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I removed the sacred ey on a VM. Now what??

  • Thread starter Thread starter Anonymous
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Anonymous

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I had some very nasty carbs. Bike had been sitting for 14 years and I had never seen anything like the mess these carbs were in. I read the book (not as thoroughly as I should have) and pulled carbs apart and have dipped them this week.

During my reading on assembly I realised I have removed the jets that were never to be removed. Can I salvage these carbs or am I in serious trouble and need to move to another set of carbs?

RG
 
What carbs off what bike, and which jets are we talking about?

If it's a GS, then all jets (pilot, mains, and needle) can and should be removed for cleaning purposes.

Legally speaking, the one thing you shouldn't touch is the idle mixture screws (emissions legislation) but no one I know gives a rat's left whisker about that. 2 or 2.5 turns out is usually the standard adjustment for these on a stock standard GS.

But you'll need to put down more info.

Mike.
 
CV carbs have mixture screws (one screw regulates an already combined flow of fuel and air). Frequently, the adjustment of the mixture screw on a CV carb will be between 2 and 3 1/2 turns out. VM carbs have a pilot air screw and a pilot fuel screw. Both must be adjusted to regulate mixture.
Average setting on VM carbs for pilot air is 1 to 2 turns out and for pilot fuel, its usually between 1 and 1 1/2 turns out.

Earl

tfb said:
Legally speaking, the one thing you shouldn't touch is the idle mixture screws (emissions legislation) but no one I know gives a rat's left whisker about that. 2 or 2.5 turns out is usually the standard adjustment for these on a stock standard GS.

But you'll need to put down more info.

Mike.
Click to expand...
 
Re: I removed the sacred ey on a VM. Now what??

You have to remove all the jets to clean the carbs. Youre doing it right.
No problem, just let us know what model bike you have. Having VM carbs already tells me it is 1977-78 or 79. :-)

Earl


rgierer said:
I had some very nasty carbs. Bike had been sitting for 14 years and I had never seen anything like the mess these carbs were in. I read the book (not as thoroughly as I should have) and pulled carbs apart and have dipped them this week.

During my reading on assembly I realised I have removed the jets that were never to be removed. Can I salvage these carbs or am I in serious trouble and need to move to another set of carbs?

RG
Click to expand...
 
The bike is 1978 550
The jet in question is the unnamed preset jet referenced in the Clymer manual as keep your hands off. It did not appear worthy to have a formal title.
The carbs are VM22SS

thanks

RG
 
That's the fuel screw, don't worry you're doing it right, just follow what earlfor gave you for settings and you'll be fine.
 
I have to confess that I won't have the oppurtunity or inclination to finish these carbs until after Christmas but I am hoping for more guidance as even after puling about 20 pages of vm guidance from this site I need some help as I didn't count turns or make notes as I tore these down.

When I was 18 I would have been meticulous, at 50+ I have gotten a little sloppy.

RG
 
Not a problem. Give a yell anytime. :-) We all be here. :-)

Earl


[quote="rgierer"
When I was 18 I would have been meticulous, at 50+ I have gotten a little sloppy.

RG[/quote]
 
If your bike is stock, your pilot fuel screws (underneath) will most likely have been between 1/2 and 1 turn out. For starters, I would set them at 3/4 turn out and go from there. Always seat these screws LIGHTLY. Be sure to follow this adjustment by adjusting the SIDE AIR SCREWS for the highest rpm.
Adjust the side air screws to 1+1/2 turns out to start. Put the bike on the centerstand and warm it up first. Turn each side air screw slowly (either way) until you hear the rpm's max out. When the rpm's stop rising, stop turning. You may want to go back about 1/8 turn to allow for listening error. These screws usually end up about 1+1/2 to 2 turns out. Now turn the idle down to 1,100 rpm's by using the idle adjuster knob. Go to the next carb and do the same thing until all four are set and the idle is set. These pilot and air screw adjustments should get you started.
As for fine tuning the pilot screws, you'll have to test and take plug reads.
Keep record of any adjustments. Even a 1/8 turn will effect plug color over time. Turning the pilot screws out, richens the mixture. You may find that your final adjustments are not all equal. The pilot fuel screws are intended to fine tune the pilot circuit and because of differences in each cylinder, the screws may have to be set differently from each other to get a uniform burn. These screws are sensitive and it can take some patience to get the pilot circuit right.
The most accurate way I've found to get pilot circuit plug reads is to ride the bike around at a steady speed of about 30 mph in 4th gear. A few miles should be good and to avoid any color influence by choking the bike when it was cold. It's still better to do a "chop test" at the end of a longer ride though. As you pull into your driveway, quickly pull in the clutch and close the throttle and turn off the ignition. Coast with the clutch in to a stop and check the plug colors. Because the vacuum fluctuates so much at idle with these carbs, if you allow the bike to idle before this plug read, you'll get inaccurate results.
Do what the plugs and performance tell you.
Obvious signs such as inability to hold a colder idle or slow warm up indicate the pilot screws are set too lean. A stumble just off idle is usually a lean condition too. Excessive decel' popping indicates a lean condition.
Rpm's that are very slow to return to idle are usually a rich condition...
Another note about plug reads, IF YOU DISTURBED THE JET NEEDLES OR THROTTLE SHAFT, you MUST re-synch the VM carbs with a vacuum gauge. You'll get uneven plug reads and trying to correctly set the jetting is not possible, especially the pilot circuit. Of course, this advice assumes the motor is otherwise in good tune.
You're not alone here. Let us know if you need help. :)
 
