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Discussion Starter · #1 ·
Riding home the other day on my '09 VTXR with 115,000 miles, I noticed it didn't sound quite right on start up and warm up (runing a bit rough). Got on the freeway and as soon as I got over 70 started to feel an intermittent loss of power. Slowed down and tried a few things, speedign up and slowing down, only seemed to be when I was above 70. Made it home, let everything cool down and then pulled the plugs thinking I had a bad plug. All were in good shape, only one showed different darker color. Put new plugs in and went for a ride. Seemed like it did the trick, but I decided that I would push it a bit on the freeway. Had it up to 90 when it started doing it again. Less than before but it was there. Came back to the house slowly. Opened the air cleaner and had a bunch of water in there from riding in the fog/drizzle here. Thinking maybe I was pulling water drops from the air box into the carb.I dried all that out and again went for another ride, same issues. Brought it back to the house and waited until the next evening, to check the plug wire. Pulling it out I did find that the wire was not quite solidly connected. But this was because as I tried to pull it out (front left) it was very hard to detach from the plug (yes dielectric grease used). Pair of pliers to the boot successfully tore the boot in half and the wire popped off. Again pair of pliers to the boot and broke a piece off the insulator. Finally though it disengaged from the plug. Cut a bit of wire off and successfully reassembled the boot with electrical tape and heat shrink wrap. (Note: also went down to the shop and ordered a new boot, $27 for one :rolleyes: still awaiting the arrival of it) Took it for a ride and still feeling the same issues. Made an appt at the shop to have them take a look at it (carb issues?), but thought I might ask if there is anything else to check? I did check the battery connections and they too are tight. Don't seem to have the issue or maybe just don't notice it below 70 MPH. Ideas?
Thanks,
 

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Sounds like either a carb tuning issue or a fuel flow problem. I would check the two filters in the fuel system. One is at the fuel inlet to the carb and the other is up inside the tank protruding from the connection to the petcock.
 

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You might also look at the vacuum piston in the carb. At low throttle settings the venturi in the carb is producing plenty of vacuum, but when you approach full throttle the venturi is producing almost no vacuum. The vacuum piston causes the main needle to go up and down in the bore to adjust fuel mix while riding. If there is a pin hole leak it will allow an amount of vacuum to leak around through the diaphragm (the rubber membrane that allows the piston to slide up and down in the bore) and will cause the piston to not be in the correct position to adjust the fuel mix and if the leak ls severe could let the piston drop to the closed position at wide open throttle and cause a severe lean condition which could cause the engine to die or overheat and damage the engine. To test the diaphragm you would need to remove the cap on the top of the carb and remove the spring, the piston and the needle assembly then with a strong light source behind the diaphragm gently stretch the rubber working your way all around the piston for pin holes or cracking. If you find a hole or crack you will need to replace the diaphragm!!!
 

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Discussion Starter · #4 ·
So got the bike back from the shop. Cylinder head gasket is leaking. Low compression in the front cylinder. Looks like I am either without this ride permanently or for a while to pull the engine and rebuild cylinders. :confused:
 
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