carb boots
 

Has anyone had any trouble with aftermarket carb boots possibly on wrong angle or shorter than original boots?

the rubber air intake are 5mm short - alignment indicators are lined up with airbox notches...

Cheers

Funny, I just replaced my XT600Z carb boots (intake) with aftermarket ones today.
They fit perfectly. They have 43F marked on them as well as 1VJ.

Regarding angle, make sure the right one points outwards. Mine went outwards by 1mm but it's hard to see.
I have the vacuum operated ones. That vacuum tubed one goes on the left


:oops2:
edit: i just realized you are talking about carb<>airbox?.. since you are talking about the alignment...
Sorry can't help you there. Still using the stock ones

I brought the cheapest one from aliexpress and found the clutch side boot not as angled and looks straight. The previous set had 43F marked on them slightly longer but didn't last long before the rubber separated ..... I loosened the airbox bolts and managed to find a couple of mm just enough to clamp the ducts..... possibly the age of the rubber ducts shrinking..

Cheers

guess you get what you pay for :)


i had luck with after market boots from ebay.de, cheaper than OEM but not dirt cheap as aliexpress....


and no, there's no way carb boots will shrink 5mm... worst is they harden to rock state, but certianly no 5mm shrink, sounds like wrong boots to me

btw, few months ago i've met one guy, who used to ride ~90's xt600 during couple years.
he said that when he had one of that boots failed, he removed both, tore rubbers away and reshaped carb looking sides with tig weld to create cylindrical elevation, and, as he told, he got a "lifetime solution" about them just with some rubber tube of proper diameter and thickness..
and he sad that he hasn't noticed any later issues with performance (my question was about an impact of possible changes in gas flow through that improvised routes).

so, i plan to try his method when the time will come to change my boots. it will be well less than half price of good quality aftermarket boots.

my 92 is still on originals, feel soft and supple... maybe im lucky...but even if you had to change them every 5-10 years, sounds total overkill to me.... and welding the carbs (if i understood right) has a good chance of distorting the bodies.


all my race bikes have custom manifolds for flow, but all i do is turn on the lathe an adapter to fit a cylindrical rubber to the head (sudco has a range of sizes), never had to weld carbs or head

sorry, my explanation of that guy's solution was far from perfect.
he didn't welded carbs at all, just reshaped lower (i.e. front) metal parts of the manifolds and then welded few mm rings (pieces of the metal tube, i guess) with the same inner diameter as of manifold.
and then he used pieces of the rubber tube between that new rings and carb body, clamped them on the both end.
so he still had rubber between engine and carburetors, something like a diy replica of the original manifolds.

nice to find out that sometimes manifolds last so long.
in my case, bike came with aftermarket ones, which were about to dissolve.
replaced them twice, with also aftermarkets, first pair lived 2 or 3 years, now running with another pair since last year, so far they look good and soft, but I see some cracks are about to develop sooner or later.

ok, thats more like i do....


but you should use universal rubbers made for carb manifolds that have a smaller diameter step in the middle. using a generic tube there will be an ugly step between carb and holder that will hurt flow at full throttle.

If you ride at half throttle most of the time, not a big deal :)


check the sleeve rubbers at the bottom...


http://www.allensperformance.co.uk/c...ormation-page/

Why would a generic tube have a step? I don't understand? Some more explanation would be great. I bought non-OEM ones and they seem identical

yes, and it's quite logical that significantly altered passage will have at least some impact on the flow.

well, luckily, i've got a clear example in my local scrapyard :)
- here's the cross-section of one of my late boot.
https://i.ibb.co/fqQJgb5/c.png
inside the metal, (22mm and on) it goes straight.
and there actually is something like a step, starting after the groove, ~13mm and on.
if i correct, carbs go deep all the way until the step and result will be smooth passage, which will not be easy achievable using a generic rubber tube.

thanks for one more useful link :)

Very true.... made the rubber air ducts stretch and clamped to carbs...still not perfect but its holding... I will need to keep an eye on it...

I have thought about this... it's never nice welding contaminated alloy then not knowing how much it's going to distort... have to reface it and cut a o-ring groove?

Easier to start from scratch with stainless... I haven't measured the diameters but I imagine there must be tube out there close enough.... I guess there will be possible internal steps that may disrupt the air/fuel flow....trial and error I guess...

according to what i've heard, he had used same metal bases, so obviously he already had grooves and o-rings.
and despite of that guy's mention about no concerns with performance, so far it's an open issue - point is that passage must me as smooth as possible.
original cross-section shape (even though without a bead) must be somehow reproduced on the new rubber, i suppose it's a bigger challenge than welding/shaping a metal..

a bit of a confusional discussion :


In 40 years of wrenching and welding many parts, never had a problem with weld contamination. but this is a side discussion



At least what I mean by using universal boots is this solution:


https://drive.google.com/file/d/1c9T...ew?usp=sharing


you need to make your own adapter on the right (easy for a machinist with a lathe) or find in allens catalog something that fits.






The other thing is that you can not use "just a rubber tube"... to stand gasoline it has to be nitrile rubber. maybe you save on the tube but unless it's a proper gasoline resistant rubber you will be changing it quite often.


In short N67, that guy maybe got away from buying expensive yamaha parts, but to me it sounds like a lot of effort for a so-so solution.


If you are in some dark corner of the world and cant get parts, maybe makes sense, but if otherwise, get good quality rubbers, not worth the headache IMHO, but it si your bike and time :)

agreed with above.
in the best case, result should be something like on your photo, just with shorter adapter in the case of xt600.
and whole this method makes sense for me only with gasoline resistant material.
well, this corner of the world is not dark but also quite far from the brightest.. so, if i will be able to realize this plan properly (both in terms of materials and shape), in the long shot it seems better option.
and one last thing - maybe for one with the experience like yours, it's really a headache. but for me so far it looks more like a nice practice : )