2009 Royal Star Venture misfire

My Royal Star venture has a misfire under moderate to heavy acceleration in both 4th & 5th gear. 5th being overdrive. It has 7000 km on it and has done this from new. My 550 Maxim accelerates smoothly even at low speed in higher gears. The dealer does't seem to be able to find it and actually doesn't acknowledge it exists. The thought is that I'm lugging the engine. I would have thought that accelerating from 100kph would be normal especially with almost a hundred horses and high the torque generated. The shift point recommended in the manual for 5th is 50 kph. The bike is unridable in the upper gears if the recommended shift points are used. I am going to the Bike Show Dec 11 and will talk to the Yamaha reps as it is still under warranty. Just wondered if I am expecting too much. This is the biggest bike I've ridden and have nothing to compare it to.

 

It should run as smooth as a digital watch. There is a rev limiter, but you should be well below that kicking in.

It's winter, it's under warranty - get it to the dealer.

 

Thanks for your input MiCarl. That is what I thought. The warranty is five years and right now there is a foot and a half of snow in my driveway and the dealer is about 70 km away. I guess it'll have to wait for spring. If the reps at the show don't have any thoughts, I'll have the dealer principal take it for a ride as the service department seem to think it's running OK. They have tried syncing the carbs on two occassions.

 

I guess if you wanted to diagnose it yourself, and it wasn't snowing, you'd hook up a timing light, taped to your handlebars and see for yourself if the plugs are firing, one plug at a time.

If the light pattern flashes consistently, then you assume a fuel delivery problem, and tell the dealer mechanics what to do.

. . .and what do you mean, they TRIED to sync it? Either they nail it or they have no idea what they are doing.

 

The advice below is good advice. Let me suggest the following: Get it to a different dealer. And do it NOW! Put it in a trailer, rent one if you have to, or a truck, again, rent if you have to but get it in. If you wait 'til the snow goes away you will be one of hundreds trying to get service. The dealer has employees on staff now who are needing something beside snowmobiles to work on.

Work with the regional reps and get their support. They will be the driving force for getting it fixed. I know you wont do this but do not threaten legal action or a smear campaign for the Yamaha line. This will guarantee no help from the regional guys.

BTW, the thing should pull like a bull up to red line! Even from a lower RPM. When I'm riding the twisties I never ever shift at less than 5K RPM and often run it at the 8K red line. Mine does not have near the low end pull your twin should have. Exhilarating!

Best of luck on this!

Loren

 

Thanks for the input Wamaxim. I don't want to go to another dealer except as a last resort. I know that the owners of the dealership will make sure it's right. They have been excellent in all other dealings. Yamaha surveys are constantly sent and I don't want to put an adverse mark on the dealership until all avenues are exhausted. Today all transactions are relayed to the manufacturer and questions arise as to why another dealer was involved. I will talk with the Yamaha reps at the bike show this weekend to see if this is a "one of" problem.

The bike is actually 4 cyl, liquid cooled not a twin and unfortunately was not equipped with a tach. The techs were treating it as a fuel issue, not electrical as I believe it to be.

 

Not that I have cracked open my carbs yet, but how similar are the venture carbs (overall not specific details)?

BTW: I look them up. They sure are nice looking non-GW tourers Reviews said much better than the HD UGs and GW are just in there own universe and basically nothing compares. LOL

 

As the bike is still under warranty I haven't opened up the carbs or even taken the tank off myself. I understand they are Mikunis.


Other than the misfire it is really a dream to ride. It is slightly top heavy but still handles well. I chose it as a Harley or Suzuki required all sorts of options to equip as well as the Royal Star. By the time either of the competition was brought up to that equipment level or even a Gold Wing with all its toys, I was looking at $40,000 Cdn. The Royal Star was less than half that.

 

It's not so much top heavy as having lots of trail to the front suspension geometry. That makes it "feel" top heavy at low speeds but makes it very stable at higher speed.

The Royal Star Venture uses a down draft carburetor as opposed to the side draft carburetors in the XJs (SECAII excepted). While all the functions are the same the down draft carburetor requires a different float bowl geometry because it hangs off to the side.

**EDIT**

There are a couple differences.

There is a throttle position sensor that is used by the ignition system as an input to spark advance.

The RSV carburetors have electric heaters to prevent icing. It's not unusual for them to be disconnected to free up power for accessories.

 

I wonder, could a defective TPS cause my problem? I wasn't aware that it was on the bike. If that failed and the spark didn't advance under load it might miss. I guess when the warranty expires I will need a manual to find out all the technical advancements made since 1981. Of course when it expires I'll be in my late, late sixties.

 

I've never seen retarded timing result in a misfire. It's more of a power loss (and quite noticeable).