Hi all and thanks for the great welcome received when I joined the clinic.

I have a 2005 Road Star that has developed a problem over the last year or so and neither my local shop nor the Yamaha online guys were able to assist with. (they certainly tried though)

My bike has about 25,000 km (15,000 mi ??) and has started to drop a cylinder after about 15 minutes running. It starts fine, and if I pul over once it drops a cylinder and just sit idling for a minute it comes back onto 2 cylinders but only for a short period then drops out again. (Really noticeable on uphill stretches.)

The bike is stock apart from pipes and hasn't done this during the first 24,000 km.

The local shop has fitted new coils and done a bunch of other stuff checking carby and fuel flow, tank breather etc but to no avail.

I have read both on the Clinic here and on other info I found on Google about possibly dropping rear cylinder due to a head/valve or a hydraulic lifter problem but I'm not sure how to identify what could be going south.

Any thoughts appreciated. Cheers, Peter.

SVS problem. Your rear valves are carboned up. curt has a good remedy for it. "04s and'05s had the most problems with it.

The valve guides were reamed out more on '06 and later models. But any of them can carbon up.

tell your dealer to look up this service bulletin:
http://weislake.com/sig/mucker/2-16-07.pdf

if the ring free does not do the trick, the ultimate fix is to ream the valve guides and put in heavier valve springs. Think they were using the Speedstar or Warrior valve springs. The guides is where the issue is, I think some guides were made on the smaller side of the tolerence, and if the guides get gunked with oil due to an improper oil level, the valve stems get caught in the guide and you lose the cylinder.

And it's not unheard of for a dealer to not know of this issue, some dealers just don't see enough Roadies during a yr to see all the issues. My dealer probably see's a few hundred Roadies a yr, whether it be repairs or just maintenance.

Yup it sounds like SVS alright. Seafoam is your friend

Excellent thanks all. I will give the SeaFoam equivalent here in Aus a go first and let you know what happens.

Cheers, Peter

Yes sounds like SVS like all have said. Click on the blue link at top left of my sig picture and go to the "Projects" button and go to the second page then scroll to the bottom of the second page. There are a number of downloads so get anything you think you might want. The SVS cure works good but to keep it from coming back you really need to rejet because the factory jets too rich which causes SVS some times. Also look in the tech section and find the choke knob trim article that is a must do on any bike. Feel free to ask me anyquestions and you can e-mail me from my site.