Fuel pump going? Dirty fuel filter?

 

Study the symptoms a bit more. If you can tie the onset of the problem to a particular throttle position, and tie the resumption of normal operation to another throttle position after that, it’s most likely the throttle position sensor – the TPS.

You can confirm that the TPS is bad with an ohmmeter. About $100 for the TPS if you install it yourself.

I just replaced a bad one. One thing I noticed was that with the bike switched on but not running, I could hear the secondary butterflies close when I twisted the throttle to the beginning of the bad spot, then open again once I got past the bad spot.

Rob

 

Rob,

what sort of resistance should I be looking for with the TPS? Where is it located?

 

Fuel flow check

 

I will check this when I get home tonight. The idea of an external filter also sounds like an excellent plan. I may perform that mod as well.

I'm just a bit curious if this would cause the problem I'm experiencing though. The bike isn't acting like it is starved for fuel but rather like I hit the kill switch or the kickstand got bumped down.

 

R.P.M. cut out

Due to the engines tuning design. I'm wondering why you reach the cut out rpm seemingly often, as very little extra power is felt after 7500rpm. As for the next gear being reached it still seems high rpm.
I have found the bike pulls best when short shifting rather than revving it out as this is a torquey little engine not a high HP engine.
Just wondering, no other reason.

Ride safe
Saturn 5

 

Due to the engines tuning design. I'm wondering why you reach the cut out rpm seemingly often, as very little extra power is felt after 7500rpm. As for the next gear being reached it still seems high rpm.
I have found the bike pulls best when short shifting rather than revving it out as this is a torquey little engine not a high HP engine.
Just wondering, no other reason.

Ride safe
Saturn 5

It's got 10k RPMs available. Might as well have use of all of them. I generally don't rev it that high but the fact that something isn't working to spec bothers me.

 

I've never heard of a TPS problem causing a high speed cutout or a resistance check to test a TPS. A problem with the secondary butterflies would be caused by the STPS and there is a resistance check for that.
http://www.stromtrooper.com/feedback-suzuki/712-surging-correct-mixture-2.html

 

Hi Greywolf,

First of all, I’ve benefitted from your posts quite a bit over the past few years. Thank you.

I didn’t describe a problem with the secondaries, but rather a symptom of a TPS problem that involved the secondaries. I suspect that when the signal going from the TPS to the ECM goes to one of the voltage rails (because of the failing TPS), the ECM 1) cuts off or drastically reduces the on time of the fuel injectors and 2) closes the upper secondary butterfly.

You can measure the output of the TPS by measuring the voltage, but that requires the sensor to be connected. It’s much easier to do the resistance measurement because you do it with the sensor disconnected and you have full access to the pins.

Lastly, the TPS problem would not be engine speed dependant, but rather throttle position dependant. This matches the original post and it’s why I recommended the OP try to determine if the problem comes/goes at certain throttle positions. That’s also why the secondary butterfly moves even if the engine is not running!

I also have my own way (what I’ll call superior) to adjust the TPS, but that’s for another post.

Rob

 

I like the TPS adjustment to be done by checking the setting in degrees with an OBD tool at this point. I'm always interested in finding better ways to do things. I'll look forward to your further posts.

 

Mike, could you be actually hitting red line, but your tach needle is slow to respond? you'll have to play this one by ear.

 

I guess the answer to that would be what kind of rev limiter does the DL650 have? Most I have seen either kill fuel so you can't rev anymore as sort of a "soft" rev limiter. The other main one is the ECU cutting spark producing a notable stutter.

This acts more as if I just hit the kill switch. RPMs drop to 0 and then come back. It actually sounds more electrical the more I think about it.
I jumpered the kickstand switch last night but didn't really get a chance to test it this AM.

 

hi rpm problem

Is this only happening in 5th or 6th gear or is it in all tranny positions?

 

Is this only happening in 5th or 6th gear or is it in all tranny positions?

It has occurred once in a lower gear and then the remaining few times have been in higher gears at speed. The most recent was on a quick overnight trip from Las Vegas to Laughlin on a smooth, flat, straight section of highway. I wanted to see what the 650 would do and got it to...um...a good bit over the legal speed limit when the engine cut.
Backed off the throttle and within a couple seconds, it came back. This was before disabling the kickstand switch.

I also have had a sick baby (the crying and pooping kind) at home so I haven't had a lot of time to troubleshoot over the past week. I'll dig out my multimeter and check the TPS tonight if der infant cooperates.

 

hi speed cut out

The strom has a rev limiter that cuts in only in 5th and 6 th gears. I only found out once on a trip back from Daytona on I 4. at about 80mph mine cut out in fifth gear. A quick shift up to 6th and every thing was fine and has been for 64000 miles. I sounds like it is doing what it should.
Curt

 

The strom has a rev limiter that cuts in only in 5th and 6 th gears. I only found out once on a trip back from Daytona on I 4. at about 80mph mine cut out in fifth gear. A quick shift up to 6th and every thing was fine and has been for 64000 miles. I sounds like it is doing what it should.
Curt

:thumbdown:
This is interesting. What is the rev limit for 5 and 6?

 

an update for those who care or just want to file some useless knowledge away.

The high RPM cutout seems to have gone.

1st step taken was to jumper the kickstand switch. This had the most noticeable effect as the bike hasn't cut out since.

Just to be through though, I went through connectors I thought might be related and discovered a couple things. One was that the connectors going to the switch on the clutch lever seemed loose. I cleaned the contacts as best I could and tried to make sure the connectors were in nice and tight.
Also came out to the bike one afternoon after work and discovered that it didn't want to turn over. A little prodding of the start switch eventually got it to kick over and catch (think: incrementally working the kick start on a big single with no compression release) and get me home. Stuck the battery on a charger overnight but later decided to just replace the battery as this one was looking old and the Las Vegas summers are hard on small moto batteries.
I have also noticed lately that the starter button may be a little worn. If I hit it from a funny angle or don't apply correct pressure, it doesn't work. I will replace the switch later on should it become more annoyance than minor quirk.

It looks like it may have simply been the kickstand switch...which bugs me and would have been disabled anyway.