My email to Chris @ MotoGPWerks this morning:
Good Morning Chris,
I purchased a swingarm from you back in August but ran into some issues. My motorcycle is a 1978 CB550K. Please note; I wasn not able to test fit this until last month as I was out of town for most of August. Please also keep in mind I purchased an exhaust from you as well and would like to keep future business active.
When attempting to test-fit it I noticed the pivot bolt that goes into the front portion of the swingarm into the frame was very loose inside the tunnel of the swingarm in between the bushings. I called you and you stated the collar had to be swapped over from my stock one and it had been test-fitted just fine. At that point I sent it to Mark "HondaMan" who has been specializing in this stuff for years as I did not feel comfortable messing with something so crucial with limited tools.
Upon his review he came back with the following:
"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 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!"
"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 langed or unflanged versions of bronze bushings out there will also be too long, so measure carefully before installing."
I hope you don't take this the wrong way as I just figured someone should make you aware of these fitment/safety issues to help prevent it in the future.
The bill for all of the above was $285, is there anything that can be done to make this right? I surely didn't expect to dish out half ofthe swingarm after purchase, I simply didn't know about these issues.
Hope all is well.
Two responses I received:
1) "Hi,
what is going on ,
I just fitted this swingarm to a customer bike ,I have seen 15-20 others without any issues ,if your guy was that stupid to pull out the bushes then thats his issue .These bronze bushings are machined to fit this swingarm only I never said honda ones would fit as we make them from better material ... OEM honda bushings will not fit .
Then i fit the bushings i line bore it straight so its a perfect match.
All you had to do was to get a 75-77 sleeve and it would just go in fits perfect ...i just tested again this morning with one here.
Send the it back for a full refund if your guy screwed it up then its on you and no refund ...also i need his phone number so i can speak to him since he has no idea.
thanks chris"
2)"Hi,
As i said too you from the start all you had to do was to install a cb750 or a cb500-550 75-76 sleeve ... number 14 ...have a look at the photo i sent ...your honda expert should have known this as all honda cb750-550 from 1969 to 1977 have the same sleeve .
Tell your guy to call me and explain why he didnt tell you this ."