Topic: MotoGPWerks Alloy Swingarm Fitment

[Stilltime]

Looking for anyone who has installed MotoGPWerks aluminum swingarm.  This was described as to work with the stock CB550 rear brake setup (i.e. Not having to convert to disc).

First the overall fit of the arm in the frame is great.  The supplied rear adjusting brackets are too narrow at the welded end and prevent full adjustment of the chain... 

Next, it is way too beefy on the right side and rubs against the brake pivot arm and pivot arm rod.  I doubt I'll be able to bend this enough to make it work.  The only good solution looks to be converting it to rear disc, which I wouldn't mind doing but a) I have money tied up in my rear wheel and really wanted to keep the stock rear disc. 

Last, the supplied billet brake stay looks great, but the mounting setup is completely different than stock and the factory shoulder bolt will not work on the front pivot side.  Still looking for ideas from members who have mounted one of these arms on getting a different shoulder bolt to make this work.

Please don't misconstrue this, I REALLY like this arm and if I can get these issues resolved I'm sure it will outperform the rest of the chassis.  I was just hoping for the fit to be a little more like stock, since it was designed as a stock replacement.

Hope someone else has mounted one, I'm curious to see your setup!

[GV1390]

Bump.

Anyone else have poor fitment with these? Primarily with the swingarm pivolt bolt?

[70CB750]

Did you try to reach the company?  Is it a retrofit or is it made to fit your motorcycle?

[SOHC4 Cafe Racer Fan]

I recall someone else who bought one for a 750F but had a 750K, and had to do some adjustments.

[Retro Rocket]

These are an copy of the original Calfab swingarms from the late 70's early 80's, the were an option race part at the time, I have one for my 750's but its  all modified so nothing is stock at the rear, I'm running a rear disk on the K frame, I don't know about yours, but the 750 arm is longer at the adjustment part of the arm so you still have stock length adjustment. Buy a good chain and it will be of no concern....

[nicks2319]

Almost bought one of these. Subscribed. Interested to see how it looks mounted.

[Retro Rocket]

Bump.

Anyone else have poor fitment with these? Primarily with the swingarm pivolt bolt?

 What was the exact problem...? Be a bit more specific...

[GV1390]

For anyone buying one of these please be aware of the pivot bolt dilemma.

Just a couple quick notes:

"The ID of the swingarm bushing holes is smaller than Honda's design, so "OEM" bushings for the 750/500/550 would never fit right, in any case. They must be custom-made bushings. The ID of the swingarm is 1.0370" one side and 1.0374" the other (brake) side, where the Honda arms are more like 1.0440"-ish on all of the arms (give or take .0008" either way). So, I will make some to fit, and to use the Honda-style collar."

"The insides of the swingarm itself, where these bushings reside, is very jagged and poorly machined, which caused the new bushing to jam."

"The swingarm: the welding looks real nice: I'd say he is an accomplished welder from that standpoint. The machining work could be better, at least as regards the hole finish for the bushings. The original bushings that came in it surely would never fit a Honda collar properly, much too loose. The struggle there is then: the holes in the swingarm for the bushings are much smaller than OEM size, so none of the Honda parts will fit, and probably none of the aftermarket one would, either. The holes were/are 1.0375" ID, where the swingarms are either 1.0440" or 1.0444", so bushings made for a press-fit will be 1.0444" to 1.0448" OD. This would leave the owner trying to press-fit a bronze bushing that is (1.0444"-1.0375")= 0.0069" (almost seven thousandths!) bigger than the swingarm's holes. This will destroy the bushings. The ones that came in it when you sent it to me were almost .0030" larger than the biggest Honda collar, too. That's not good, as it will leave almost 0.250" (1/4") side-to-side play at the rear axle. That's dangerous!"

[Retro Rocket]

For anyone buying one of these please be aware of the pivot bolt dilemma.

Just a couple quick notes:

"The ID of the swingarm bushing holes is smaller than Honda's design, so "OEM" bushings for the 750/500/550 would never fit right, in any case. They must be custom-made bushings. The ID of the swingarm is 1.0370" one side and 1.0374" the other (brake) side, where the Honda arms are more like 1.0440"-ish on all of the arms (give or take .0008" either way). So, I will make some to fit, and to use the Honda-style collar."

