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hoping that the ultrasonic bath did it's magic
The ultrasonic bath makes it shinny. But you must still blow the heck out of each passage with carb cleaner and compressed air. Then do it again. Every tiny passage must flow freely when you blow it through with carb cleaner. Oh, and wear eye protection and an old shirt. It gets everywhere.
 

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Finally...an update on my '01 carb rebuilding journey. I decided to use a temporary auxiliary plastic fuel container. I haven't finished with the tank and wanted to eliminate the possibility of crap from the tank causing problems from the beginning. With this setup, the airbox/filter are NOT installed and I've plugged the rear carb vacuum line that normally goes to the tank fuel valve. I got the bike started without much trouble and the rear cylinder appeared to be not firing. Bike would "idle" at about 900 rpm with just the front cylinder firing. Because of this, the bike had only about 1-2 minutes of run time. After checking the spark plug, it was wet with fuel so I assumed it wasn't getting spark. A bit of a few simple changes and tests (new plugs, check coil wiring, compression check yielded 210 psi) and all checked good. I thought I was still chasing a bad cylinder and the last test was with the bike running (still on the front cylinder only), I sprayed hot start (quick start/spray ether) into the rear carb and low and behold, it momentarily fires. I repeated this a few times to confirm it wasn't my imagination. The carb definitely has fuel in the bowl as initially there was fuel leaking from the carb bowl drain screw (forgot to tighten properly on reassembly) and tightening it stopped the leak. I'm ready to remove the carbs and go through the rear one first. I'm hoping that I made a simple mistake and can figure it out. Otherwise, back to complete disassembly and back in the ultrasonic bath. I'm a bit surprised that if the rear carb is putting in too much fuel that the cylinder won't even fire. During reassembly, the float heights were checked and within the 7mm spec so I didn't need to bend the float tang. The rebuild kit (All Balls Racing brand) had the needle and brass seats so these were used as the original brass seats were corroded and the o-rings were damaged (original needles looked ok) . The pilot jets, main jets and needle jets were all cleaned and looked good so I didn't use the ones in the rebuild kit. I also installed new OEM coaster valve diaphragms. Also, a reminder that the bike was running fine before the previous owner let it sit (and sit and sit) for 4+years. He also had few repair tools and practically no mechanical experience and didn't take anything apart or change anything. Any comments/suggestions are appreciated. Sorry for the long-winded update.
 

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2001 Suzuki SV650S
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It's to rule out intermittent sparking of a faulty Spark plug cap. They can cause all sorts of problems.

Click here,

Thanks for the explanation and link Straticus. So now I understand but my concern is switching the plug caps on 22 year old wires. I see that the plug cap is available as an OEM part separate from the spark plug wire. I have a multimeter and can also bench test the plug caps as well. Should I expect the plug cap to easily disconnect from the wire and then re-assemble to work correctly?
 

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Thanks for the explanation and link Straticus. So now I understand but my concern is switching the plug caps on 22 year old wires. I see that the plug cap is available as an OEM part separate from the spark plug wire. I have a multimeter and can also bench test the plug caps as well. Should I expect the plug cap to easily disconnect from the wire and then re-assemble to work correctly?
Yes. My 99 still has the original coils and leads and I just changed the plug caps for the NGK Racing ones on my page as they are cheaper. You may not have to. Just cut about 1mm off the end of the HT wire so that when the Spark plug screw goes in it has some fresh wire to go into.

This may not be your problem but it's worth doing just as a test and service point :)
 
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Did you do a bench sync of the carbs before install?

Idle speed should be around 1200 iirc

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I'm not certain how to do that. Is there a link for that? I didn't disassemble the carbs from the bracket that holds them together so the linkage was not taken apart. Would the sync still be affected if it wasn't taken apart?
 

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Discussion Starter · #90 ·
Sync should be pretty close then.

