Topic: Aligning the front end after fork rebuild

[GroovieGhoulie]

Is it a nightmare?  I need new fork seals and have the parts, but I am scared to tear apart the front end because someone on here said that if you do, it requires a full alignment and I'm not set up to do that/I don't wanna spend hours tightening/loosening/tightening/loosening all the fasteners up front only to have it never be right again.  I thought that as long as you re-tighten all the bolts to spec during re-assembly, it'll be on straight, no need for alignment.

What's the deal on this?

[ProTeal55]

I just ripped my old front-end of fmy bike last night, and installed the new one.
I was wondering if I needed to align anything after all was hooked up.

[Chris Liston]

You shouldn't need to align anything.  Just make sure both upper fork bolts bolts are where there were prior to taking the forks off.  Pretty easy and not much more detail than that.  I've had my forks off a bunch of times.  Just remember to properly tork the tripple tree clamps.  I had forgottone once and realized why things felt loose whoa...

[supersport_CB400F]

Just drop off the lower aluminium sliders put the new seals it’s not a complicated thing to do. why take the  chrome tubes off 

[GroovieGhoulie]

Just drop off the lower aluminium sliders put the new seals it’s not a complicated thing to do. why take the  chrome tubes off 

'Cause I thought I had to.

[STLrocker]

yeah, i dont know what bike you have, but if its just fork seals, on some you can just leave the upper tubes on. i do my 750's that way. dont know for sure on the smaller bikes. i think some are the same.

i believe on some of the smaller twins the tubes gotta come out though. i seem to remember the 450 being that way.

[cb650]

Even if you slide the whole tube out as long as you dont loosen the triples it will be the same. 
Also unless the tubes are bent the triples will straighten themselves. 
Would be a good time to put in tapered steering bearings.



      Terry

[eurban]

If you don't need to remove the forks from the trees then feel free to disregard, but for the sake of your original quetion. . . . .My experience has been that it is posible to develop a twist in the front fork tubes even with straight fork tubes!   Particularly if you have had the tree's completely apart rather than simply sliding out the tubes.
I have used two straight edges to get things properly straight but if you don't have a clear shot across the fork tubes at the top (stock headlight ears would be in the way) this can be problematic.  Top referencing off the handlebars or a straight piece of tubing installed instead of the bars might be possible but probably not as accurate. Start with a mostly plumb (not tilted to the left or right) bike on the centerstand and point the front wheel straight ahead.  The "straighter" ahead the front wheel is the more accurate your alignment will be but this is difficult because if your forks are twisted your handlebars and your front wheel wont correspond.  I actually began with a front to back alignment using string lines and found that when my two wheels were exactly in line and in theory the bike was pointing exactly straight ahead that the handlebars where turned a bit to one side.  This prompted me to begin  a test for fork tube alignment    Basically, you set one straight edge across the tubes up high and the other across the tubes just above the sliders. You need to make sure that the straight edges are the same distance from the top of the forks on both sides otherwise your measurements will be off.  I used 4 foot flourescent light bulbs for the purpose and zip tied them to the fork tubes.  Drop a plumb line down from the top straight edge on the left and right side and then measure the horizontal distance from the plumb line to the bottom straight edge.  When these distances are the same there will be no twist in the forks.  If you losen the upper tree's steering stem pinch bolt and its two fork tube pinch bolts and twist the handlebar while holding the wheel between your legs you should be able to detwist things.  It will take a few tries.   My project bike's newly put back together front end was a good bit off and when I removed the twist, sure enough the straight ahead  handle bar position and the straight forward front wheel correspnded.   On a side note, my 78's rear aligning marks on the swing arm were off by about 3/16 of an inch or about 3 of the smaller lines on the swing arm.  This isn't even close enough for government work!

