loss of power

[slick]

Hi guys. I'm new here and to the yamaha royal star. I have been riding Kawasakis and Harleys for the last 12 years and now am the proud owner of a 2007 RSTD. I have a problem with the bike that has just occured. I have had the bike since Dec. and have put 13,000 trouble free miles on it until now. I recently added K&N filters and on the initial ride i noticed that when cruising in the lower RPM's (lets say in 5th between 55-70mph) when I twist the throttle 100% the bike bogs down.If I roll out to about 3/4 throttle it picks back up. Once into the higher rpm's the bike doesn't bog down as bad but I can feel it is holding back. I changed out the spark plugs, went back to the stock filters and evem synched the carbs and have the same problem. I am hoping someone can give me some guidance as to what it could be. I am pretty mechanically inclined, but since this setup is new to me I'm scratching my head. Thanks for any help:confused24:

[Neil86]

any mods made to airbox when you installed the K & N's? or is everything back to stone stock now?

[Guest TFD69]

5th gear on your bike acts the same way a car does in over-drive. The gear is meant to maintain speed while lowering the rpms of the engine to save gas. If in a car while in over -drive you have to depress the accelerator to at least half way before the engine will kick up the RPM's other wise it will do as you described delayed or sluggish throttle response. Riding two up, pulling a trailer or riding in hilly country in 5th gear often feels like the engine is lugging. These bikes like high rpms so use 4th gear for rapid acceleration at mid to high speeds and stay from 5th unless your cruising above 60 mph

[GeorgeS]

Run 1/2 Can of SEA-FOAM, per tank, for about 3 tanks of fuel, see if this helps.

 

Drain your fuel tank, Dry, maby some water in the bottom of tank.

 

Maby, dirty fuel filter.

 

Drain All 4 Carb Bowls, a few times when the SEA - FOAM is in the gas.

 

Another comment, you can't drive these V-4's like a harley, they don't have the Torque of a Harley, at lower RPM's.

Whenever I'm going around 70 and I decide to pour on the Coals, I always downshift at least one gear. On an uphill, I might downshift to 3rd, If I want to get moveing past the big truck.

[slick]

Thanks for the replies guys. I did open the air intake hole on the air box up a little when I changed the filters. I know 5th is an overdrive, that was just an example because i do not have a tach and i figured everyone would know about where the engine rpm was. It does not only do this in 5th it does it in every gear and did not do this for the first 13,000 miles, this just started. I have run a can of sea foam through (second half of can is in the tank now added yesterday) Also I wanted to add that when the bike is warmed up and you are standing behind it the exhaust to the left is cooler than the exhaust on the right and feels to be pulsing where the one on the right has a more constant pressure.

[Guest JGorom]

I'm wondering if you might have a bit of gunk in the carbs that is plugging or obstructing one of the jets when you give it throttle. I had this happen to me last year...found it when the carbs were torn down. It does not take a big obstruction to do this. I run seafoam through my tank now at the beginning and end of each riding season and once or twice in between.

 

PS I purchased my bike used and the previous owner never used the seafoam.

[sarges46]

Fuel filter maybe? Just a thought there.

[flb_78]

check your the pipes coming off the heads. It sounds like your missing on 1 cylinder.

 

DO NOT TOUCH THE PIPE!!!

 

just put your hand close to it to feel the heat.

 

Better yet, use a non-contact thermometer.

 

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=93983

 

http://www.harborfreight.com/cpi/photos/93900-93999/93983.gif

[Neil86]

Thanks for the replies guys. I did open the air intake hole on the air box up a little when I changed the filters.

 

If all was well until you changed filters and modified the air box, and putting original filters back in didn't fix it....the mod probably is affecting how the slides are responding. Just speaking from 1st gen experience, most who opened up the airbox ended up reversing the mod as the bike performs worse.

[GeorgeS]

I'm thinking you have some problem with One cylinder.

 

Do the heat on the pipe test, if you find something there, I would start with a New

Plug in that cylinder, OR, a complete new set of Plugs.

 

Maby an Ignition coil problem developing on one cylinder, if the heat test pinpoints that cylinder.

 

Check the Cable from the Pick Up Coils going to the TCI, there is a Plug enroute, might have a High Resistance Connection on One of the 5 pins in that Plug.

 

I would get to the TWO plugs on the TCI, ( 6 pin and 8 Pin ) pull them out, and clean all the contacts. Maby a high resistance connection here.

[Squeeze]

If all was well until you changed filters and modified the air box, and putting original filters back in didn't fix it....the mod probably is affecting how the slides are responding. Just speaking from 1st gen experience, most who opened up the airbox ended up reversing the mod as the bike performs worse.

 

 

I don't know how sensitive the 2Gen's are in this Matter, but how in the World you came to that Conclusion in your first Post ?

 

I never would think about a Rider modifying the Airbox on a fairly new(2007) Bike.

[Neil86]

Squeeze....

Just a hunch, looking for more air flow with K & N's, mods.

[slick]

Thanks for all the input. problem solved. I made a plate to cover the enlarged hole in the air box, then I cut a hole that looked about the same as what the oem hole was and bike runs fine again. You live and learn I guess.

[yamahamer]

Also I wanted to add that when the bike is warmed up and you are standing behind it the exhaust to the left is cooler than the exhaust on the right and feels to be pulsing where the one on the right has a more constant pressure.

STUCK DIAFRAM IN CARB. STAR RYDERS 07 HADE SAME PROBLEM THE SEA FOAM HAS BROKEN IT LOOSE. NOW GET YOUR CARBS SYNC DONE. AS FAR AS AIR BOX MODS I HAVE K&NS WITH THE FRONT OF BOX CUT OUT BUBS SLEEPERS AND LOVE THE POWER, SOUND, AND 50mpg.

[Squeeze]

Squeeze....

Just a hunch, looking for more air flow with K & N's, mods.

 

 

:thumbsup: