Loose swingarm bolts

[cjmeg]

A quick note.
My '85 had a 170/80 15 Mettzler rear, and a pronounced speed wobble at 110mph.
When I changed the tyre yesterday, I went back to stock size, also noticing that although there was no side movement in the swingarm I could detect, the RH swingarm bolt was quite loose.

So I torqued it up to specs..
Noticed today that the wobble is gone.
Lately it's been 'twitchy' at times on undulating roads - that's gone too.
I'm thinking the swingarm may have been the cause.
Bike now feels much more stable.

Thought comment might help..

 

[KJShover]

Good follow-up,

Many ppl, myself included, forget about the swingarm when troubleshooting steering issues.

 

[4gasem]

Everyone should check the torque on their swingarm. I did this after about 1500 miles and will probably do it again this year as well.

Chris

 

[gamorg02]

which bolts specifically are you guys talking about?

 

[maleko89]

They are behind the round chrome plastic swing arm bearing covers. Near the passenger foot pegs.

 

[Rusty McNeil]

Be very careful with the right hand side bolt, it only torques to around 4ft/lbs or so against the bearing, the nut around it that torques higher is what holds it in place, after setting the bolt itself to 4ft/lbs or so with an allen driver.....It's difficult to keep the bolt from turning when torquing the locking nut,


What I did was torque the bolt and put a reference mark on it so that I could keep playing with the locking nut and the "starting" point of the bolt (it's going to turn when you torque the nut, there's no stopping it) so that when the locking nut is torqued the bolt inside of it stops where you want it....

There are some special tools from yamaha to avoid this pain in the ass, but to me it's easy enough to get around having to buy them....

Your supposed to set the left side first since it's basically tightened all the way to 70ftlb against the frame...

The left side is basically a fixed point that the swingarm seats against, and the right side is your adjustment just like setting a taper bearing on a car spindle, although these aren't taper bearings (if I remember correctly) and are therefore more delicate

If you do the right side wrong (overtorque) or do the right side first and then torque the left side left side afterwards you can destroy the bearing...

And FYI, I pleasantly found that the swingarm bearing are basically drop in and don't need any special tools to change, just pull the seal out and they come out fairly easy, I had thought they would be tighter...

 

[gamorg02]

i'm going to try this just b/c i want to get rid of my wobble... anyways...

so is there really no way to hold the right hand bolt while messing w/the nut, just tight a the nut a bit then move the bolt back to where the mark is supposed to be?

if i read that right?

I also find it kind of silly to go buy a torque wrench to measure 6 Nm, how important that thats right on? i was going to do like hand tight plus a 1/5 to 1/4 turn...

 

[naughtyG]

Sounds like I need to get in there on my bike, I shall do this as soon as I get back near it. I'll prolly drop the bearing to give it a good inspection too - considering some of my PO's work leftovers I wouldn't be surprised if it was dead or destroyed!

 

[4gasem]

Sounds like I need to get in there on my bike, I shall do this as soon as I get back near it. I'll prolly drop the bearing to give it a good inspection too - considering some of my PO's work leftovers I wouldn't be surprised if it was dead or destroyed!

You may as well plan on replacing them. In that environment and with a bike that old the seals and bearings could probably stand being replaced. Especially if you're digging that deeply into it.

Chris