"The insides of the swingarm itself, where these bushings reside, is very jagged and poorly machined, which caused the new bushing to jam."

"The swingarm: the welding looks real nice: I'd say he is an accomplished welder from that standpoint. The machining work could be better, at least as regards the hole finish for the bushings. The original bushings that came in it surely would never fit a Honda collar properly, much too loose. The struggle there is then: the holes in the swingarm for the bushings are much smaller than OEM size, so none of the Honda parts will fit, and probably none of the aftermarket one would, either. The holes were/are 1.0375" ID, where the swingarms are either 1.0440" or 1.0444", so bushings made for a press-fit will be 1.0444" to 1.0448" OD. This would leave the owner trying to press-fit a bronze bushing that is (1.0444"-1.0375")= 0.0069" (almost seven thousandths!) bigger than the swingarm's holes. This will destroy the bushings. The ones that came in it when you sent it to me were almost .0030" larger than the biggest Honda collar, too. That's not good, as it will leave almost 0.250" (1/4") side-to-side play at the rear axle. That's dangerous!"

I know a couple of guys that have fitted these already with no problems what so ever, I have mine sitting next to me as we speak and i have no idea what you are talking about, mine is a 750 one though, the guy that started this thread  has his fitted as well {500-550}and said it was a "great fit"....anyway, I was just curious as to what problems you were having because mines perfect...  Is that a copy of an email, it says "you" in there, I didn't sell you anything..?

Mick

[Retro Rocket]

It appears from GV's post, that whomever bought that swing arm intended to use stock Honda bushings. Whereas the new swing arm is reamed for a slightly different, but widely available stock size. OD and ID of new aftermarket bushing areas may not always conform to original stock sizes. I only see a problem if you order replacement stock bushings and didn't notice the machined difference. Me, I'd rather have a stock measurement bushing to increase their availability.

As for the measurement, its obviously not metric to re-use the stock bolt OD any longer. But that too makes it a bit easier to find/make a new bolt. You can always machine metric threads in an SAE rod to maintain metric uses. Something to be aware of I guess. Also, these were early run units, no? Maybe he's still tweaking his final product and needs the feedback if he will continue to fabricate them. Lots of years/models and changes between Ks, Fs, 550/750 bikes. Each differs just slightly.

I'm fitting mine next week so I can put my frame on a jig and check for straightness, I'll report back after that...

[GV1390]

For anyone buying one of these please be aware of the pivot bolt dilemma.

Just a couple quick notes:

"The ID of the swingarm bushing holes is smaller than Honda's design, so "OEM" bushings for the 750/500/550 would never fit right, in any case. They must be custom-made bushings. The ID of the swingarm is 1.0370" one side and 1.0374" the other (brake) side, where the Honda arms are more like 1.0440"-ish on all of the arms (give or take .0008" either way). So, I will make some to fit, and to use the Honda-style collar."

"The insides of the swingarm itself, where these bushings reside, is very jagged and poorly machined, which caused the new bushing to jam."

"The swingarm: the welding looks real nice: I'd say he is an accomplished welder from that standpoint. The machining work could be better, at least as regards the hole finish for the bushings. The original bushings that came in it surely would never fit a Honda collar properly, much too loose. The struggle there is then: the holes in the swingarm for the bushings are much smaller than OEM size, so none of the Honda parts will fit, and probably none of the aftermarket one would, either. The holes were/are 1.0375" ID, where the swingarms are either 1.0440" or 1.0444", so bushings made for a press-fit will be 1.0444" to 1.0448" OD. This would leave the owner trying to press-fit a bronze bushing that is (1.0444"-1.0375")= 0.0069" (almost seven thousandths!) bigger than the swingarm's holes. This will destroy the bushings. The ones that came in it when you sent it to me were almost .0030" larger than the biggest Honda collar, too. That's not good, as it will leave almost 0.250" (1/4") side-to-side play at the rear axle. That's dangerous!"

I know a couple of guys that have fitted these already with no problems what so ever, I have mine sitting next to me as we speak and i have no idea what you are talking about, mine is a 750 one though, the guy that started that thread we commented in has his fitted as well {500-550}and said it was a "great fit"....anyway, I was just curious as to what problems you were having because mines pertfect...  Is that a copy of an email, it says "you" in there, I didn't sell you anything..?

Mick

I quoted a forum member who took a peak at it, he will chime in if he wishes.

