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Discussion Starter #1
1997 SS CR. I just had the motor out, checked the valves, put in new belts, put in higher compression pistons, put it all back together. Seemed to run well in the garage.

Test ride: Fired it up, warmed it up, and took off. Seemed to run fine for about 2.5 miles, then it started missing and then seemed like only running on one cylinder, until it stalled out on the road. I got it restarted and turned around for home and got about a mile, still running rough like only one cylinder firing, and it stalled again. I let it sit for a few minutes and it restarted, and I rode it the rest of the way home, although on this last mile or so, it was firing on both.

So I poked at it for a week in the garage. It will start and run normally in the garage. Checked the timing with a timing light, checked the synchronization with a Carbmate. Checked the compression. Checked all the grounds (and added additional grounds, and additional wires from the battery to solenoid, etc).

Today, Test Ride 2: A little hard to start, but started and warmed up, took off. Ran normally for about 2.5 miles and then started acting again like only one cylinder. It actually stalled out at the same street at which it happened last week. then it stalled out again on the way back, at about the same distance. And, again, when restarted (after letting it sit a bit) running the rest of the way home, about a mile, it was firing on both cylinders.

Once home, I pulled the plugs. One looked normal, the other (vertical) had a little wetness on it and smelled like raw gasoline. By the way, after it had cooled down a bit, and I put the plugs back in, it started right up and was running on both.

Is this intermittent problem likely just a loose connection around the coil or plug, or an indication that the coil is about to go bad? Not sure how to undertake a fault diagnosis here.

I should add, before I started messing with it, it was running fine.
 

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Kokusan were the supplied OEM ignitor units....switch them, see if the problem follows to the other cylinder.
Ohm test the coils, check all connections.

Or is the vertical cylinder carb allowing runaway fuel, causing fuel fouling?
 

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Look for an air leak everywhere in the intake system, like said before switch the coils & igniters see if it changes to the other cylinder, check grounds-does yours have the ground on the port side @ the rear airbox mount?-is it correctly in place? --with the higher comp setup did you change carb jetting or is it the same as before? could be 1 or more issues
 

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Have you checked your fuel feed? Sounds to me like you're starving the carb bowls. The normal culprit is the one way valve on the external vent tube getting blocked and creating a vacuum in the tank - as the tank empties the vent can't replace the volume of fuel with an equal volume of air. You should be able to blow into the tank pretty freely, but have a pretty hard time drawing air out of the tank.

Some hints - blow into the tank vent if it stalls. I stopped having this problem when I set up the one way valve about 1" from the tank outlet, so that if any fuel splashes up it doesn't go over the top and act like a trap in your sink. Instead it has a natural path to drain back to the tank.

Also - have you verified your fuel lines aren't kinked after lowering the tank?

I'm in Portland (Beaverton actually) and would be happy to help you troubleshoot if needed.
 

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Make sure your plug wires are tight in the coils and the caps are tight on the wires. Change the wet plug.
 

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Remember one simple rule--There are only 3 things needed for your bike to run--Fuel, Fire, & Air thats it
 

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Discussion Starter #8
OK, I may have it.

Fuel line and return line were mis-routed when I put it back together. They were on top of the cross-brace, not under it. My theory is that they were getting pinched when the tank was lowered and reducing the fuel flow. Won't know for sure until I try it again, which will probably be in a couple of days when we get a dry day.

In my tests in the garage and before the actual road tests, the tank is almost always up, the lines un-pinched, so the fuel pump is keeping the carbs full, and in any event it is usually being warmed up, etc at 1200, 1500, rpms. So, not drawing too much. Then, when I am ready to ride, I lower the tank, put the seat back on and go for the ride. Starting with full carbs, but maybe reduced fuel flow. It runs fine. After a couple of miles, the carbs run empty and the pinched hoses keep the fuel pump from supplying adequate fuel. When it dies out on the side of the road, the carbs are not drawing anything, but the fuel pump is still on while I try to start it, and even though pinched, is supplying enough after a bit to get it going again, weakly.

Anyway, that's my theory. I hope this is the cause. We'll see in a couple of days.

I never even considered the routing of the fuel lines, but discovered searching this site on multiple queries about fuel lines that there is a right way, and there is my way, lol. Love this forum!
 

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You should remember these bikes are old. Always do a Search for your problem. There is nothing happening to your bike now that hasnt already happened multiple times to others.
 

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Discussion Starter #10
Duc96cr. you're so right. Lesson I had previously learned working on my even older airhead BMW. There is probably more written about those than commentaries on the Old Testament.
 

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Discussion Starter #11
Well, back to the drawing board. That didn't work. Had dry pavement this morning and took it out.
Similar symptoms. Although it died after about a mile. On the way back it died again and I coasted in the last half mile.

Figure I'll go through all the fueling system, hoses, filter, choke, cables, etc.
 

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Sorry, I've lost track of what's been done since the symptoms - do you have a clear inline fuel filter? Don't get yourself killed but look down while you are riding to make sure it is always full. Put a bright color food coloring in the gas tank if you can't see it or temporarily use a longer hose so it sticks out from the bike. Again, don't get yourself dead taking your eyes off the road, go somewhere safe - empty parking lot even.

Fuel always full in the clear filter right up to the point where it dies? Good, it is electrical .

There are like five hard suggestions upthread on electrical - do them all.
 

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Did I miss it somewhere ? Ever since I first started working on motorcycles the first thing I’ve always done is change spark plugs.
There is a restrictor jet (pill ) located in the return fuel line to force an adequate volume to the carbs. Make sure it’s there. Watch your return flow while the fuel pump is running for a broken line inside the tank.
 
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