front end wobble

[stumpy]

hey all. Hope you all had a good 4th of July. Bless all the vets out there. Thank you for covering our butts.

Ok heres the problem, I have a 79 XS1100 special with around 36,000 miles. At about 92 mph the bike gets a wobble in the front end. Like its trying to turn the handlebars from side to side. It gets kinda scary and i'm wondering where to start checking for problems. Any ideas? Still havent put that clutch in either. Thanks all.

[planedick]

Me too....

I had the same problem, what I found was: Front wheel bearings bad, and steering colum loose, and it helped lots to fix those things, but I understand that the T-Kat fork brace will take care of the remainder of the high speed wobble. Now it only happens during high speed and heavy cornering with a rough road. One should stay away from that combination anyway. LOL

[superdave]

front end shake.

front end shake can be from a lot of different things. loose or worn stearinmg head bearnig, uneven fork tubes, low fork oil. un even preload in fork tubes . tire out of ballance/bent rim, ply in tire/ cord broke ,bent fork tubes,wheel bearing bad, worn rear swing arm pivot and links, soft sprindg in one of the fork tubes.Sludge in bottom of a fork leg. I would get the bike in the air/ weight off the suspention and inspect for worn parts. My xj had a bit of head shake and was fixed by replacing head bearings/ they had a flat spot/ cupping if you follow me , in the race.And found forks not trued through the tripple clamps/ used the old " 1/4 " mirror on tube" I probable missed a few obvious solutions but i'm not jesus Christ... good luck and don't let go of the bars!!!

[prometheus578]

Ok, I'm curious

""""'used the old " 1/4 " mirror on tube" """
????
Explain that one, please.

[fxrer]

My 80 SG had a wobble that was bad at 80+ mph.

I hit a curb too hard once, and never gave it a thought (or didn't notice). New tires didn't cure it, so I checked other things. The manual shows how to check wheel "run-out" with a dial gauge. The lateral runout on my front wheel exceeded the allowable (2 mm) by just a little.

As the wheels are not serviceable, I bought one on E-bay for $10, and problem solved! Been running smooth ever since.

[superdave]

Prometheus

the fork tubes are secured at the top and bottom of the tripple tree, with a pinch bolt setup, if the top and bottom trippls arn't paralle, it puts the front axe out of plane with the chassis. The mirror is placed against the fork tubes between the botton tripple and the lower fork legs. the mirror normaly is almost flat and wont flex. if the mirror doesn't contact both tubes and wabbles the tube/s may be bent or out of alignment. To allign loosen the front axel and lower tripple pinch bolts and give the bars a slight twist.Retighten all pinch points and axel and re check. Its not all that hard to adjust but i'm not all that good with explaning things... wish i were as smart ar frado...from the "godfather" I would post pic's ! Hope this helps ya!

[Ken Talbot]

Excellent tip there, superdave! I can understand exactly what you're saying.

[superdave]

My 2 cent correction.

After pulling my old race notes I found that after I trued up the front forks that solved the high speed lean angle wobble I got on my 89 fzr6oo at bir turn 2. Flat no camber 130 mph right hanger that use to scare the he#@ out of me. So that probably wouldn't be the problem in a streight line wabble. Just a tracking issue. (would look like a crab going down the highway)

[prometheus578]

Thanks Super Dave. That's a great tip... as I envision it. I was trying to figure what the significance of the mirror was... say.. over a regular pane of glass. And to think that last week, when cleaning the garage, I almost tossed out three old boxes of those mirrored tile things that people stick to their walls! Finally found a use for them.

[superdave]

prometheus

Maybe I'm not the only pack rat out there. Heres another one, after I bored my ride out to 1179cc Iwanted to install k&ns and had a set for a old gsxr 750. but didnt want to spend any more money on new xj ones so I took the carb boots off my stock air box and swaped them with the ones on the on the gsxr's k&ns. they fit just fine. Now thats cheep !!!

[prometheus578]

SuperDave...
Anyone can turn a wrench, but only a true mechanic can improvise! (And understand the value of not throwing anything away.... provided that one has the space to store all that crap!)

[superdave]

prometheus

We might have to change your name to philosophe. opened up websters for some spelling and found it. I appreciate your kind words. Now nascar !! Later Bro !