Depends Keith on whether you are talking about low rpm that will not come UP to idle rpm, or high rpm that is slow to come down to idle.
Wanna elaborate? :-)

Earl

KEITH KRAUSE said:
Rpm's that are very slow to return to idle are usually a rich condition...
Click to expand...
 
I was talking about the rpm's not dropping back down to idle normally. Not as a definite sign, or an only possible cause, just generally.
 
Ok Keith. You had me a tad puzzled because I have seen it go either way depending on other settings.

Earl


KEITH KRAUSE said:
I was talking about the rpm's not dropping back down to idle normally. Not as a definite sign, or an only possible cause, just generally.
Click to expand...
 
hope this helps you out

GS550L (77-79) the specs are for the VM's

idle r/min 1100-1200
carb mik vm22ss
id no 47110
bore size 22 (0.87)
float height 24.+/-1.0 (0.95 +/-0.04)
fuel level 4.0+/-1.0 (0.16 +/-0.04)
air screw 2.0 turns back
cut away 1.5
jet needle 5dl35-3 (the -3 3rd notch??)
pilot screw 1.0
pilot jet #15
pilot outlet 0.6
needle jet 0-6
by pass 1.0
main jet #80
Click to expand...
 
Now that I have all of these responses I would like to clarify what I understand.

During the course of assembly the carbs lightly tightened pilot and main jet. Do not back off these at all.

The jet next to, almost touching the main jet is lightly tightened and not backed off at all.

The pilot air screw is lightly tightened and backed off 1 and 1/2 turns

The fuel screw is lightly tightened and backed off 3/4 of a turn

Set float height and look for metal fuel tubes

The next task is to start the bike, let it warm and go through synching of carbs.

Please confirm if I have an appropriate understanding of your instructions.

I believe I had read someplace that silicone should be used with platic fuel tubes. Do you have any thoughts on this?

Thank you for your time and patience.

RG
 
rgierer said:
"The pilot air screw is lightly tightened and backed off 1 and 1/2 turns"
.**************** 1 1/2 to 1 3/4 turns out should do just fine****




"The fuel screw is lightly tightened and backed off 3/4 of a turn"
***********When I first got my 79 750 (VM carbs), the pilot fuel screws still had the yellow factory sealant unbroken. The screws were set between 7/8ths and 1 turn out. That adjustment was noticably lean. I suggest trying 1 to 1 1/4 turns out. I found 1 1/4 to be about right with stock exhaust system and airbox with filter.**********



"Set float height and look for metal fuel tubes"
*********the float height I found to work best was 24mm.*******



The next task is to start the bike, let it warm and go through synching of carbs.

Please confirm if I have an appropriate understanding of your instructions.



I believe I had read someplace that silicone should be used with platic fuel tubes. Do you have any thoughts on this?
************ I would not use silicone in contact with gasoline, it will turn to a sticky jelly and clog anything it can get into. Whenever possible to use, a wrap or two of teflon tape is a much better choice.*****


Earl
Click to expand...
 
Just to add: the pilot fuel screws come set at different settings, depending on the bike. I've seen them set on stock bikes anywhere from 1/2 to a little past 1 full turn. That's why I suggested the 3/4 turn as a starting point. You'll almost certainly have to test and make adjustments. 3/4 turn will most likely not start you off by fouling the plugs. Nobody can say for sure. It takes testing. If indeed your screws were set at 1/2, then you'll find out 3/4 is too rich. But you won't stain/foul the plugs, they'll just run darker. If your stock settings were closer to a full turn out, then 3/4 will be too lean, but that's easy to adjust for and going leaner to richer is easier to read the plugs and what your adjustments are doing to the color. Only when jetting the pilot circuit would I say this makes it easier. With the needle and main circuits, it's better to jet richer to leaner.
Also, you said the pilot and main jets were tightened lightly and not backed off. The brass jets are never backed off, so you're OK there. But these jets should be tightened firmly, such as 2 ft/lb. If just lightly tightened, they'll probably vibrate loose over time.
 
When I reattach the carbs to the plate, Is there a specific order the carbs should go in or are all carbs alike?

RG
 
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