Author Topic: Wheel alignment (offset from each other) question (Read 14758 times)

DaveBarbier · « **on:** January 20, 2018, 02:48:06 PM »

My rear wheel is about 8mm offset from the front wheel. I'm thinking this isn't good and would like to have both wheels aligned with each other. Front wheel is perfectly centered between the forks. I ran string along the back tire to the front and took a picture of the difference. It measures about 15mm but I want to move it half that amount (the right edges of both tires are almost exactly inline). The rear tire needs to move to the right.

What are my options? My chain and sprockets are perfectly inline also so I'd rather not mess with that. I'm thinking turn down my right spacer (I have a little lathe), make another spacer on the left to take up the space but then get a spacer to go between the sprocket and hub so the sprocket is back where it was.

OR...you can say that being this far off center isn't an issue.

tlbranth · « **Reply #1 on:** January 20, 2018, 04:59:32 PM »

I made an alignment gauge out of a long piece of plywood. I set it on blocks and made cutouts to clear the various things that got in the way. Then setting it up on each side of the bike in turn with the plywood touching front and back of the rear tire I move the steering so the front and back of the front tire are equidistant from the plywood and note that distance. This number should be the same on both sides of the bike. If it isn't, adjust the rear wheel until the alignment is correct. If the index marks then don't agree on both sides, one or both wheels may have the wrong offset and need the spokes adjusted. All this assumes the spacers are correct and nothing's bent.

Don R · « **Reply #2 on:** January 20, 2018, 06:02:08 PM »

Adjust the rear wheel adjusters so the rear wheel aims a little more left. The cast in marks on the swingarm aren't always perfect.

Yamahawk · « **Reply #3 on:** January 20, 2018, 08:05:57 PM »

Well, now we have a conundrum... hehe. You really should measure from the center of the swing arm pivot bolt to the center of the rear axle on both sides to affirm that the marks on the chain adjuster are correct. If you just adjust the chain adjusters without measuring the distance of pivot to axle, you run the danger of your sprockets not being aligned. Once your rear wheel is square with the swing arm, assuming the swing arm isn't damaged from an accident, then your wheel should be square with your bike and you can remeasure the string thing. Unless you tires and rims are identical in size, your front wheel will always be narrower than the rear, and you would have to measure the center of both the front and rear wheels to determine whether they are in line, or if one is offset.
If I remember, there is a post about the front wheel not being trued to the hub (spoked wheel), and you could re-align it by using the spokes and loosening and tightening the respective sides to get the rim aligned with the rear. This results in the tire now being offset in the front forks, and can be determined on future bikes by measuring the distance between each fork and the front wheel. I think Hondaman had a post in his thoughts on this, or somewhere... But that could be your answer. Start with the swing arm and rear wheel, then if you still have a difference in the front wheel, align that instead of doing all those spacers in the rear.
Charlie

DaveBarbier · « **Reply #4 on:** January 21, 2018, 04:39:23 AM »

Should have clarified in the original post but I thought the title was enough. The rear wheel is aligned properly. I do measure from the swing arm pivot to the rear axle to accomplish this.

The bike is far from stock, '78 550 frame, R6 front end, '82 650 motor and a '75 (I think) swing arm. All these changes probably add up to the rear wheel slightly being off set from the front. I vaguely remember adding different spacers to the rear axle so the sprockets line up with each other but must have forgotten or dismissed wheel to frame centering.

I ran a string from the spine of the frame down to the rear wheel and it proves the wheel needs to shift to the right if the goal is perfect frame centering.

I have a 110 rear tire and a 100 front tire so I'll have about 5mm on each side when I run my string from the rear tire to the front again.

I was thinking of messing with the spokes but they're very rusty and it probably won't go well. Also, I don't feel that introducing offset into the wheel is the proper method. I think I want to go about this by spacers on the rear sprocket and the axle but curious if there are better options.

