Carb Intakes but not as you know it?

kavb

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Commenced the carb strip down today (still can't get the head off - tight screws) but the intakes don't look right.

What I found is in the first picture. The bent tube pushed on (a good fit) onto the carb intake and the metal end pushed into the softish boot within the air box.

From looking at the microfiche and studying photos of other bikes I think the bent tube should be the other way around as in the 2nd picture, i.e.

- carb,
- rubber pipe (new) + 1 jubilee clip,
- bent tube,
- insert (which I don't have yet) + 2 x jubilee clips
- air box

Is this correct?

If the above is right I am a bit confused why I only see one jubilee clip (on others bikes) on the intake, why not two as per the pipe between carb and cylinder head?

Hope that makes sense.

Thanks

kavb
 

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Ok but isn't that different fom the OEM microfiche below - for the connection between carb and inbox? Or perhaps I have been looking at it too long and now got in a muddle.
 

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Yep, you're quite right finally figured it out. I got confused because the carb itself isn't shown in the microfiche. Live and learn.

Thanks for your help.
 
Drill the top screws out fellow. Be careful though, dont "nick" the alloy top.
 
Drilling out a bit ambitious for me especially with rudimentary tools I have in Dubai. Could take it somewhere but you take your chances on it being damaged. WD40 soaking and better screwdriver tomorrow, hope it works.
 
Rob Farmer said:
WD40 is a waste of space.
Click to expand...

+1

A few years ago, there was a guy trying to sue them. He quirted that junk everywhere on his yacht as they say its a moisture repellent and it corroded his PCB's in some electronic devices.

He had quite a vitriolic (pun intended:D) web page but its gone now... Bought off I assume.

John
 
Changed tack and went and bought a screw head for my socket spanner. A bit of elbow grease and the top of the carb popped straight off.

Ive put the carb (with new gaskets and O rings back on) but feel the top jubilee clip where the pipe enters the airbox is just not right.

The top jubilee clip I used to clamp the soft rubber boot (12) and the metal pipe (14) which involves pulling the rubber boot out of the airbox a little. Numbers refer to microfiche in earlier post. Is this correct - everything was a very tight fit? First photo shows what I started with and 2nd/3rd photos what I have now.

Anyway the good news is that the bike started and after a bit of throttle cable adjustment misfire stopped and seems to run nicely. The stuck choke was solved with the new O ring.

Thanks

Kavb
 

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Hi

Its a bit difficult to see what you have done without bigger photos but from your description it does not sound right.


The hard plastic tube (5) should have one end on the carb held by one jubilee clip. The soft rubber tube (12) stays completely within the airbox (3) with its lip in a depression in the side of the airbox aperture. The metal collar (14) is pushed into this tube with half its length protruding and holds the soft rubber tube in place. A short rubber tube (7) covers the protuding half of (14) and the last bit of the hard plastic tube (5) and joins them. A jubillee clip is at each end of (7) and holds it all together.

I can understand why you are confused. The diagram you are looking at is incorrect and does not match that in the BMW workshop manual.


Steve
 
The screws in my carb tops were seized in when I got it, I loosened them with an impact driver, very easy so long as the underside of the screw is supported by something very solid, I used a corner of my bench vice.

Don’t forget to lube the new screws with a dab of grease and don’t over tighten.

Oh, and valve grinding paste will help stop the screw driver bit from slipping when trying to loosen them.
 
Steve, thanks for the reply.

Things falling into place gradually (I now know the boot shouldn't comeout of the airbox and fits in a recess), but I'm not quite there yet. The only confusion is end between the pipe and airbox, everything else fits.

What was on the bike I bought is shown in the first photograph - only the rigid plastic pipe and metal sleeve, the small diameter end of the metal sleeve pushing into the soft rubber boot of the airbox. From your well written description I am missing a rubber pipe. I did buy one from Motorworks and it is shown in the 2nd photograph. This is too small to fit over the rigid plastic pipe and even if it did the jubilee clip would just squash the plastic pipe because its unreinforced.

Anything obvious I'm missing?

Thanks

Billy
 

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Hi Billy

I thought the easiest way to make everything clear was to go out to the garage, dissassemble the left hand side air tube and photograph putting it all together. The bike is a 1989 R100GS.

Here are all the parts in the order they go together.

airtube1.jpg


First, push the narrower end of the metal collar into the soft rubber tube. In the picture you can see the end of it protuding from the airbox.

airtube2.jpg


Then push the rubber tube right over the hard plastic tube, hang the jublilee clips over the lot and attach to the carb by tightening the lower jubilee clip.

airtube3.jpg


Push the rubber tube onto the projecting part of the metal collar, and tighten the upper two jubilee clips. You are done.

airtube4.jpg


If the rubber tube doesnt fit over the hard plastic tube and the metal collar it is the wrong rubber tube. Heres a picture of it over both.

airtube5.jpg


The jubliee clip does not crush the plastic pipe because the plastic pipe has a metal re-inforcing ring inside it.

airtube6.jpg



Hope this helps


Steve
 
Steve that is brilliant! Its all fallen into place now. The time and effort you took to do that is much appreciated. I think I have the right tube since its part number seems to tally with the microfiche. Hovever its a damn tight fit. I only just got it over the plastic tube by stretchinng it first between two spanners (standing on one and pulling up). Perhaps they stretch out over time but its going to mean putting it on the bike tomorrow might be a tad difficult.

Thanks again.

Billy
 
Hi Billy

I have tracked down the microfiche you are using. It is for a US specification bike - they are different around the airbox and I believe they have 32mm Bing carbs whereas the 1000cc european ones have 40mm Bing carbs.

If you look at the motorworks catalogue the part you should be using is FUA64392.


Steve
 
Steve, mine are the 32mm Bings. Yep thats the part I have - FUA64392.

Found the last problem. My ducts for whatever reason do not have the reinforcing ring - which you point out when I re-read your post. Still the carbs are on the bike and whilst not 100% right, just about there.

I'll have to order the new ducts but need to check they have the reinforing rings.

Thanks again.

Billy
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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