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Author Topic: Throttle Body Replacement  (Read 31778 times)

Offline TimTyler

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Throttle Body Replacement
« on: January 09, 2015, 01:37:20 PM »
I will be replacing my bike's throttle body assembly in a few days.

My engine has never run as smooth as other K's and the TB's are about the only thing that haven't been overhauled or replaced. Against some recommendations I adjusted the butterfly screws last spring right after a valve job and that improved things a little, but the engine still idles a little rough.

I found a clean '93 TB on Ebay for $50 with the blue paint still on the butterfly and idle screws. I'll also be replacing the pressure regulator and intake manifolds. The airbox bushings and fuel lines are almost new, and the injectors were overhauled about a year ago @ MrInjector.

I was thinking of spraying out the new TB's with carb cleaner. Wish I could find fresh O-rings for the brass adjusting screws and injectors. I'll install a new fuel filter too.

Any advice before I get started?
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Offline koapono

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Re: Throttle Body Replacement
« Reply #1 on: January 09, 2015, 04:44:11 PM »
this link may help with o-ring search or maybe a caterpillar diesel shop, they use more o-rings than most any one else.
http://www.oringsusa.com/
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  • prince george, VA (25 miles south of richmond)
  • 1994 K1100LT

Offline wmax351

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Re: Throttle Body Replacement
« Reply #2 on: January 09, 2015, 05:55:47 PM »
Quote from: TimTyler on January 09, 2015, 01:37:20 PM
I will be replacing my bike's throttle body assembly in a few days.

My engine has never run as smooth as other K's and the TB's are about the only thing that haven't been overhauled or replaced. Against some recommendations I adjusted the butterfly screws last spring right after a valve job and that improved things a little, but the engine still idles a little rough.

I found a clean '93 TB on Ebay for $50 with the blue paint still on the butterfly and idle screws. I'll also be replacing the pressure regulator and intake manifolds. The airbox bushings and fuel lines are almost new, and the injectors were overhauled about a year ago @ MrInjector.

I was thinking of spraying out the new TB's with carb cleaner. Wish I could find fresh O-rings for the brass adjusting screws and injectors. I'll install a new fuel filter too.

Any advice before I get started?


Definitely spray them with carb cleaner. Or dunk them in Pine-sol overnight. O-rings should be standard metric ones. McMaster-carr probably has every one you need, just make sure you use some that are oil and gas safe. Injector O-rings are standard. You can buy them at any Auto store. Just say they are for a 1984 BMW 318i.
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  • Albuquerque, NM
  • 91 BMW K75 Standard, 98 Moto Guzzi California EV
Bikes:
Current:1991 BMW K75 Standard, 1998 Moto Guzzi California EV11
Past: '83 BMW R65LS, '75 Honda CB550F, '69 Honda CB175, 1999 Royal Enfield Bullet 500, 1973 Triumph Tiger TR7V, 1971 BMW R75/5 in Toaster outfit, 1979 Harley Davidson XLS-1000 Sportster Roadster

Offline TimTyler

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Re: Throttle Body Replacement
« Reply #3 on: January 09, 2015, 06:04:39 PM »
Thx, Koapono.

Looks like the BMW part# for injector O-rings is 13641730767 superseded by 13641286708 and the spec is 7.52 X 3.53. South Sound BMW had one of each and inspected them for me over the phone. The old part# is a dull rubber and the new is shiny rubber with a slightly smaller I.D.. Maybe the new one is fuel resistant Viton. It costs 4x as much too. Mr. Injector now sells bulk packs.

The O-ring on the air adjuster screws has never been available separately from BMW and the $8 screw w/ O-ring is not even available from BMW in the US.
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Offline Elipten

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Re: Throttle Body Replacement
« Reply #4 on: January 09, 2015, 06:05:16 PM »
I got those little o rings from BMW last year.  I just used carb cleaner to clean mine, checked the throttle shafts were not worn, and applied some lube on all the moving parts.  I like LPS, but other types will work well.
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  • San Antonio, TX
  • 1990 K75RT

Offline TimTyler

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Re: Throttle Body Replacement
« Reply #5 on: January 09, 2015, 06:05:55 PM »
Quote from: wmax351 on January 09, 2015, 05:55:47 PM
Injector O-rings are standard. You can buy them at any Auto store. Just say they are for a 1984 BMW 318i.

