Subtle clutch slippage after ECU flash and exhaust upgrade

[kjetil4455]

Dear friends,

I write this short post as a warning. My S10 gained a lot of performance with the ECU flash and full exhaust upgrade that we installed, so it wasn't easy to identify the problem. I had been noticing for a while that the bike was accelerating a little less powerfully when the bike was really warm, and behaved vaguely better when cold. I didn't think much of it as I didn't know any better. When I upgraded to a Barnett pressure plate I first went with the soft springs which still didn't cause obvious slippage (to my ignorant ears, at least nothing like clutch failure that I've seen due to wear on other bikes), but there was a very obvious power loss at higher RPM. We went with heavier springs and, wow, what a difference. In this moment I realized that my clutch had been slipping for a while, even before the pressure plate upgrade. I gained a good amount of [perceived] power with the upgraded springs compared to OEM.

The point here is that you might want to consider upgrading your clutch springs if you have an ECU flash and full exhaust upgrade. The slippage is not obvious, it is subtle; at least it was for me. When we took the plates out they were slightly burnt.

Hope this helps someone.

 

[Sierra1]

Are you certain that it's not the back tire spinning. That's what happened on my FJ when I put a full exhaust and rejetted. Thought it was my clutch, turned out to be tire spin.

 

[kjetil4455]

Are you certain that it's not the back tire spinning. That's what happened on my FJ when I put a full exhaust and rejetted. Thought it was my clutch, turned out to be tire spin.

Yes, 100% sure

 

[dvd]

dvd
Thanks for the insight, now i wonder if my "new 2016" has had any mods. since i havn't owned it for long i cant compare with previous performance, but it did occur to me that when i twist the throttle there should be a bit more pep. I am a very easy goer so i don't go there much. Would anyone know how could I tell if there has been a flash upgrade? I bought the ST from a 3rd party cycleshop on consignment and they said all the extras like rear seat, pannier luggage and whatever else was burnt in a fire. Good to know the fix is in the springs. one day I may go for an upgrade but there is plenty of power for an easy cruiser like me. Thanks

 

[kjetil4455]

If you inspect the discs and they have heat damage (even if it's small) and you don't remember any time where you screwed the clutch due to a mistake, then it's probably long term slight slippage like I had. I really had no idea that I had any slippage, and I doubt I would have ever noticed if I didn't see such an obvious difference between the new and old springs. It just feels much crisper when the clutch bites "right" and the acceleration is improved throughout the entire RPM, at least it was for me.

If your discs are original and they're completely void of any heat blemishes then it's probably not slipping.
It's easy to take off the clutch cover and, on this bike, at least for me, the gasket didn't injure at all. I did have a backup just in case, though.

 

[~TABASCO~]

Add a Barnett pressure plate..... The slip is even more evident after you put in the Barnett because the rider now has a true comparison between the two clutches.

Another note, if anyone has a 'hot rod' bike and you do virtually any off road, I highly suggest the Barnett.... The dirt, sand, mud will slip the clutch even more and it will end up burning it......

Back in 2013, at the Colorado ride. One guy did just this on a rocky climb just out side of Ouray. I guess the clutch got so hot it started melting parts.. The whole clutch was basically coming apart.... (this is a very extreme and RARE case of use / abuse..... but it's always possible)

 

[kjetil4455]

Add a Barnett pressure plate..... The slip is even more evident after you put in the Barnett because the rider now has a true comparison between the two clutches.

Another note, if anyone has a 'hot rod' bike and you do virtually any off road, I highly suggest the Barnett.... The dirt, sand, mud will slip the clutch even more and it will end up burning it......

Black in 2013, at the Colorado ride. One guy did just this on a rocky climb just out side of Ouray. I guess the clutch got so hot it started melting parts.. The whole clutch was basically coming apart.... (this is a very extreme and RARE case of use / abuse..... but it's always possible)

I am very happy with my barnett clutch, thanks for suggesting it

 

[WJBertrand]

Loss of power would be something else. A slipping clutch will cause engine RPM increase with no speed increase.

 

[kjetil4455]

Loss of power would be something else. A slipping clutch will cause engine RPM increase with no speed increase.

If your RPM increases and no speed it feels like the bike has no power...

 

[mybackhurts]

Dear friends,

I write this short post as a warning. My S10 gained a lot of performance with the ECU flash and full exhaust upgrade that we installed, so it wasn't easy to identify the problem. I had been noticing for a while that the bike was accelerating a little less powerfully when the bike was really warm, and behaved vaguely better when cold. I didn't think much of it as I didn't know any better. When I upgraded to a Barnett pressure plate I first went with the soft springs which still didn't cause obvious slippage (to my ignorant ears, at least nothing like clutch failure that I've seen due to wear on other bikes), but there was a very obvious power loss at higher RPM. We went with heavier springs and, wow, what a difference. In this moment I realized that my clutch had been slipping for a while, even before the pressure plate upgrade. I gained a good amount of [perceived] power with the upgraded springs compared to OEM.

The point here is that you might want to consider upgrading your clutch springs if you have an ECU flash and full exhaust upgrade. The slippage is not obvious, it is subtle; at least it was for me. When we took the plates out they were slightly burnt.

Hope this helps someone.

Yeah I got a mix of hard and soft. I will go up in springs next oil change.

Notice some slip if I'm not careful.

Would not go back to OEM either way. Much better.

 

[dvd]

dvd
Thanks all, I'm heading for another adventure in California Sierra's ( Ebbets' Pass and Carson Scenic Byway along with some offroad ) this Saturday, I will watch for tach moving without any corresponding speed relation. I will look into getting a Barnet assy. soon. I'm doing more off road than i anticipated and want to be on the safe side. Also, totally wore out the handlebar riser shock mount grommets on last Saturday's ride. Brutal pounding on a fire road with wash outs hiding in the shadows and whatnot. Thanks for great response and valuable knowledge! Cheers

 

[dvd]

Yeah I got a mix of hard and soft. I will go up in springs next oil change.

Notice some slip if I'm not careful.

Would not go back to OEM either way. Much better.

dvd
i will post a response when i get the handlebar shock mount grommets. If i can get polyurethane then maybe better..? Thy are aftermarket and came already with the bike. All is unknown at this point because the bike was acquired 3rd party ( Cycleshop concession ) and all of the records, back seat , pannier suitcases and all whatnot was burned in a shed fire where things were being stored. The guy has moved out of state so everything is a quest.
Thanks for your many inputs and help! Also want to get the Barnett clutch soon..