Need to give the front end an overhaul.

[renegade_xs11g]

Ok, Here's the Problem:

I have a slight shimy, only between 30 - 35 MPH
And I have a 'Bounce', over 60 mph, pretty severe

Need to replace the tire, brake pads, rebuild the front master, and plan to update the lighting system,
So, while I'm at it I may as well go thru the shocks, and while at that....do something with the triple-tree.
also have the 140 MPH speedo from a '78 XS750 Standard

Are there any specific problems I should be looking for???
And will the speedo be accurate or will I need something else from the 750

[petejw]

bounce

Hey Renegade,

That bounce u speak of i get it at 120km/h,
i think thats bout 60mph
this bounce u describe, wen looking at the front
lower forks is the thing bouncing up and down
bout an inch or so pretty violently?, it also stays there
past that speed, ive taken it 2, 140 - 150km/h still there.


Ive had this bike 4 3 yrs and this bounce came with it,
i think the reason the po sold it.

Anyway, ive replaced the front rims (twice), had new tyres fitted (twice),
fitted a fork brace, replaced the front wheel bearings,
repacked and retorqued the steering bearings,
even the other day i swapped the forks over and made
no difference, so i put the original forks back on replaced
fork oil, and put air in the forks, the more air, less feel in the bars
but still have the bounce, i also replaced front springs,
and made sure the forks were aligned correctly.
I also took out the drive shaft and regreased the uni joint.
Ive almost run out of things left 2 do,
other than pull the forks completely apart.

so cut a long story short if u figure it out please let me know. :-)

good luck with it all.


pete

[renegade_xs11g]

That describes it exactly....I can visibly see the shock working, A LOT!

Never noticed it until after I crashed the bike, it was full dressed.

I layed the bike in a ditch at 45, damaged the fairing, hard bags and bent the luggage rack...
bent the bars, and brake lever, broke the right mirror off at the master

It has to be caused from the front end being too light
It gets worse whenever my wife is riding

[petejw]

Thats a bigger worry i think now,

its possible thats something is bent maybe?

ive never dropped the bike since ive had it
(touch wood) but the bike had broken engine fins on it
dents in the tank and scraping 2 the side covers.

so i guess now, how do we go bout checking the
alignment of the bike?
could anything else other than the front end cause
this bounce?

I also repacked the swing arm bearings and adj rear
wheel alignment.

lookinmg forward to any possible theories.

[egsols]

It gets worse whenever my wife is riding

As a passenger?

How are the rear shocks set up? Preload firstly, dampening secondly.

[renegade_xs11g]

OK, I've gotta explain the crash a little...

I guesstimate we (Yes, SWMBO was along for the ride) were doing 45 MPH upon entry into a curve, it starts shallow left and gets purdy darn steep, I get ahold of too much rear brake and start to slide on the pebbles that I didn't see, recovered, heading straight for the ditch

I did manage to slow down....some, to maybe 30 MPH.

It gets kinda hazy after that, my poor wife......
Well... she got thrown off, I rode til the bike stopped......
My wife and I have both healed, and still ride

The bike, only took damage to the "DRESSING" as I said earlier...

Yes, my wife is a 'rider', not a 'driver',

As for rear shock set-up, stock shocks - lowest notch on the 'steps' and IIRC the dial is set to 2

When I say that it gets worse when she rides, I think it because of
(looking over my shoulder, to make sure she's not looking)
the added weight, but on the rear of the bike, with that front-end being a lot lighter, is some how messing with it

Now, I didn't tell ya'll, it's also worse if 'crusing' along, start into accel or decel and it all but goes away.....
That points me toward the tire.......but I may be wrong.

[petejw]

Funny we have the exact problem for sure,
I pillion my daughter and it gets worse,
ive mucked around with the rear shocks (preload etc)
makes no difference.
Front shocks and can pump air into them to make them
stiffer doesnt stop the problem, only lessens it slightly.
And as renegade describes it much worse at cruise
and u dnt seem 2 notice it on acceleration,
btw, Ive replaced both front and rear tyres
since with no difference watso evr.

[50gary]

Sounds to me as if there's little or no damping (compression or rebound) There also me be other problems? Too little weight on the front could be partially solved by dropping the triple clamps on the forks. Start with a moderate amount maybe .25" (6 mm)
Cheers, 50gary

[petejw]

Hi Gary,
I had tried dropping the fork tubes down,
in my instance it made the matter worse.
When bouncing the forks manually, with mine anyway
there appears to b a dampening effect.



Is there anything internal of the forks
that could cause this problem
the only thing i havent done yet
is stripping the forks down completely.

[Dsxs11]

Add another one to the list. I actually thought the problem was the crappy Michigan roads. But when I changed front brake pads the front axle would not come out it was bound. I loosened the triple trees and the forks popped axle slid out easy. I put it all back together and the problem went away. Now I can't say for sure that the forks were the problem but the bike was layed down hard before I bought it. I'm not even sure I can point to the brake pads. but something moved when I let the trees loose and the bounce went away. Good luck with it. I have a set NOS forks to put on it this winter I'll see where that leads this spring.

[AlanB]

Hi Guys,

If you can see and feel the fork bottoms "working" as you drive along a flat, smooth road, the problem will be wheel balance.

If it is bad, the bike will feel unstable; almost likt the wheel is not touching ther road?

I have had it on two bikes; one had a "self-sealing" compoung in the tyre which had half-set, the other had a dinged rim.

I now ALWAYS balance wheels; especially fronts!

Do it at home; quick and easy, no special kit.

I am pretty sure there are instructions on the site; if a search fails, let me know and I will type it up!

AlanB

[petejw]

Hi Alan,
Ive had both front and rear tyres balanced
at the shop and have checked it at home as well,
Ive have had 2 front tyres and rear tyres fitted,
and the problem has still persisited.
Ive also used 2 other front rims.

The feeling isnt like a wobble more like a bounce,
like the tyre is out of round, is probably the best way i can describe it.

Ive also loosened and realigned the fork tubes several
times again with no difference.

My bike is so smooth until I reach that 120Km/h mark and onwards.

Btw, I recently bought Bridgestone BT45 tyres, these are the best tyres
ive had on this bike to date, the grip is fantastic, the rear tyre
has a harder compound in the center and softer on the sides, I really enjoy taking corners with these tyres. for the price I highly recommend them.

[79XS11F]

Have you disassembled and rebuilt any of the forks that have been used on the bike? They may have been serviced by a PO and not put back together properly or modified inside. Also, a LOT OF SLUDGE can develop in the fork legs and that may affect the way they work. I took apart a pair of forks in the fall so I could discard the bent tubes and there was close to an shot glass full of heavy sludge in each leg.
If all other things are good to go ... disassemble, clean & rebuild the forks.
Rob

[renegade_xs11g]

I do need to replace the tire, I've had the monster for almost 3 years and haven't replaced it yet,

If you look at the pic in my signature, you can see that I also need to rework the front brakes, at least the right side,

I'm also reworking the lights and dash on the front, so I might just as well go the rest of the way, Right????

I'm in process of building my work bench, turning part of the basement into a shop, SANTA brought me tools
Now just gotta find some wood!

[renegade_xs11g]

Dxsx11...........I just re-read your post,
Makes complete since, 'cause my fender was tweaked a little....
loosened the bolts, and it popped back. I didn't even think.....
Damage to right side....right side brake looks like that....

no...wait, I've had the triple tree 'top' off....
unless the lower is the clamp.......HMMMMM