DIY carb boot, advice welcome

[Gripit'n'ripit]

I started this thread awhile back, but lost it in the crash.

The carburetor boot on my 250R is getting pretty riddled with cracks and breaks, repairing is getting pretty ridiculous, and a new one is being difficult to find without paying $$$. For a quick fix i cut off the ring that meets the carb, and shimmed it into a boot for a different machine. It worked OKAY for a bit, but I need something more reliable and permanent. Still has chronic air leaks and the gas is eating away the gasket seal (didn't say it was a GOOD idea).

Made a new boot out of stainless, but I'm worried it'll be more trouble than it's worth. Biggest concern is the new boot's a pipe that meets to a flat surface instead gradually flaring out to meet with the motor.

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Anyone try this before? Will this just kill the machines performance? Kill the machine? Re-tuning or jetting of the carb? Better/cheaper/ easier options?

[fabiodriven]

What you've made does look like it may affect your performance, but it's a damn good effort nonetheless.

If you got a bit fancier with your fabbing, I bet you could replicate that rectangular/tapered shape the original boot has. Then you'd never have to worry about it again.

All in all, nice effort.

[just ben]

jeswinehart has a thread up now about the different resins used to make parts and said he is going to put up info on the mold making.

[Mosh]

45 bucks is cheap for a intake built by the pros.


http://www.ebay.com/sch/i.html/?_nkw=250r%20intake%20upp&redirect=mobile

[fabiodriven]

45 bucks is cheap for a intake built by the pros.


http://www.ebay.com/sch/i.html/?_nkw=250r%20intake%20upp&redirect=mobile

Well that right there pretty much solves your problem.

[Gripit'n'ripit]

My carb is a 28mm. I should probably just upgrade my carb to a larger and more common size and a new boot.

[Gripit'n'ripit]

So I cut the pipe down and the boots installed. Connected the carb using a piece of filler hose for a cars gas tank.
No problems with air leaks, holds study enough.
Kills the throttle response a little. Need to do some carb adjustment, doesn't idle very well, guess i should be riding and not sitting.

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Still looking to upgrade. Anyone have luck using a flat side from a CR250?

[jeswinehart]

Don't know about the carb question but will say I too am very impressed with your fab skills.
Sure wish I could weld like that ~ drool.
Hats off to you Nick, darn fine work !

john

[MTS]

That large long gap between your piston intake and carb is whats causing the crapy low speed performance too much volume not enough pressure difference to pull/ push the fuel in, shorten it up as much as possible...should smarten it up on the low end, nice work!

[Gripit'n'ripit]

I'm not that good a welder. Friend helped me, and that didn't come out nice until after the 2nd, 3rd, and 4th try. Have some other failed attempts sitting on the shelf. A good learning experience.

Shortening the distance makes sense. I'll have see what imporvements can be done!

Still gonna try to upgrade. Have a CR250 flat side with a decent boot. Gonna try to put it in this week. Not sure if i'll be able to get used to a twist throttle. Which may lead back to the current set up (just shorter) :)

Thanks for the feedback guys.

[MTS]

Think you might find with the larger carb it will get worse...with the long tube, mikuni makes rubber intake flanges for carbs...if you can weld up a flange it should make life a bit easier,,check out sudco's website

[Ranvier]

I'm bumping this thread because all my 350x airbox/carb tubes are short. I have done multiple searches and tried a heat gun and boiling. The wintergreen oil treatment made them more pliable but they are still a touch short and after a good jump, they pop off. Next would be notching the airbox or moving the mounting tabs but I was thinking even a very small 5mm shim between the intake and rubber carb boot would make a difference. Obviously, I don't want to hurt performance but all the used tubes I am buying are still short. Any thoughts guys?

[yaegerb]

I'm bumping this thread because all my 350x airbox/carb tubes are short. I have done multiple searches and tried a heat gun and boiling. The wintergreen oil treatment made them more pliable but they are still a touch short and after a good jump, they pop off. Next would be notching the airbox or moving the mounting tabs but I was thinking even a very small 5mm shim between the intake and rubber carb boot would make a difference. Obviously, I don't want to hurt performance but all the used tubes I am buying are still short. Any thoughts guys?

what do you mean they are "short" Are you referring to the distance between the airbox bell on the carb and the air box is to long, making your OEM boot to short? If so, is this because you are running a different carb?

[Ranvier]

what do you mean they are "short" Are you referring to the distance between the airbox bell on the carb and the air box is to long, making your OEM boot to short? If so, is this because you are running a different carb?

Stock carb. Yes, the distance you described is too long. Out of four boots, I made one work but had to pull the carb back from the intake a little so the carb (engine side) no longer sits in the flange of the rubber intake boot.

[yaegerb]

Stock carb. Yes, the distance you described is too long. Out of four boots, I made one work but had to pull the carb back from the intake a little so the carb (engine side) no longer sits in the flange of the rubber intake boot.

What isn't stock then? If everything is oem from head to airbox, everything should work perfectly. Do you have an aftermarket intake boot or aftermarket airbox, or????

[Ranvier]

I think with age they dried out. All stock. I have two riders and two parts 350x's they are all the same

[yaegerb]

well, that's interesting. I would say keep trying new ones until you get one to work and fit tightly, or check a parts fiche to ensure nothing is missing in that system.

[Gripit'n'ripit]

Just a thought, I regularly let my rubber parts, especially carb boots, sit in brake fluid to condition them. I'll leave a boot submerged for a week, and it will be significantly more pliable. It minimizes cracking also. Just my 2 cents