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Author Topic: Main jets?  (Read 6356 times)

Offline Justin B.

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Re: Main jets?
« Reply #30 on: May 13, 2018, 08:30:14 PM »
Fantastic!
Justin B.

2004 BMW R1150RT
1981 R100RT - Summer bike, NEKKID!!!

Offline Tony Smith

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Re: Main jets?
« Reply #31 on: May 13, 2018, 09:32:28 PM »
Quote
Update:  seems that points gap was too tight.  I corrected it and re-timed and bike pulls like a champ now!

I am VERY glad that you have fixed the problem.

You are also now entitled to be a card carrying member of the "When you think it is carbs, it will be Ignition and when you think it is ignition it will be carbs" society.

Oh....And it was nothing to do with those "evil" non-OEM diaphragms!
1978 R100RS| 1981 R100RS (JPS) | 1984 R65 | 1992 KLE500 | 2002 R1150GSA |

Offline wilcom

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Re: Main jets?
« Reply #32 on: May 13, 2018, 11:09:12 PM »
"Once you are absolutely sure that your carbs are OK, start checking ignition components - on the well established principle that if you *think* it is fuel it will be electrical - and vice versa"

........as Tony Smith said!
Joe Wilkerson
Telephone man with a splash of Data
Menifee, CA

Present:
1984 BMW R65LS "Herr Head"
past:
1982 BMW R65LS
1979 R65
1980 R65
1982 R80RT
1974 R90/6
1972 R75
1964 R50/2
19xx R27
ZX-11

Offline DadsR65

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Re: Main jets?
« Reply #33 on: May 14, 2018, 05:57:10 AM »
Thanks to all for the help!

Next issues are bouncy speedo and inability to get idle low enough.

On the idle, I can get it down to ~1200rpm and balanced, but no lower.  If I continue to back out the left side idle speed screw, it no longer touches the throttle lever.  I can push on the throttle lever with a long screwdriver and idle will drop.  This tells me it's a mechanical issue.  I ordered new throttle return springs as step 1.  If that doesn't work, then new throttle cables.

Offline Barry

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Re: Main jets?
« Reply #34 on: May 14, 2018, 06:52:13 AM »
Quote
Next issues are bouncy speedo and inability to get idle low enough.

Bouncy speedo could be the cable.  You could try driving the speedo using something like an electrical screw driver or variable speed drill to see if the speedo unit itself is OK.  If not OK then generally a faulty speedo is best repaired sooner rather than later before more expensive internal damage is done.


Quote
On the idle, I can get it down to ~1200rpm and balanced, but no lower.  If I continue to back out the left side idle speed screw, it no longer touches the throttle lever.  I can push on the throttle lever with a long screwdriver and idle will drop.  This tells me it's a mechanical issue.  I ordered new throttle return springs as step 1.  If that doesn't work, then new throttle cables.

It could be cables but it would be unusual if stock return springs were at fault as they are actually a fair bit stronger than they need to be. It's more likely an issue with the butterfly spindle or alignment. Has the butterfly been detached from the spindle and if so did it go back the right way up. Was it correctly centred in the venturi before tightening the screws.
« Last Edit: May 14, 2018, 06:55:00 AM by bhodgson »
Barry Cheshire, England 79 R45

Offline DadsR65

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Re: Main jets?
« Reply #35 on: May 15, 2018, 03:49:29 AM »
Quote
Quote
Next issues are bouncy speedo and inability to get idle low enough.

Bouncy speedo could be the cable.  You could try driving the speedo using something like an electrical screw driver or variable speed drill to see if the speedo unit itself is OK.  If not OK then generally a faulty speedo is best repaired sooner rather than later before more expensive internal damage is done.


Quote
On the idle, I can get it down to ~1200rpm and balanced, but no lower.  If I continue to back out the left side idle speed screw, it no longer touches the throttle lever.  I can push on the throttle lever with a long screwdriver and idle will drop.  This tells me it's a mechanical issue.  I ordered new throttle return springs as step 1.  If that doesn't work, then new throttle cables.

It could be cables but it would be unusual if stock return springs were at fault as they are actually a fair bit stronger than they need to be. It's more likely an issue with the butterfly spindle or alignment. Has the butterfly been detached from the spindle and if so did it go back the right way up. Was it correctly centred in the venturi before tightening the screws.

The butterfly on both carbs did come out during rebuild.  Shafts, o-rings, and tiny screws are new.  I've double checked them and they appear to be correctly installed.  Also no light coming through any gaps.  The fact that I can push on the throttle lever at the carb and get the revs to drop still makes me think cable and/or spring.