Topic: cb550F sprocket alignment issue help needed

[rosewood]

Hoping some of you may be able to assist with my latest dilemma rebuilding this 97/98 550f.

This bike has sat for 15 odd years and I am rebuilding everything from scratch. As far as I am aware everything is original but I'm hoping some of you may be able to see something that is obviously wrong.

I am in the stages of checking sprocket alignment after i have rebuilt the wheels with new bearings and having the rims trued. I am confident I have rebuilt the wheels correctly with regards to bearing installation with an all balls bearing kit. Both sprockets are also new JT sprockets.

What made me check alignment was noticing the rear wheel not sitting centred under the subframe.

I have made a stand to sit the frame on and reinstalled the motor, swing arm and rear wheel assembly (minus the tyre). I also made an alignment tool with a length of angle section as the straight edge and clamped to the rear sprocket. I have heard differing opinions on whether the markings on the rear wheel adjusters are accurate so i tried to line the sprockets up parallel with my tool by eye. the rear sprocket appears to be approximately 10mm to far to the left in relation to the front sprocket and this may also be how far the rear wheel is out compared to the subframe but i am yet to measure this accurately.

As far as i can see i have the correct wheel spacers for the brake cover/housing on the right side of the hub. mine is the smooth cover which takes the 50mm spacer according to what i have read. My swing arm I am assuming is correct with the closed ends the axle goes through for a F model but i am not sure if this 100% accurate and I am unsure how to find this out.

Any help would be appreciated if i am doing something wrong or whether anyone notices i have any wrong components assembled..

thanks in advance.

rosewood..

[rosewood]

pic of wheel alignment with subframe, hubs and alignment setup

[540nova]

Dish your wheel to bring it in alignment. If it needs to go to the right, loosen all of the left-hand spokes and tighten all of the right-hand spokes to bring your rim centered in the frame.


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[rosewood]

Thanks for the reply nova....i have read people doing this to help align wheels but how does it correct my sprocket alignment issue which i thought would be the first problem to correct?

[jlh3rd]

It won't......I'm just real curious if that spacer is somehow not a stock one. I don't know how that could happen as I ve never heard of different ones. You mentioned 50 mm but I just go by Honda part numbers . And I'd never retrue a wheel that's off that much using that spoke method.
    I can't tell by a pic, but that spacer looks longer than my stock 550 f's is....
    Just real curious, sorry I'm not any help.......but I wouldn't mess with that wheel...
And you meant 1975-1978 ,right?.....and is there anyway in that bike history that the swing arm was bent or tweaked.

[540nova]

What made me check alignment was noticing the rear wheel not sitting centred under the subframe.

Ah, I was focused on the wheel not centered in the frame. Forgot about your sprocket. Many times a rebuilt wheel needs dishing to be centered.



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[Jimray23]

Did u compare the old sprockets to the new sprockets?

Jimmy
1979 kz1000 ltd

[Darren Jakal]

I have this same problem. In my case it's a different rear wheel with with the incorrect spacers.

I found some information on stringing the frame and measuring offsets from different critical frame points to check the frame for damage and to line up the wheels and sprockets.

Using this technique you can line up the centre of the rear wheel with the bike centreline and that should (in theory) also align the sprockets, as I believe the centreline to sprocket offset is pretty much the same throughout the Honda line at the time (again from what I've read). I think I have a rear wheel from a 450 twin on my 550.

Anyway when I line it all up on my bike and measure the inside distance between swing arm and hub I get 44mm and through my research I have found 44mm spacers are used on some models (not saying this is the case for you). Once you know the offset for the one side measure the other side and look for (or make) that spacer.

Hope this helps, Darren

[jlh3rd]

If he has a stock 550f, with a stock rear wheel, stock swing arm and sprockets...then a stock spacer is what is needed.
    If there is an alignment problem then something is bent. There's no reason to go through all this other monkey motion...

[Jimray23]

But the sprockets have been replaced so they could be just different enough to cause alighnment issues

Jimmy
1979 kz1000 ltd

[Darren Jakal]

" As far as I am aware everything is original but I'm hoping some of you may be able to see something that is obviously wrong. "

If he has a stock 550f, with a stock rear wheel, stock swing arm and sprockets...then a stock spacer is what is needed.
    If there is an alignment problem then something is bent. There's no reason to go through all this other monkey motion...

If that's for certain then disregard my post.

Cheers, dj

[jlh3rd]

But the sprockets have been replaced so they could be just different enough to cause alighnment issues

Jimmy
1979 kz1000 ltd

Not a 10 mm offset...
Check...that...spacer...

[Scott S]

 That appears to be the correct spacer for an F model bike, which is what he has. The K bikes used a shorter spacer.

[rosewood]

Thanks for your input Cal but that diagram from CMNSL is for a 'k' model 550 mine is a 'f'...

A lot of the information I have picked up is from this post...

 http://forums.sohc4.net/index.php?topic=119176.0

As far as I am aware I have the right spacers...and yes the sprockets have been replaced with new JT sprockets but I highly doubt that would be causing a 10mm offset that I am measuring.

I'm starting to think my swing arm might be from a different model? would this cause this problem?

or worst case my frame and/or swingarm are bent or tweaked slightly.

Not sure how to proceed to the next step of eliminating my issues....

How do I go about checking frame and/or swingarm alignment?

[rosewood]

Jakal any chance you could direct me to this information on stringing the frame?..

I have this same problem. In my case it's a different rear wheel with with the incorrect spacers.

I found some information on stringing the frame and measuring offsets from different critical frame points to check the frame for damage and to line up the wheels and sprockets.

