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Discussion Starter #1
As some of you know, I've had a performance issue with my F7 Snopro for some time now.. The problem is that most of the time my F7 will top out at only 85mph while reving ~7600rpm. But once in a while, for no apparent reason, I will get normal topend over 105mph with normal rpm of ~8000. I've had two seperate dealers try and analyse this problem without sucesss. I have replaced all of the wear componets in both clutches. Since AC had "updated" my ecu earlier this winter, it was suggested that perhaps the remapped ecu was the cause of my problem. So, on this last trip I had another ecu to exchange out for test purposes. This is a report on that test. The "test" took place on a TQ35, a railroad bed trail.

To set a baseline, I made repeated runs with my "updated" ecu, in which I confirmed that it still would top out at 85mph at 7600rpm. Then I stopped, exchanged ecus, and made several more attempts. I was now able to exceed 105mph, and the engine was reving between 7960 and 8060 rpm. I was again able to cruise at 90mph at part throttle for miles on end, something I had not been able to do for quite some time. I continued to try the WOT performance a number of times on both thursday and then again on friday. Everytime I tried, I saw excellent performance with rpm of 7960 or greater. Problem solved, or so I thought.. However, on the final 2-mile long straightaway back to the motel parking lot I pinned it and to my disapointment I again could only do 85mph at 7600rpm. And as a final clue to this puzzle, catman16 was right behind me on HIS F7 snopro, and he said that he had the same problem in that field, 85mph at 7600rpm.

So, what are my conclusions? I still think that the ecu without the remap was stronger for some reason than the remapped ecu. But I think there is an additional problem here..One that hasn't been identified yet. A problem perhaps in a sensor, or clutching, or somewhere else. But now I don't think it is just limited to my F7. Catman16 had the same problem too, and I bet there are others out there. Intermittent problems like this are easy to dismiss and blame on "snow conditions". In my case, snow conditions were consistent thoughout this trip. Wet groomed snow, above freezing temps. Very fast trails. Lots of lubrication, no chance of any heating issues. Catman16 had a temp gauge on his F7 and it never came off the bottom of the scale. A lot of you are going to make "easy" suggestions, but they have all been thought of and tried already. Whatever the cause of this problem, it is not readily apparent... The main reason for me posting this now is to see if anyone has experienced a similar problem.
 

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I rode with a F7 standard, same performance as mine. He lost his spark, turned out to be the stator. After dealer replaced his stator the sled will not go over 7600 rpm. The dealer did not change anything else. So is the stator not giving out enough power???
 

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Discussion Starter #3
Originally posted by fast 600@Mar 22 2003, 11:29 AM
I rode with a F7 standard, same performance as mine. He lost his spark, turned out to be the stator. After dealer replaced his stator the sled will not go over 7600 rpm. The dealer did not change anything else. So is the stator not giving out enough power???
I've thought of that, but have no way to check for sure. I have tried WOT with handwarmers and ele shield on, and then with everything turned off, and it makes no difference in performance.. :wacko:
 

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rob.
Look at the plugs and plug caps. If you have any black streaks in the porcelein, and/or a wet appearance inside the plug cap, replace both and try your test.
 

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Discussion Starter #5
Originally posted by gls@Mar 22 2003, 11:35 AM
rob.
Look at the plugs and plug caps. If you have any black streaks in the porcelein, and/or a wet appearance inside the plug cap, replace both and try your test.
Greg, thanks for the reply.
The plugs have been changed several times during the problem, and a new set are in now. There was no carbon present at all. Plugs do look rich when I have checked them (dealer said the same thing when looking at the inside of the manifold and pistons).
 

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Rob
How about the cap's though. Wev'e had some issues with caps on 700's and 900's. They lose some voltage transfer ability, and the engine just starts to act weak on power. Just a thought.
 

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Discussion Starter #7
Originally posted by gls@Mar 22 2003, 11:44 AM
Rob
How about the cap's though. Wev'e had some issues with caps on 700's and 900's. They lose some voltage transfer ability, and the engine just starts to act weak on power. Just a thought.
They are clean and look normal.. My dealer didn't see anything odd either.

This has been a long-term problem.. I've been trying to fix it since february.
 

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Rob,

I too have experienced this problem and agree with you that it is not just an issue of snow conditions etc. I have a buddy with a standard F7 and his so far has not exibited the same behavior but he has not ridden as much as I have.