Yamahawk · « **Reply #5 on:** January 21, 2018, 05:00:06 AM »

Oh wow, you are far from stock lol... Now, your CB650 motor and the rear wheel... what wheels are you using, the stock '78 CB550 wheels? I am not sure whether there is an offset like the later CB750's of 10mm or not, but you would know that. Also not sure how much offset your wheel was to begin with vs the CB650 front sprocket. If, after you aligned the front and rear sprockets on the bike by using custom spacers at the rear wheel, that is most likely why your wheel is not centered in the frame.
Now... getting to the R6 front forks, are they the early models with conventional forks (not USD) and the blue star calipers? Or are they the later USD ones? And, when you installed them, were you having to adapt with spacers to fit the front CB550 wheel into them...? Am sure that is the case, and you most likely centered the wheel between the fork legs.
It is a question as to how it rides and handles, and whether the front wheel would be easier to shim over to align with the rear wheel, and if you think it would improve the handling by centering the rear wheel to the frame, which 'should' line up the front also.
Shifting the rear wheel to the right would offset your sprockets, and is there a way to mod the front sprocket to match the amount you would move the rear wheel? If not, then your sprocket carrier would have to be spaced, and this is something I am unsure of, as to whether the CB750F carrier can be used in the later CB550 hub? If so, it has a 10mm offset for the later CB750 engine. Just a thought, not sure if it would work.
Charlie

DaveBarbier · « **Reply #6 on:** January 21, 2018, 05:20:18 AM »

Thanks Charlie, yeah the front forks are 2003 so they're the conventional forks with the blue star calipers. I made spacers on my lathe so the forks will accept a spoked wheel (Something I'm meaning to add to my build thread but I'm kind of putting off writing about it). The front wheel is perfectly spaced between the forks and moving the front wheel isn't an option as that would move the discs so they wouldn't be centered in the calipers anymore.

And yes, I'm using a '78 550 rim and hub on the rear (front I think is a '74 hub, haha, it's all crazy) I honestly don't know if the rear wheel has any offset.

I haven't ridden it like this yet with the fork swap but I did ride it last season with the motor and swing arm as it is now and didn't notice an issue but also never checked the rear wheel alignment.

I'd like to get this done over the winter so next spring I don't have to do any disassembly and messing about. So I don't really want to just ride it and see what's up.

The more I think about it the more I do want to just introduce offset with the spokes. That will keep the sprockets inline but I don't know if moving the wheel over 7-8mm is the improper way and might cause issues. Also the fact that my spokes are rusty also makes me second guess that option. I'm not against re-lacing with new stainless spokes...as long as the consensus on the forum is that offsetting my wheel is fine. I'm rambling now, haha.

Yamahawk · « **Reply #7 on:** January 21, 2018, 05:32:13 AM »

Cool Dave, sounds like quite the build, I am sure you have enjoyed it! I have installed a few different wheel/caliper/disc options on a couple bikes, and it is a challenge with the rotors and calipers on the front. I am currently finishing a 1986 EX250 Ninja for the track, I installed 2008 17" EX500 rims on the front and rear, and adapted the front rotor which is larger to the forks off of a 2004 EX250 Ninja. I am thinking of just swapping the later EX500 forks on the front as it will make things simpler in the alignment department. The rear was a piece of cake, just weld a piece on the inside of the swing arm for the slot in the caliper stay.
Now... your rear wheel, not sure if the sprocket carrier off of a late CB750K or F that has the 10mm offset in it will fit you CB550 hub, but if not, have you considered using a rear wheel off of the CB750K that has the 10mm offset for the front, or using the rear wheel off of a CB650 to match the front sprocket? These are perhaps easier options, if they will match up, to give you a centered rear wheel without having to offset the rim using the spokes. It would take some measuring, etc to be sure, and most likely more lathe work for the spacer on the right. I know the 1980 CB650 std. model has wire wheels, as my friend Pat has one in the back yard at his shop. It's pretty rough however, it does have spokes. But, there are a few options that may work for you!
Charlie

DaveBarbier · « **Reply #8 on:** January 21, 2018, 06:46:28 AM »

Nice project you got going on. If you haven't posted that in the "other bikes" section maybe you could show it off, haha.

Yeah maybe offsetting via the spokes isn't as good of an option as I'm thinking. Lathe work is no issue but it's a small 6" swing lathe so axle spacers and stuff are cake but if I need to make a spacer that's the diameter of the rear sprocket then I'll have to outsource that. I do now think spacers are the way to go. I'll look into the 750 sprocket carrier, I have no idea if that will fit or not. I'm not really keen on swapping out the whole wheel as that's more expensive and more trial and error and I might have to make spacers anyway to get it perfect. Also I believe the 650 rear wheel is smaller than my existing one so I'd have to get a new tire. I think that's the case, I'm not actually certain. But again, buying wheels to mix and match doesn't seem that easy unless I can pre-measure everything before I spend money. I think I just have a crazy mix of stuff so custom spacers might be the best option.

