Wed, 07/20/2011 - 12:36
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Another new guy. I have a beautiful 1973 toaster tank blue R60/5. I went through a basic clean up for a machine that was in storage and recoated the inside of the tank. I set the carb at the specs about 2 1/2 turns out and kick started it. Runs... the carbs have two adjustments and a tickeler. How do I adjust them, so far the more I turn ether screw in the faster the engine runs. Help
Thanks Rich
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Thu, 07/21/2011 - 10:19
#2
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Carb Adjustments
Thanks, The answer was just what I was looking for, I will give it a try as soon as I come up with a spark extender. I am impressed with the VBMO..
Rich.
Wed, 08/17/2011 - 12:06
#3
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Do you guys know if you can
Do you guys know if you can do a carb sync without a working tach?
Wed, 08/17/2011 - 18:00
#4
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Sure...you just won't know
Sure...you just won't know the numbers. But if the engine sounds fine to you and performs reasonably well, it should be just fine.
Fri, 08/19/2011 - 12:01
#5
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OK stupid question
I recently got my 72 R75/5 up and running and need to synch the carbs. So where exactly do you hook up the synch tool? I can't seem to find a tap screw or anything on the Bing. On my old Honda there were screws on the manifold so it was easy. Can't seem to find anything on the Internet. I'm feeling rather stupid! haha
Fri, 08/19/2011 - 20:55
#6
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Chris -
Your bike is too old
Chris -
Your bike is too old and won't have the vacuum takeoff ports for hooking up a manometer or other device for measuring the vacuum. You'll have to resort to the plug-shorting method or try one of the other devices offered. I'm not sure if these are offered for the /5, etc., but I bought a pair of devices for my R69S made by EMPI. It was posted on the Vintage forum quite some time back. They are attached in place of the air intake tubes and have a small dial which indicates the level of vacuum, flow, etc. One can compare left-right to dial in the carbs to provide the same reading. Here's a past thread on the devices:
Sat, 08/20/2011 - 18:12
#7
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Thanks
Thanks Kurt, I was thinking that might be the case after exploring the Internet some more. The good news is the bike runs so it's just a matter of tinkering and having a box fan to cool it while I do!
Tue, 08/23/2011 - 12:08
#8
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Any suggestions for a quick,
Any suggestions for a quick, get it back on the road fix for my right carb leaking gas when either of the fuel lines are open? I think it's the float needle. Just want to get it running so I can ride it then do the full carb work over a weekend.
Tue, 08/23/2011 - 12:37
#9
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So, fuel petcocks are "on"
So, fuel petcocks are "on" but the carb leaks or dribbles gas? A couple of things come to mind. First, you may have some debris that is preventing the float needle from seating. To clear it, turn the petcocks off, and remove the float bowl. Probably want something to catch the flowing gas for the next step. While holding the petcock in the closed position, turn on the petcock. At this point, you can release the petcock and close it a couple of times to help flush out the debris. Hopefully that's it.
Something else is that the float could be binding and can't actually close on its own. So, check the movement of the float. There could be a burr or something on the float seat. You can take some grinding compound and a shaped dowel end and give it some light turns to smooth the seat out.
Most likely it's just the debris. If the float doesn't float very well, then there's really no fix but to get new floats.
Tue, 08/23/2011 - 13:26
#10
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Thanks Kurt. There was a
Thanks Kurt. There was a little debris in there. I sprayed some compressed air in there to see if I could shake any debris loose but no luck. I will give it a shot. Never happended before until my recent fill up.
Wed, 08/24/2011 - 10:00
#11
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I got under there yesterday.
I got under there yesterday. the fuel is actuallu coming from the connection where the fuel line meets the carb. Replaced the line and it no longer leaks when bike is standing still. took it for a ride and it started again. It seems that if I put pressure on the spot where the line means the carb (valve, nipple something) the fuel spills out. I'm guessing now that the clog is in there. Trying to blow some air through there, my new catch all attempt but no luck. Gasket is blown as well
The tickler is your choke, so there's really no adjustment there. There should be two screws on each carb - one to set the idle mixture. On the slide carbs, this screw controls the amount of air that is injested at idle. Turning the screw CW shuts off air and makes it rich; CCW adds air and makes it lean. The second screw should be for idle speed. Basically, turning it CW pushes the slide in the carb higher and higher, probably causing it to rev like you were saying. There is a third adjustment which is for the throttle cables, but it is not a screw necessarily, but a knurled knob where the cable comes into the carb.
Basically you want to make adjustments so that each carb is pulling exactly the same as the other one...that's the balance you're looking for.
So, the carb balance does something like this:
- get the bike fairly warm; a 15-20 mile ride
- get home and put a fan on the engine to keep air moving
- restart the bike and adjust the idle mixture screw in and out to find the point where the idle speed is the highest. As you turn it in, the engine will stumble; as you turn it out, the engine will stumble. Find the middle point and turn the screw CW about 1/8 turn to make it slightly rich.
For the next adjustments, you'll need some kind of spark extender...something that goes between the spark plug cap and the spark plug. This lets you take a plastic handled screwdriver and short out the spark to the engine. This does no harm. What you don't want to do is pull the spark plug out without ground the plug...this can damage the coils. The purpose of shorting a plug out is to shut one cylinder down so you can make adjustments on the running cylinder.
So, continuing:
- with engine running, short out the left cylinder. Note the RPM.
- release the left cylinder and short out the right cylinder. Note the RPM.
- if not the same RPM, the make adjustments on the idle speed screw
- in the end you want the bike to idle around 1000 to 1100 RPM.
The last adjustment is the cable tension. When you open the throttle, you want the cable to have equal tension so each carb slide is pulled up at the same time.
- be sure there's a little slack, about 1-1.5mm in the cables at the knurled knob.
- hold the RPM up to about 1500 RPM.
- short the left cylinder. Note the RPM.
- release the left and short the right cylinder. Note the RPM.
- if the RPMs are not the same slacken the knurled knob on the faster cylinder some.
- recheck the RPMs by shorting.
There are other ways of doing this, but this is the classic way. You can buy a TwinMax which is a differential pressure gage. There is a $4 manometer that can be made to measure the vacuum on each side. However, these things might not work on the /5 slide carbs if they don't have the vacuum takeoff ports.
A website to read about the classic method is here:
http://bmwmotorcycletech.info/synchcarbs.htm
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2