Curing handle bar vibration?

big_bore_500 · Post by **big_bore_500** » January 18th, 2009, 12:45 pm

Hope this is the right section to post this question. I have set up my AFC for ice racing this winter 14/43 gearing is giving me 87 mph at the end of the 1/8 mile straight . My problem is the vibration through the bars, my hands are shot after 3 laps. My ? is how much do the Flexx bars reduce handlebar vibes? and any other suggestions to smooth this thing out woud be greatly appreciated.

Post by **AlisoBob** » January 18th, 2009, 2:10 pm

teemtrubble · Post by **teemtrubble** » January 18th, 2009, 2:17 pm

Your on a roll today...

big_bore_500 · Post by **big_bore_500** » January 18th, 2009, 2:18 pm

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Bottom end? Highly doubtful considering the motor has less 20 hours since being completly rebuilt. (meaning every bearing replaced) but thanks for the suggestion. Any others?

Balaclava · Post by **Balaclava** » January 18th, 2009, 3:49 pm

i don't know man...but riding in the winter on ice is a fuuuckin blast...

MICK · Post by **MICK** » January 18th, 2009, 4:14 pm

big_bore_500 wrote:Bottom end? Highly doubtful considering the motor has less 20 hours since being completly rebuilt. (meaning every bearing replaced) but thanks for the suggestion. Any others?

I understand that but suck a little dirt in one time and you can kiss that fresh bottom end goodbye. 20 hours is more than enough time to eat a little dirt here and a little dirt there you know? Good OEM bearings are always a good place to start. I mean, if the motor vibrates too badly nothing you can bolt on is going to change that. Live with it the way it is...or it's bout time to split cases again

100hp honda · Post by **100hp honda** » January 18th, 2009, 4:40 pm

from what ive seen, crank bearings typically last for many years if they dont get dirt in there and have good supply premix oil. with only 20hrs i highly doubt its bearings but its possible i suppose. bad clutch bearings could be part of the problem. another thing to look at is your chassis. you put a motor in there that aint supposed to be there. like putting a cr5 in qaud chassis, for some reason the vibes are horrible. i havent heard anyone complain about vibes with AF conversion but you have to expect those sort of problems when you mix and match parts that werent designed for each other. kind of like clearanceing the crankcase for the rear spring, and heat gunning the tank, and repositioning the radiator spouts, and changing coil location, and raising the Y, and using plexi glass to hold the airbox together

ShanMan · Post by **ShanMan** » January 18th, 2009, 4:47 pm

best way to cure the vibes is to ride a CR250R...LOL. Seriously though, the Flexxbars really do work, but are pretty pricey obviosly.

100hp honda · Post by **100hp honda** » January 18th, 2009, 4:53 pm

ShanMan wrote:best way to cure the vibes is to ride a CR250R...LOL. Seriously though, the Flexxbars really do work, but are pretty pricey obviosly.

i kind of agree because the cr5 does vibe alittle but if the vibration gets to the point of hurting your hands or arms there is definatly a problem somewhere. without seeing the bike its hard to say where the problem is. when i first bought my '00 steely it would make your hands numb after about 1 hour, i replaced every bearing and it fixed the problem. ya it still vibes alittle but you can ride it all day at glamis without hands going numb

JBaze · Post by **JBaze** » January 18th, 2009, 5:48 pm

I used to put a piece of rubber tubing through my bars. Can't say wether it helped or not, I still wound up with carpal tunnel syndrome! So I just learned how to hang on with my knees!

lewisclan · Post by **lewisclan** » January 19th, 2009, 6:59 am

I got a 2 bikes with flex bars they where hard to get use to but do work

oggo69 · Post by **oggo69** » January 19th, 2009, 10:25 am

i know this might sound a bit off , but did u try and bar weights ?? they will look odd on a dirtbike , but they have their purpose

Post by **MojoScojo** » January 19th, 2009, 10:38 am

JBaze wrote:So I just learned how to hang on with my knees!

IF you are sitting down, you should be doing this anyway. Relax your grip on the bars and don't rely on your arms / hands. Use your core muscles (abs). You'll last a lot longer and be far more balanced.

redrocket190 · Post by **redrocket190** » January 19th, 2009, 2:54 pm

You can fill the bars with silicone, sand or buy some inserts from Faast Company. Flex bars are there to serve a different purpose but they will damp out the vibration. Loosen your grip.

