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Carb Noob

  • Thread starter Thread starter MisterCinders
  • Start date Start date
Found a set of 4 on ebay for $24. I guess this gives me a few more days to play with valves, clean carbs, and watch others enjoy the beautiful riding weather.
 
Oh boy, this gets better and better.

Got the carbs off and separated.

Pulled the slide assemblies out to find that the slide on No. 2 is dented at the bottom edge. Here are some pics:

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Checked Z1 and Bike Bandit, neither has that part. How the hell do I replace that?

Also the pilot screw on No. 1 had no spring.

The adventure continues.

Now, you beginning to grasp the previous owner syndrome

You just never know what you're going to find!

I wonder how he managed to bend a slide?

Was there any debris/gunk in the carbs?
 
Actually, there is a mistake in my prior post. That slide is for No. 3.

I have not disassembled Nos. 3 and 4 yet, so I don't know what the bottom of that carb looks like yet.

So far, 1 and 2 look pretty clean inside. No real gunk that I can see.
 
Other details, FWIW.

Glad I picked up those rebuild kits.

The float seal gaskets are pretty shot. They are so stuck in the bowls, that they have only come out in pieces. Hopefully, I can scrape out the remaining bits after the soak.

Still more questions.

The carb slide show has an ingenious "special tool" using a wire brush bristle to poke into small openings. Fearful of harming more brass, will any wire brush work for this? Should I stick to a certain bristle type?

Any other ideas for good poking tools?
 
OK, so the float drain plugs on two of the carbs are never coming out. Seriously, the brass screws on them have been stripped to ****. Soaked it in penetrating oil and carb cleaner.

That plug is not budging.

Any ideas on how to get that out?
 
OK, so the float drain plugs on two of the carbs are never coming out. Seriously, the brass screws on them have been stripped to ****. Soaked it in penetrating oil and carb cleaner.

That plug is not budging.

Any ideas on how to get that out?

Heat them up, the aluminum bowl will expand more than the brass plug

Put them in a 400 oven if you can

The, use a proper size screwdriver or impact bit on the drain plugs

Lots of people poke a wire strand in, I just soak and spray to clean it
 
Now, you beginning to grasp the previous owner syndrome

You just never know what you're going to find!

I wonder how he managed to bend a slide?

Was there any debris/gunk in the carbs?
Id bet money that the PO experienced PPO syndrome :D The VM carb bodies were made of very very soft compound metal, mostly zink and aluminum and some magnesium from what I understand. The BS series were a bit more solid, a bit harder. If those VM carbs were left exposed to precipitation for any length of time, the corrosion of the slides vs the bore of those carbs will lock the slide up tighter than a drum. I made this mistake once.....ONCE. And I tried EVERYTHING in the world to unstick the slide. Prying only did damage (just like the pic) to the slide, and no chemical soaks I tried (Berrymans, CLR, Boiling it in CLR, etc etc) would free that puppy up. Apparently the compound metals in the older carbs and the slides become VERY VERY fond of eachother.

You'll definately want to replace that slide. While the damage done initially would look fairly superficial, the cutaway on those slides are precise and necessary. While I cant say that it would cause a whole lot of problems, at this point, you need to eliminate as many problems or possible problems from your equation as possible.

Which brings me to my next point. Your plan of attack sounds quite sound. I would suggest that you follow the carb cleaning to the letter. And better still, do it twice. Even a little tiny bit of gunk in, say, the choke pickup in the float bowl, or the pilot passages, will cause you grief. The tollerances here are very very small. Besides the soaking in dip, the cleaning with spray etc, some strands of COPPER wire are your best friend here. Copper is softer than the brass in the jets, pick up tube, and passages in the bodies themselves, so it wont do any damage to them such as gouging or the like that could cause problems in the AFR later on. But copper will likely be harder than any crap that might be lodged in the pilot jet, needle jet or emulsion tube etc etc. Use it liberally, push that crap out and then blast the passages and jets with carb spray, making sure each sprays roughly the same pattern. Oh, be sure to wear saftey glasses here. Some of those passages come right back around to your face, and carb spray in the eye is exquisitely painfull. Dont ask how I know..just trust me :)

While youre waiting on your carbs to soak (and let them soak a day, 24 hours, but no more, as the bodies will start to "skin" with a metallic, sticky residue that could cause your slides to stick... dont ask how I know about that either. And if you can get one, a nylon bottle brush is a nice tool to have on hand to assure your slide bores are nice and clean..) adjust those valves! This is key to assuring you have a proper baseline to start your carb tuning. If you do the carbs first, and then adjust the valves, you'll find you might have to mess with the carbs again.

