Can anyone tell if this frame is bent?

[Fang]

Noticed the forks where a bit tilted towards the left side (if looking from the front)
took everything off thinking it might be bent tubes or maybe the bottom tree was bent, maybe something misaligned, I wish
Looks like the neck has been twisted a bit
Is this something I can fix on my own?
Saw lots of people online saying to heat it up and bend it back, other's saying to take it to a frame straightening shop
I don't see any stress on any welds, no cracking etc, not sure if I would even be able to see other damage since it is hardly bent
In the future I plan on making a frame jig to rake it out a bit and make it a rigid frame
Can anyone tell from this poor quality pic if the neck is in fact bent

 

[Fang]

Here's a picture of the bent gusset near the neck (left side)
Compared to the one that isn't bent on the right
This is the only other damage I can see and its very small

 

[gggGary]

Well if you are going to cut and rake, this would seem like a good frame to do that to. IMHO the twist isn't in "one" place, it's kind of spread out in the frame between the neck, engine mounts and beyond but there is only so much you can do. Horizontal on the frame is easy a level on the lower engine mount bolt. How to get "true vertical" on the neck isn't so simple. A red flag on a seriously bent frame might be if you can't get the engine bolted back in without beating bolts into place.

Same thing works on the yokes; both "straight" tubes should slide into both yokes without forcing. A lot of times it's all subtly twisted,

 

[pamcopete]

Fang,

1.Take it all apart.
2. Clamp the triples to a very flat surface.
3. If they are bent, it will show, as in this pic.

4. Take the forks apart.
5. Roll the inner tube part on a flat surface.
6. If it is bent, it will show.

7. Use a laser level set up to project a horizontal line and aim it at the bottom of the frame.
8. Secure the frame.
9. Use a laser level set up to project a vertical line and aim it at the yoke.
10. If they do not line up you will see it.

Note: Can be done with one laser level if you hold the frame in place after aligning it with the level on the bottom of the frame and then do the yoke.

Note2: The forks in the triple tree shown in the pic above were not bent and neither was the frame in this case, but it's all very dynamic and unpredictable. If the PO made an attempt to straighten it out, then it will be even more mysterious. If the fork tubes are just very slightly bent, you can eliminate the crooked handlebar problem by rotating the fork tubes to place the bend on the side of the fork and not fore or aft. Generally, place the bend so it causes the forks to come closer together and eliminate any front to back displacement.

Note3: There is a 16" Laser Level currently on sale at Harbor Freight for $29.99 that is suitable to mount on a tripod.

 

[Fang]

IMHO the twist isn't in "one" place, it's kind of spread out in the frame between the neck
A red flag on a seriously bent frame might be if you can't get the engine bolted back in without beating bolts into place.


Same thing works on the yokes; both "straight" tubes should slide into both yokes without forcing. A lot of times it's all subtly twisted,

Those where my thoughts that maybe the welds all around the neck area would be partially bent or cracked
I've tried backing out the bolts on the trees to see if the tubes would slide through and they both did with ease which makes me think the trees might not be bent
I don't currently have the tool to tighten the jam nut back on after dis assembly of the front end
I've read online you can remove them with a hammer and screwdriver if you dont have the tool
But on mine it looks like there is two, How would I hold the bottom one in place while tightening the top
Trying to find homemade tools online but no luck yet

 

[Fang]

Fang,

1.Take it all apart.

I have the double jam nut on my bike
Currently trying to find a homemade tool to take it apart until I can buy one
I'd really like to make it if possible

 

[gggGary]

spanners for the stem nuts
http://www.xs650.com/forum/showthread.php?t=33022

 

[Fang]

spanners for the stem nuts
http://www.xs650.com/forum/showthread.php?t=33022

Thanks again Gary
I'll be making one at welding class tonight!

 

[pamcopete]

Fang,

You need two of them. Make two.

 

[figure8]

I need to get a spanner, I've been using a long flathead and a hammer.

 

[pamcopete]

I need to get a spanner, I've been using a long flathead and a hammer.

Yes, allows you to make precise adjustments, but much, much easier with two spanners.

 

[gggGary]

Those home brew didn't need the extra "teeth", it works better with just one tooth on the end.

