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Discussion Starter #22 (Edited)

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Discussion Starter #23 (Edited)
Re: Understanding Carbs

VM29SS Carburetor Service Manual (.pdf format)

http://www.mediafire.com/?fgzdfgbwxwn


Big thanks to RobinM for scanning the manual!


Note: You will need to download and install a program to view .pdf files (if you dont have one already) You can download Adobe Reader at the link below for free

http://www.adobe.com/products/acrobat/readstep2_servefile.html?option=full&order=1&type=&language=English&platform=WinXPSP2&esdcanbeused=0&esdcanhandle=0&hasjavascript=1&flow=&getsconly=1&dlm=nos&x=64&y=13




If for some reason you cant download the .pdf, you can view it here too...http://www.gixxer.com/forums/showthread.php?t=178425
 

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Discussion Starter #24
Re: Understanding Carbs

HOW TO : BENCH SYNCHRONZING YOUR CARBURETORS

Tools needed:

1 long zip tie
Phillips screwdriver
Vernier calipers


So after your cabs are all cleaned up, you should bench sync. the carbs to get them close. Its reccomended the carbs should be synched with a professional sync. tool. after you get the carbs on and bike running.

Note: I have bench synced my own carbs using the method below and then synced them with a mercury manometer and they were VERY VERY close. All cylinders were on except for one that needed a very small adjustment. So if youre cheap like me, and dont want to buy the sync tool, this method should work fine.

First thing to do is zip-tie the throttle lever open all the way. You can look in the picture to see where i ran the tie. I believe this is the best way. After you have the zip tie on, manually try to open the throttle more, if its open all the way it wont move any more, if you can still move it, you need to tighten the zip tie more.






Starting with the carburetor that has the throttle stop (see pics) you will need to measure from the bottom of the throttle blade to the lowest part of the throttle bore. Right before you get the caliper all the way to the bottom of the bore, rock it back and forth a small amount. You will feel it drag, then get loose, then drag again. When it loosens up, you are close to the lowest part of the bore. Roll the micrometer down until it hits the low spot then record your measurment, then move to carb #2 and adjust it to your first measurment. Then 3. Then 4. Measure and adjust in order 1-4 (see pics)



Measure this carb first, it is the base setting for the rest of the carbs.



Red circles show adjusting screws.




Example: You can see in the last pic the base carb measurment was 0.664. So now when i measure carb #2, if the measurment is 0.667 i can turn the adjusting screw between carbs #1 and #2 until the measurment for carb #2 is 0.664, the same as carb #1. Do the same for carbs 3 and 4, then youre all done. Easy right?
 

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Re: Understanding Carbs

If you don't have or don't want to buy a mercury manometer a test tool is easy to make. you need the following

2 6" lengths of 2"PVC pipe
4 end caps for 2" PVC pipe
12' 5/16th clear hose
4 barbed nipples to fit 5/16th hose
1 small tube silicone adhesive/sealent
mounting straps for the PVC and the hose
4' of 2x6 board
1/2 pint transmission fluid

Drill the end caps for the PVC to fit the hose barbs
Install the barbs in the newly drilled hols and use the silicone on the inside of the cap to seal it.

Install the lower end caps onto the PVC tubes and mount the tubes onto the board at one end.

Cut the clear tubing to a six foot length and attach it to both of the lower barbs already on the board. This should form a loop which you should attach to the board with wire holders or other mounting straps

Slowly pour enough transmission fluid into one of the PVC tubes until it is just below the halfway point in your loop.

Attach the other two endcaps with barbs to the upper portion of the PVC tubes and cut the remaining piece of clear tubing in half. Attach these to the upper barbs and your finished.


This tool allows you to adjust one pair of carbs at a time, or one carb to the reference carb depending on your setup. The PVC tubes keep the fluid from being sucked up into the carbs if they are that far out of adjustment. I use transmission fluid as its easy to see and is thick enough (just) to allow for viewing your adjustments when you make them.

Your tube size may vary due to differnces in carbs. I started using this a few years ago when my local shop was out of mercury type manometers. Since then I've never used anything else.

If you have any questions please PM me and I'll answer as quick as I can
 

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Re: Understanding Carbs

I think it's great that someone took the time to do a write-up like this! Good Job!

I don't mean to sound as if I am being critical or anything, but there are a few things I can add that may be helpful.

First thing, for removing and reinstalling the emulsion-tubes (also sometimes called needle-jets) you will find that a long screw with M5 threads on it will screw right in where the main-jet was installed - much better than a drift or punch for removal, and makes installation a lot easier (if you have a screw long enough to push up through the carb body).

I also noticed that you're not showing the metal "backing ring" that goes between the spring and o-ring on the mixture screws... obviously you can run the carbs without this part, but it does help protect the o-ring from getting chewed-up by the spring when you're adjusting things.