[HondaMan]

Here's how roadracers align the front forks after new seals:
1. Tighten the fender brace first.
2. Tighten to spec, then slightly loosen, the axle caps. Just a 1/4 turn loose from tight will do.
3. Loosen the lower triple tree clamp bolts about 1/4 turn.
4. Get a friend to help next.
5. Bike on centerstand (preferably), lock the front brake and force the tubes down-up-down about 4-6 times, like a pogo stick, rapidly. Don't leave the ground with the front tire, or start the count again. This sets minor twist imperfections and alignments out of the lower end of the sliders.
6. Finish the pogo business with your weight ON THE BARS and have your friend tighten, in order, the axle clamps, then the lower fork tree clamps.

The result of this little trick will be smoother sliding, less stiction and ultimately less seal leakage. Especially at 100+ MPH. 

[TwoTired]

Once upon a time, the SOHC4 site had a wrenchbender file on front fork tuning, by Mike Nixon (Oldfart).
I can't find the article on this site or Mike's either.

Anyway, from it (I think) was a quite useful tip for aligning the front forks.  Use a piece of flat window glass to assure that the forks weren't twisted in the tripple trees.  Glass is made very flat and doesn't flex much.  Essentially, you loosen the tripple trees and the fork clamps with tubes installed.  The lower trip tree clamps are tightened just enough so the forks don't slide out.  Place the glass across both forks and twist the upper tree until both forks are flat against the glass. Tighten the fork clamps and the upper tree pivot, and recheck the glass for flatness.  If nothing moved during the tightening, it's all straight.  This can be done with or without the lower sliders unless you have accordian boots on your forks.  Then this is best done without the lower fork sliders, and the accordian boots removed.

Cheers,

[bwaller]

These are great tricks for aligning, and HondaMans advice addresses "fork binding" also. Something that often is overlooked was this business of forks not being parallel. When installing the front wheel the axle nut is centered in one cap but there is a space between the other leg and the speedo drive. If so never push the fork leg tight to the speedo drive and tighten the axle cap as this will cause binding, stiction and increased wear. On all my sohc's this is the case, it's rare to find one with forks parallel.

It's better as HondaMan suggests to let the legs "find their place" on the axle and leave the space. The legs won't be parallel, but will eliminate the stiction problem. On the 550 I'm building now I installed just the fork tubes and measured between them just under the triple clamp and compared that with the measurement at the very bottom of the tubes. They were way off, wider at the bottom than the top.  In this case it I added a 0.001" shim between the tube and the top triple clamp toward the steering center on both forks and that's all it took to get them parallel. When the top clamp is tightened the shim stays in place. There was still a space between the leg and the speedo drive, but just machined a spacer to take up that space and all is good!   

This is only a quick fix, to really address the problem a better machinist than me would need step in here.

[theunrulychef]

I'll be putting my front end back together this weekend.  I don't suppose anyone knows of any diagrams or pics to aid in the measuring?

Thanks,
Jay in Philly

[Chris Liston]

This may sound stupid but I'll ask anyway. If you don't have any reason to believe your tubes are bent or the tripples are twisted is it still recommended to align the front. I usually just make sure its in the height level that my shop manual states.  Once its in I put the wheel back on.  The axle centers on the forks.  Never had a problem using this method.  But again, my forks are straight.

[putnaja1]

Hey, has anyone ever confirmed that the CB550 forks can be rebuilt without removing the chrome tubes from the triple clamps?

I'd like to leave these in place, as all I have to do is replace the fork seals and dust boots.

Jason

[78 k550]

Hey, has anyone ever confirmed that the CB550 forks can be rebuilt without removing the chrome tubes from the triple clamps?

I'd like to leave these in place, as all I have to do is replace the fork seals and dust boots.

Jason

Yes, they can be rebuilt without removing the chrome tubes.
 I have done many this way.

Paul

[Bodi]

Yes. You undo the allen bolts countersunk between the axle studs and the sliders will come off.

[jaknight]

Hi Everybody.........

     Rebuilding without removing everything is great for convenience, but.........