Using this technique you can line up the centre of the rear wheel with the bike centreline and that should (in theory) also align the sprockets, as I believe the centreline to sprocket offset is pretty much the same throughout the Honda line at the time (again from what I've read). I think I have a rear wheel from a 450 twin on my 550.

Anyway when I line it all up on my bike and measure the inside distance between swing arm and hub I get 44mm and through my research I have found 44mm spacers are used on some models (not saying this is the case for you). Once you know the offset for the one side measure the other side and look for (or make) that spacer.

Hope this helps, Darren

[rosewood]

Thanks for all this info Cal, I don't have a bike jack but hopefully the stand I made can be used...

When you say measure between the forks are you just referring to the rear wheel or front as well? ( I am yet to assemble the front end but will do this weekend)

As for the spacer I did eye it up with a vernier and it was pretty close to 50mm. I will however dismantle it all and double check. If a shorter spacer is required would i need to make the difference up on the other side?

I do have access to a lathe so I can machine my own spacers, but if everything is correct this shouldn't be necessary.....which is making me think my frame/swing arm is where the problem is.

Does anyone know the measurement between the rear fork arms from inside or outside faces where the axle is mounted?

In theory should the center of this gap be aligned with the center of the frame? is this an accurate assumption to make? I can then determine if my swing arm is bent..

Rosewood - Can you please measure your current wheel spacer and let us know what it is? I have a few in the bin, perhaps I have one that is 10mm shorter than yours.

As for alignment of the tires:

Use a plumb bob on the front steering neck and insure the wheel (or as closely as you can the tire's center) is dead center of the forks.

Lift the rear seat, use the seat rail brace and suspend a bob from it to locate the rear wheel center. If necessary, remove the wheel spacers, and adjust the location of the rear wheel. Once in place, confirm the sprocket alignment. If these are aligned, measure the distance from inside of the swing arm to hub on both sides. If your current spacer moves you too far left, shorten the spacer or use a stock shorter spacer. If too near on the right, a longer spacer is needed.

To check the frame for straightness, remove the tank and seat. Bike on a jack. Level the tubes running below the engine. Plumb the steering neck. Suspend a bob from the neck, from the rear gusset, and commence measuring offsets to swing arms (foreward and perpendicular to the driveline). Measure diagonally from left axle to right rear shock mount. Repeat on right side to left. Shock mount to steering neck. You get the idea... The more measurements, the better the determination.

[Lostboy Steve]

I had a spacer made by my friend at a machine shop to use comstars on my 75 550. It's not like it's expensive material or super labor intensive. If you have a local machinist and the current spacer I'm sure you could have it turned down as much as you need.


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[Darren Jakal]

Jakal any chance you could direct me to this information on stringing the frame?..

I have this same problem. In my case it's a different rear wheel with with the incorrect spacers.

I found some information on stringing the frame and measuring offsets from different critical frame points to check the frame for damage and to line up the wheels and sprockets.

Using this technique you can line up the centre of the rear wheel with the bike centreline and that should (in theory) also align the sprockets, as I believe the centreline to sprocket offset is pretty much the same throughout the Honda line at the time (again from what I've read). I think I have a rear wheel from a 450 twin on my 550.

Anyway when I line it all up on my bike and measure the inside distance between swing arm and hub I get 44mm and through my research I have found 44mm spacers are used on some models (not saying this is the case for you). Once you know the offset for the one side measure the other side and look for (or make) that spacer.

Hope this helps, Darren

I found this helpful:

http://forums.sohc4.net/index.php?topic=126594.0

Once I had the wheel aligned with centre the sprockets lined up and I was able to get a measurement for the spacers.

Good luck, dj

[jonda500]

Hi rosewood, Looks to me like you definitely have the correct spacers (36 & 50mm). Unfortunately I think you probably have a bent swingarm as the wheel looks 10mm off too, John

[rosewood]

Thanks for all the feed back Guys! has been very helpful.

I plan to do a few checks with stringlines and a plumb bob this weekend to help confirm what is wrong. My gut feel is swingarm is a bent but there's no obvious sign that it looks bent at all.

Is it normal practice to mend swingarms? I am assuming this can be heated and bent back into shape?

Other than that I am thinking my quickest and easiest fix is to machine up some new spacers for either side to correct the 10mm, and be done with it..

rosewood

[pjlogue]

Is it normal practice to mend swingarms? I am assuming this can be heated and bent back into shape?



rosewood

I would not heat the swing arm to bend it back into shape if it is out of alignment.  Heating will soften it and that's not good for a suspension component.  You would be better off bending it cold or find a good used one.

-P. 

[jonda500]

Here is a link to an old related thread...   John

http://forums.sohc4.net/index.php/topic,151654.msg1736918.html#msg1736918

[rosewood]

OK I had a chance to run a string line and a bob from the suspension mounts..

I think I have a combination of problems which is probably not a surprise on a 40 year old bike.

I think the subframe might be slightly out from the spine of the frame..

Bobbing the mounts shows the swing arm is way out though, so it is more than likely bent.

I think my easiest solution is machine some new spacers to correct the sprocket alignment and not try and correct the swing arm for the reasons everyone has mentioned.

Being in New Zealand finding a replacement swing arm is not an option unfortunately. 

[rosewood]

Will do tomorrow Cal....yes she is WAAAY off....Ive come to accept that if anything can be wrong on this bike it most likely is..

I have measured the sprockets are out by approx 8mm. should have both new spacers machined up tomorrow

[rosewood]

Thanks Cal I hear what your saying..

I have a contact in NZ that realigns bike frames so I have contacted him with this issue and some pictures so will see what he also advises.

Yes NZ is a great place but being so isolated makes projects like this very expensive. no market for parts here and shipping anything is a killer..

Here's a side view pic anyway..