Author Topic: What mono shock swing arm fits a Honda cb 550? (Read 10332 times)

Ray S · « **on:** December 11, 2012, 04:09:14 PM »

Hi folks, I'm new the site and have started a Cafe project for my 1975 Honda CB 550. What I would like to do is build a modern Cafe bike using the old Honda 550 Frame, engine etc, but add a new inverted fork to the front.[ Already have a GSXR 2001 Front End complete with wheel, brakes etc and realize I need specil bearings from Alls Balls. I also have the rear swing arm, shock and complete wheel assembly from the GSXR, but it looks like a complicated machining nigthmare to make it fit. Are there any monoshock swingarms that have the same pivot bolt size and would fit easily into the frame with a little welding for the Mono shock? I have seen a brat version of the bike similar to what I want created by Steel Bent customs, but there is zero info available about the build. I appreciate any advice on my project. I can be reached through the forum.
Thanks Ray

754 · « **Reply #1 on:** December 11, 2012, 04:41:37 PM »

A Hawk one will slide into a CB 750, so check frame width at swingarm pivot..

Retro Rocket · « **Reply #2 on:** December 11, 2012, 05:13:13 PM »

Do you want the bike to handle well..? If yes, its not as simple as just bolting everything on, or whether it fits or not....

Ray S · « **Reply #3 on:** December 11, 2012, 05:19:20 PM »

Hi 754

Not sure if I want a single sided swing arm from a 650 hawk, or are you referring to something different?
The frame width at the pivot is 9 1/4 inches at the pivot point.
I think the pivot bolt is 15 mm, not sure becuase I do not have a micrometer to measure it.
The overall length of the swing arm is 24 inches +/- a tad.
I would like to purchase an entire assembly with swing arm, mono shock, brake and a 17 inch wheel.
Any ideas?
Thanks for your help. Ray

Ray S · « **Reply #4 on:** December 11, 2012, 05:23:02 PM »

Hi Retro Rocket
Yes I want the bike to handle, I do not want to build just a pretty bike that is non functional. I raced bikes a while back and understand that steering geometry etc, can be affected by the changes I'm proposing, but it appears others have tried this type of modification with some success? Do you have any advice. Thanks Ray

Retro Rocket · « **Reply #5 on:** December 11, 2012, 05:39:53 PM »

Hi Ray, the GSXR clamps have a 35mm offset, if you measure the 550 offset it will be around 50-60mm, the smaller offset of the GSXR clamps will slow down steering response at the front, every monoshock conversion i have seen on these old bikes using modern swingarms are far too long, the more length at the rear, the slower the steering response when cornering {sorry if i'm telling you stuff you already know} The 17 inch wheels will also lower the bike which will also effect handling. I am doing a GSXR conversion front and rear on one of my 750's and am having custom triple clamps made up for the front and instead of using the monoshock GSXR arm , i have had the mono shock section removed and the arm shortened {twin shock now} , in its monoshock form the arm was 6 inches + over the stock length, around an inch is ok but if you start going much longer in the rear the bike will be very stable in a straight line but will not corner any where near as well as it was originally intended...

Ray S · « **Reply #6 on:** December 11, 2012, 05:50:41 PM »

Hi again Retro Rocket.

The GSXR swing arm is only 2 inches longer and with 17 inch wheel the bike should turn in quicker not slower, although if I go with wide tires it will affect the handling somewhat. The problem with the 2001 GSXR swingarm is the massive pivot bolt and all the machining requried to make it fit plus the engine does not make enough power to handle a wide tire , so I'm thinking of a different set up for the rear, maybe an earlier GSXR with a narrower rear tire or possibly a Yamaha yzf 600 rear? I have also been advised that an early 1988 to 1992 Honda CBR 600 F2 swing arm could be a match, but I'm not sure. Either way I will need to beef up the frame to prevent PRETZEL logic. I.E.[twisting]. Please keep the advice flowing it is much apprciated. How's the weather in Brisbane? We have 17 degrees farenheit and snow flurries here in Maine.