Cool. Thx.
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Offline 552255

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Re: Throttle Body Replacement
« Reply #6 on: January 09, 2015, 11:49:52 PM »
A "while your there" tidbit...the o-ring/gasket that's located between the actual block and the throttle body bushing/riser I think can go bad pretty easily, ie. high temps, metal to non-metal contact.  May want to replace.  One of mine had grains of sand/dirt? visibly on it when I carefully pulled the risers, compared to the others...you may have already replaced at one time, just mentioning.  Good winter project!
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Offline TimTyler

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Re: Throttle Body Replacement
« Reply #7 on: January 10, 2015, 12:56:07 AM »
I know that O-ring exists for the K1100's, but do the K75's have them too?
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Offline wmax351

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Re: Throttle Body Replacement
« Reply #8 on: January 10, 2015, 01:51:50 AM »
Quote from: TimTyler on January 10, 2015, 12:56:07 AM
I know that O-ring exists for the K1100's, but do the K75's have them too?


The K75's don't have those.
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  • Albuquerque, NM
  • 91 BMW K75 Standard, 98 Moto Guzzi California EV
Bikes:
Current:1991 BMW K75 Standard, 1998 Moto Guzzi California EV11
Past: '83 BMW R65LS, '75 Honda CB550F, '69 Honda CB175, 1999 Royal Enfield Bullet 500, 1973 Triumph Tiger TR7V, 1971 BMW R75/5 in Toaster outfit, 1979 Harley Davidson XLS-1000 Sportster Roadster

Offline johnny

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Re: Throttle Body Replacement
« Reply #9 on: January 10, 2015, 09:50:46 AM »
donts know abouts o rings... butts i knows a thing or too abouts hoe rings...

j o
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Offline billday

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Re: Throttle Body Replacement
« Reply #10 on: January 10, 2015, 10:41:14 AM »
Quote from: wmax351 on January 10, 2015, 01:51:50 AM
Quote from: TimTyler on January 10, 2015, 12:56:07 AM
I know that O-ring exists for the K1100's, but do the K75's have them too?


The K75's don't have those.

When I did the throttle body refurb on my '85 K100, I put a small bead of Permatex in there. I decided to do that after I realized that new replacements (as I recall BMW calls that part the "manifold," and there is no separate O-ring) were $50 per each.
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  • New York State, USA 10977
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Offline TimTyler

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Re: Throttle Body Replacement
« Reply #11 on: January 10, 2015, 11:59:02 AM »
Bill, Is their a place for an o-ring, or did you just add sealant between the two flat surfaces? Oh, I see - you added sealant since you did not restore the manifolds.

I found OEM manifolds a little cheaper at $41 from http://www.ecstuning.com/ES1900132/   I suspect the high cost is due to their ability to withstand the heat. Hopefully take delivery in a few days. ECS told me they order them from BMW and then ship.
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Offline billday

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Re: Throttle Body Replacement
« Reply #12 on: January 10, 2015, 12:55:04 PM »
There's a place that looks like a place for an o-ring, but it's not. That's where I put the Permatex.

You're getting a good price on new manifolds. Plus, you get the K75 discount: you only have to buy 3 of 'em.
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  • New York State, USA 10977
  • 1985 K100

Offline K75rt

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Re: Throttle Body Replacement
« Reply #13 on: January 10, 2015, 01:15:03 PM »
Quote from: TimTyler
Wish I could find fresh O-rings for the brass adjusting screws

I bought three for $1.87 each for my K75RT from Bob's not a week ago, PN# 13111257819 "Gasket Ring" aka "O-ring Choke Valve."  Same part is used in a bunch of airheads:

http://www.maxbmwmotorcycles.com/fiche/PartsSearch.aspx?&searchtype=partnumber&parts=13111257819%0A

I guess if you tell them it is for an airhead they will make an exception ;)
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Offline TimTyler

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Re: Throttle Body Replacement
« Reply #14 on: January 10, 2015, 03:46:29 PM »
Quote from: K75rt on January 10, 2015, 01:15:03 PM
I bought three for $1.87 each for my K75RT from Bob's not a week ago, PN# 13111257819

Thanks! Ordered.

