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Discussion Starter · #1 ·
Yesterday was supposed to be a good Saturday. I had planned to rebuild my extra set of carbs, replace my choke cable, plug wires, and spark plug caps (2000 SV650, 15k miles), mow the grass, and enjoy the sun. In fact, I woke up early in excitement, just to get the day started.

My bike was running, it just ran rough at steady throttle (2,500-4,500 RPMs), and has run rich since I bought it a month ago. About three weeks into my ownership, the bike died. So, I rebuilt the existing carbs, changed the oil, flushed the radiator, and changed the spark plugs. Ultimately, I found the main problem was a tank of bad gas. I flushed the tank and added good gas (non-E10) and Seafoam, and it cleared up. The bike still ran rough and rich, but at least it ran.

During yesterday's activities, my "good" Saturday, I lost a carb shim and a needle spring, so finishing the carbs will have to wait until I can get the parts. I'm sure the parts are hiding somewhere in my garage, but to me, they disappeared. So I turned my focus to working on my bike.

Straticus has often recommended testing spark plug caps when trying to isolate problems. Sure enough, when I testing mine, I came up with 10.3 and 9.9 ohms of resistance. Testing the new NGKs (SDO5F) came up to perfect 5s. So I replaced the caps, and replaced the wires for good measure (standard 7mm cut-to-length car wire).

I also decided to replace my choke cable and mechanisms thinking a sloppy choke system may be contributing to my running rich. One thing I found: getting the choke cable onto the slider, while holding the spring is a bitch! I did the rear carb, then the front. But when I was hooking the slider to the cable on the front carb, I loss control of the spring, and it went flying. So I began my search for the rebel spring. After an hour of looking, no luck. Then it occurred to me, I had the front plug out. Maybe it somehow fell into the combustion chamber. Oh shit. I hooked up my bore scope and started searching down the plug hole. Then the bore scope ran out of battery. Lovely.

I set the bore scope on the charger and decided to change my thoughts. I read in the forums of some folks eliminating their choke systems altogether. I decided to do this, but just on the front carb. I fashioned a spacer made up of a carved piece of fuel hose to keep the plunger in place, and thought I could start the bike with the rear choke only. No problem. I installed my genius choke system and left for Autozone to pick up some new plugs. Heading out the garage, I stepped on something. It was the rebel spring. Quickly, I undid my previous work and installed the front choke mechanism.

Back on track, I cancelled my Autozone trip, choosing instead to simply clean my existing plugs. They only had a few hours on them, and the bike was running on them. But they were black, so I took a torch to them to burn off the oil, then I cleaned them with contact cleaner. This contact cleaner, by the way is good stuff. I also used it to clean out loads of gunk in the left handlebar control when I had it apart to install the new clutch cable. After that I filled the control housing with silicone spray for good measure.

Getting everything zipped up, I was excited to hear her purring for the first time, without the rough and rich running. She started right up with the smooth actuating choke. I backed out of the garage, she popped a little as always, but was warming up. Suddenly at the end of my driveway, she died. I set the choke to full and it started initially, then died. Fu*k! Pushed it back to the garage and gave up for the day.

This morning I woke up at 4:am with a burning thought. Did I hook up the PCV tubes to the airbox yesterday? I went to the garage to find both hoses dangling free. Again, maybe I should leave mechanicing to the professionals. Anyway. my plans today are to hook up the PCV hoses and change the plugs. My thought are my issue could be a few things.
  1. The unhooked PCV hoses
  2. I may have ruined the plugs by torching them
  3. Maybe I should not have filled the left handlebar controller with silicone spray
After I poke around and check these things I'll report back. I'm hoping upon hope it's only the plugs. That way I can take a joyride, and get the yard mown, and have a happy house again.
 

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Discussion Starter · #2 ·
Okay, this is frustrating. I hooked up the PCV hoses and changed out the plugs. No difference. Still will not start. Just for grins I replaced the new NGK spark plug caps with my old ones, and it fired up straight away. Very strange. Each of the old caps have 10 ohms of resistance, but it runs with them, and not with the NGKs. Runs like shit, but it's running.

While it was on the stand running, I removed the air filter, and the RPMs jumped by 1,000 RPMs. Obviously too rich. It is firing on both cylinders, but about every 10 seconds it backfires out the carb. Just a single backfire. It is also backfiring through the exhaust consistently, but randomly. I am thinking about swapping the new plug wires back to the old ones just to see what happens. Keep in mind, it was running before I started messing with it, Just rich and rough, but not nearly this rough.

Any ideas, I would certainly appreciate.
 