Retro Rocket · « **Reply #7 on:** December 11, 2012, 06:02:53 PM »

Brisbane has been HOT, 4 days over 100 F last week, in the 90's today, nice sea breeze though. The Earlier GSXR arm is what i have {GSXR1100J 1988}and by the sound of things, they are a lot longer than the later arms, with the whole monoshock section removed and shortened as far as it can be its still 45mm longer than stock, i will use that arm on an F model 750 i have, they have a slightly longer arm anyway. The early GSXR 750's are shorter and may be better, i have seen one modded on a 500 race bike and it looked awesome, when i find the link i will post it up.

Found it....

http://forums.sohc4.net/index.php?topic=63938.0

There's a complete list of all the modifications in the first post...

Ray S · « **Reply #8 on:** December 11, 2012, 06:08:14 PM »

Hi Retro
Thanks for the advice and weather update, I hope to make it Australia someday, one of my daughters stayed in Australia for a month while attending college. She loved your country and people, claiming it was wonderful. I'm signing off this evening as I awake at 5 am and its time for some sleep, I will check in tomorrow. Thanks again, Ray

luap · « **Reply #9 on:** December 11, 2012, 06:09:24 PM »

I put on a secaII 91,92 swingarm on a 550. had pivot bolt made,had to drill out pivot mount holes would have been nice to get a couple spacers made up but went with washers 750 axle bolt for length- had to drill out axle bolt holes to fit 750 axle an get a new rear wheel spacer made stock is to long.

Retro Rocket · « **Reply #10 on:** December 11, 2012, 06:11:42 PM »

Quote from: Ray S on December 11, 2012, 06:08:14 PM

Hi Retro
Thanks for the advice and weather update, I hope to make it Australia someday, one of my daughters stayed in Australia for a month while attending college. She loved your country and people, claiming it was wonderful. I'm signing off this evening as I awake at 5 am and its time for some sleep, I will check in tomorrow. Thanks again, Ray

No worries Ray. I should also mention that the early GSXR swingarms are a direct bolt in, i couldn't believe how easy it went in, the Honda steering stem pressed straight into the 43mm 1989 GSXR1100 fork clamps as well... Even though i am not using those clamps now...

Ray S · « **Reply #11 on:** December 12, 2012, 02:34:52 PM »

Hi Retro
Just got home from work and looked over the responses so far. My question for you is what year and model GSXR front end and swing arm are you using? Also your bike is a Honda 750 correct, do 750's and 550's have the same swing arm bolts and distance between the pivots? Also is the front stem the same? I can look for the parts to do the swap, but I don't want to waste my time if they will not fit.
Once again I appreciate your advice. Thanks Ray

Retro Rocket · « **Reply #12 on:** December 12, 2012, 03:03:35 PM »

Quote from: Ray S on December 12, 2012, 02:34:52 PM

Hi Retro
Just got home from work and looked over the responses so far. My question for you is what year and model GSXR front end and swing arm are you using? Also your bike is a Honda 750 correct, do 750's and 550's have the same swing arm bolts and distance between the pivots? Also is the front stem the same? I can look for the parts to do the swap, but I don't want to waste my time if they will not fit.
Once again I appreciate your advice. Thanks Ray

Hi Ray, yes mine are all 750's, i am pretty sure that the 750 swingarm is the same width at the pivot, i seem to recall somewhere that some 500-550 racers use the 750 arms. The front end i'm using is a 1989 GSXR1100 K right side up {normal} forks, they are 43mm and retain a more stock type of look to the upside down forks. The swingarm is from a last model slab sided 1988 GSXR1100J, the arm i will use on the other bike will be an early {1985-6-7} GSXR750 arm, they are smaller in length and can be cut down to the correct size i want, they are not as beefy as the 1100 arm but far stronger that the stock 750 arm.... Not sure about the stem length on the 500-550. The bike in the thread i linked has a cut down early GSXR750 arm.