For the "bench synch" the way you describe it is good - but you don't need to go through that much of a process to get it close - you can just adjust the idle-screw til you see the blades start to uncover the holes for the pilot-circuit in the carb-throat, and you can use those holes as a reference-point for the synch - no, it's not precise/exact, but it's close enough to get the bike idling so you can connect a manometer/stix/whatever. ...you're going to find that even if you get the blades *precisely* aligned with each other, even if they are gnat's-*ss exact, you will still need to tweak them slightly once it's on a running motor to make up for tiny variations in valve-lash from one cylinder to the next.
 

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Discussion Starter #27
Re: Understanding Carbs

FastCat, dont feel as if youre being critical. Im all for finding more efficent ways of operation. I never even thought of putting a bolt into the emulsion tube to press it out, that is a good idea.

The washer between the spring and the o-ring ive never even seen. When i removed the plugs on my carbs and took everything out, there wasnt one in there. Makes sense to have one in there though. Its possible i could have lost it while taking everything out the first time but i doubt it.

You are right on with the carb sync too, ive heard of uncovering the transiton ports with the butterfly to synch. the carbs with. If someone didnt have a set of calipers hanging around that would be the way to do it. I guess i just went for the more precise way since i personally dont have a good carb synch laying around. Even if i did, its a pain in the ass to synch the carbs and im too cheap to buy the tool/reserve tank.
 

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Re: Understanding Carbs

Just a question on the cleaning of the carbs, what product do you use to soak the carbs in? I'm from Australia and I'm finding it hard to find. The only product we seem to have here is in a can.

Thanks
 

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Re: Understanding Carbs

Soak it in regular gas or kerosene just to get the loose dirt/grime off. Then you can use Brake-Kleen or other spray carb cleaner in the aerosol cans to clean the jets/circuits out. Do not let the spray cleaner come in contact with rubber/plastic parts.
 

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Re: Understanding Carbs

A wee trick I learned a few years ago, the cheapest and I find the best way to clean carbs is actually to drop the complete set ( not dismantled) into a 20 litre bucket of water. Leave them completely submerged for at least a week, then remove them, strip them and blow all the wayer out of them, they will now be very clean. It works a treat.
the attached photo is the GSXR1100 ones I did last week. ( I know I should have repainted the tops, but I didn't)
 

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Discussion Starter #32
Re: Understanding Carbs

^ Good tip, this does work good as I tried it personally myself. Ill add this though, I think it will help with some baking soda, lemon juice (or white vinegar) and dawn dish detergent. I tried this cocktail and it worked better than Gunk carb cleaner. I would take the carbs half apart when doing this (take the carb tops/diagphrams out and the float bowl/float out) You'll need to blow dry everything afterwards.

Dont even waste your time with the Gunk stuff, there are better, cheaper, SAFER ways.

Still looking for some Berryman B-9 cleaner to test....





Got some good info coming on testing your needle/seats and why you shouldnt use 38mm carb tops on 36's. Stay tuned
 

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Re: Understanding Carbs

HOW TO: TEST YOUR NEEDLE AND SEATS

This is one thing I have seen that causes a lot of problems with the way the bike runs. A bad needle and seat will cause gas to keep rushing in when it should stop flowing when the float pushes the needle against the seat. This will cause the engine to run very rich and will probably flood the engine to the point it wont even start. Most wont agree with me but Ill say it anyways, if you think for any reason your carbs have overflowed (even a little bit) CHANGE THE OIL + FILTER. Gasoline will dilute the oil which could ruin the engine. I know its a pain, but $20 for an oil change is cheaper than a $1,000 engine.

So first a quick explanation how the float/needle/seat operates. When there is no fuel in the bowl of the carb the float is in its lowest position. The needle is hooked to the float by a small clip so when the float moves, so does the needle. So now that the float is lowered there is open space between the needle and seat which will allow fuel into the bowl. As more fuel flows in the float will rise which will push the needle closer to the seat. The float will continue rising until the needle is pressed tightly against the seat and no more fuel will be let in from the gas tank. The float tang determines at what level of fuel in the bowl the needle/seat will close. This is covered more in the cleaning posts i put up.

There are various types of needle seat combos. Some are brass needles and a brass seat. Some are brass seat with an alumminum body needle that has a Viton rubber tip. Some are plastic seat with an alumminum body and rubber tip, etc. The two types that i have seen for our bikes are, the brass seat/alumminum needle and plastic seat/alumminum needle. The plastic seat/alumminum needle seem to last forever as the rubber Viton tip rubbing on the plastic seat does not cause much wear at all.


When you have the carbs apart to clean or you know the needle/seat is leaking take a look at some of the causes below

Needle
-cuts or pits in the rubber tip (sharp rust from the gas tank will make small slices/pits that you may not see without a magnifying glass)
-tip does not have a uniform taper
-spring bumper on needle is seized or sticky from varnish/rust (this you may be able to cure from a soaking in WD-40 or a quick shot of Brake Clean but I would just replace it to be on the safe side. You would have to decide how bad it is i guess.)
-varnish from old gas ( the needle has to slide smoothly in the bore of the seat to work correctly. It could keep the needle from fully closing)

Seat
-does not have uniform taper(look for groove/step in the taper)
-chips/pits
-varnish
-o-ring/washer not sealing
Example:the floats assemblys on the bst36's have an o-ring that keeps fuel from bypassing the needle/seat and going directly into the bowl. The bst38's have a brass seat that i believe threads into the body of the carb, not sure if there is a sealing washer there (doubtful) but if there is it should be checked/replaced. When the carbs are cleaned there should be new o-rings installed anyways. If the seat screws in, just make sure its tight.