Lastly, If your airbox is in workable shape (and a good cleaning and a spray with some Duplicolour Low Gloss Black will make her look damn nice again) USE IT FIRST. Its much easier to tune the bike for aftermarket performance parts when it is running well in the first place. Remember, you're setting a baseline for everything here. So having it running in STOCK setup is the best baseline for later changes...


Good luck!

TCK
 
Didn't read every post.
If the bowl drain bolts won't come off you can always get some used bowls or live with it for now.
I think your biggest problem may be compression. You mention black/oily plugs. Even if you have good spark and fuel flow, combustion will be poor with low/uneven compression. Leaky valve seals will keep fouling your plugs. Worn rings too. You need to check the compression first and fix it if needed. Any smoke and/or popping at warm up or later?
Carb and electrical service are expected on these older bikes. If your ignition is still points then they need to be checked too for being in good condition and properly gapped. Verify the main jet and pilot jet sizes while you have things apart to be sure the PO didn't make poor changes. Verify jet needle e-clip positions too. I assume the bike is stock and if so the jetting should match the factory installed jetting.
 
OK - Checked valve clearances. They are all terrible.

My smallest feeler is 0.127mm. None of my valves have clearance to let this pass.

Don't have the tappet tool, but tried to use the zip-tie trick to hold the valves open. http://members.dslextreme.com/users/bikecliff/images/valve_tool_zip_tie.pdf

Didn't work.

So I need to get a tappet depressor to figure out what shims are in place. Thought about springing for the full shim set, but I may need more small shims than the set will provide. So I get to wait for the tool to come in and then figure out what shims to order and wait for those to come in.

Also need to replace the gasket for the valve cover and breather cover, as neither survived careful removal to get to the valves.

At least 2 of the main jets are never coming apart, so I guess I am replacing those as well.

Finally, the intake boot on the No.1 carb resists all measures to remove it. Dremeled a slot, but the screw head prefers crumbling to turning. Even a screw extractor refuses to grab anything in this damn bolt.

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Zip tie method probably didn't work because the valves are way too tight.
As for the boot, I would get a new one ordered, than using a propane torch to heat the head where the threads are then try removing the screw.

Be careful Aluminum melts at 1200 F
Propane gets about 1100 F
Mapp gets about 2350 F
Oxy/Ac gets about 2700 F+
 
I thought that might be the problem with the zip-tie method.

Ordered the tappet tool, some fuel line and filter (why not) and some gasket sealant.

Looking at the valve cover gasket, replacing the vale cover gasket and breather cover gasket is $40!! I suppose "patching" the torn gasket with some liquid gasket is not going to work. Or would it?

For the float-bowl plugs, I may hunt down an old set of carbs on ebay to cannibalize replacement bowls.

****es me off that parts/tools are so hard to find in the city. Basically, I have Auto Zone, and one cycle shop nearby, but the cycle shop is pretty weak, has crappy hours, etc. Hopefully, I can find a local source for shims, or it will be Christmas before I have the bike up and running again.

To think, I almost opted to change out to fresh fuel to postpone this work until winter. If only . . .

Thanks again to everyone for putting up with my posting. This thread has turned into a newbie wrench blog. If I get my crap together, maybe I will put a photo log of re-building the carbs (i.e., putting all the parts together). The VM guide on Basscliff's site is good, but a couple of the steps on removing and splitting up the carbs are confusing. Maybe I can provide some clarity to redeem subjecting you all to this saga of misery.
 
MC,

Z1Enterprises is THE place to order ALL of your basic maintenence stuff from. Shims, special tools, jets, whatever.. the only thing they DONT have that I have seen are the Oring kits that Robert Barr sells (www.cycleorings.com)
THeyre fast too.. orders placed early in the day (before 2pm EST i believe) will be sent out that day. I usually get my stuff from them in 3 days tops. You're just as close to them as I am...


As for your feeler gauges. Make SURE you're not transposing those numbers. Of course you cant fit a .12mm feeler in there. Thats WAY too loose anyway. The spec calls for a clearance of .03-.08MM. Anything larger than, say, .09 to .10mm is loose enough id worry about spinning a shim out of the bucket at high revs. Autozone DOES sell a set of feelers that go down to .04mm, and honestly thats small enough that if its that tight you cant get it in there, its time to change it. Even a clearance of .04, *I* would change to the next shim simply because I dont want to have to do it again in another month. (if you change to the next shim size from .04 you'll have a clearance of .09mm.. a lil loose, but acceptable.)