I recommend you ride an air-cooled 480/500 for 45 mins and then your bike will feel just fine. It's all relative.

big_bore_500 · Post by **big_bore_500** » January 19th, 2009, 4:05 pm

Am I right in thinking that the aluminum frame transfer more vibes than the steel frame does. No past experience, when i bought the '86 the motor was out before I ever rode it. Like to here some replies from the guys that have SMed their bikes to see if they are experiencing the same problems cause I know not to many dirt guys are running 14/43 gearing and doing 90 mph on a regular basis.

britincali · Post by **britincali** » January 19th, 2009, 4:08 pm

big_bore_500 wrote: cause I know not to many dirt guys are running 14/43 gearing and doing 90 mph on a regular basis.

15/46 on my nitrous bike

I filled the bars on my AF with bathroom caulk (silicone) and it felt better.

Balaclava · Post by **Balaclava** » January 19th, 2009, 4:45 pm

everything feels better filled with caulk to you though brit...

JBaze · Post by **JBaze** » January 19th, 2009, 5:42 pm

MojoScojo wrote:
JBaze wrote:So I just learned how to hang on with my knees!
IF you are sitting down, you should be doing this anyway. Relax your grip on the bars and don't rely on your arms / hands. Use your core muscles (abs). You'll last a lot longer and be far more balanced.

Years and years of Belfair singletrack taught me that one!

100hp honda · Post by **100hp honda** » January 19th, 2009, 11:13 pm

britincali wrote: I filled the bars on my AF with cock and it felt better.

lewisclan · Post by **lewisclan** » January 20th, 2009, 10:36 am

100hp honda wrote:
britincali wrote: I filled the bars on my AF with cock and it felt better.

I knew that was going to happen

Post by **AlisoBob** » January 20th, 2009, 10:44 am

Brit told me he liked his hands going numb.... its how he invented " The Stranger"...

http://www.urbandictionary.com/define.php?term=stranger

ShanMan · Post by **ShanMan** » January 20th, 2009, 12:35 pm

for what's it worth, I do not believe a properly tuned 500 in an aluminum chassis will transmit more vibration than an equally prepared steelie. I thought all 500's shook hard until I rode AlisoBob's bike at Jawbone....as most of you know, he is a stickler for crisp jetting, etc. and that bike was flat out buttery...it wouldn't have mattered if was bolted into a Huffy.

That said, my last 500 had the bars filled with silica sand and the ends sealed with caulking, and it worked pretty well....worth the 1/2 lb. of sand. Probably the only time having sand on your caulk is a good thing.

dannygraves · Post by **dannygraves** » January 20th, 2009, 1:01 pm

My gen-4 vibes like a SOB, but I know the cause, the rod bearing was a little lose, not enough for me to justify holding off on putting the motor together until I could buy a brand new crank (like I am doing for the gen-3) but enough to make the vibes a problem for any girly man who might ride my bike

my gen-1 doesn't vibe nearly as bad, but I still get the hands numb rollin' bowls at dumont. I also know whats wrong with that one... it has a hotrod kit which is fine, but I didn't realize until my last time having it apart that when my main bearings failed (sucked in sand) the crank journals wore down. I had the hotrod kid installed while I was replacing the mains and the crank slid back into the bearings w/o any resistance. So the crank is allowed to move just a little independently of the bearings and this causes my minor hand numbing.
the fact remains the crank is a big heavy off balance peice that rotates really fast... if you have a vibe problem, that is where you should look.
the cr500 is a freaken ass reliable SOB and will run with f-ed up parts for a long time, but that doesn't mean they don't have to be replaced.

south central hoon · January 20th, 2009, 1:11 pm

dannygraves wrote: the cr500 is a freaken ass reliable SOB and will run with f-ed up parts for a long time.

yup.

Post by **AlisoBob** » January 20th, 2009, 1:13 pm

Brit rode all through AZ with a shattered piston, failing tranny, massive and cooling system corrosion.

He never suspected a thing....

BannedCR500Riders.com

Curing handle bar vibration?

Curing handle bar vibration?