Stretching an airbox boot

[Dammit!]

I'm giving it another shot. Didn't have any luck last time but now I'm armed with a heat gun.

So yeah, the boot that goes from the airbox to the carb on my R. It's gotten really stiff in it's old age (no viagra needed!) and I can't ever manage to get the stupid thing over the bigger carb (38mm). I tried sticking a Corona bottle in it and soaking it boiling water and that didn't work. Left the bottle in there for a week and that didn't work. The bottle is pretty much exactly the same diameter as the carb. This time I finally have a heatgun. Never used one before. It's got 650 and 1000 degree settings on it. Only tried the 650 degree setting so far. I don't want to melt the thing or cause the bottle to break. Probably being a little over cautious there though.

Anyway, what's the best way to get this thing to actually keep the new shape? I figured just repeating the process of heating it up with the gun, then letting it cool a few times. It's so freakin' hot here though that it won't really cool down unless I stick it in the fridge. Would that cause it to crack?

Pointers appreciated. :TrikesOwn

[ATCnut]

IMHO, you want to use the heat gun to get it hot enough to be soft. I would carefully use the gun to heat it slowly. Once it is hot enough to get soft, using a pair of gloves you should be able to streach it over the carb. Once it cools down it will be tight as hell and on there really good.

[Dammit!]

Part of the problem though is I need to be able to easily get this thing on and off. I want it loose enough that I don't have to fight with it every time I need to put it on. I do a lot of adjustments out on the trail so heating it up every time is not an option.

I just finished heating it up for the third time on the 1000 degree setting. Now it's sitting in the house to cool off real good. Might stick it in the fridge once it's down to room temperature. I'll probably repeat this process a few times and see if it holds the new shape or not. Unless someone has a better idea? I'm all ears (err... eyes).

I might get it hot and stretch it out with my hands as well like you said. Kinda worried that I might cause it to tear though.

[jeswinehart]

hey ,,, you guys remember the old post along time ago about what part of a trike do you hate working on ???
if i remember correctly ,,,, air box boots was the hands down winner of being the most P.I.T.A. part to work with. i know it got my vote of being so.

john

[bigredhead]

How much extra do you need ? half inch .. ???

How thick is the existing rubber ? might be able to shave a mm or 2 from the inside diameter if you have enough material to keep it strong enough not to tear.

Any chance on making a collar to fit over both the carb and the boot ? You could have a metal ring inside the boot to keep it from squishing and use pipe clamps over the boot cover...

i dunno.. just thoughts.

[wheelie king]

If boiling water will not do it, then the heat gun may not, either. If all that fails, try a custom application made from cuts of hose.

[bigredhead]

on .org someone posted the result of submerging rubber in kerosene and it went from a shrunken state back to original.... is yours shrunk or just too small because of a bigger carb ?

[Dammit!]

3legged dog used a piece of rubber connector to do this (and he actually sent me one) but for the sake of appearance I really want to get the boot on there if I'm gonna use one at all. I have been just using a Uni clamp on right to the carb since I got the 38mm carb but I'm really wanting to go back to my K&N inside the airbox. Not so much for performance reasons but versatility and a little bit extra dust protection. Would be nice to have the option of just putting the lid on if it's a little wet out. Can't ride in even slightly wet conditions with a clamp on.

I seem to be making progress. I pulled the bottle out and it seemed to hold it's shape pretty well this time. Not done yet though.


on .org someone posted the result of submerging rubber in kerosene and it went from a shrunken state back to original.... is yours shrunk or just too small because of a bigger carb ?

Bigger carb.

[wanta86r]

i got my 38mm a/s from esr for 220.oo with a carb adapter ring that is pressed into the carb and eliminates this problem

[Dammit!]

i got my 38mm a/s from esr for 220.oo with a carb adapter ring that is pressed into the carb and eliminates this problem

Do you know if they sell the ring seperately?

[wanta86r]

Do you know if they sell the ring seperately?

i think you'd have to send them your carb unless you have a machine shop you trust. i think there is some minor machining before it can be pressed in. it is very slick however

[Dammit!]

Well if this don't work I'll definitely keep that in mind. Thanks for mentioning it.

