018, 12:25:53 PM
Quote from: Deltarider on November 21, 2018, 06:03:07 AM
Thanks for the pics, Peter. I just wondered if you aren't going to miss the mathematically stepped ratios the CB500 gearbox offers. To me it makes the impression of a more 'racy' gearbox than the CB550s but I could be wrong.

I guess I'll just find out, Deltarider. The general wisdom appears to be that the 550 gearbox is "better". I don't know if that relates to smoothness of action, ruggedness or ratio options. I did read of a company that offered a couple of different gears for the intermediate ratios that when used in conjunction with a taller countershaft sprocket, give you a close-ratio gearbox. Unfortunately, I haven't been able to track down an address and one of those lovely six-speed gearbox sets from England are way above our budget. The clutch on the 550 has a different, lighter operation mechanism and I'm confident I'll be liking that as my poor old arthritic left wrist certainly feels it after a five-lap race. Oh to be young again.

RAFster122s · « **Reply #19 on:** November 25, 2018, 10:27:27 PM »

Brent Waller's ID is bwaller
I think the gearbox was from a cb350 initially that had been reworked. Brent is helpful with others that race with him... in the VRRA (?acronym)
He is in Ontario Canada.
The gearbox required case mods of course and I think it deleted the kicker, of course no starter on a race bike.

Here's the lengthy thread about the race bike and they only have a few secrets...
http://forums.sohc4.net/index.php/topic,83871.0.html
Their 550 has over 70hp on the dyno...it is a powerful beast they and Mike R have developed with the pistons and head work. Brent had his own cb550 pistons made to handle the compression and meet the needs they had...

David

754 · « **Reply #20 on:** November 26, 2018, 05:30:34 PM »

Peter, very cool bike you have there m I love the curved mufflers.
Which fork do you have? What width Dymags ?

Peter I think it would be great to have a pic orvtwo of your bike in the inspiration thread, and somewhere in the High Performance thread.

peter400four · « **Reply #21 on:** December 17, 2018, 11:36:31 PM »

Sorry about my tardy response 754. Had relatives visiting and couldn't get to important stuff (anything to do with two wheels). My forks are 39mm, off a RS250 Honda GP bike, at least I think that's the model. My wheels at the moment are a bit wide for my liking, a 3" Dymag on the front and 4" Suzuki 250 RGV on the back, 'cos I couldn't get a Dymag at the time. Well, after nearly three years of looking, I've landed a pair, 2.5" front and 3.5" rear. I do like the quicker turning you get with a thinner tyre. Now all we have to do is decide whether to use the 3.5" or the current 3" front wheel on the back.
I'm happy to put up some pics if you reckon there'd be interest, but the bike is pretty well documented on caferacer.net in a thread my son started when the bike was little more that an article and some photos in a U.K. historic racing magazine. Just search "Flying Dragon" and it should come up.

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Author Topic: CB500/CB550 interchangeability (Read 1952 times)