Triple tree stem lengths? Front end swap issues

D-rock11

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So I was told from 70-73 the xs650 had short triple tree stems and the rest are longer. Is there any way verify what year a triple tree if off of?

I'm doing a zzr 600 ninja front end swap. Bearings aren't available to swap the ninja triple trees, so I had a machine shop press an xs650 stem into the ninja bottom clamp. I saw this swap done before on the forums here and thought it would be a simple swap. I bought the stem off eBay and it was either a 76 or 77, my bike is a 81. Well after fitting up the modded triple trees with a new set of tapered bearings, the stem is too short. Only a few threads stick out of the top of the frame.

So did I get the "short" xs650 stem? I guess it's possible that I grinded too much off when I removed it from the original bottom clamp, but for how short I am I find that doubtful.

Also my bearings seem to stick out of the top of the frame a good bit, I thought they would be flush? Even the lower bearing sits up a little from the bottom clamp. Maybe a combination of the bearings and too much grinded off the stem?
Any help is greatly appreciated guys, I just love the way this bike looks with the front end!

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In 74 was when they did a lot of frame mods to improve frame strength. Going to a slightly longer neck was one of those mods. So any stem from 74 up are the long ones.
The earlier stems were about 8 3/16 in. The later about 9 inches long.
When you remove the stem from the lower tree there is a flange that stops the stem from going to deep in the tree. The measurements I quoted are from the tree side of this flange to the top of the stem.
When you took the trees out of the XS650 frame, A bunch of loose ball bearings came out. These balls rode in races, one race on the bottom of the stem, one in the bottom of the neck. One in the top of the neck and one on top. The two in the frame were pressed in, the one on the lower end of the stem was pressed on. The top race just dropped on.
From looking at what you show it looks like you didn't remove the two racers in the neck.
In the pic that just shows the stem and lower bearing, it's sets a bit crooked, and not on all the way.
The new race for the tapered rollers that goes up in the bottom should go up in just past flush. If you look up in the neck without any race in there it will have a straight section. The new race fits so it's just a bit past flush with this straight section.
On the top race it will set just a bit proud of the neck. like 1/16 inch. Yours looks closer to 1/4 inch.
I would remove the trees and inspect the neck and see if you left the old racers in the neck.
Leo
 
Leo,

I do recall removing the ball bearing races. I know this because I didn't take them out the first time I tried to fit everything, haha! So maybe the top race needs pressed in a little more?

650skull,
I actually used that link to make sure I was doing the install right, but still don't understand why my bearings stuck out a little bit more at the top. I didn't think they needed pressed in, but I figured when I tightened the locking nuts on the stem it would compress it all together.. However when I did this the stem started to pull out of the lower triple [emoji58]


Here is what he stem looks like. The machine shop lathed the stem down to fit the lower clamp. The measurement in the picture is from the line where they stopped. If the stem was pushed all the way down, it would sit flush on the top and bottom of the lower clamp. It currently sits about half way in the clamp, and the measurement in the picture is roughly 8.5in. I planned on welding the stem to lower clamp, but I didn't want to do it yet if it's too short. I wonder if I weld it where it's at now if it will press the bearings together more when I go to tighten the top locking nuts? Or if it's even safe to weld it where it's at..

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just by looks that ZZR lower appears thicker than the XS bottom triple so you can expect the stem to be recessed.
 
Just a note.....the stock xs650 lower triple has about a 3mm platform rise that pushes the lower bearing up into the neck. I believe that needs to be addressed.


When I had everything installed the lower bearing seem to be tight up in the frame, it turned smoothly and wasn't loose.. But I'll double check that next time
 
Yeah OK, it's gonna be REAL tricky trying to weld that. The center of that triple might disappear.
 
That lower appears to have the angle placement, tubes to neck, of the forward leading axle. If that's the case then maybe a stock, steel yamaha forward leading axle triple tree would be the ticket. Find one in the diameter of those forks.......36mm?
 