[wanta86r]

Well if this don't work I'll definitely keep that in mind. Thanks for mentioning it.
no problem man. it just made sense to me because you always have to take the air boot off to rejet it, and i hate fighting the rubber to get it back on. it does work great and i highly recommend th esr pipe as well

[Red Rider]

Part of the problem though is I need to be able to easily get this thing on and off. I want it loose enough that I don't have to fight with it every time I need to put it on. I do a lot of adjustments out on the trail so heating it up every time is not an optionWhat kind of adjustments are you doing on the trail that you need to remove the airbox boot from the carb? If it's just jetting changes, try buying different tools that allow you to get to the jet without moving the carb. If your messing with the needle clip position, usually just loosening both carb boot clamps & twisting the carb will provide enough clearance to remove the carb cap & slide. If not, simply partially remove the gastank to provide enough room. Unless absolutely necessary, I won't remove the airbox to carb boot in a fully tooled garage, much less on the trail with limited tools available. All of the above options are usually easier in the long run, even with the stock size carburetor.

[hrc85250r]

dude, just have someone push the boot towards the carb for you while you work it on with a screwdriver....i have my pops help me out and it takes 1 minute max...i dont even lube it up or anything, and i dont even scratch or rip the carb or boot...just dont be a puss with it...o ya, i have a 38 a/s.....

[Dammit!]

I can change the main jet and clip by just turning the carb on an angle a little bit. If I stretched the thing over the carb the way it's been it would have been so tight I doubt it would have even turned without taking the airbox off so the hole boot could turn with it. I damn near changed my pilot jet when I went to Cinders though. I resisted the temptation but that's the only way it would have ran completely right up there. That 7000 feet elevation is a PITA.

Bottom line is, I just want the stupid thing to go on and off easy. :lol:

I think the repeated heating and cooling is working. I'll try putting it on in the morning and see how it goes. I just hate the idea of having to take it off on the trail (for whatever reason) and not being able to get it to go back on. Hell when I finally got the bike running again a few months ago, that was the hardest part of the entire rebuild was getting that damn thing on there. And that was with the stock carb! :mad:

I checked out the one KASEY has on his 500R and mine is definitely way stiffer than normal. Unbelievable pain in the neck to work with. Really aggrivating for such a stupid thing. It's in great shape other than that. No cracks or anything.


dude, just have someone push the boot towards the carb for you while you work it on with a screwdriver....i have my pops help me out and it takes 1 minute max...i dont even lube it up or anything, and i dont even scratch or rip the carb or boot...just dont be a puss with it...o ya, i have a 38 a/s.....

I live alone and never have anyone around when I'm working on my trike. I'm telling you guys this boot WOULD NOT go on a 38mm carb before I started doing this. I couldn't even get it to go on when the carb was off the trike. It's not all soft and rubbery anymore. I'm sure it would have been easier with an extra set of hands but I'm not gonna have somebody drive over here to help me with something so little. If I can't stretch it to the point that it slides on and off there easily I'll just keep using the clamp on and steering around puddles. ;)

[Mr. Sandman]

Dammit, Maybe you need to drink another brand of beer! Seriously, I used an MGD bottle and had no trouble with mine at all. Or, if you have the time, pull the carb and boot completly off and put it together off the bike. This way you can do it easily and then let it set for a week or so and hopefully by the time you try to remount it, the boot will have the new shape/size it needs and will assemble easily.

[Dammit!]

Done!

Corona bottle + heat gun = A WINNAR IS ME!

Slips right on now. No fighting with it at all. I even had it off the bike and without the bottle in it for about an hour and it held it's new shape and went right back on again.

So much trouble over such a dumb thing. :wondering :mad: :lol:

Edit: for people using the search in the future, all I did was grease up a corona bottle, put that into the boot (neck first), used the heat gun on the 1000 degree setting to get it almost to the point of melting but not quite. Let it cool down to room temp, then stick it in the fridge for a while, then back to room temp and then heated again. Rinse, repeat. Did that three times.

[nimda78]

great closing! great info too

[TeamGeek6]

Try heating it in an oven at 175*F - 200*F, that will heat it evenly so it doesnt tear. Most plastics dont like more than 250 - 275*F