Author Topic: Headshake and tach (Read 15382 times)

darthbane71 · « **on:** April 03, 2016, 12:44:12 PM »

Hey everyone. Sorry in advance if this has been discussed before but I couldn't find anything about it. Just got my K75RT going for the spring. The only new addition to the front end is a new front rim. However it's developed a nasty bit of headshake around 40ish mph to about 48mph. Is this a balancing problem? Wheel bearings? Headstock bearings?

Also, unrelated, my tach needle sticks in direct sunlight, I've heard mention of other members regluing the backing paper to the plate but I'm curious as to what type of glue would be good for that?

Thanks!

johnny · « **Reply #1 on:** April 03, 2016, 12:59:43 PM »

greetings darthbane71...

what tiors you using... whats their date code... post up photos... lets take a look...

did you put your old tior on your new rim...

a new rim must be checked for whack... take a straight edge from fork tubes to the rim... spin it... should be the same both sides all the time...

if its whack you will be able to see it... if whack it needs to go to a rim straightner... if not whack its proally the tior or pressure or outta balance...

wheel bearings usually dont wear like that... steering head bearings usually dont wear like that...

so... prolly the wheel the tior the balance or all three...

note... whack in the back can do that too... bad rear tior or shock or rim can do that too... butts prolly not in your case if you told us the whole story...

you did tell us the whole story didnt you...

j o

Laitch · « **Reply #2 on:** April 03, 2016, 01:43:26 PM »

Sometimes trying different search word brings results, darth. If you had used "wobble", this would have appeared.

You need to work your way through a diagnosis of each element as johnny suggests. Tire pressure to spec? Rims undamaged? Tires upcupped? Steering notchy, or smooth with the front end suspended? Rear shock weak? Fork oil amount and condition correct? Fork tubes at same length? Fork tubes in correct alignment?

For faceplate adhesive, a thin application weatherstripping cement should work.

darthbane71 · « **Reply #3 on:** April 03, 2016, 02:11:44 PM »

Wow, thanks for the replies guys. I will do a full check on everything when I get home. The rim is straight, and the old tire was mounted on the new rim, but I had no issues with the tire previously and it only has about 3k miles on it.

Both tires are Michelin pilot active.

Martin · « **Reply #4 on:** April 03, 2016, 03:03:30 PM »

Check to see if the tyre is seated all the way round.
Regards Martin.

johnny · « **Reply #5 on:** April 03, 2016, 05:02:16 PM »

yawl...

who mounted it... did they balance it... is the lactation arrow pointing the right way...

loosen the pinch bolts big and loosen the axle little... then pull the front brake lever and bound the front end... this will getts the wheel in its proper place on the axle... then tighten the axle... then pull the front brake lever and bound the front end again... then tighten the pinch bolts...

what else did you do... why the new rim... was this thing wrecked... whats the whole story...

j o

darthbane71 · « **Reply #6 on:** April 03, 2016, 05:05:45 PM »

The guy that mounted it balanced it. He's the guy I go to for all of my bike tires.

I'll give that a try. It's possible I didn't seat the axle right.

And it hasn't been wrecked to my knowledge. It's got a clean title and no significant damage that would suggest a wreck. However when I first got the bike Mitch (guy from the shop that mounts my tires) told me the rim was bent but I decided to give it a go anyway. It lasted a while but would go flat every few days so I bought the new front wheel, painted it and installed it after swapping over the tire.

johnny · « **Reply #7 on:** April 03, 2016, 06:32:29 PM »

so now we are getting more of the story... tell us more...

how many miles did you personally have on this moto before replacing the rim...

post of some good photos of that front tior... whats the date code on that tior...

a rim bent bad enough not to hold air means to me that there is most likely more damage... think about it... thats a tremendous hit to cause a tior not to hold air... and if that tior was on the rim at the time im thinking it could be whack too being bias ply and you just caints see it...

darthbane71 · « **Reply #8 on:** April 03, 2016, 07:40:06 PM »

Okay, so here's the full rundown. I didn't have my paperwork and I was at work earlier so I couldnt give full details.
I bought the bike last august at 35,000 (it's now at 38,559 so i've ridden approximately 3,500 miles with it.) for the 7ish months I've owned it I've ridden approx 3,500 miles. All of these miles were on the original front wheel and the tire I mounted when I bought it. When I put the brand new tires on the original rim, my mechanic told me that the rim was bent and that it might not hold air. I decided to see if it would work and I had zero issues with it all season until early this year (Middle of February) that the tire ran flat, and ever since then, it had run flat after 2-3 days. I dunked it in a bucket of water to determine where the leak was and it was at the point of the bend.

Then I purchased a used rim that was white, repainted it, and installed it, putting the tire that had around 3,500 miles on it (still plenty of tread and no cracks or issues with the tire itself. It was mounted and balanced professionally.

When I purchased the bike I changed the tires, brake fluid, battery, and rebuilt both master cylinders. I also changed the engine oil, trans oil, and final drive oil. I flushed and refilled the forks.

When I started experiencing the issue the only thing that had changed was the rim, and the brake pads.

I know that's a lot of reading but you wanted the whole story, hope this helps!

