latheboy
Active Member
This is my situation.... THis in my 2nd season on my max. It is a high milage bike, 53k. Ran fine last season. This spring I replaced all carb and intake boots. Replaced valve cover gaskets.
I have had a problem of the bike running weak on one cylinder. The left rear. The carbs were properly balenced, and carbs setup for good color on the plugs.
Now the meat of what I have learned... The will run great, when it wants to. Other times it will run on 3 cylinders until I get it over 3k rpm or so, then the 4th picks up. One time last week, i got home from work and it was running rough, so I did a compression check. These are the numbers I got, 170 175 180, 30. Yes, 30 on the left rear. I could hardly belieive it. I tried again. As I cranked it, WOT, it read 30, 30 30, 160, 175, 175. Seems that a valve was stuck, and it closed completely as I read the gauge. NOt sure exactly what to do, i cranked it some more. It read 175 consistently. Then I figured a valve was sticky, so I fired it up and gave it about 3 cap fulls of seafoam at 4k rpm right thru the vaccum fitting. Bike ran good the rest of the week. The suspect cylinder ran weeker than the rest, but it was firing at idle. This moring, I go out and fire it up, and sure enough, its running on 3. Pull off the wire for the left rear, nope, not running on that cylinder. Tried a little more seafoam to no avail. I rode it around the block a few times, and it runs on all for only after I get above 4k, or if I crank it right from idle its fine. Most of the day it would not run right. Late today I took it out of town to a freinds house, about 10 miles out. IT ran similar, not fire on the one bad cyl until i was up on the rpm, or there was a load on it. On the way home it ran like brand new! I even reached down and pulled the plug wire at 3k rpm on the rode, and it was running on that cylinder like it should. When i got home it idled perfectly and was fireing on all 4. I have checked for vaccum leakes and tried new plugs, wires and coils....ect.
anything else i can do for this sticking valve, or could it be a broken spring? Looks like i may be jerking the motor out of the frame......
I have had a problem of the bike running weak on one cylinder. The left rear. The carbs were properly balenced, and carbs setup for good color on the plugs.
Now the meat of what I have learned... The will run great, when it wants to. Other times it will run on 3 cylinders until I get it over 3k rpm or so, then the 4th picks up. One time last week, i got home from work and it was running rough, so I did a compression check. These are the numbers I got, 170 175 180, 30. Yes, 30 on the left rear. I could hardly belieive it. I tried again. As I cranked it, WOT, it read 30, 30 30, 160, 175, 175. Seems that a valve was stuck, and it closed completely as I read the gauge. NOt sure exactly what to do, i cranked it some more. It read 175 consistently. Then I figured a valve was sticky, so I fired it up and gave it about 3 cap fulls of seafoam at 4k rpm right thru the vaccum fitting. Bike ran good the rest of the week. The suspect cylinder ran weeker than the rest, but it was firing at idle. This moring, I go out and fire it up, and sure enough, its running on 3. Pull off the wire for the left rear, nope, not running on that cylinder. Tried a little more seafoam to no avail. I rode it around the block a few times, and it runs on all for only after I get above 4k, or if I crank it right from idle its fine. Most of the day it would not run right. Late today I took it out of town to a freinds house, about 10 miles out. IT ran similar, not fire on the one bad cyl until i was up on the rpm, or there was a load on it. On the way home it ran like brand new! I even reached down and pulled the plug wire at 3k rpm on the rode, and it was running on that cylinder like it should. When i got home it idled perfectly and was fireing on all 4. I have checked for vaccum leakes and tried new plugs, wires and coils....ect.
anything else i can do for this sticking valve, or could it be a broken spring? Looks like i may be jerking the motor out of the frame......
