CB550 front end swap question.

[QuackAttack]

Hi there i know there are a thousand threads about this but i have a couple questions about the swap.

First off i have the bearing kits from ALL BALLS RACING my question is what do the bearings sit on? Do i use the old bearing race or the ones from my swap?

Second i noticed when i did bolt everything up there was a bit of gap there so i used a spacer to fill the gap. Will that be safe. I am just nervous about getting up to speed and having death wobble. If there is any advice on how to ensure the safest ride the first time i would appreciate it.


Thanks for any help. Please post only if it is helping answer a question. I am trying to be safe not stupid.

 

[Bert Jan]

You'll have to get the old bearings out completely, the races need to tapped out of the frame with a hammer and a driver thru the frame.
Install new races with piece of wood between hammer and bearing, or if you have a bearing press, do that obviously. Try to tap around the race, so that it slides in straight.

You say you have a gap? Where?

 

[o1marc]

You should measure the depth of the old race before removing them. I had the same issue with the CBR600f1 swap to a CB400f The new lower race went too deep by .335" causing the lower tree to hit the neck. I had a spacer made to bring that race back down. You can use the old race against the new one to hammer it in. Put the new race in the freezer over night and with a propane torch heat the neck area to help expand it before inserting the frozen and shrunken new race, should slide right in. You can get it fairly hot without damaging the paint.

 

[Bert Jan]

Hi there i know there are a thousand threads about this but i have a couple questions about the swap.

First off i have the bearing kits from ALL BALLS RACING my question is what do the bearings sit on? Do i use the old bearing race or the ones from my swap?

Second i noticed when i did bolt everything up there was a bit of gap there so i used a spacer to fill the gap. Will that be safe. I am just nervous about getting up to speed and having death wobble. If there is any advice on how to ensure the safest ride the first time i would appreciate it.


Thanks for any help. Please post only if it is helping answer a question. I am trying to be safe not stupid.

Are you just changing bearings or are you doing a swap to a non cb550 bike?

 

[QuackAttack]

I had a 93 GSXR750W front end given to me so i called all balls and got the bearing to swap in. That front end will be in a 1974 CB550. I am kind of worried cause since they have since put out that list of bikes i noticed my front end was not listed.

As well when i got my frame back from powder coating i noticed that he got some over spray on the bearing races.

 

[Bert Jan]

Ah, new info

A suplier of aftermarket bearings (like allballs) only makes sure the diameters are ok. The height of the bearing is not important to them. Besides, you're lucky enough if the bearings fit anyway! The height of bearings needs to be handled with spacers and washers when you do a swap that's never intended to be done. Custom fab work will be needed.

There is a problem with cb frames, as the top race is 48.5 if i recall right. Thats such an oddball that the only bearing they make for it is the stock one, 48,5x25. Thats 48.5mm OD (outside diameter) and 25mm ID (inside diameter).

If you are sure the ID's and OD's are compatible, you then have to see if the stem is long enough. The stem is the piece of tube that goes in the frame where the bearings are on. It needs to be the same length as the stock one, because the bearings and so on need to be on the right place of the stem to work properly. Also, the nut to lock everything up need to have the threads in the right place. It's not uncommon to make more threads on a stem because the threads didn't go far enough down to clamp it all down.

Another way to do it, and possibly the easiest IF you have the resources, is to swap the stem tube. Press is out of one triple and into the other. You will need a flex, lathe, press and welder. When you have a machine shop nearby, i suggest asking there.

Swapping forks is no easy thing and needs to be done accurate. If you feel you're in over your head, stop and get somebody there to help you. Feel free to ask more questions, i'll be happy to tell you more.

 

[Bert Jan]

I had a 93 GSXR750W front end given to me so i called all balls and got the bearing to swap in. That front end will be in a 1974 CB550. I am kind of worried cause since they have since put out that list of bikes i noticed my front end was not listed.

As well when i got my frame back from powder coating i noticed that he got some over spray on the bearing races.

You left the races in when PC was done? If so, tap em out. If not, make sure the area is clean before you install the new race.

Tip: I ship out powdercoat on a weekly basis, and i normally close up areas like that with 2 pieces of wood and a large bolt. Also put bolts in every hole with threads. After PC is done, remove wood and you've got a clean slate to work with.