Vibration in handlebars

[rd2005]

Ok we got our son a used 08 Apex 90cc. It's stock & very clean & raced very little. With that being said now that we have owned it a couple of months we have begun to learn about these machines. We are having trouble with I think more than usual vibration in the handlebars. We made sure that the stock bars were not tightened down to tight & we have just bought a pair of Pro Taper SE 7/8's bars to hopefully help reduce the vibration along with Torc1Racing HotLap ATV grips that my son loves. Is there anything else we can do to help reduce the vibration? I'm just not going to put allot of $$$ into this thing until my son gains more experience in racing, but I want him to be as comfortable & safe as possible. I have also heard of putting caulking in the steering stem to help reduce vibration...has anyone ever tried that? We have not put the new bars on yet, but we wanted to hear from other folks first to see if we are headed in the right direction with this. Thanks!

[redonkulousruntsracing]

Just make sure that all mounting points are isolated. There should be urethane bushings in the stem, make sure that no washers or other hardware are not touching metal. Any metal touching metal will transmit vibration. A sure fire fix is a set of ATV Fourplay soft bars, no vibes and the flex of the bars helps so much in control in the rough stuff and they give on hard hits helping reduce injury in young riders.

[tyler70t]

We reduced the vibration by making sure the steering stem wasn't tightened too much where it mounts to the frame, helped us some because ours was way too tight........Jeff

[hwf-racing]

Sorry, but it's the nature of the beast, they vibrate! Your son will get use to the vibration. I put atv4play bars on and still vibrates through them. Wait till your front bumper starts to make noise. It is ear piercing:scary: Derek

[tyler70t]

Our front bumper was making lots of noise too. What we did was drill out the rivets and put it back together with rubber washers between the grill & bumper, worked great.........Jeff

[hwf-racing]

That bumper looks real nice!!!!

[selbygirl]

i put a set of anti vibe inserts in the bars on the one bike my boy likes them an the other bike has the flexx bars and he loves them inserts are cheaper then the flexx bars check all the nuts and bolts on the bike and motor mounts if ther lose may make bike vibrate

[rd2005]

Thanks for all the great feedback on this. We are currently tearing the bike down to bare frame to paint. Can't find any metal on metal but we did find 2 washers that we will replace with a rubber coating or a rubber type washer with them to help reduce vibration. We also put the Pro Taper High ATV bars on just to see if vibration was any better but it's the same. We did also find that the steering stem was waaaayyyy to tightened to the frame. We had to use a cheeter bar to help looses the blasted thing! So all in all we think we can better this issue when we put the bike back together thanks to your input! :) Will be posting new question here in a few about a coolant leak, Thanks again All!

[Hooligan]

I've heard of caulking in the bars to, never tried it though.

Is there a torque spec for how tight the steering components should be, or just "not too tight"? My sons is the same way, my arms were numb the first time I rode it lol ....until it started shooting coolant through the line above the radiator and never started back up :mad:

[rd2005]

Ouch Hooligan! Yeah the bars just personally vibrate too much. My son does not have that much issue with it but as his parents we try to make the ride as comfortable as possible & within budget. Both his parents raced in the late 90's & I remember the arm pump & fatigue from racing & we wanted that vibration gone! I know that like hwf-racing stated "it's the nature of the beast" but then again to have another mechanic from a rider in your kid's class walk up & touch your bars & say "God those are vibrating terribly!" Tells me I need to do something. I was hoping to find someone out there that put the caulking in the steering stem but so far have not heard of anyone! I agree with how tight is too tight? I am finding out that each machine has its preferred settings. Like someone tightened our axle nut just for example...it did not roll right after he tightened it until I loosened it up some but his son's machine same axle nut (stock) could handle the tightening he put on it. I am finding out its really trial & error on these mini quads. You just hope you don't screw something up! It's nice to have a place to go & ask questions & find folks that can assist or give you heads up on the general idea of what you're doing! :D

[tyler70t]

I filled the steering stem up with spray foam insulation but it really didn't do much for the vibration..........Jeff

[selbygirl]

www.vibranator.com this is what i put in my bars i think hot quads carry them thats who told me about the inserts

[Hooligan]

A stabilizer might help out, it cut down a lot of movement in my 450. Not sure the sizes of them, but I think Precision also makes anti vibe mounts for the bars now..of course, with most of these it's just a matter of throwing enough $$$ in them, which not many of us want to do.

I'm going to look mine sons over and see if I might be able to put thicker o-rings in anywhere to reduce dampen some of the vibration.

[rd2005]

Originally posted by Hooligan

I'm going to look mine sons over and see if I might be able to put thicker o-rings in anywhere to reduce dampen some of the vibration.

That's what I was thinking about doing was trying out o-rings. Anything has to help. I've decided not to try caulking at this time. Also going to see if I can put something around the area were the steering stem connects ( if you have a stock unit it's plastic red peice on stem) We'll see! I'll post updates if anything works. Thanks All for the advice & words of wisdom! :)

[selbygirl]

i seen cheaper anti vibe bar ends on ebay and bike bandit ther like 10 bucks and bike bandit has some reveiws on the product plus bike bandit will give you a extra 10% off if you are a ama or a atva member

[rd2005]

Originally posted by selbygirl
i seen cheaper anti vibe bar ends on ebay and bike bandit ther like 10 bucks and bike bandit has some reveiws on the product plus bike bandit will give you a extra 10% off if you are a ama or a atva member

Thanks for the info but I could not find any for ATV's. The one's on eBay are for street bikes & the same for Bike Bandit.

[FISH ON!]

What ever you put inside the bars have to be able to absorb the energy of the vibration. Foam or caulk doesn't have enough mass or weight to do that. Those inserts work because the insert is a weight that absorbs that energy. Fill the bar with sand and caulk the ends might work a little better than straight caulk but i still don't think it will give much improvement because you want that weight at the end of the bar where the deflection (vibration) is worst. My $0.02 worth. We went with ATV 4-Play bars and my son loves them. They are great for when your kid comes up short on a jump too........ I truly believe we have avoided a broken wrist with those bars!

[selbygirl]

if its a 7/8 bar it should fit like the ones on ebay i would go with the flex bars or the 4 play bars my boy loves his flexx bars he had a bad wreck at atco a few months back and got back on the bike and finished the race i really think the bars saved his wrist well that's what he told me i even emailed flexx bars and thanked them for a great product i have learned to spend money on the safety aspects of racing and not speed in the long run you save money and your child comes home safe take care tommy

[rd2005]

Thanks for all the info!

[coffing918]

try flex bars , our apex used to vibrate bad

[JIM GRACE]

If the exhaust header is resting on the bottom frame rail it will vibrate like crazy. Solution raise the front motor mounts.

[LT Bill]

if they would have balanced the crankshaft they wouldn't vibrate if you take time on next rebuild you will find that the crank needs to be balanced and welded. It will also help with the over heating problems. The vibrations are causing the cooling systen to develop cavitation bubbles. which starts an erosion of the aluminum in the head which plugs the radiator then the bike always runs hot. kind of a domino effect of troubles. If you fix the crank when you set up the bike it really makes a differance And there is no vibrations at all.