SeX Viper
Member
I just finished a major over haul on my Viper and when I fired it up for the first time last night it will only make 6000 rpm when running it on a stand. I did not try to ride it yet. Here is a list of what I did this summer, it ran fine when I put it away last year.
-Rebuilt both clutches including new bushings, buttons, and springs
-Rebuilt top end of motor including new pistons, rings, bearings, and gaskets
-Replaced spark plug caps and plugs
-New belt (washed it)
-New fuel filter, gas was drained and replaced with new yesterday
-Cleaned carbs per Mr. Viper's instructions including the screens under the floats
-Changed oil in chaincase, adjusted and inspected chain (I replaced all of the bearings last year)
-Checked clutches for alignment and center distance the best I could with a straight edge
-Power valves cleaned and adjusted and the servo was working when I was running it
Track spins easily when I turn it with the secondary clutch. It idles fine and sounds like it is running strong but just will not rev up past 6000 rpm. I pulled the plugs today and the mag side is tan like it would be after some riding, the cener had a little black spot on the tip and the pto side looks like it just came out of the box. When I looked down at the top of the pistons you could still easily see the A that is stamped on top of the piston on the pto cylinder but the other two it is already burned off. I am guessing it may not be firing on the pto cylinder? I guess this would explain the low revs. I checked the spark and all three are firing like crazy. I was going to pull the carbs off tonight and give them another look but wanted to see if anyone else had any ideas. Does anyone have a good trick to know whether the cylnder is firing or not? Thank you in advance, without this site I wouldn't have been able to do everything I did this summer or at least with confidence.
-Rebuilt both clutches including new bushings, buttons, and springs
-Rebuilt top end of motor including new pistons, rings, bearings, and gaskets
-Replaced spark plug caps and plugs
-New belt (washed it)
-New fuel filter, gas was drained and replaced with new yesterday
-Cleaned carbs per Mr. Viper's instructions including the screens under the floats
-Changed oil in chaincase, adjusted and inspected chain (I replaced all of the bearings last year)
-Checked clutches for alignment and center distance the best I could with a straight edge
-Power valves cleaned and adjusted and the servo was working when I was running it
Track spins easily when I turn it with the secondary clutch. It idles fine and sounds like it is running strong but just will not rev up past 6000 rpm. I pulled the plugs today and the mag side is tan like it would be after some riding, the cener had a little black spot on the tip and the pto side looks like it just came out of the box. When I looked down at the top of the pistons you could still easily see the A that is stamped on top of the piston on the pto cylinder but the other two it is already burned off. I am guessing it may not be firing on the pto cylinder? I guess this would explain the low revs. I checked the spark and all three are firing like crazy. I was going to pull the carbs off tonight and give them another look but wanted to see if anyone else had any ideas. Does anyone have a good trick to know whether the cylnder is firing or not? Thank you in advance, without this site I wouldn't have been able to do everything I did this summer or at least with confidence.
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Newfoundlander
New member
Just had a similar issue with my srx it would only hit about 7000 and seemed like it was hitting the rev limiter. It was a little corrosion on the flywheel causing the pickup coil to not read correctly.
SeX Viper
Member
I checked the flywheel tonight and there was some rust on the magnets, not sure if it is enough to cause a problem. I cleaned it up but won't be able to run it until Wednesday night. I will post back with my results, thanks for the tip.
Devilin AblueDress!
New member
Two things come to mind. Ethanol jelly ball that was in lines or pump made it to the PTO carb, no/lacking fuel = no/lacking fire. Carb vents, I have heard of them getting pulled out of airbox causeing a pig rich low RPM condition. I would be careful how many RPM you let it turn on a stand being as it was all just put back together
SeX Viper
Member
Update: I cleaned the rust spots off the flywheel and it was still missing. I pulled the carbs and found the needle was stuck open on the cylinder that wasn't firing and the airbox was full of gas. I fixed it all up and it runs perfect now, smooth idle and revs up just fine. Now I just have to find time to ride it.
Newfoundlander
New member
Thanks for the update