Mine is a 500/550 not a 750. Just because others have had good luck doesn't mean everyone will, I have not simply put. I received my swingarm with no collar leaving a gigantic space between the bolt and bushings. When I reached out to the seller he stated you can reuse your old one. While my old one was toast(virtually impossible to remove while not damaging), I inquired about a new collar along with bushings as they did not fit properly.

[GV1390]

It appears from GV's post, that whomever bought that swing arm intended to use stock Honda bushings. Whereas the new swing arm is reamed for a slightly different, but widely available stock size. OD and ID of new aftermarket bushing areas may not always conform to original stock sizes. I only see a problem if you order replacement stock bushings and didn't notice the machined difference. Me, I'd rather have a stock measurement bushing to increase their availability.

As for the measurement, its obviously not metric to re-use the stock bolt OD any longer. But that too makes it a bit easier to find/make a new bolt. You can always machine metric threads in an SAE rod to maintain metric uses. Something to be aware of I guess. Also, these were early run units, no? Maybe he's still tweaking his final product and needs the feedback if he will continue to fabricate them. Lots of years/models and changes between Ks, Fs, 550/750 bikes. Each differs just slightly.

I'm fitting mine next week so I can put my frame on a jig and check for straightness, I'll report back after that...

That's all groovy but still doesn't change the fact that, I purchased a bolt-on high quality item that was not bolt on and that it had defects. I acted accordingly and sent it to someone who knows these in and out. I just want potential buyers to proceed with caution as it can be dangerous if an inadequate part is installed.

[GV1390]

Agreed.

The part does look like a nice quality piece, I will not argue that. The Customer/Techincal Service aspect is free though, that takes nothing to change for the better that is. I don't care if you spend $1 or $10000 with a company, that is the future of your business.

Not trying to bash, just want people to be cautious, that is all.

[Powderman]

You stated in your OP that you wouldn't mind changing to a disc rear, but you have money tied up in your rear wheel and really want to keep the stock rear disc. Does something there need correcting?

[754]

More than .001 between the two bushing bores is sad..
Having to get bushes custom made, and fitted.. Would likely run 80-100 bux or higher..
 Next issue is are the bores aligned to each other, and is it parallel to the axle.

[HondaMan]

More than .001 between the two bushing bores is sad..
Having to get bushes custom made, and fitted.. Would likely run 80-100 bux or higher..
 Next issue is are the bores aligned to each other, and is it parallel to the axle.

I did the "rebuild" of this particular arm: the bore holes were well-aligned to the tube, but the machining had several deep gouges (in both sides) in the area where the bushings reside - it almost looked like the boring head lost a bit, or it got loose, or something like that, during the bore work - both sides. The bushing holes are also undersize for the OEM bushings (by several thousandths), so trying to install any 500/550/750 bushing in it would not work (and didn't...). I had to start by pulling out the ones that apparently came with the arm, which had clearance of more than .0020" over the stock collar, brand new. It almost looked like the wrong bushings were installed for the Honda? Don't know about that part of it...

After I made bushings to fit, the jagged bore edges caught one of my bushings (even though I always cut insertion tapers on their ends!) and squished it, stopping it about 1mm short of the insertion depth. I had to pull out my ruined bushing and hone that side, then made a new one to install again.

Also noted on this particular arm: I had to make the sleeve-style bushings 1.5mm shorter than OEM length, in order to fit - the holes are not bored as deep as the OEM swingarms. This means that any of the flanged or unflanged versions of bronze bushings out there will also be too long, so measure carefully before installing.

The welding sure looks nice, and it measures straight! It's also quite light.

[70CB750]

Looks like the production has few bugs to resolve - or maybe the final inspection - or both?

[GV1390]

Thanks for clarifying Mark.

I am stoked to finally bolt-on my swingarm.

[FunJimmy]

I would agree that only factory parts fit like factory parts but this sounds like a factory second and should have been sold as such. Im sure this was an exception but the excessive work Mark had to do adds significantly to the cost of the swinger.

[Retro Rocket]

For anyone buying one of these please be aware of the pivot bolt dilemma.

