ruff running cutting out

[thunder1295]

Hello, I got a 85 royal with 75 k's on it the problem I'm having with the bike is once I ride it 15 or more miles it begins to drop a cylinder under 3000rpm, it sputters, feather the throttle and get it above 3 grand it starts running on all cylinders. Starts right up when cold and hot.

Any ideas what the problem could be????

Sure would be a big help, thanks in advance

 

Thunder

[bongobobny]

Problem is most likely carbeuration issue, like the idle circuit is plugged up. Try running a can of Seafoam additive to a tank of gas. You may also be well served with a new set of plugs after the treatment as Seafoam can and will loosen up a lot of gunk and this gunk will foul your plugs out.

 

Another possibility is a bad TCI when warm. Try the seafoam and plugs first to see if that helps...

[thunder1295]

Thanks I will try that, hope it's not the TCI.

Another question, it looks to me on the diagram of the carb's that I can get to the pilot screw without having to remove the carbs and if need be I can remove the factory caps they put on in order to clean and adjust them, is this correct?????

[Prairiehammer]

Thanks I will try that, hope it's not the TCI.

Another question, it looks to me on the diagram of the carb's that I can get to the pilot screw without having to remove the carbs and if need be I can remove the factory caps they put on in order to clean and adjust them, is this correct?????

 

The pilot (idle mixture) screws (not to be confused with the pilot jets) are accessible without removing the carbs.

Edited April 18, 2015 by Prairiehammer

[thunder1295]

Excellent, didn't feel like taking off the carb's, hope adjusting them will solve the problem of the motor dropping a cylinder when the rpm's are under 2500. I synchronized the carb's without the pilot screw, hope adjusting them fixes the problem.

Keep you posted.

Thanks

[thunder1295]

Pilot screws were not to far off the 2 1/2 turns out except 1 which was out about 6, turned that back in, syn the carb's again and it running good.

Thanks for the help.