So now you think everything is good but you should stil test before you take the time to put the carbs back on the bike. First thing to do is put some clear fuel line on the carbs and set them up over a pan that can catch fuel if it runs out of the carbs. The pictures I took are just an example, theres a better way to set them up but I used what was in arms reach :biggrin






Ok, now pour fuel into the fuel lines. The level will rise and fall as the bowls take in fuel. Once the fuel level has stabilized make a mark with a permanent marker and let them sit overnight *. When you come back in the morning, the fuel level should be the same or close to it. If it is, youre safe to put the carbs back on. If it isnt anywhere near, you have a problem with one or more of the carbs. You can usually tell which carb is the leaking because it will pour fuel out of the pilot air jet or emulsion tube.




*you can see that I made a mark close to the carbs. I made a mistake and you should fill the entire line and make the mark close to the end. This is because under normal operation, the lines are pretty much full and the weight of the extra fuel will have an effect on whether the needle/seat works correctly. Hey its my first mistake of the year, im allowed two right?:wacko

Lemme know what yah think, ill prob fine tooth this write up later.
 

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So you want to rebuild a 1st Gen 1100 shock (Pt.1)

Disassembly:

Pull that dirty stocker off and give her a look-over.



So far so good. No nasty leaks to be seen, no gnarly acid attacks from a battery gone bad...


This one is clean enough that any further elbow grease warrants removing the spring. That means lefty-loosey with the lock rings, while holding the top mount in a padded vise.



Spin the lock rings as far off/up as possible (until they hit the reservoir hose). Then invert so that spring and lock rings are again, as far up as possible so that you have clearance to tip the lower spring retainer askew and slide it out. You might need to push the bottom out bumper up the shock shaft to clear.



Now the spring comes off and she's ready for a clean-up. I like carb cleaner. Use what you like. Kerosene might be a bit more friendly on the rubber bits. Carb cleaner will definitely take off the OEM warning sticker, so consider yourself warned.





Now's where the fun begins. This is the factory "valve cap." The schraeder valve that pressurizes the shock is under this plastic cap. The ones I have done have been tight enough to require a bit of channel-lock persuasion that hints at a factory "do not disturb" perspective. In the end, I am going to use a nice metal valve cap both for appearance as well as protection during servicing, which you will see shortly.



Once you have the plastic cap off DEPRESSURIZE THE BLADDER by pressing in the schraeder valve. I suggest pointing it away from your face when you do this. Factory is around 150-180 psi, but if yours has any pressure at all (assuming never serviced), then you have just experienced a sign of encouragement. This means that the bladder itself should still be sound and re-useable.



Now that you have DEPRESSURIZED THE BLADDER, use a valve-core tool to remove the valve core and set it aside.



Now we are ready to remove the bladder. Keep in mind that oil should not come out until the bladder is removed. If any measurable amount does, it is a further sign that the rubber bladder is compromised. The bladder is held in with a circlip that you cannot necessarily see right off the bat. Let's put the res. back in the padded vise and snug it down LIGHTLY.



Here's where a couple things happen. We are ultimately going to tap the top of the bladder down to expose and remove the previously mentioned circlip. Before I do that, I spray a bit of WD40 to penetrate down into the interface, then I thread on that nice metal valve cap all the way and give it JUST a touch of snugness with a tool (barely more than fingers). The valve cap gives me a point to tap on with my hammer and push the bladder top down into the reservoir body. REMEMBER, you are working with aluminum that is not super durable, so if something isn't moving...



Here is the bladder top tapped down into the res. body and the circlip exposed.



And here I am with my bent up dental tool about to fish out the circlip.



Now that the circlip is out, we can wiggle out the bladder. It will be tight, so be patient, "walk it out", and try not to let the channel locks slip off the flats too violently (your goal is not at all).



Here comes the bladder. Get ready for that oh so sweet smell of two decade old suspension oil. No one needs to tell you that that is a bad smell...

And ugh...it looks like watery JB Weld.





Let's cycle the shock and pump all that crap out. There is nothing at this point that will fall into the oil pan. If something does...umm...you didn't need it. Keep doing it, you'll know when you're done.



Followed by a spray (or half a can) of carb cleaner and a wipe.



Congratulations. Now that all the bladder and all the oil is out, we are ready to disassemble the shock body. More to come. Mom says it's time for bed...
 

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Re: So you want to rebuild a 1st Gen 1100 shock (Pt.1)

Thanks guys. I'll continue this soon. Going to go do some pedaling in the high country today:

 
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