 

[fredintoon]

Noticed the forks where a bit tilted towards the left side (if looking from the front) - - - Can anyone tell from this poor quality pic if the neck is in fact bent?

Hi Fang,
yeah, looks kinda bent to me.
How does it ride?
What you can do with a bent-frame bike is hang a sidecar on it.
A sidecar rig don't care about a bent frame; they corner all weird anyway.

 

[Fang]

Those home brew didn't need the extra "teeth", it works better with just one tooth on the end.

Thanks again Gary and pete I followed your design and it worked great!
Always a major plus to construct your own tools!
Took everything apart and clamped the bottom tree to a piece of glass
It was less than half a mm apart so I think the trees are good
Found the neck was missing some steering bearings so at least I found that out the easy way, new bearing set all around is next on my list

 

[Fang]

Hi Fang,
yeah, looks kinda bent to me.
How does it ride?
What you can do with a bent-frame bike is hang a sidecar on it.
A sidecar rig don't care about a bent frame; they corner all weird anyway.

It actually rides great, the front end starts to wobble when I let go of the bars for too long which I assume is from cupping on the tire, bad bearings, or maybe a untrue wheel
A new tire is needed anyways since it's pretty cracked and some new bearings also
Then all that's left is to bust out the truing stand and go to work on it
But besides the wobble and the bars being slightly cocked to the side it rides straight as an arrow
It doesn't really bother me besides actually knowing it's there
I figure riding it around the neighborhood a little until I can do some heavy frame mods wont hurt
I was thinking the same thing for a sidecar after someone else suggested it too but since I live in CA and lane splitting is an option I want to make this bike as narrow as possible

 

[gggGary]

Nice way to check tubes is in a lathe clamp the upper in the chuck bring the tailstock center up to the bottom of the lower, oil, add enough pressure to compress the springs just a bit. Hand rotate the chuck, watch the tubes, if you can't SEE any wobble you are golden. If you're AR put a dial indicator on it. Unless both tubes are very slightly bent the same amount (rare), bent tubes create a bunch of stiction in the fork action. I'll disagree with Pete a bit, if you HAVE to keep using a bent tube rotate the bend forward not sideways. this may cancel some triple twist also. If the bend is left or right it will make for worst case fork stiction. a slightly bent lower triple is easily straightened by inserting a fork tube just a bit, snug the pinch bolts and bend it back. without the top triple's support on the tube bending the lower triple is easy. The parts will never be new again but might good enough for street riding.

 

[pamcopete]

Thanks again Gary and pete I followed your design and it worked great!
Always a major plus to construct your own tools!
Took everything apart and clamped the bottom tree to a piece of glass
It was less than half a mm apart so I think the trees are good
Found the neck was missing some steering bearings so at least I found that out the easy way, new bearing set all around is next on my list

Doesn't sound like much, but think of extending that .5 mm down to the axles. In my book, they have to be perfect, like 0.0.

If the start of the .5mm was at the upper triple, which is 7" away, then there will be an additional .5mm every 7". The axle is at 28" from the upper triple, so that .5mm will be 2.0 mm at the axle, which will be noticeable by the handle bars not lining up because you then have to take that 2mm displacement and extend it to the end of the handle bars, where it could be as much as half an inch.

Having gone through a similar exercise, I opted to replace the triples. I rode the bike home with the triple shown in the above pic and the handle bars were cocked about 2". The front end alignment is surprisingly critical.

 

[fredintoon]

- - - I was thinking the same thing for a sidecar after someone else suggested it too but since I live in CA and lane splitting is an option I want to make this bike as narrow as possible

Hi Fang,
well, OK, you shouldn't try lanesplitting with a sidecar rig.
OTOH, you can't carry 8 dozen beer & 4 bags of party ice & your camping gear to a rally on your skinny solo.
Go buy a second bike!

 

[Travis]

Hey Pete, I'm wondering about the clamp method for checking lower triples. The believe the bottom of tree is cast and not machined. If the casting isn't perfect you could get some variation just from that. I think the top is machined, so maybe it would be better to clamp it upside down in the corner of a table or something? I think your method would still work if they a bent significantly, but .5mm of a gap could be explained by the cast finish perhaps.