As for those stubborn bolts holding the boots on. If you can manage to get one of the bolts in each of them out with an impact driver, you SHOULD be able to actually twist and turn the boot itself to break the other loose. Doesnt always work, but just a tip. And, when you replace them, make sure to use the anti-seize liberally. Robert Barr also sells stainless steel allen heads to replace those with, pre-lubed, ready to install for a small fee.
 
Finally, the intake boot on the No.1 carb resists all measures to remove it. Dremeled a slot, but the screw head prefers crumbling to turning. Even a screw extractor refuses to grab anything in this damn bolt.

picture.php

Did you try an impact driver?

That's an essential tool for old bikes. Get one at Sears or Harbor Freight
 
MC,

Z1Enterprises is THE place to order ALL of your basic maintenence stuff from. Shims, special tools, jets, whatever.. the only thing they DONT have that I have seen are the Oring kits that Robert Barr sells (www.cycleorings.com)
THeyre fast too.. orders placed early in the day (before 2pm EST i believe) will be sent out that day. I usually get my stuff from them in 3 days tops. You're just as close to them as I am...


As for your feeler gauges. Make SURE you're not transposing those numbers. Of course you cant fit a .12mm feeler in there. Thats WAY too loose anyway. The spec calls for a clearance of .03-.08MM. Anything larger than, say, .09 to .10mm is loose enough id worry about spinning a shim out of the bucket at high revs. Autozone DOES sell a set of feelers that go down to .04mm, and honestly thats small enough that if its that tight you cant get it in there, its time to change it. Even a clearance of .04, *I* would change to the next shim simply because I dont want to have to do it again in another month. (if you change to the next shim size from .04 you'll have a clearance of .09mm.. a lil loose, but acceptable.)

As for those stubborn bolts holding the boots on. If you can manage to get one of the bolts in each of them out with an impact driver, you SHOULD be able to actually twist and turn the boot itself to break the other loose. Doesnt always work, but just a tip. And, when you replace them, make sure to use the anti-seize liberally. Robert Barr also sells stainless steel allen heads to replace those with, pre-lubed, ready to install for a small fee.

So CafeKid reveals that I am a moron.

Not only was I using a crappy set of feelers that went no lower than .127, but I had been measuring with two blades stuck together. :o

After grabbing a better set of feelers and double checking that I was only using ONE blade each time. I find that my clearances are a bit scattered. A couple of them are too wide and a couple are too tight. 4 valves are out of spec, and a fifth is pretty borderline on the wide side.

As for impact drivers, I do not have a compressor. My power drill has a "hammer" setting. Perhaps I will drop a driver bit into it and take a shot.
 
This is the impact driver he is talking about. Never used one before I bought the GS 650. I can say they are amazing. I have been able to remove stripped screws that never would have had a chance of removing with out doing damage.

http://www.harborfreight.com/7-piece-reversible-impact-driver-set-93481.html

http://www.harborfreight.com/impact-screwdriver-set-with-case-37530.html

I have the second one, works great but the rubber slides off after a bunch of wacks with a hammer. Would go with the all metal one if I had the money... ok its only a dollar more and I might buy it anyway.
 
Is the other screw out?If you have one side out tap that side lightly with a hammer.Once it moves you have a loose screw.Remembered this taking off a set of boots to take to a local customer for parts.
 
Both screws on that boot are jammed in there.

I thought impact drivers were only a powered tool. Will grab a hammer blow version right away.
 
Heat them up, the aluminum bowl will expand more than the brass plug

Put them in a 400 oven if you can

The, use a proper size screwdriver or impact bit on the drain plugs

Lots of people poke a wire strand in, I just soak and spray to clean it

Thanks. I will try the Easy Bake Oven method on the float bowls.

I have a related problem with three of main jet/needle jet assemblies. They are deeply in love and refuse to separate. I have sprayed and cleaned them as a unit, and my wire strand confirms that they have clear passages all around. But the brass heads on the main jets are mangled, preventing any grip from a driver to separate them. Cleaner, penetrating oil, etc. do not work. Any kitchen remedies to help pull these apart, given their hot "brass-on-brass" action?

If everything else comes together, I may just replace the o-rings on these and reassemble, with an eye towards replacing the needle jets and maybe the float bowls over the winter.
 
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