Throttle Position Sensor

[Barnacle442]

I have a 1999 Royal Star Boulevard, XVZ13AL, and I am having issues. Last fall it died; left me stranded on the side of the road 90 miles from home. I used this as an excuse to buy a new bike, (new to me,) a 2008 RSV-S. Love that Yammie! But I still love my big, heavy, Royal Blue sled and I want to fix her.

 

I have her in the garage, now. She'll start. She'll idle, but when you twist the throttle she coughs and sputters and dies. Everything and everyone says fuel problem. Last spring I had the carbs rebuilt and the 20 year old manifolds replaced so I don't think its that. I have pulled the fuel pump (which works just fine). I have replaced the fuel filter which was a bit of a pain. I replaced all of my hoses, (even the ones which are no longer made.) I hung an Auxiliary bottle and tried running it on gravity. The problem remains.

 

Yesterday I removed the Carbs from the manifolds. That was when I noticed the Throttle Posistion Sensor. I did not realize there was a TPS on my bike. I don't have fuel injection and I don't have cruise control. Can anyone tell me about the TPS on the Royal Star? What does it do? Could it be causing my pain? Do I really have to pay 200 buckaroonies to replace it if its bad? Is it somehow tied to my ignition?

 

I have tried searching through the forums for info on this topic but have been unable to find any answers. Any help would be appreciated.

 

Thanks

[cowpuc]

Sure,, I would say a faulty TPS could indeed cause what you mention.. I did know of the TPS on the later RSV/RSTD's either BUT I have never owned or worked on one either.. Before is forward what I found about the TPS,, gotta ask,, how long did the bike set after having the carbs done last spring? Did it run correctly after having them done? Has it been setting for a year? I would do the TPS check as shown in the pics from the clubs RSV service manual I am including but I would also take a really close look at plugged jetting if it has been setting for a year..

Concerning the TPS on the carbs.. Years ago Mom Yam stuck something similar on the Banchee quads.. Basically what it, the TPS, did was guard against sticking throttles and or throttles hanging up by monitoring the position of the carb(s) slide(s) in comparison to each other.. Not sure but I suppose its possible for Mom Yam to have decided to do the same with the later model multi carb V-4's.. Could also be the typical TPS sending info to a computer but I suspect this to not be the case because, as you mention,, this are not EFI bikes..

Regardless,, here is the info I came up with on how to check the TPS(s).. This info is from the RSV manual but should work for your bike too,, I hope.. Do you have a shop manual? If so, this info should be in there.. The club does not have a specific manual for your bike, hopefully this is accurate:

[cowpuc]

not sure that last set of pics came out in proper order,, I am retrying the order here and see if they match:

 

[cowpuc]

and then continuing here:

 

[cowpuc]

There,, now they are for sure in order as shown in the manual.. Hope this helps Barney!!

Puc

[Barnacle442]

Thanks for all that. I printed out the Carburetor section of the manual and have it in my garage next to the bike. The boulevard is essentially a stripped down version of the Royal Star. There are no bells and/or whistles. It has a flashy paint job and a custom leather seat. I'm pretty sure the idea was to cruise up and down the street because the 4 gallon gas tank is pretty pointless for travelling. After I had the carbs done I rode it all summer and into the fall. Sometime in October is when it went down. It sat for a couple months before I got it running in February. I don't think that is the problem though. I have the carbs off now. I have been inspecting the Manifolds to make sure there are no problems there. everything is nice and pliable, no cracks or holes. I think I have a vacuum leak somewhere but I am not certain where. I have a video of it on my fone and on Youtube but I am not sure how to get it on here. I checked the TPS according to the manual, (or at least I tried to.) I need to either make a better connector for testing or make a friend to hold everything while I work. It all seemed to check out. I will next dig into the wiring schematic to decipher the ignition system and if/where the TPS figures into it.