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This seems to be my standard answer to just about any problem...but it might be of help here: Have you checked all tune-up items? Tight valves can cause issues such as these and I'd make damn sure they were adjusted properly before doing any troubleshooting of other issues were you me. When they're borderline tight the overlap becomes excessive which can cause spitting back through the carbs and general bad running. This also can manifest itself as a 'quit running' when it warms up and things expand and get tighter. I always work by elimination and have found starting with the basics the best place to start. Once all of them have been addressed then move on to the more difficult things. Remember trying to cure a mechanical problem by working on the carbs is doomed to failure. :)
 

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Discussion Starter · #6 ·
This seems to be my standard answer to just about any problem...but it might be of help here: Have you checked all tune-up items? Tight valves can cause issues such as these and I'd make damn sure they were adjusted properly before doing any troubleshooting of other issues were you me. When they're borderline tight the overlap becomes excessive which can cause spitting back through the carbs and general bad running. This also can manifest itself as a 'quit running' when it warms up and things expand and get tighter. I always work by elimination and have found starting with the basics the best place to start. Once all of them have been addressed then move on to the more difficult things. Remember trying to cure a mechanical problem by working on the carbs is doomed to failure. :)
Good points all around Rob, and thanks for your input. I've not looked at the valves because they scare the crap out of me. To me, the carbs seem like the easy stuff. Valves seem kind of icky (borrowing a term from my daughter). But, you're right. I should check the valve clearance. Oddly though, this problem occurred suddenly. Friday it was running. I work on it. Saturday it does not run. To me it seems like I screwed something up by working on it.

I've read a lot in the forums about checking valve clearances, including a lot of your posts. And yes, it goes back to the basics. Dammit, I will check the clearances. But if it needs adjustment, I will send it to a professional. I understand the adjustment part is quite technical. I don't have the balls to dive in that deep.

Thanks for your advice Rob. I will follow your wisdom. This coming week if you look in the direction of New Orleans, and you see a mushroom cloud in the air, you'll know I fu*cked up.
 

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Good points all around Rob, and thanks for your input. I've not looked at the valves because they scare the crap out of me. To me, the carbs seem like the easy stuff. Valves seem kind of icky (borrowing a term from my daughter). But, you're right. I should check the valve clearance. Oddly though, this problem occurred suddenly. Friday it was running. I work on it. Saturday it does not run. To me it seems like I screwed something up by working on it.

I've read a lot in the forums about checking valve clearances, including a lot of your posts. And yes, it goes back to the basics. Dammit, I will check the clearances. But if it needs adjustment, I will send it to a professional. I understand the adjustment part is quite technical. I don't have the balls to dive in that deep.

Thanks for your advice Rob. I will follow your wisdom. This coming week if you look in the direction of New Orleans, and you see a mushroom cloud in the air, you'll know I fu*cked up.
I just take mine to a pro for check/adjustment. Even though I'm perfectly capable of checking, I figured if it needs adjustment, I'm not buying a whole shim kit, so why bother going in there only to find out I have to put it back together and bring it to the local guy? That said, my SV didn't need any adjustment until 48k. I'm due for another checkup as I'm over 64k now.
 

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Discussion Starter · #8 ·
I just take mine to a pro for check/adjustment. Even though I'm perfectly capable of checking, I figured if it needs adjustment, I'm not buying a whole shim kit, so why bother going in there only to find out I have to put it back together and bring it to the local guy? That said, my SV didn't need any adjustment until 48k. I'm due for another checkup as I'm over 64k now.
What up GC! 64k miles? Damn I'm impressed. I'm only at 13k (and crying uncle).

Anyway, I'm going to check the clearances as Rob advised. It doesn't look that difficult, and I'll learn a thing or two. But yes, if adjustment is needed, going straight to my mechanic. Faaarrr above my pay grade.
 

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What up GC! 64k miles? Damn I'm impressed. I'm only at 13k (and crying uncle).

Anyway, I'm going to check the clearances as Rob advised. It doesn't look that difficult, and I'll learn a thing or two. But yes, if adjustment is needed, going straight to my mechanic. Faaarrr above my pay grade.
Years ago when I first got my SV and the forum was hopping, I rode somewhere between 10 and 13k per year for 3 or 4 years straight. The motorcycle picture game and being single were big reasons for the miles I put on. Been more like 3k miles per year the past few years. Hoping to get to 100k before I upgrade, although if I was still going the rate I was when I made that goal, I'd be there by now.
 

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Okay, this is frustrating. I hooked up the PCV hoses and changed out the plugs. No difference. Still will not start. Just for grins I replaced the new NGK spark plug caps with my old ones, and it fired up straight away. Very strange. Each of the old caps have 10 ohms of resistance, but it runs with them, and not with the NGKs. Runs like shit, but it's running.

While it was on the stand running, I removed the air filter, and the RPMs jumped by 1,000 RPMs. Obviously too rich. It is firing on both cylinders, but about every 10 seconds it backfires out the carb. Just a single backfire. It is also backfiring through the exhaust consistently, but randomly. I am thinking about swapping the new plug wires back to the old ones just to see what happens. Keep in mind, it was running before I started messing with it, Just rich and rough, but not nearly this rough.

