Topic: How do I tell what is bent on my front end???

[Ford40]

I recently purchased a 1976 Cb750K and after riding it for a couple weeks I noticed that the handlebars don't point straight when riding in a straight line. After looking over the front end a little more closely I get a suspicious feeling the bike was in some kind of accident. Some things I noticed were that one of the steering stops on the triple tree has a small bolt threaded into it to keep the headlight ear from hitting the tank on the left side, left side of tank has a small dent on the front by the headlight ear and it appears that a small piece of the end of steering stop welded on the frame has broken off (hence the need for the small bolt). I have ordered some tapered roller bearings but don't want to install them if the trees will need to be replaced so how do I go about checking to see if anything needs to be replaced on the front end or how do I get the handlebars to line up with the front tire. Thanks in advance.

[754]

First step , eyeball the tubes againt each other from the side.
 2nd step, if that looks out, give it the kneetweak a few times,

If that dont get close to straight, they gotta come off for work or replacement.

[Bodi]

Check your rear wheel alignment first!
Also the fork tubes might be twisted and clamped in place that way, just loosening the triple clamps and tweaking it a bit may fix it. Have the bike weight off the front wheel for that.
Serious problems would be a bent frame or bent fork tubes. A slightly bent main frame is pretty hard to diagnose, but if you see damaged/repaired tubing in the frame around the engine or around the neck it's not a good sign. I've seen a few bikes that had been is hard collisions and twisted the neck "down". The damage where someone had heated the frame tubes and forced it back to what looked OK was quite obvious and explained the wacky steering and handling.
The rear fork (swingarm)  can be checked with a level and plumb bob. With the bike on level ground on the centre stand - a flat concrete garage floor is good enough -  and rear wheel off the ground, level the frame with a spirit level across the main frame tubes under the seat (shim under the centre stand feet with whatever works). measure from the ground up to the bottom of the fork flat sections under where the axle is. The measurements should be identical but don't sweat about a quarter inch off. To really check it, it has to be off the bike. The swingarm is often bent in a crash where the bike went in a ditch or similarly bounced around a bit.
Broken steering stops aren't really rare, and don't necessarily mean a crash severe enough to bend anything.
Bent fork tubes are hard to see on the bike but very easy to diagnose if you take them out. Just roll them on a flat surface: a bent one will be obvious.

[albertaboy]

I low sided a few years ago on a modern sport bike and noticed something similar you describe. I fixed mine my loosening the top and bottom triple bolts, grabbing a fist full of front brake, pumped up and down on the handle bars, then tightened everything back up to spec and presto!.  That's how a tech told me to do it. They wanted 3 hours labor for what took me 20 minutes. 

[Stev-o]

First step , eyeball the tubes againt each other from the side.
 2nd step, if that looks out, give it the kneetweak a few times,

If that dont get close to straight, they gotta come off for work or replacement.

Kneetweak?   Is that a technical term?!

[754]

I would not go off the seat portion to check ANYthing for level.
 I strongly disagree that bent tubes are hard to spot on the bike, I can do it easy from 10 feet away..
 And a lot of them can be straightened..

[Ewan 500K1]

bent steering stem from front ender ?

first photo = bent stem .  second = good stem

[Ford40]

Thanks for the tips I'll try messing with it this weekend when i get some time

[scottly]

Kneetweak?   Is that a technical term?!

Knee-tweak: a process for straightening misaligned fork tubes. To apply the process, the front tire is held firmly between the knees, while the handlebars are used as levers to twist the tubes back into alignment.
Commonly used on off-road bikes following wash-outs, endos, high-sides and loop-overs.
  

[Stev-o]

Kneetweak?   Is that a technical term?!

Knee-tweak: a process for straightening misaligned fork tubes. To apply the process, the front tire is held firmly between the knees, while the handlebars are used as levers to twist the tubes back into alignment.
Commonly used on off-road bikes following wash-outs, endos, high-sides and loop-overs.
  

Ha!  Well, I've done that on bicycles but never street bikes.

[754]

We have to add it to the SOHC Dickshunary..

[scottly]

Kneetweak?   Is that a technical term?!

Knee-tweak: a process for straightening misaligned fork tubes. To apply the process, the front tire is held firmly between the knees, while the handlebars are used as levers to twist the tubes back into alignment.
Commonly used on off-road bikes following wash-outs, endos, high-sides and loop-overs.
  

Ha!  Well, I've done that on bicycles but never street bikes.

We learned the technique on bicycles such as Schwinn sting-rays, and naturally adopted it to small dirt-bikes. Unlike street bikes, dirt-bikes may get the front end tweaked on a daily basis.