754 · « **Reply #13 on:** December 12, 2012, 04:00:25 PM »

Kawi Zepyhr arm fits, and shock mounts are right if you want to go dualshock..nice arm but 3 inches over. They use eccentric adjusters, whick may give you height options.
Ifthe pivot is bigger use your bolt and sleeve it..

Ray S · « **Reply #14 on:** December 12, 2012, 04:29:14 PM »

Hi 754 and Retro Rocket

Thanks to both of you for the advice.
I'm going to a junk yard this weekend to look for parts. I bought a micrometer and will take a metric ruler to check lengths, widths etc. Hopefully I will find what I need to make the conversions.I'm also thinking about finding narrower wheels than the traditional GSXR rear which I believe is 5.5 inch X 17 inch rim. I believe a 4.5 inch X 17 rim would be better and there are plenty of good radial tires in that size range. Any thoughts? Thanks again Ray

Retro Rocket · « **Reply #15 on:** December 12, 2012, 06:10:41 PM »

If you are going to stick with the Suzuki 3 spoke rims, the GSXR750 J and GSXR1100K both had 4.5 inchx17 rear rims, another option in 3 spoke is the GSXR1100J, 4.5x18 rear and 2.75x18 front....
Continental have excellent tyres in the sizes needed... Look for continental road attack or similar...

Ray S · « **Reply #16 on:** December 15, 2012, 01:37:09 PM »

Hi Retro Rocket

I found a couple of swing arms from older GSXR 1100 & 750 that would fit my frame and the width at the swing arm pivot is perfect but the pivot bolt appears to be 17 mm vs the Honda Cb 550 15 mm? I also found and old thread with a picture of your 750 and the swing arm, was it a direct bolt on or did you need to machine the frame?
Thanks Ray

Retro Rocket · « **Reply #17 on:** December 15, 2012, 01:56:48 PM »

Quote from: Ray S on December 15, 2012, 01:37:09 PM

Hi Retro Rocket

I found a couple of swing arms from older GSXR 1100 & 750 that would fit my frame and the width at the swing arm pivot is perfect but the pivot bolt appears to be 17 mm vs the Honda Cb 550 15 mm? I also found and old thread with a picture of your 750 and the swing arm, was it a direct bolt on or did you need to machine the frame?
Thanks Ray

It was a direct bolt in, the Honda 750 rear axle was the same size as well.

Ray S · « **Reply #18 on:** December 16, 2012, 08:05:37 AM »

Hi Retro Rocket
Ok let me clarify so that I undersatand what you mean.
You have a 750 that used a mono shock swing arm from either a GSXR 1100 or 750 that was a direct fit with no machining to your Honda CB 750 frame? The pivot bolt size is the same and you did not need to modify the hole or frame?
In an earlier post you mentioned the GSXR 1100 and 750 with 4.5 inch wheels , but you did not mention the years they were produced?
Considering you are in Australia and I'm in the USA were there any differences in the models in our respective countries?
Yesterday I visited a motorcycle salvage yard with micrometer and ruler and could not find a GSXR swing arm that had a pivot bolt small enough [15mm dia.& 13 inches long] that would fit my Honda CB 550 frame. All of the swing arms had 17mm to 20 mm pivot bolt diameters. They also were from either the late 90's or early 2000's. So can I assume your swing arms are from earlier bikes? I was also told that the following swing arms could be direct fits to my frame. Honda CBR 600 F2, Yamaha gzx 600 1992,Yamaha YZF 600 94 to 98Suzuki SV650 98 to 2000, Kawasaki EX 500, Kawasaki ZXR 600 98 to 2002, Kawasaki ZZR 600 95 to 98. I have no idea if these swing arms would fit or the size of the pivot bolt as most of the posts or searches I have discovered are limited on information. I would appreciate any advice from you or other builders that have read this post. Happy Hoildays, Ray

754 · « **Reply #19 on:** December 16, 2012, 02:15:05 PM »

Dont worry about 17 mm pivot, you canrun thin sleeves to take up differenece. Or drill your frame, but trust me few are equipped to PROPERLY bore the hole to 17 mm in the frame. Anyone can make the holes bigger, but getting a nice fit, and. In line wth other hole, and maybe round..isa bit of work..