Manifolds and Suzuki clamps arrived today. Might get to work on this tomorrow if it warms up a touch.
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Offline TimTyler

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Re: Throttle Body Replacement
« Reply #15 on: January 10, 2015, 09:48:09 PM »
Old

New
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Offline Elipten

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Throttle Body Replacement
« Reply #16 on: January 10, 2015, 10:48:46 PM »
Tim.
I Like those clamps, wish I had known last year when I did this job.  Can you supply details please.
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  • San Antonio, TX
  • 1990 K75RT

Offline TimTyler

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Re: Throttle Body Replacement
« Reply #17 on: January 10, 2015, 11:13:17 PM »
Quote from: Elipten on January 10, 2015, 10:48:46 PM
Tim.
I Like those clamps, wish I had known last year when I did this job.  Can you supply details please.

3 x 09402-48208 CLAMP (Suzuki) $3.04

3 x 09402-50208 CLAMP (Suzuki) $3.12

I bought them from Partzilla.com
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Offline wmax351

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Re: Throttle Body Replacement
« Reply #18 on: January 11, 2015, 12:55:08 AM »
What are the sizes on those clamps?
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  • Albuquerque, NM
  • 91 BMW K75 Standard, 98 Moto Guzzi California EV
Bikes:
Current:1991 BMW K75 Standard, 1998 Moto Guzzi California EV11
Past: '83 BMW R65LS, '75 Honda CB550F, '69 Honda CB175, 1999 Royal Enfield Bullet 500, 1973 Triumph Tiger TR7V, 1971 BMW R75/5 in Toaster outfit, 1979 Harley Davidson XLS-1000 Sportster Roadster

Offline TimTyler

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Re: Throttle Body Replacement
« Reply #19 on: January 11, 2015, 12:56:48 AM »
Uppers are 50, lowers are 48.
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Offline Elipten

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Re: Throttle Body Replacement
« Reply #20 on: January 11, 2015, 01:10:09 AM »
Thanks Tim
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  • San Antonio, TX
  • 1990 K75RT

Offline wmax351

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Re: Throttle Body Replacement
« Reply #21 on: January 11, 2015, 02:01:53 PM »
Quote from: TimTyler on January 11, 2015, 12:56:48 AM
Uppers are 50, lowers are 48.


Great, thanks. I need to get some clamps on mine. Will order some from McMaster-carr.
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  • Albuquerque, NM
  • 91 BMW K75 Standard, 98 Moto Guzzi California EV
Bikes:
Current:1991 BMW K75 Standard, 1998 Moto Guzzi California EV11
Past: '83 BMW R65LS, '75 Honda CB550F, '69 Honda CB175, 1999 Royal Enfield Bullet 500, 1973 Triumph Tiger TR7V, 1971 BMW R75/5 in Toaster outfit, 1979 Harley Davidson XLS-1000 Sportster Roadster

Offline Inge K.

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Re: Throttle Body Replacement
« Reply #22 on: January 11, 2015, 02:16:21 PM »
A standard clamp is usually to wide to fit in the groove.
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Offline Elipten

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Re: Throttle Body Replacement
« Reply #23 on: January 11, 2015, 03:47:47 PM »
But there are ones narrow enough from McMaster-Carr which is what I used, but those Suzuki clamps look better.
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  • San Antonio, TX
  • 1990 K75RT

Offline rbm

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Re: Throttle Body Replacement
« Reply #24 on: January 11, 2015, 04:03:58 PM »
The Suzuki clamps are the correct width for the bushings.  I use them on my K75.  Careful with positioning them properly though; the clamp screws can easily interfere with the operation of the throttle cam because they are so tall and the clamp screws so long.  Try to orient the lower clamps like this:
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  • Regards, Robert
Toronto, Ontario

1987 K75 - Build Blog @http://k75retro.blogspot.ca/
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