Any ideas, I would certainly appreciate.
Check how to test the coils in the WSM.
 
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Removing the air filter will make it run lean, backfiring is a sign of a lean condition. Have the carbs been cleaned recently? Sounds like some of your initial problems were pilot jets likely stopped up from sitting. Might try to remove the carb jets spray carb cleaner and air through them. Ideally you would disassemble the carbs and soak the bodies in a good cleaner. If a bike was running (although poorly) and doesn't run after the work something you did is likely causing the problem.

Having been around carbureted motorcycles for nearly 50 years has taught me most poor running is caused by the carburetors. If you don't know what you're doing either take the time to research and learn or take to a qualified shop - not Bubba down the street. When you hold a clean pilot jet up and look at a light/sun you can barely see through it, one that sat over the winter with ethanol fuel will be nearly impossible to see light through it. If it runs better at higher RPM you can rest assured the pilot jet is stopped up.
 

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Discussion Starter · #14 ·
Thanks Salty. I cleaned/rebuilt the carbs following ziptech's posts about two weeks ago. I rebuilt them because the bike ran rich (black plugs and major unburned fuel smell) and stuttered like a two-stroke riding through the pits between 3-5,000 RPMs.

After cleaning the carbs, it ran the same way. But I do recall that maybe I did not get a good carb cleaner stream from the three pilot circuit jets next to the funnel. I say this because last Saturday I cleaned/rebuilt my extra set of carbs, and noticed I got solid, strong blasts of carb cleaner from the pilot circuit jets in this set of carbs.

Bottom line, at the next chance I am going to swap out my existing carb set with my other cleaned carb set and see if there are any changes. I also plan to check coils and the valve clearances. I'll update.
 

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This is the fun of working on 20+ y/o new-to-you carbureted bikes. It could be fuel (most probable), it could be spark (not as likely but possible), it could be valves (at 15k miles?? okay...), it could be a combination of the three, plus whatever other unknowns you have yet to find.
My Dad likes to bring up the advice an old manual he had from a past bike offered (Triumph, Zundap, can't remember): "one morning your bike won't start. Before you tear the engine apart, sit down and light a cigarette." There's an awful lot to taking the simple approach. We can get distracted by what the problem could be instead of the symptoms we are actually experiencing. Remember: don't think, LOOK!
 

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Discussion Starter · #16 ·
Good point Drew. The first time I cleaned my carbs, I also changed plugs, flushed cooling, changed oil, etc. Bike ended up running after that, but got worse in 10 minutes, then died. If I had followed your Dad's advice, I would have stopped and lit a cigarette, retraced my steps, and realized I had just filled the tank before the bike started running badly. My whole (or main) issue was bad gas. With that pause I would have saved a lot of headaches.
 

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Discussion Starter · #17 ·
The bike is still running the same, popping and such. Shooting in the dark I sprayed contact cleaner on the left side of the bike and the revs jumped dramatically. Vacuum leak! I found out the caps I used on the sync lines I installed last rebuild were not doing their jobs. In fact, one was missing completely. I'm surprised it was running at all.

I installed new caps and zip-tied them securely, and she fired right up, ran better than all weekend. Still popped a little, but I'm on the right track! I shut her down and gathered my thoughts. I'm still not running perfectly, so I added some Mechanic In A Bottle (out of Seafoam). Maybe I still have traces of bad gas in the system. Fired it up to get the stuff into the carbs, then will let it sit overnight.

Yesterday morning I fired it up and she started right away. On choke reved to about 4,000, then died. Completely. I walked away in frustration. I've not been able to start it since. I will check the spark this morning, but this is fu*ked up.
 

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I've mentioned before that if you have a pal or someone with a bit of motorcycle knowledge who can give you a 2nd set of eyes it may help spot something. I've done this in the past when frustrated and just having someone else there to bounce off can help :)

Also back to basics. In the Service manuals there are troubleshooting sections and I've used these in the past to try and track an obvious thing I've overlooked
 

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Discussion Starter · #19 ·
Thanks Straticus. An old racing buddy of mine is coming by tomorrow afternoon to be, as you said, a second set of eyes. He has a 1978 Gold Wing project bike, yes, four carbs. He was able to get that running, so he will have some insight. And, good idea with the service manuals. I have factory and Clymers. I am going on vacation next week and will bring them with me. I chuckle when I picture an old man on the beach reading service manuals.

Poking around this morning I decided to drain the tank and replace with new gas. I will also, again, inspect the petcock screen. Plus, I wrapped up rebuilding my extra set of carbs. So this evening and tomorrow morning I plan to swap out the carbs and see what happens. I will also swap out the new plug wires for the old. It ran with the old ones, so why not?

Thank you for your advice. I really appreciate it.
 

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I am going on vacation next week and will bring them with me. I chuckle when I picture an old man on the beach reading service manuals.
Service manuals are a good thriller read. It's usually the Addendum that did it<grin> :D
 
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