That lower appears to have the angle placement, tubes to neck, of the forward leading axle. If that's the case then maybe a stock, steel yamaha forward leading axle triple tree would be the ticket. Find one in the diameter of those forks.......36mm?


Never heard of that before. I'll look into it. I did think about just trying to find different triples that fit. From what I looked up I think they're 41mm but I went to measure it myself to make sure the info from the seller and info I found online were correct
 
Stem length from the top of the 3mm platform that pushes the lower bearing into the lower neck is 8 7/8". From the flat top of the lower triple, bypassing that platform is 9 1/8".

Compare the stock triple to the one you're converting to and just see if the neck to tubes angle is different.

You may have enough metal to do the swap but Gary brings up a valid point on it being aluminum.
 
Stem length from the top of the 3mm platform that pushes the lower bearing into the lower neck is 8 7/8". From the flat top of the lower triple, bypassing that platform is 9 1/8".

Compare the stock triple to the one you're converting to and just see if the neck to tubes angle is different.

You may have enough metal to do the swap but Gary brings up a valid point on it being aluminum.


I think that puts me at about 1/4" short, and if I pull the stem out another 1/4" I don't think that would leave much left in the lower clamp. At least not enough that I'd feel safe to ride/abuse on.. Do you think I'd be better off trying again with a new xs stem or just look for triples that fit my forks and bearings available for that conversion? I'm kind of thinking new triples
 
Well it depends on what you're going for.
XSLeo has put an xs1100 on his '75 I believe, and I've done a '77D Standard xs750 swap onto my '83. I went for the extra inch and three quarter length, which I don't use because of handling issues HA! And for the stiffer36mm tubes. Sometimes I'll stretch her out for a day of looks but I prefer the function 98% of the time.

Do a study on the forward leading axles. I believe the Viragos are mostly forward leading. They reduce the angle of the tube to neck and then mount the tire forward of the forks. It gave the illusion of an extended front end.
Putting straight forks on a leading axle triple tree will bring the front tire closer to the frame.....putting leading axle forks on a standard triple tree will put the tire forward in a bit of a rake. No idea what kind of handling will result in either application.

It would be interesting to know if that ninja has the same angle of the xs triple.
 
I like the way this front end sits. The gap from the wheel/frame is right where I like it. I wanted a sport bike front end and I found this for dirt cheap. Even if it's not a more modern suspension I figured it would be somewhat of an improvement over stock. I'd like to use the zzr triple, although I want a different top clamp, or I'll modify the hell out the one it came with to clean it up and try to add handle bars. I'm getting drained with searching again again over these damn triples so I think it's time I get in the garage and make something work
 
Another question: how interchangeable are top clamps? I want to run handlebars vs clip ons and wasn't sure if anything with the same Fork MM would fit? I wasn't too worried about the center hole for the stem, figured that could be bored out to fit easily if it's too small. Only other thing I thought to look for was the forward leading axel and try to find one close to the same width over?
 
Frankenbike concoctions sure are fun!
Swapping the top triple would have to be an exact fit as far as angle from the neck to the tubes and, of course, the same diameter as your forks. Anything is possible to manufacture with the right machinery and know how.

Still not sure how that zzr matches a stock xs650 triple as far as the angle from neck to tubes to determine if a complete forward leading axle Yamaha would fit the bill for what you're going for. I guess it may be possible to drill a couple of holes in that zzr upper triple to put a set of risers in for handlebars ? Dunno as I'm not familiar. Are the zzr's clip on?

Once you do figure if you're going to use the xs stem in that zzr, by all means assemble the forks into the upper and lower triple for exact and proper alignment and then weld the stem in. It doesn't have to be in the neck of the frame but know the length of the stem for sure. How would I know? Yeah.......

Post a pic of the zzr and the xs triple lower.....say, an above and below shot to compare the tube to neck angle. Might be able to tell if a forward leading triple is where you're going.......though 41mm might not be in the Yamaha line.
Fun stuff.
 
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