Retro Rocket · « **Reply #20 on:** December 16, 2012, 03:28:41 PM »

Quote

Ok let me clarify so that I undersatand what you mean.
You have a 750 that used a mono shock swing arm from either a GSXR 1100 or 750 that was a direct fit with no machining to your Honda CB 750 frame? The pivot bolt size is the same and you did not need to modify the hole or frame?

Yes, the swingarm is a shortened GSXR1100J 1988 model, direct bolt in.

Quote

In an earlier post you mentioned the GSXR 1100 and 750 with 4.5 inch wheels , but you did not mention the years they were produced?
Considering you are in Australia and I'm in the USA were there any differences in the models in our respective countries?

No differences, the models were the same. The 1100's with 4,5 inch rims are, 1988 GSXR1100J , first model 1100 with 3 spoke rims, the sizes were 18x2.75 front, 18x4.5 rear, the GSXR 1100K 1989 model had 17x3.5 front and 17x4.5 rear, the 1988 GSXR 750J had the same size rims as the 1989 1100K. Bearing sizes may differ between models but thats easily fixed as they are common size bearings.

Quote

Yesterday I visited a motorcycle salvage yard with micrometer and ruler and could not find a GSXR swing arm that had a pivot bolt small enough [15mm dia.& 13 inches long] that would fit my Honda CB 550 frame. All of the swing arms had 17mm to 20 mm pivot bolt diameters. They also were from either the late 90's or early 2000's. So can I assume your swing arms are from earlier bikes

Yes, the earlier GSXR parts are the ones that fit, forget the later model stuff as its a lot harder to modify...
I posted this link earlier in the thread, go have a read, he uses an early GSXR 750 swingarm {GSXR750 G-H, 1986-1987} and wheels {not the 3 spoke wheels}
I would PM the guy in the link i posted below as it is a 550 and he races his bike , it is set up well, looks great too...

http://forums.sohc4.net/index.php?topic=63938.0

Ray S · « **Reply #21 on:** December 17, 2012, 05:54:31 PM »

Hi 754
If I understand your suggestion , you would use the existing 15mm pivot bolt and sleeve it to fit the larger hole in the swing arm?
I agree that drilling out the frame to accomadate a larger pivot bolt would be dificult witout a jig and a special adapter for a drill press.
Please reply at your conveniance. Ray

Ray S · « **Reply #22 on:** December 17, 2012, 05:59:37 PM »

Hi Retro Rocket
Once again thanks for the information and the link to the racer, there is some very interesting information in that link.
I think I will continue to look for a swing arm that bolts directly to the frame and has the same size pivot bolt.
I appreciate your help and advice, any time you have suggestions please send them on it would be of great help.
Enjoy the hot weather in Brisbane, we got 5 inches of snow last night and it only reached 28 degrees F today. tonight is a mix of freezing rain and light snow making the roads a virtual skating rink.
Oh well I chose to live in Maine, so I guess I should not complain.
Ray

Retro Rocket · « **Reply #23 on:** December 18, 2012, 12:18:59 AM »

Quote

Enjoy the hot weather in Brisbane,

I'll try send some your way, last night it was 80F all night with 89% humidity....

754 · « **Reply #24 on:** December 18, 2012, 07:25:08 AM »

Unless you havea lot of horespower, I dont see the gin of changing from 15mm. But if you have the equipment to do it nicely, and get a clean, in tolerance hole , do it.
A poorly drilled hole a bit loose, I cant see an advantage, plus it makes it harder to go back to stock..

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Author Topic: What mono shock swing arm fits a Honda cb 550? (Read 10332 times)