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Bridge the gap between carb and airbox?

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This 1986 XR80R came with the wrong carb. I bought a Chinese carb for it, but it isn't long enough to reach the airbox boot. What can I do to bridge the gap? I'm considering a piece of bicycle innertube, just to get the bike going, but I'd like to do something more permanent. 

The boot isn't very flexible, and won't stretch enough to reach the carb spigot. 

I'm not sure why it doesn't fit. The boot looks original, and I think the Chinese carb is a close copy of the carb that came with the bike.

Any homemade adapter ideas, or any other solutions or ideas are welcomed. 

20170917_184258.jpg

20170917_184322.jpg

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yeah,

id make a spacer like ^ posted but thick enough to get that bell all the way into the boot

then, id find a suitable chunk of peak or delrin and some calipers, measure the carb diameter and the boot diameter, have the piece of delrin machined, then split drilled, tapped, counterbored for a little allen screw, you put some silicone in the split, and over the bell, slip it on tighten the bolt, then tighten up the boot

 

that hole process is a lot harder if

you dont have calipers, lathe, mill and some delrin laying around,

with all that stuff it can be done in about 30 mins

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I kind of had the same problem.  I did not have that much of a gap but, I loosened the airbox bolts and then attached it to the carb then just tightened the bolts.  Worked for me.

Edited by chemguy

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^^^^^^^ Or you can put the boot on, the tighten the carb up.  It should pull the boot forward and work.  Maybe, move the airbox a 1/4 inch forward or so (or whatever is possible).  Maybe get a radiator hose to fill the gap.  We've done that.   Does it run with that carb???

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It's frustrating, because everything looks fairly stock, but the carb it came with is from an older bike, or at least seems to be.  Because I can't figure out exactly what that carb is from, I can't find jets that fit it.  The chinese carb is supposed to be a really close copy of the factory carb, and looks a lot like the factory diagrams, but the parts on the bike don't fit it right.  Like the pic shows, the airbox boot looks totally factory, but it doesn't reach forward to the carb.  It also doesn't tighten down enough to fit on the chinese carb.  Fits well on the larger carb that was on there.  This is an 80, and I don't think it would run very well with a really oversized carb.  This is for my kids to learn on, so low end is much more important for learning the clutch, than top end with a low end that stalls out easily.

With the carb that came on the bike, there is a step between the carb throat and the intake manifold, all the way around.  That carb is at least several millimeters too big.  I bought the bike with no back wheel, as a project.  It had been "restored" and wrecked (back wheel pac-man'ed) then given back to the guy who "restored" it.  Then it sat for a dozen years at his shop, and I got it.  Seems like the restoration was done with whatever parts he could find.  I just tried to put a factory front brake lever on, and the lever is too thick to fit in the perch.  Who knows what the perch came from, but I'll probably grind on the part and make it fit, because I don't want to spend more money, and I'd probably have to buy new perches and levers if I want to know what I have...

I ended up making a spacer like the ones mentioned above between the carb and intake manifold, and wrapped electrical tape around the mouth of the carb so I could tighten the boot onto it.  Now I'm trying to get it to start.  It doesn't want to start, doesn't even seem to pop most of the time.  The few times I got it to "pop", it seemed like it was out of time, like the pop was stopping it, rather than getting it going.  Tomorrow I'll pull the cam/valve cover and the timing cover again, and check the timing marks on the cam and flywheel, make sure they line up right.  The spark is good, and there's really not much to do to set the timing on this bike, except for making sure the timing chain is on right (unless the timing chain is bad...)  I'm pretty sure the point gap is set correctly, but I'll double-check that, too.

My 13 year old son is dying to go riding on this, with me on my DR350.  So close, but always one more thing...

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My best advice is to throw the carb away and get a Real Honda carb.  A good used from ebay is a million times better than a junk chinese one.  A brand new one from Partzilla is about $103.  I saw a real nice one with extra jets and a manifold for $75 on ebay.  

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On 9/18/2017 at 3:57 AM, 80sDweeb said:

This 1986 XR80R came with the wrong carb. I bought a Chinese carb for it, but it isn't long enough to reach the airbox boot. What can I do to bridge the gap? I'm considering a piece of bicycle innertube, just to get the bike going, but I'd like to do something more permanent. 

The boot isn't very flexible, and won't stretch enough to reach the carb spigot. 

I'm not sure why it doesn't fit. The boot looks original, and I think the Chinese carb is a close copy of the carb that came with the bike.

Any homemade adapter ideas, or any other solutions or ideas are welcomed. 

20170917_184258.jpg

20170917_184322.jpg

Taka a car cooling hose.

The are big flexible and can take heat and cost nothing

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