     I had to rebuild my front end completely........ got hit by a car ($#@%$$$###!!!!).

     For those of you who have them......... The upper chrome covers..... over the tops of the tubes and sweeping forward with a holder for the headlight bucket....... your rubber gaitors right below them.........  The amount of rust I found in and under those pretty chrome covers was as scary as ducks flying in with 12 gauges of their own!!!

     Serious hidden damage.  My 750 K4 only had a little over 24,000 miles on it.  I had to replace the upper tubes any way (seriously bent, Triple Tree OK).  If they hadn't been bent, the rust would have made replacement necessary anyway.  I strongly suggest you take it ALL apart and check out the rust condition..........   Hate to be a downer guys, but..........

     ~ ~ ~ jaknight ~ ~ ~

[KB02]

No, no. That's a good point. Fror guys like me, though, who don't have that cover, we cam just leave them right in place.    

I have been reading this thread with interest since I have two projects coming up that will be able to use this. The first of 750 F1. I have abad fork seal on the right side. BUT, since I seem to have lost a coil last month, the bike is probabkly going to sit untill spring as I take the time and save up for a Dana ingition, But since the winter is coming, I am planning on takeing care of front end and reshaping it a little bit, This will require the removal of the forks for a brief bit (might as wel rebiuld them while they're off).

And my buddy just gave me a '78 CB400T that has a bit of twist in the forks. He and I have been threatening to fix it for the last two years (he doesn't ride much since he works with a traveling company). But, since he has now given it me, the forks WILL be realigned!!!... finally... probably... We'll see...   

[doug_id]

so, what is the trick to removing the upper fork chrome covers?  The ones that have the headlight ears attached to them?   On my CB550 that I am restoring they are pretty rusted and just want to chuck them.  Kind of scratching my head on how them come off though.   

Thx,
Doug

[citizencia]

These are great tricks for aligning, and HondaMans advice addresses "fork binding" also. Something that often is overlooked was this business of forks not being parallel. When installing the front wheel the axle nut is centered in one cap but there is a space between the other leg and the speedo drive. If so never push the fork leg tight to the speedo drive and tighten the axle cap as this will cause binding, stiction and increased wear. On all my sohc's this is the case, it's rare to find one with forks parallel.

It's better as HondaMan suggests to let the legs "find their place" on the axle and leave the space. The legs won't be parallel, but will eliminate the stiction problem. On the 550 I'm building now I installed just the fork tubes and measured between them just under the triple clamp and compared that with the measurement at the very bottom of the tubes. They were way off, wider at the bottom than the top.  In this case it I added a 0.001" shim between the tube and the top triple clamp toward the steering center on both forks and that's all it took to get them parallel. When the top clamp is tightened the shim stays in place. There was still a space between the leg and the speedo drive, but just machined a spacer to take up that space and all is good!   

This is only a quick fix, to really address the problem a better machinist than me would need step in here.

I like the idea of a shim, I do not however have the space for a shim between the tube and the triple clamp.  My profile pic shows my bike before it's operation of getting stock forks back on it.  The forks that were on it were 7 over and the old tubes had a slightly smaller diameter than the "new" tubes. (I rebuilt the forks to address bad seals).  These "new" forks came off of a 74 750 (same as mine) that I can confirm as being stock.  It makes me suspect that my fork tree may not be stock.  But then as I am quoting, my fork on the brake (left) side seats nice and even.  There is a good amount of space between the other fork and the speedo drive.  I think that when new, there was no space and everything lined up properly.  Will having a gap there or placing a steel tube of the same outer diameter create a safety issue?  I commute to work, summer is coming and I don't want to risk my life for the sake of saving gas.

[HondaMan]

Honda is good at making many (pretty) good parts at a time, but the accuracy of the hole centers on the triple trees is nearly as much art as engineering. You can "see" how the non-parallel problem appears if you realize that the trees are drilled to within production tolerances of .005mm (about .0002", pretty tight!), but they are about 30" away from the axle. This makes a (.0002" x 30") = .006" out-of-parallel error at the axle. In good tubes, the slider tolerance is only .002" to .004", so it's easy to see how you can get .002" to .004" binding, even with brand-new parts.