I like to use a 1/4" wide strip of printer paper as a feeler gauge for the throttle butterfly. I try to get the drag of pulling the paper out about the same on each carb before installing. Gets sync and idle speed real close

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I'm not certain how to do that. Is there a link for that? I didn't disassemble the carbs from the bracket that holds them together so the linkage was not taken apart. Would the sync still be affected if it wasn't taken apart?
There's rarely a need to split the carbs so leave them be on that score. Even if the carbs were out-of-balance both cylinders should still fire OK. There could still be a blockage in the rear carb so if you have access to compressed air give it a good blast out.

If and when you want to sync the carbs,

 

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Discussion Starter · #92 · (Edited)
Can you give it throttle while it's idling?

Did you change the mixture screw setting?

Or it's electrical noted by the wet plug.

And I assume that the other vacuum line that runs the fuel pump is connected or capped?

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Can you give it throttle while it's idling?

Did you change the mixture screw setting?

Or it's electrical noted by the wet plug.

And I assume that the other vacuum line that runs the fuel pump is connected or capped?

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1. It's a rough idle and sometimes cuts out unless I blip the throttle if I think it's going to stall. It'll take throttle (had it up to about 5000 rpm) but it's very slow to respond. I can feel that the engine isn't making much power. With the engine running and the spark plug wire to the rear cylinder is removed, there's no change in rpm

2. I assume that you mean the pilot jet screw setting. On U.S. model bikes, the pilot jet is sealed with a plug covering access to it. The Suzuki service manual indicates how to drill out the plug. It seems tedious and you run the risk of drilling into the pilot jet (says drill no deeper than 6mm). The Clymer service manual says this procedure should be avoided as most times there's really no need access it. The rebuild kit or OEM Suzuki parts websites don't show the plug as a separate part so I'm not sure what I would use in place of it if I drilled it out.

3. The spark plug is wet with fuel. I thought also no spark but there's spark with the plug removed from the cylinder, attached to the lead wire with grounding the plug to the engine. Also, when spray ether (quick start/hot start) is sprayed into the rear carb while the engine is running, the engine momentarily increases rpm significantly. I did this several times to make certain that it was indeed happening.

4. Although I'm using a temporary auxiliary fuel tank, it's connected to the fuel pump and the vacuum line (from the front carb) is also connected to the pump. The rear carb has a vacuum line that goes to the fuel valve and this line is capped when using this fuel setup.
 

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Discussion Starter · #94 · (Edited)
Bizarre that the plug is fuel soaked, yet adding fuel makes that cylinder fire.

I have encountered loss of spark through the plug boot and breaks in the lead wire grounding to the engine block before.


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I agree. Straticus mentioned to check the resistance of the spark plug boot and explained it on a post so I've got a few more things to do. I had already removed the carbs and disassembly indicated (at least to me) no problems (or mistakes) so back in the heated ultrasonic cleaner yesterday. Carbs are awaiting final dousing with spray carb cleaner and compressed air blow through before reassembly.
 

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Don’t overthink it. You’re on the right track. Petroleum is actually one of the harder fuels to burn. So if the rear carb is ‘dribbling’ large amounts of fuel, which the air can’t atomize, the spark plug could ‘drown’ in fuel. Weird thing is that would take a LOT of fuel, since a substitute for ether is to pour a tablespoon or so of gas right into the spark plug hole or down the carb throat, and you’ll still usually get fire… Carbs are simple, but can be finicky. try the cleaning again, and really look for plugged passages internal to the carb body.

The only other thing is to take what the previous owner said with a grain of salt. When I bought new jets for my Shadow, the original ones had a HUGE oriface compared to the new ones. My mechanically-minded father was the previous owner, and he admitted that he‘d cleaned them with a little drill bit some years before. Never gave a second thought to how easily that would tear out the brass! So always double-check.
 

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From my experience with vintage cars/motorcycles (I own a '72 Olds Cutlass, '76 RD400 and '78 GS750), most repairs/upgrades almost always take significantly more time/money/learning curve than expected at the start. Sometimes playing a "Monday morning quarterback" tells you that perhaps you should have taken a different approach from the start. At least I now have the confidence and tools/equipment to do the carbs on my '06 GSX600F katana...once I get this SV running good...I hope. Purchasing used SV carbs has certainly been a thought over the last few weeks, but I guess I like the challenge!
 
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