Anyone know if there are places to get rear sprocket spacers if I don't end up making one myself?

Yamahawk · « **Reply #9 on:** January 21, 2018, 07:06:17 AM »

Yep, the CB650 has a 17" rear wheel, either spoke or ComStar type. It would be great if your 1978 CB550K sprocket carrier could be swapped with the CB750F, with its 10mm offset. I have a 1971 CB750K1 with a set of ComStar wheels and forks off of a 1978 CB750A, and it has the 17" rear wheel, which probably originally had the 10mm offset, but the PO probably swapped the early sprocket carrier in it to get rid of the 10mm offset and line up with my front sprocket on the 1971 motor. It handles really well and tracks straight as an arrow!
Charlie

seanbarney41 · « **Reply #10 on:** January 21, 2018, 08:48:53 AM »

I am not sure the wheels were ever aligned very well on these sohc4 right from the factory. I know lots of guys have checked and tuned up their alignment. I don't know how noticeable an improvement it is as I have never bothered to check this stuff myself and you would really have to have checked several very unmolested bikes with known crash history.

I have noticed handling anomolies on a few different cb750s where you take both hands off the bars and it takes a slight lean to one side or the other to go straight. I never bothered to figure out the cause of this as there could be dozens of contributing factors (such as road crown, tires, side winds, is my ass out of alignment?, etc.) and it's easy enough to just adapt to the bike.

DaveBarbier · « **Reply #11 on:** January 21, 2018, 03:11:46 PM »

I'd be really curious how off a completely stock SOHC4 is if at all. I may have been riding on these misaligned wheels from the get go and not noticed anything.

So Sean, are you saying that this isn't really an issue or are you just stating your doubts? I'd love for you guys to say not to worry about it and how far off my wheels are isn't an issue

DaveBarbier · « **Reply #12 on:** January 21, 2018, 03:23:02 PM »

So I was out today in the shop and I guess my front wheel isn't perfectly aligned to the center of the bike frame. It's centered just about perfectly in the forks though. But I had my strings on the rear wheel without any spacers on and the chain removed so I can slide it until it's inline with the front wheel. Well, the wheel had to be pretty far to the right to be inline. Enough where it's visibly off center of the bike frame. I may just split the difference and be a bit off center of the bike frame and also maybe 3-4mm offset from the front. Frustrating. My frame does not look bent at all and I can't see any signs it's been in an accident. Forks are also straight. Not really sure what's going on.

38rudge · « **Reply #13 on:** January 21, 2018, 03:54:14 PM »

My understanding is that the original 750K's, apart from the first ones, had a std 3 to 4mm offset to the left of the front wheel, when sitting on the bike. This was to compensate for the potential fitting of a RH disc.

So it seems that it was common for the bikes to have the front and rear wheels out of line from manufacture?

seanbarney41 · « **Reply #14 on:** January 21, 2018, 04:12:27 PM »

Quote from: DaveBarbier on January 21, 2018, 03:11:46 PM

I'd be really curious how off a completely stock SOHC4 is if at all. I may have been riding on these misaligned wheels from the get go and not noticed anything.

So Sean, are you saying that this isn't really an issue or are you just stating your doubts? I'd love for you guys to say not to worry about it and how far off my wheels are isn't an issue

I guess I am saying there is room for improvement but I don't really know how much. Do we really need to get out 50 different string lines, straight edges and the slide rules every time the chain needs adjusting? Were frames really even 100% true from the factory brand new? It seems there are infinite variables. Respect to you for trying to figure it out though. This thread should hopefully be a good source of info to cut down on some of these variables.

DaveBarbier · « **Reply #15 on:** January 21, 2018, 05:43:03 PM »

I think I remember Hondaman talking about factory offset also. Can't recall the context though. Either way, I'm going to do what I can and see how it goes. I will be machining axle spacers and a sprocket spacer to make everything a bit more inline. I'll post back when I get it figured out and I'm happy with it.