Just a couple quick notes:

"The ID of the swingarm bushing holes is smaller than Honda's design, so "OEM" bushings for the 750/500/550 would never fit right, in any case. They must be custom-made bushings. The ID of the swingarm is 1.0370" one side and 1.0374" the other (brake) side, where the Honda arms are more like 1.0440"-ish on all of the arms (give or take .0008" either way). So, I will make some to fit, and to use the Honda-style collar."

"The insides of the swingarm itself, where these bushings reside, is very jagged and poorly machined, which caused the new bushing to jam."

"The swingarm: the welding looks real nice: I'd say he is an accomplished welder from that standpoint. The machining work could be better, at least as regards the hole finish for the bushings. The original bushings that came in it surely would never fit a Honda collar properly, much too loose. The struggle there is then: the holes in the swingarm for the bushings are much smaller than OEM size, so none of the Honda parts will fit, and probably none of the aftermarket one would, either. The holes were/are 1.0375" ID, where the swingarms are either 1.0440" or 1.0444", so bushings made for a press-fit will be 1.0444" to 1.0448" OD. This would leave the owner trying to press-fit a bronze bushing that is (1.0444"-1.0375")= 0.0069" (almost seven thousandths!) bigger than the swingarm's holes. This will destroy the bushings. The ones that came in it when you sent it to me were almost .0030" larger than the biggest Honda collar, too. That's not good, as it will leave almost 0.250" (1/4") side-to-side play at the rear axle. That's dangerous!"

I know a couple of guys that have fitted these already with no problems what so ever, I have mine sitting next to me as we speak and i have no idea what you are talking about, mine is a 750 one though, the guy that started that thread we commented in has his fitted as well {500-550}and said it was a "great fit"....anyway, I was just curious as to what problems you were having because mines pertfect...  Is that a copy of an email, it says "you" in there, I didn't sell you anything..?

Mick

I quoted a forum member who took a peak at it, he will chime in if he wishes.

Mine is a 500/550 not a 750. Just because others have had good luck doesn't mean everyone will, I have not simply put. I received my swingarm with no collar leaving a gigantic space between the bolt and bushings. When I reached out to the seller he stated you can reuse your old one. While my old one was toast(virtually impossible to remove while not damaging), I inquired about a new collar along with bushings as they did not fit properly.

Did you send all that info in your post to Chris..? Its pretty hard to dispute that somethings not wrong here , the others i've seen haven't experienced this, you may have ended up with the first one built, prototype by mistake or one of his workers needs a kick in the butt for turning out shoddy work, I'm pretty sure these were out sourced for the bushings, Chris has only just recently bought his CNC machines, well after these were made, either way, I would have contacted him with all the relevant facts including the measurements and faults mentioned here, if you weren't sure exactly what it all meant, Mark could have spoken to him for you possibly...? Personally, I wouldn't have repaired it myself unless it was very cheap or discounted, I would have sent it back so he could see for himself and worked it out from there.. ... 

[Stilltime]

I apologize, didn't realize there was activity in this thread.  I didn't have a problem with the pivot bolt, although I had to use two M14 washers on the clutch side of the arm. 

I used a shoulder bolt and sleeve to make the front brake pivot bolt work - it definitely wouldn't work with the stock setup in any way shape or form.

I ended up bending the brake rod to attempt clearing the arm, which was a poor choice but my only one to have rear brakes.  It is completely less than ideal but I am at a loss of a simple fix for it.

I need to correct the first post, I would LIKE to swap my rear drum out for a disc setup, I've looked high and low and can't ever source one.  Yea I have a little money tied up in powdercoat, but I'm building a new rear wheel anyway.

I love how the arm looks, and there is no more slop in a chicane or S-turn, but damn I was sold a part that was a "bolt on replacement for factory" which plain and simple was and is not compatible with a factory bike. 

Not to bash Chris at all, but he basically told me he's sold others with no problem and he can't help me.

[SOHC4 Cafe Racer Fan]

You can swap to disc. One way is to rebuild a wheel with a 1975-76 CB750F rear spoked wheel hub.  They are less frequently available on eBay. You can also check with Bill Benton. He sold me mine.

[Stilltime]

That's what I've been looking for.  I only get around to looking every few weeks but have yet to see one available.  I'll send a message to Bill, thanks!

[754]

Look for a used flattrack knockoff wheel..might get one around 300 bucks.. 1/2 the weight of a Stocker.
 Will need custom caliper.
Bare hub looks like this....

[Stilltime]

Looks like you have one available right there