Hey guys, new to this forum. I just got my in laws ancient rig up and running from the grave. At first I was having Low rpm, right around 900 to 1100, I got it up to 3100 at idle, it goes steady for the mins an goes out. When I ride, it cannot get to 5000 rpm, and when I do, it bogs out and goes back down to 4000-4500 rpms. How can I fix that?
What's the compression? If it's below 100, it may be time for a top end refresh.
If compression is over 100, I would first change the spark plugs and make sure you have a bright blue spark at the plug. If not, unscrew the plug boot and snip off a bit of the wire to make sure you are making good contact. If that doesn't help, pull and clean the carbs, paying particular attention to the jets. Make sure you remove the pilot jet to clean it completely. You may have to take a fine wire to clean out all the passageways in the carb. (a strand of Cat-5 wire with the insulation on works great.)
Bogging can also be clutch related, especially if you have a broken spring in the primary or secondary. It's always good maintenance to remove and clean both clutches each year. You will need a clutch puller for the primary and when you remove the secondary, make sure to account for the number of shims on the bolt and behind the secondary. They are important to keep the clutches aligned. If you can't remove the primary, at least blow it out with compressed air and then wash the sheaves with Simple Green and a green Scotchbrite pad. Look at the flyweights and rollers to see if they are damaged, too.
2017 SKS 800, 2007 Dragon RMK 700 155", 2008 RMK 600 155", 95 Prowler 550 2-up, Really OLD AC Cheetah
The spark plugs are all changed and working. Did low maintenance to the carbs.. I'll go and clean them out at noon. If that doesn't help I'll check the secondary clutch.(in law said that the primary should be okay)