Thanks all for the help, much appreciated.

tlbranth · « **Reply #16 on:** January 21, 2018, 05:55:13 PM »

I would think that having the wheels aligned would trump some of the other off-kilter items. If the wheels aren't aligned, I'd bet you'd be up for some pretty decent front wheel wobble.

Yamahawk · « **Reply #17 on:** January 22, 2018, 03:49:08 AM »

Here is the excerpt from the Hondaman Thoughts FAQ on tire (tyre) alignments:

Check your wheel alignment like this:
1. prop the bike upright (not on centerstand), as vertical as possible - or, get a friend....
2. Adjust the rear wheel so that the marks on both sides are dead equal (the marks are good on these swingarms).
3. Tie 2 strings onto the rear wheel. Rotate it until they are as high to the rear as you can get it, while pulling the strings to the front wheel, without hitting something underneath. You are going to measure the parallellism of front against rear wheels.
4. I use 2 wooden blocks for this part: set the strings on each side of the rear tire so they touch the tire on the front sides, then anchor them to the wooden block (nails?).
5. Set the front wheel straight. You'll probably find that the wheel is offset to one side. So, measure how much, then start adjusting spokes. TAKE YOUR TIME. You'll find it to be either 3mm off or 5mm off center, if someone else hasn't already tried this.

The wobble is caused by the front and rear wheels being parallel, not in line. When you're done, you may notice the odd-looking difference of wheel spacing between the front fork tubes. Remember that "look", then look for it when you see your next K0 model...it's a secret...but it's out in plain sight!
HTH!
Charlie

DaveBarbier · « **Reply #18 on:** January 22, 2018, 04:21:36 AM »

I would love for others, that have bikes that they feel ride nicely and have no handling issues, to do this string measuring and see if their wheels are perfectly inline and also how aligned to the bike center it is.

It doesn't take long and it can help solve the "is this really an issue" question.

The string method is pretty much as Hondaman says in his book. Similar to this video below, but the front of the strings I tied to the legs of two different chairs. You can move the chairs around and get it perfect. Better than trying to hold it by hand or tying it to a ruler or something.

Tied to chairs like at the end of this video:

Anyone up for getting some numbers?

Yamahawk · « **Reply #19 on:** January 22, 2018, 04:42:29 AM »

Here's a thought.... If you have 8mm of difference between the front and rear wheels now, and you rear wheel sits to the left of the frame center, not sure how well this would work, but an old rear sprocket could be used to make the spacer with longer bolts. Just trim the sprocket below the chain level, and use longer sprocket bolts. This would give you 3/8" space that you could shift the rear wheel with a new axle spacer, and that is right at 8mm or so. You could keep the left axle spacer and just cut down the right one the width of the extra sprocket. Then, adjust your spokes in the front to get the difference if there is any.
EDIT: This would be easiest with an old aluminum sprocket

Charlie

DaveBarbier · « **Reply #20 on:** January 22, 2018, 07:33:15 AM »

Ah, I like the idea of an old sprocket as the spacer. Already with the hole pattern and rough thickness. I'll try that, thanks Charlie.

jaytee-nz · « **Reply #21 on:** January 22, 2018, 01:24:43 PM »

One issue that no one has mentioned is the possibility of a bent frame through accident damage. You only need the frame headstock to be moved a millimetre or two and that will translate to a lot of misalignment where the front wheel hits the ground.
These bikes are all 40 plus years old so many will have been in some form of a crash - mostly front end related.

Yamahawk · « **Reply #22 on:** January 22, 2018, 02:10:43 PM »

That is a good thing to check, jayteenz. If you check the level of the front and rear wheels, or 'plumb' them, as the case may be, you could find out if that is the case. If your rear wheel is square and plumb, check the front wheel for being square with the rear and plumb also. That will tell you if your frame or steering neck has been compromised in an accident.
Charlie

DaveBarbier · « **Reply #23 on:** January 22, 2018, 05:02:15 PM »

Right, that is something I should check, thanks. As I said before, I don't see any obvious signs of a collision but looks can be deceiving.

DaveBarbier · « **Reply #24 on:** January 28, 2018, 05:45:59 AM »

Thought I had a spare rear sprocket to use as the spacer but I don't. Anyone have an old used rear 550 sprocket they want to send me?

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Author Topic: Wheel alignment (offset from each other) question (Read 14758 times)