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davidmcctan
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Hi guys,
Happy holidays to everybody..
I took apart the engine which was on my r60 / 2 which was running perfectly to do a Slinger change out and now my right cylinder is running a Rich. Went through the motions from plugs, carbs, compression, valve timing and all seems good. I swear it fells like i left a rag in the intake manifold, but I've gone through it and can't find anything. One thing i did change were the mufflers . I will try and put back the old one on the right side , but grasping at straws at this point. Any input appreciated

Ps..on a heat gun, the right side runs 75 degrees cooler than the left after a while, like 5 minutes. Plug is wet on idle

Beemer100
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David ... 75 degrees

David ... 75 degrees difference .. is this in Fahrenheit or in Celsius? If it was Celsius I would say the right cylinder is not running at all.
So I assume it's in Fahrenheit.
You say you went through the obvious: Valves, compression, timing and carbs. Since it apparently only ran at idle I would check the carbs again. Mainly the float and the idle circuit. Then I would make sure the carbs are in sync. Definitely change the wet plug.

MikeL46
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I have to agree. Sounds like

I have to agree. Sounds like the float is sticking and flooding the cylinder.

Mike

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davidmcctan
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Temp was in F I did run it

Temp was in F
I did run it around for 30 minutes and the plug was darkened ( Fuel Foul)

Question: if the bowl sticks, wouldn't the fuel start coming out of the overflow...

Also...if the float sticks , doesn't the engine still run normal (not rich), it just has fuel spilling out of the carb?

davidmcctan
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What if i exchange the Carb

What if i exchange the Carb top cover & the float between the left and right..that should confirm sticking carb or bad needle seat

Still confused as to a bad float making it run rich...
Unless it dumps the excess fuel back into the carb, that would affect it...

Where is the overflow in a Bing?

ahistand
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Overflow

There is no overflow per-se on the Bings to the outside of the carb. When the fuel level rises too high it does and can go several places like out the air inlet for the main and idle jet circuit and then yes into the main air intake. But usually it dribbles pretty good out of the idle mixture screw threaded hole since this isn’t exactly a perfectly sealed area to the exterior of the carb.
It should be easy enough to check if you have a float and/or needle that isn’t seating properly without switching tops or floats. Just turn the fuel petcock to the on position with the engine not running. Then pull both tops off and compare the fuel levels. I don’t have the exact measurement on me but the fuel level should appear surprisingly low, like lower than you might expect it to be if you aren’t used to looking at this.

312Icarus
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First, once the plugs are

First, once the plugs are clean, pull the plug wires one at a time and see if each side is running and how well compared to the other. Then turn the fuel peacock off and see if, if it runs better for a bit. Then check to see if each slide is in the same pin hole on the slide

Icarus

Beemer100
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before pulling a plug wire

before pulling a plug wire while engine is running make sure you don't have an electronic ignition installed. They need both spark plug wires grounded!!!

back to my first contribution: Check if the carb floats are clear and don't stick. Changing tops doesn't necessarily give you the answer since it also can be the little seat on the bottom of the bowl or also the the side where the collar of the float rubs the bowl. Check also the floats if they are dry inside. Use "ahistands" idea to check if both bowls contain the same amount.
You are right, excess gas will come out of the carb (mainly through the idle adjustment screw ... it is meant to be the overflow valve to avoid that the gas runs straight into the engine) but already before reaching this level, this cylinder will get more gas. Again check, if your idle jet is free of any dirt. The hole is veeeeery little and veeeery little debris can cause problems.
Once that is done, again, check if the 2 carbs are in sync. You can pull the plug wires one at a time (if you run the original ignition), or you use your ear, or the rear mirror or your hand on the tank. You can hear or feel if both carbs don't work the same. You also can use syncrometers. Helps me a lot ... too much Led Zeppelin in my earlier years. You have to make sure that both cylinders do the same works (means have the same revs at any given throttle position). Otherwise, the cylinder which does more work WILL get hotter than the other one.

Klaus

davidmcctan
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Do you guys grind the needle

Do you guys grind the needle and seat with grinding compound?

ahistand
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Seat

I’m assuming you have the old style carb tops, not lever tops?
I believe that valve lapping paste is too abrasive for lapping the needle and seat. I’ve used Autosol as a lapping compound which is a metal polish and has very fine abrasives in it. If you need anything more aggressive than that to get the needle to seat well then you have bigger problems to deal with.