Prior to hearing of your woes I was starting to lean toward possible over clutching thinking maybe my body weight and with the heavier track it was a bit much for the motor? Have also wondered if Cat has some type of slightly enrichened mode that the ECU goes into if it senses "something" (I know, what something would that be?)?

Will be interesting to see what you find out as when mine is running good it is wicked as it comes out of the hole like a shot, but when it is in this mode it is quite weak on the top. Feel free to email directly if there is additional info you would like as we try and help find out what is going on.
 

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Discussion Starter #9
Originally posted by sweetm@Mar 22 2003, 03:32 PM
Rob,

I too have experienced this problem and agree with you that it is not just an issue of snow conditions etc. I have a buddy with a standard F7 and his so far has not exibited the same behavior but he has not ridden as much as I have.

Prior to hearing of your woes I was starting to lean toward possible over clutching thinking maybe my body weight and with the heavier track it was a bit much for the motor? Have also wondered if Cat has some type of slightly enrichened mode that the ECU goes into if it senses "something" (I know, what something would that be?)?

Will be interesting to see what you find out as when mine is running good it is wicked as it comes out of the hole like a shot, but when it is in this mode it is quite weak on the top. Feel free to email directly if there is additional info you would like as we try and help find out what is going on.
thanks for the post.. your problem seems exactly like mine. Over-clutching is a possiblity too I think. Or perhaps a combination of several factors. In any event it has spoiled my total enjoyment of this sled for well over a month now, and the season is ending without any real answers. :(
 

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Rob, I had a similar problem at the beginning of the year, It turn out to be my stator, Not sure if it will help but other symptoms seemed to be running on 1 cylinder after restart.
 

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Rob,
Read your post this morning and Mike and I talkesd about it quite a bit today. Mike said he was only getting about 90 mph out of the ZL600SS across the same strait away and he was losing ground to us. It felt to him that the track was spinning due to loose snow. On TC35 Thursday his speedo was pinned when we were reading low 100's, which means he was going much faster on Thursday. I am wondering that maybe the snow had loosened up considerably by Friday afternoon and the large paddles on the SnoPro tracks were creating more drag, thus pulling the rpm's down and top end. I didn't get over 7600RPM and 85 mph out of my sled. If he didn't experience the same lack of top end I wouldn't propose this theory. What's your thoughts?
 

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Discussion Starter #12
Originally posted by Catman16@Mar 22 2003, 06:32 PM
Rob,
Read your post this morning and Mike and I talkesd about it quite a bit today. Mike said he was only getting about 90 mph out of the ZL600SS across the same strait away and he was losing ground to us. It felt to him that the track was spinning due to loose snow. On TC35 Thursday his speedo was pinned when we were reading low 100's, which means he was going much faster on Thursday. I am wondering that maybe the snow had loosened up considerably by Friday afternoon and the large paddles on the SnoPro tracks were creating more drag, thus pulling the rpm's down and top end. I didn't get over 7600RPM and 85 mph out of my sled. If he didn't experience the same lack of top end I wouldn't propose this theory. What's your thoughts?
RPM should have been normal regardless of the snow conditions. Did Mike happen to notice his rpm on ZL in that field? I bet it was normal. The lack of rpm on our F7's indicates a problem. And I think we should have been able to totally blow away the ZL600.
 

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Mike didn't notice what rpm's he was running. He just knew that he wasn't able to get the speed out of the sled that he was able to get on Thursday. And he says we still were blowing him away.
 

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Discussion Starter #14
Originally posted by Catman16@Mar 22 2003, 06:45 PM
Mike didn't notice what rpm's he was running. He just knew that he wasn't able to get the speed out of the sled that he was able to get on Thursday. And he says we still were blowing him away.
Earlier on friday I was able to get normal rpm and 100+mph on both TQ85 (while it was raining, and briefly on the powerline shortly before we stopped at the Relais for lunch. I don't think conditions affected it. It was actually warmer and the trail was sloppier on TQ35 thursday.
 

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Rob,

I am having the same problem. This started about a month ago 1(500 miles ago). I have had the dealer go over the clutching and clean and adjust the power valves with no improvements.

I am wondering if the power valves are working all the time. Like you my season is over and will have to deal with it next year.
 