Here are the pictures of the rim:
http://i1378.photobucket.com/albums/ah99/mike_smith46/Mobile%20Uploads/IMG_20160403_180551897_zps8xmooqiy.jpg

http://i1378.photobucket.com/albums/ah99/mike_smith46/Mobile%20Uploads/IMG_20160403_180559764_HDR_zpstmykjwrt.jpg

Are either of these the tire code?

http://i1378.photobucket.com/albums/ah99/mike_smith46/Mobile%20Uploads/IMG_20160403_180658157_HDR_zpslsykdmrj.jpg

http://i1378.photobucket.com/albums/ah99/mike_smith46/Mobile%20Uploads/IMG_20160403_180703292_zpsrel4y0tl.jpg

Scott_ · « **Reply #9 on:** April 03, 2016, 07:59:16 PM »

The date code looks to be "1715" ie 17th week of 2015.
So it is just less than a year old.

darthbane71 · « **Reply #10 on:** April 03, 2016, 08:02:37 PM »

okay that's what I thought, so that's not excessively old right? I've never had tires for this long. Also, I tried what Johnny suggested with holding the brakes and pushing with everything loosened and it had no effect.

Laitch · « **Reply #11 on:** April 03, 2016, 08:27:25 PM »

Based on my understanding of what you have written, I think the tire has been deformed by lack of rim support in that portion of its sidewall and bead, and will be a problem from here on regardless of its date of manufacture. If it were my bike, I'd mount a new tire.

darthbane71 · « **Reply #12 on:** April 03, 2016, 08:34:17 PM »

Is there any way to test that? That's a $135 fix and I'd rather not just throw money at the problem.

Not to say my safety and peace of mind isn't important, if it's necessary i'll buy a new tire, but I'd rather not if I don't have to

johnny · « **Reply #13 on:** April 03, 2016, 08:34:47 PM »

yawl...

i asked the donald... he said new tiors to make your motobrick great again...

if you wait 4 years all motobrick tiors will be made in the usa...

he also suggested to make sure you dont have warped rotors... and that your lactation arrow is pointing the right way...

j o

darthbane71 · « **Reply #14 on:** April 03, 2016, 08:37:25 PM »

Well tires seems to be the consensus, so I'll check the rotors to be sure but I'll order some new tires then. Judging by the weather this week I have time to get them shipped.

The Mighty Gryphon · « **Reply #15 on:** April 03, 2016, 08:57:14 PM »

Before I dropped another $135 on a tire I would take the wheel off and take it to another shop or two to have the balance checked. The guy who did your tire originally may just have had a bad day on your tire. It's possible that he put the weight in the right spot on the wheel, but on the wrong side of the rim. Happened to me when I balanced one of my front wheels. I put all the weights on one side. dumb chit...

Another option may be to get balancing beads if you can find a place that will put them in for you.

Also, have you done anything like lowering the front end?

darthbane71 · « **Reply #16 on:** April 03, 2016, 09:00:22 PM »

No, I haven't touched the front end other than changing the fork fluid and that was right after I purchased it.

johnny · « **Reply #17 on:** April 03, 2016, 09:35:01 PM »

i have had many wobbles over time... different motobricks... different tiors... every time its been a bad rear tior causing a front wobble or a bad front tior causing a front wobble...

you can put a bottle of this in there and see if it smooths out... i used to run this stuff all the time on unbalanced rims... i can say it absolutely works... butts you know its prolly the tior...

j o

Laitch · « **Reply #18 on:** April 03, 2016, 10:36:40 PM »

Gryph's and johnny's suggestions are cheaper than a new tire, for sure, and won't hurt to try.

Martin · « **Reply #19 on:** April 03, 2016, 10:50:25 PM »

+1 Johnny sounds like a bent rim have you checked it as suggested.
Regards Martin.

darthbane71 · « **Reply #20 on:** April 07, 2016, 04:30:00 PM »

okay, update. I had the tires/rims rebalanced, and reseated the axle and it hasn't made a difference. There's no noticeable wear or issue with the headstock bearings. Next I'm going to check the rim/wheel bearings

TrueAce · « **Reply #21 on:** April 07, 2016, 04:49:42 PM »

Air pressure, over or under, can induce wobble. Check the fork oil for differing quantities from spec, since you changed that, too. A disproportionate rebound in one fork will definitely induce wobble. A warped (out of round tire carcass) will, too.

darthbane71 · « **Reply #22 on:** April 07, 2016, 05:04:06 PM »

Air pressure is good. How would I go about checking the fluid amounts? I've only ever emptied and refilled. The tire is last on my list but I may buy a new one

TrueAce · « **Reply #23 on:** April 07, 2016, 05:39:18 PM »

"I flushed and refilled the forks. "........................................in your post you said this, so I am suggesting the fork oil could be imbalanced, possibly one seal leaks, creating disproportunate rebound rates. It's either the forks, the wheel, or an out-of-round tire. where did you source the new tire? Spend what you need to for the wobble to go away, it's major unsafe at speed, and the typical ER bill for simple stuff will cost you a thousand easy.

darthbane71 · « **Reply #24 on:** April 07, 2016, 05:51:18 PM »

You're right. It's not to say I'm not willing to pay what it takes to make it safe, I'd just like to eliminate the options before buying a new tire.

I will check the forks although they do not appear to be leaking. Also, I didn't have problems with it after I did the forks. It was fine all season.

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Author Topic: Headshake and tach (Read 15382 times)