Ultimately if you have a needle and seat that will not seal after some work, you’ll probably need to switch to the new lever tops which use a rubber tip on the needle which I believe is Viton.

So what did you find on the float bowl fuel level test?

Beemer100
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I use the cigarette ashes my

I use the cigarette ashes my brother leaves in the ashtray of my workshop. Usually does this job. As already said, if not, you have bigger problems.
I wouldn't change to the newer version of the bowl top ... would simply buy a new needle. I personally prefer the simpler older construction, but thats my personal view.

Klaus

davidmcctan
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Sorry..haven't got anything

Sorry..haven't got anything done yet. Just waiting for the holidays to end and some peace and quite to get the job done.

I will give the update the minute i open the tops.

Yes, i have the original tops to the carbs..but the floats are the new ones from Vetch..

schrader7032
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Something to check when

Something to check when you're back into the carbs. On my R25/2, I bought the new plastic ethanol compatible float. I overhauled the carb and put it back on. Every time I opened the petcock, the carb literally overflowed. I went back into the carb a number of times trying to figure out the problem. I thought I had slid the float onto the needle far enough to engage the detent. Finally I realized that I had not gone far enough for the float clip to engage the detent. Duh! Then it worked fine.

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davidmcctan
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So..checked the levels..the

So..checked the levels..the side that was running rich was 62.7 mm from the top, the other side was 56.7. Is 6mm difference enough to create the problem.

I switched the covers and the floats. Ran the bike for 15 minutes
It seems to runs OK but ..doesn't seem to have made any difference. I can feel the heat difference with my hands.

The last thing I checked was the plugs..The picture is the rich side..I should have put new plugs

  • 20191229_103916.jpg
Beemer100
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are you sure these are the

are you sure these are the right plugs for your bike? I'm asking because of the first couple of threads are black. These seem to be plugs for LK (Lange Kerze = long plugs) heads. If you don't have LK heads (its embossed near the plug hole) then these plugs are too long.

Next, check the idle jets (clean or replace them with new ones) and sync the carbs and yes, 6mm diff sounds like considerable.

KLaus

schrader7032
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On the side that was running

On the side that was running rich, the fuel level is 6mm lower than the side that is running OK. Seems like if it was running rich, the fuel level would be higher in the bowl...if the level were higher, it would be easier to get sucked in by the air going through the carb.

I agree with Klaus...strange to see so many threads blackened suggesting they're sticking far too deep into the combustion chamber...if they stick too far in, they could contact the piston.

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wa1nca
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3/4 plug

That does look like a 3/4" plug in a 1/2" threaded head
You may have one 3/4"LK head and one 1/2" threaded head
Does the other plug show the same blackended on the threads

Tommy

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davidmcctan
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Hi guys, Sorry..got the

Hi guys,
Sorry..got the heights backwards..The side that was rich is 56.7. How do you adjust the fuel height??
Does anybody know what the correct fuel height is??

The plugs..I swear they were what Vetch sent me, but I do agree they seem to long...any recommendation on a good plug i can get at autozone?

Attached is a picture of the OK side

  • screenshot_20191230-080457_gallery.jpg
schrader7032
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What year R60/2 is this? It

What year R60/2 is this? It has been mentioned the idea of long reach plugs, or "lange kerze". Do you see the letters "LK" around your spark plug hole like this:

http://www.w6rec.com/duane/bmw/head/head6.JPG

What brand and number plugs did Vech send you? With that, we can do some cross referencing. Duane has this page on his website which might help:

https://w6rec.com/bosch-spark-plug-id-change/

I have Bosch W3CC plugs in my long reach R69S. For NGK, a 1/2" reach plug is probably B8HS...check that to be sure.

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'78 R100/7 '69 R69S '52 R25/2

Beemer100
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as Kurt mentioned ... first,

as Kurt mentioned ... first, check what cylinder heads are installed: LK or the earlier ones for short plugs

wa1nca
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Ashfield Ma.
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NGK Plugs R60/2

NGK B8HS correct heat rang for short reach 1/2" plug

NGK B8ES correct heat rang for long reach 3/4" plug

I use NGK B7HS for my R69s short reach 1/2" plug
NGK B7ES R69s long reach 3/4" plug

Tommy

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54 R51/3 55 R50 64 R27 68 R69US 68 Sears Allstate 250 (Puch)

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