This is similar to the last post, "Roadstar engine running weak." I have an 07 roadstar 1700. I bought it new in 08 and have put 110,000 miles on it so far. I have had this problem twice and only for about 5 minutes each. While cruising freeway 8 at speeds between 75 and 80 I will lose horsepower and the exhaust sounds baffled. I have cobra speedsters so anyone who has this product knows we set off car alarms. Both rides were very early morning. It almost seems as one of the cylinders are mis-firing. I cut the engine then restarted but had no effect. Than all the sudden everything was back to normal. Any ideas? My biggest question is why has this only happened twice and a few thousand miles apart for only 5 minutes each? I use mid-grade fuel and no engine knock. Thanks!

I talked to the guy I ride with and he said since I park in a carport out in east county, ca and since both incidents were early morning commute, it might be moisture in the intake. What do ya think?

Not sure of your problem, but I know you ride alot if you have 110.000 miles on already

If you have ridden 110,000 miles in 1 year and have only had 10 minutes of this problem then you don't have a problem.

If it happens on every ride, then you have a problem.

Doc

110,000 on o7 your lucky it runs at all wait a min'' is this april 1 because sounds like a fish story here

110,000 miles in one year? I do believe you win some sort of award.

Mine will do this occasionally when the motor is still warming up and it's cold out. Cold as in Winter cold. Rear cylinder wants to cut out. Clears itself up after it warms up. Is it cold where you're at?

I would recommend 87 octane fuel as well.

Regards....greeny

Actually I would like to apologize for the mileage. Its obviously way off...I added one more zero. If I had 110,000 in one year I wouldn’t have a job and a numb backside! lol. So again sorry for the confusion, its really 11,000

I would like to get that kind of mileage though. San Diego will hopefully give me that chance. I almost road across the country (Maryland to California) but January weather made it a pretty hard to plan.

I have an 07 star as well. And since new has had a similiar issue.
After warmup, (I live in SW texas btw{heat/humidity}), it starts shudering and acting it running on the back cylinder only. Then power would come and go. I have taken the issue with Yamaha 5 times. They cannot find the issue and told me it was normal. I started using Premium and stopped using the choke to warmup the bike. And have since had any issues. It would also lack power when treying to merge with traffic on the interstate. wouldnt run over 65-70 mph, bog badly then go away. then the bike would run great afterwards. No one could tell what the heck was wrong with it. It has over 33k on it now. I bought it in feb/08. Been to the dragon twice and once to Big bend. Lots of weekend day trips, and I live over 40 miles from work. It never sits over 1 day, I occasionaly take my wife's harley so it wouldnt sit. She never rides it. Anyway, yamaha has yet to find the problem, even the factory got involved in this one. Nothing. weird. Must be........grimlins!

Need much more detail of your bike if you expect to be helped.

Doc

Could be an intermittent misfire from a bad coil or a poorly grounded coil. Could be carbon build up on the valves. Could be a small bit of water in the gas tank, from humidity. Could be dirt or rubber from the fuel line, in the float, bowl intermittently clogging jets. Could be too much oil in the engine causing the breather to push oil into the intake. Could be fouled plugs. Could be gremlins if you fed them after midnight or got them wet.