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rob,
as I posted before I lost a few mph out of mine with the reprogrammed ecu. I thought it was going into safe mode all the time. But Im not sure mine has burnt down twice now. I took the airbox off to clean for spring and that acorrden boot that hooks to the trottle bodys was only half on. In my garage I could only get 7460 rpm with it this way on a track stand. slid the boots back on and was getting 7920rpms I don't know if that has somthing to do with it. But wouldn't hurt to look. My thought is if your ecu is telling the engine it is 30 degress out side. And if those boots are even off a little bit you are sucking in warmer air from the engine heat. which would cause it to run richer. IF you think I am wrong let me know. this is just my thought. I haven't been able to get back on the lake now that it is melted. But it seems to make sense in the garage. I hope they can get this fixed or it is as asimple as the trottle body boots coming off. Thanks for the site G-P
 

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Wow, this has certainly been an interesting thread to say the least, and has really left me (and everyone else?!) scratching my head here. I'm just kinda' brainstorming one post at a time.

Rob, you say this "performance issue" has been going on for some time now -- how long, for how many miles, and what percentage of the time will your sled only reach 85 MPH and only pull 7600 RPM? But yet once in a while (same day and conditions???) it will "come to life" again? The ECU swap test results were very interesting. You immediately gained 20 MPH and 300+ RPM? WOW... that certainly SEEMS to indicate something funky going on right there! It'd sure be interesting to see the those two particular boxes tested on the dyno. My first thought, like you said, is possibly an intermitant malfunctioning sensor or stator, but are there any kind of electrical tests or field tests to help narrow down such problems?

I found GLS's second response on the plug caps interesting too. Is there a simple electrical test that can determine if the caps are within spec? He said they had some cap issues on 700's and 900's -- how'd they discover/determine this problem? How MANY plug cap "issues" have they had?? New (good?!) plug caps should be a rather simple thing to try. Greg, any additional feedback on this???

sweetm had a couple interestng comments also, concerning the possible over clutching or the possibility of a slightly enrichened mode that the ECU goes into if it senses "something."

Catman16 makes it sound like it could've been snow conditions after all... but then again, Rob says nope, he doesn't think so! Boy am I confused!

I can only think of a couple things to add at this point:

* exhaust canister -- no loose or broken baffles inside?

* engine coolant temp: is it POSSIBLE... that the engine sometimes runs TOO cool, and thus never getting up to operating temperature and the respective fully warmed-up computer mode? You said Catman16's coolant temp gauge never came off the bottom of the scale -- what temp is at the bottom of the scale? Greg, what does the computer like to see for warmed-up operating coolant temps??? Now that I think of it, my heat exchangers are USUALLY barely even luke warm any time I've checked them. Hmmmmmm...

Greg, any other ideas lurking in the back of your mind as potential problem areas to check? Is there a simple way to check the stator, or at least the spark plug caps? Are spark plug caps a wear item -- should they be replaced once in a while?? Are there new & improved caps, or is there a better more durable high performance cap available??? Thanks for any and ALL feedback on this thread! -- Roy
 

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Discussion Starter #18
G-P, I will recheck the throttle body boots but I think they are ok..

Roy, this has been happening for most of the winter.. I've occasionally posted some reference to it. I've been searching for the answer to it for well over a month. As I mentioned, all wear components in both clutches have been replaced.. Two dealers checked it out, my dealer did electronic tests with a DVOM of the various sensors, coil, and TPS.. Everything read correctly. He thought it was the ecu. And the un-remapped ecu did seem to greatly help. Before switching ecus, it would malfunction on 9 out of 10 tries. After switching ecus it works correctly on 9 out of ten tries. Again, the problem is only from a roll at trail speeds.. If I punch it from a standing start it always revs normally and pulls very hard.
 

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Roy-T
Temp gauge was running about 105 Farenheit on entire trip. The sensor is mounted on the return side so it always shows cool readings. We were getting plenty of snow on the heat exchangers to keep the engine temp way down. Air temp was 40-50 on Thursday and high 30's or low 40's on Friday. The problem Rob is refering to happened to me at the same time, Max RPM about 7500 and max speed about 85 mph. I have about 2300 miles on my F7
 

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Rob I am experiencing the same problem as a matter of fact I was down to 7500 rpm on my last ride but the odd time it would rev 7900rpm. At the start of the season when going was tough it would rev 8000-8200rpm with no effort. Its seems strange that my handle bar grips burnt up and my tach started to screw up around the same time that I lost rpm. Stater?Plug caps? don,t know yet.
 
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