[bwaller]

That's right H-man, brand new parts and likely not parallel. The last front end I put together had slightly bent fork tubes the owner wasn't aware of (how often is this the case) and once straightened the tubes were wider at the bottom by almost 0.035"

Citizencia, you can rotate that tube into place with a 0.001" shim into the triple clamp to see if it helps. Just have something accurate to measure.

[754]

Just came into this thread..

 you missed 2 major points,

Basic alignment & after fall alignment, put bike on c-stand or have someme sit on bike. Stand over front wheel facing bike. Grip wheel with knees, then push handlebars the direction it needs, to go..keep checking.. You need to do this every time a bike gets dropped or when assembling forks.

 I am surprised how few remember this from bicycles.. My son learned it when he was 5.

When assembling the front end, do this simple check for tube straightness. With axle in and no weight on front end, rotate tube in triple trees, observe position on axle, often it will move in and out slightly. If there is a slight bend rotate to position towards front..always. Do this with both forks and aim to the front if there is a slight bend. (Or pull them apart & deal with that issue)

 While what Hondaman said about out of tolerance trees, I would bet it is more likely the tubes.

 Another issue is the trees could be bent, I can tell you how to fix them.

 Another method of alignment & checking, but it will not work with gaiters & headlight ears. Simply eyeball the tubes for parralel from the side.. quicky, easy & simple..

 I once had a 350CL. One day I had a particularily nasty endo on that bike, they were bent after that . like one of the ribs on my back, after I landed on & pulled a rock out of the ground(with my back). I turned them to the front and next time I hit something, they got almost straight!!

[TwoTired]

I roll the fork tubes across my cast iron table saw top to check for bends/straightness.
Insert the tubes in the triple trees loose but tight enough to keep them from slipping out, and the stem nut just loose enough to allow the trees alignment to twist.
Lay a piece of flat glass across the front of the tubes. 
When both tubes lay flat on the glass, tighten the triple tree clamps and the stem nut.

If the glass is cut to proper size, and you don't have fork gaiters, you can do this with the lowers assembled onto the tubes.

Otherwise, the accordion boots and the lowers are assembled onto the tubes after the forks are known parallel and tight in the trees.

Cheers,

P.S. I need to do this to a bike later this week (new fork seals, head bearing exam).  Should I take pictures?

[HondaMan]

Hi Everybody.........

     Rebuilding without removing everything is great for convenience, but.........

     I had to rebuild my front end completely........ got hit by a car ($#@%$$$###!!!!).

     For those of you who have them......... The upper chrome covers..... over the tops of the tubes and sweeping forward with a holder for the headlight bucket....... your rubber gaitors right below them.........  The amount of rust I found in and under those pretty chrome covers was as scary as ducks flying in with 12 gauges of their own!!!

     Serious hidden damage.  My 750 K4 only had a little over 24,000 miles on it.  I had to replace the upper tubes any way (seriously bent, Triple Tree OK).  If they hadn't been bent, the rust would have made replacement necessary anyway.  I strongly suggest you take it ALL apart and check out the rust condition..........   Hate to be a downer guys, but..........

     ~ ~ ~ jaknight ~ ~ ~

Not again!?  Didn't you get hit before, JK?
Or, is this reference to that one?

My K2 suffered the rusty tube tops, too. When I discovered it, I couldn't get the tubes out, nor the ears off, either. I drove the tubes out of the top tree, removed it, could barely pull off the ears, ruining the rubbers in the process. I guess Honda was worried about water going UP into those ears, put those big rubbers in there.

So, I notched out several slots in the (new) rubbers to let the water out: the next time I took them apart was 12 years later, and the rust had not returned.

Hmm...maybe I should add this to "the book'.