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Discussion Starter #1
Hi friends. K3 1k with 59,000 miles. I just replaced my rectifier with a series unit and placed my stator magnets in their proper positions (they had migrated). When I got it back together, it tested at the proper voltage, but it wouldn't rev to redline.

Per recommendations, I did the high pressure filter bypass/external filter mod. Fuel flow was unaffected from before to after. Bike felt great on the first ride to work post-mod, but on the way home the symptoms returned.

I then swapped my fuel filter/pump assembly with the pump from my buddy's crashed K3, removing the external filter since his bike's filter was in good shape and the pump was fine prior to his crash.

On the ride home from the swap, it felt perfect. On the next ride this morning, it felt great. The next time I turned it on for the ride home, the symposium had returned, to the point that it was hiccuping on the freeway at 4.5k rpm.

So- the problem appeared post-stator fix and rectifier swap, and persisted through two fuel pumps, one of which had the filter bypass done.

The max RPM varies- sometimes it will bounce off of 7.5k rpm, other times it bounces at 5-6k rpm.

I am lost. Anyone have any ideas?
 

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FORUM GODFATHER.....R.I.P. PAT
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Maybe the TPS.
 

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Have you checked for dirt in fuel tank by rechecking the fuel flow. Pump may have been good was good when installed, but rust, etc could now have worked though to block the filters after your test ride, causing to run lean??? Also test for air leak or fuel tank breather pipe pinched???
 

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Discussion Starter #4 (Edited)
Pat, the TPS checks out perfectly- tested it this morning. Last night at 2 AM I rode it home from my buddy's place, an 80 mile ride in 50-ish degree temps, and the bike felt nearly perfect again except at almost redline (it exhibited the symptoms at around 8500 RPM), so perhaps it's temperature related? I'll run a bunch more tests when I get home.

Question- electronics are my weak point in vehicle repair. Is it possible that the bike running at low voltage (it was at 12.4-ish when running previously) ruined the CDI/ECU/some other electrical component that could be causing this issue?
 

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FORUM GODFATHER.....R.I.P. PAT
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There is no reliable test for the TPS. When it develops problems, they are intermittent and heat is a major factor. I would replace the TPS on any Strom that was over 5 years old that was having a problem not known to have a specific relation to another part.
 

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Replace it.....it's cheap insurance and possibly the fix.
 

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Discussion Starter #7
The TPS is brand new as of 10,000 miles and one year ago, though... :( I guess I could just swap it for the one on my buddy's bike to test it.

What I don't understand is why this was not an issue at all before I replaced the R/R unit and fixed my stator magnets (and believe me, I played with the upper RPM range quite a bit). I know the simple answer is "you must have done something wrong with the install", but the voltage immediately jumped up to mid 14s after the work was done, where it was mid 12s before I did those things.
 

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FORUM GODFATHER.....R.I.P. PAT
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It's unlikely to be the TPS then.
 

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The only thing I can think of is the crank sensor that lives next to the stator.

Purely a WAG, but I'd cast a beady, skeptical eye on this wiring and the connector. Anything pinched, corroded, or otherwise doofy? Maybe even take the stator cover off and make sure everything's OK with this little guy, wires are routed correctly and unpinched, no magnetic schmoo stuck to the sensor, etc.
 

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Discussion Starter #11 (Edited)
The only update I have is that I rode it in to work this morning for the first time in three weeks and it was flawless. The problem seems to be very intermittent. I had planned to test stator resistances and a few other things, but my XR600R build got in the way >.<

[edit] To and from lunch, the problem exhibited itself at around 6k RPM. It seems like it might be temperature dependent. I know the TPS issue is sometimes related to temperature, but again, TPS only has 1000 miles on it and is very new... Gah. [/edit]
 

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Thanx for your update. Please keep us up to speed, if a solution is found. It may be of help to someone else in future, with a similar problem
 

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Discussion Starter #13
Here's a video I snapped today after getting home from work. The bike was PERFECT this morning on the way to work, and on the way home in the afternoon it wouldn't rev past 4500 without hiccuping and it bounced off of 5500. I'm doing some serious digging tomorrow.

 

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That would drive me insane, I would've already dropped it off at the junk yard were it my bike.......kudos to you sir for your patience and exuberance.
 

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Discussion Starter #15
Did some more testing on Saturday. The stator resistances as measured through the three regulator wires were all in spec, so the regulator was installed correctly (I had to cut the OEM harness and connect the aftermarket regulator to it, so I thought I might have done that incorrectly). The voltage stays steady at 14.5v, even when it's bouncing off of the problem area (which, again, changes- it's never a set RPM that it bounces off of).

Then I had a thought. Since it seems temp related, and the TPS failure that everyone usually reports (stalling after long freeway runs, I've had that on both my K3s which is what led me to replace the TPS on this one) is temp related, maybe I'll spray the TPS with upside down canned air and freeze the piss out of it. Welp, sure enough, fired it up after freezing the TPS and the bike revved to redline cleanly. Let it warm up again and the problem returned. Turned the bike off, froze the TPS. Perfect revving again until it warmed up. The third test resulted in the problem again, even with the TPS iced over, but perhaps that's just because the bike got so warm that the internals were still too hot.

My next move is stealing the TPS off my buddy's crashed K3 and installing it. Here's to hoping. I'll keep y'all updated.
 

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Interesting. I bought a used TPS for my SV and put it in.

I would check the output voltage.

TP sensor output voltage
Throttle valve is closed: Approx. 1.12 V
Throttle valve is opened: Approx. 4.26 V

This could be many things. STV's opening? Maybe they aren't working (closed). Injectors clogged? May need to send out and test.
 

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Discussion Starter #17
Welp, new TPS is in. Not as nicely tuned as my old TPS, didn't really have the patience to get it exactly at 1700-1800 rpm change from the middle line to the top line, but close enough.

First ride to the hardware store, nothing, but this is to be expected- the bike is cold. Then, getting on the freeway on the way home, gun it up to redline, a hiccup at 7500. Oh dear. I've ridden it a few more times since then, sometimes without, sometimes with the symptoms, but it has been cooler around here of late, and the problem seems to not happen when it's cooler. This morning, it was the most pronounced that it's been on the new TPS, bigtime not wanting to rev past 7500 RPM.

Looks like I just wasted $90. The hunt continues. Might be time to buy an FZ6... :(
 

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Get an FZ7, much better all around bike and smoother engine "twin". :)
 

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Discussion Starter #20
Get an FZ7, much better all around bike and smoother engine "twin". :)
The raw power and proven reliability of the FZ6 call to me. Plus, you can do an R6 front end swap pretty easily... And did I mention the fact that you can find 'em in the $2000 range? :D

You checked the valve clearances lately? How about a compression check?
I did the valves about 12k miles ago, so I suppose it's nearly time for another check, but from what I've read, once you start racking up the miles, the valves change very little. I'll keep that in mind, though. The compression was perfect as of about 10k miles ago when I took it to a mechanic because I thought it had a bad head gasket (which actually turned out to be a bad water pump gasket).

I'm trying to remember if there was another sensor on the stator cover... on my XT225 there was a pulser coil, but I don't think this bike has one of those. Anything else I might have messed up while I was in there? All I did was remove the stator cover, ran a ziptie through a bolt hole or two to suspend it from the bike as I worked on the stator magnets, then scraped the old gasket off with a razorblade and installed the new gasket. Is it possible that a chunk of old gasket could have gotten lodged onto something like the Crank Position Sensor and screwed it up??
 
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