Dirt bike throttle question

[AZRedhawk44]

The throttle sticks on my XR600.

I can push the throttle closed and it closes off fine, but the carb spring and cable aren't strong enough to do it on their own.

I read up that this is often caused by a kinked cable or too tight of a screw on the throttle housing on the handlebars, but I don't think that's the case here.

I disassembled this last night and it seems that my grip over the throttle tube has contracted leprosy.  It's shedding little bits of black rubber and those are working their way into the gap between the throttle tube and the handlebar.  After awhile these pieces of smut are turning into a tacky tar-like substance as the throttle tube rubs them into a gooey strip and embeds them into both contact surfaces.

I think this is what is causing the resistance that the carb spring can't overcome, not any kink in the cable.

I cleaned off the handlebars easily enough since those are aluminum, but the inside of the tube is...resistive... to giving up its deposits.  I just ordered a new throttle tube since they're only $10 or so anyways.  New grips to go with it as well.

The whole cause of this appears to be that the grip on the tube is longer than the tube itself.  This exposes part of the grip to rotational friction with the handlebar, wearing off little bits of it and leaving them nowhere to escape since the Acerbis bar-end/hand-protector caps off any escape point.

Should the grip be cut to only match the length of the throttle tube?

Do you agree that this is probably the source of the throttle binding, or is this a common occurrence in dirt bikes?

[charby]

How old is the grip on the bike, could just be age. Also a little silicon spray on the underside of the rubber will preserve it a little longer. You also live in a dusty environment oil and dust makes for a very sticky gummy situation over time.

[AZRedhawk44]

No idea how old the grips are, but they're old.  Splitting on one end, leave tacky bits of black rubber on my gloves.  Replacing them has been a to-do item on my bike refurbishment list since I got it.  But the throttle binding is something that has only developed over the last few weeks.

I think the split grip is also only a few weeks old, prior to that the grip had full exterior integrity.


Question:  from what I understand, it's conventional to use a glue when replacing grips on bikes.  You slide the grips on over the wet glue and it dries and they don't come off.  You have to cut them off.  However, when I search for "grip glue" on any of the motorcycle outlet places, I can't find anything.  What type of glue is used for securing motorcycle grips when changing them?

[Brad Johnson]

However, when I search for "grip glue" on any of the motorcycle outlet places, I can't find anything.  What type of glue is used for securing motorcycle grips when changing them?

Google it.  Only about 50,000 results.


Brad

[AZRedhawk44]

Now I see what's up.

Some previous owner cut the throttle tube down.  The outer edge of this throttle tube is all rough and looks like it was cut with a dremel or hacksaw or something.  Then someone else came along and put a standard length grip on top of this truncated tube.  That grip deteriorated and left gunk all over inside the tube over time.

New tube, new grips.  Life will be good.  New grip should fit perfectly on new tube.

[zahc]

He probably cut the end off to install handguards, which have to go into the end of the bar.

A new plastic tube will be great, but if you are feeling rich, Motion Pro used to make a teflon-lined aluminum throttle tube that was totally more valuable than you would think. Like buttah.

[Cliffh]

I've never used glue as such on grips, and I've replaced a lot of 'em.  Instead, I'll dilute some dishwashing soap with water, slather that on the bars and inside the grip.  Assemble while wet.  When dry, they stick.

[zahc]

I have extensive grip-installation experience from years of both dirt biking and BMX riding. Grip installation is a complicated art. Technique depends on application.

If you don't intend to get into dirt or water, you don't need any sort of glue. You can simply he-man the grips on, 'pop' them on by whacking the end with your palm (so the grip expands from air compression and walks on) or if you have an air compressor with a blowgun you can actually use the blowgun to create a film of air and the grip will slide on like butter due to the air film. If no water or dirt gets underneath, this is fine.

If you expect normal water and/or dirt, you need glue. If water or dirt gets under the grips they spin and that's annoying and/or dangerous. My favorite was always weatherstripping glue...made for that kind of thing and all. The downside is it's totally messy and takes a long time to dry. It also can make the grip fatter. Next up is super-glue. You are going to need a lot, like a bottle of 'medium CA' from the hobby shop. If you don't get the grip slid on before the glue sets, you are screwed. It dries instantly and works good though.

If you are into hardcore dirt biking, glue alone isn't enough. You have to use glue+safety wire; as many circles as you think you need. So water and dirt will get under the grips but hopefully the safety wire stops it from migrating under all the way.

[AZRedhawk44]

All the parts finally arrived yesterday.  Ended up using Gorilla Glue to secure the new grips onto the bike.

New throttle tube and grips solved the sticky throttle problem.  Nice and smooth roll-on now, much better control on this bike at low throttle now that it doesn't bind.