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Throttle/Fuel issues

Jesse P

Jesse P

Just got it firing!
GT Famiglia
Joined
Dec 25, 2014
Messages
21
Location
San Francisco
I'm experiencing a weird issue that I'm not too sure of the cause. The issue first happened right after my ECU was flashed at GT. When I left the bike acted like it wasn't getting fuel almost like it was choking. Power was sporadic feeling like it was getting fuel then not then getting fuel again. Shortly after I left GT I actually turned back around to go back but it cleared itself up as I got closer so I turned around and went home.

Since then it's been mostly fine but the issue started back up about a week or two ago. I didn't ride at all last week due to a snapped bolt on the header mount. I fixed that up and went for a ride Friday and for the first hour it rode fine. Then coming back from San Jose it started to occur again. I really noticed it at around 4700 RPM's. I'll have the throttle open and as I'm holding it steady the bike acts like I took my hand off the throttle, just starts to slow down. It also sounds like it's bogging (I should probably record it and post the video so you can hear it).

If I get back on the throttle (open it up more) it takes off again. I was trying to work out exactly where and when it's occurring but it's very sporadic. If I'm cruising at low RPM's it sounds boggy and at times when I give it more throttle it doesn't just take off.

It's extremely strange and I'm not sure where to begin to troubleshoot. Could it be the fuel filter? I just went over 15k miles on my 2013 Stone. Running an Arrow exhaust with GT flash (which I've been very happy with).

Look forward to hearing any ideas.
 
If it had a snapped bolt on the header, did you replace the gasket? If not, do. The gaskets do not do well with a leak, meaning it may likely still be. This would likely be the cause of the strange sporadic running. The fuel filter could also be contributing to the problem, but usually it works OK right up until it doesn't. Once you have these items resolved, and it still does it, write me direct for a map correction.
 
Jesse P said:
I'm experiencing a weird issue that I'm not too sure of the cause. The issue first happened right after my ECU was flashed at GT. When I left the bike acted like it wasn't getting fuel almost like it was choking. Power was sporadic feeling like it was getting fuel then not then getting fuel again. Shortly after I left GT I actually turned back around to go back but it cleared itself up as I got closer so I turned around and went home.

Since then it's been mostly fine but the issue started back up about a week or two ago. I didn't ride at all last week due to a snapped bolt on the header mount. I fixed that up and went for a ride Friday and for the first hour it rode fine. Then coming back from San Jose it started to occur again. I really noticed it at around 4700 RPM's. I'll have the throttle open and as I'm holding it steady the bike acts like I took my hand off the throttle, just starts to slow down. It also sounds like it's bogging (I should probably record it and post the video so you can hear it).

If I get back on the throttle (open it up more) it takes off again. I was trying to work out exactly where and when it's occurring but it's very sporadic. If I'm cruising at low RPM's it sounds boggy and at times when I give it more throttle it doesn't just take off.

It's extremely strange and I'm not sure where to begin to troubleshoot. Could it be the fuel filter? I just went over 15k miles on my 2013 Stone. Running an Arrow exhaust with GT flash (which I've been very happy with).

Look forward to hearing any ideas.
Click to expand...

Sounds like exactly what my V7 was doing a few months ago before I did the ECU reflash. I have replaced the spark plugs and trimmed the leads back on the plug cap side as they felt quite loose, now they're nice and tight. Since doing this I haven't had the same issue! It's easy and very cheap to do!
 
Wow, didn't realize how long I've been dealing with this. Had to order parts and find the time to get to work. It helps that I finally got a lift to make things easier.

Last week I put on the new gasket on the header. What's the proper direction for the spacers? There's a flat end and the other end curls up? When I first put it back together they were rattling so I turned them around and no more rattle but wasn't 100% if it was correct. I then discovered a leak from my final drive to add to my complications.

I'm about 1000 miles away from my scheduled valve adjustment but was thinking this too could be contributing to the issue? This past week it's gotten much worse. It sounds off, the power situation has gotten worse. There are times when I pull back the throttle and there is a hesitation. Other times with the throttle open it sputters with power, then fades, then kicks in again. It just sounds and rides like shit right now.

So two questions, does it sound like a valve adjustment could be needed and possibly address this issue? I've never done one before but I'm prepared to give it a go. I watched a few videos and I know I need to adjust something in front to turn rotate the Pistons but I couldn't find photos of that part. I removed what I thought I needed to only to discover that's where the generator lives. Do I need to remove that in order to get to the part I need to rotate?

Should I replace the fuel filter just in case?

Appreciate any help and guidance. Was hoping to spend tomorrow working on it.
 
Jesse, find someone near you that has done a valve adjustment before and can teach you how to do it. It doesn't have to be on you particular machine, but something similar will do. From the questions you are asking you need help. Writing the procedure would take pages for someone at your skill level, but can easily be explained/shown in person. As for the running issues, very difficult to diagnose over the internet. For the exhaust spacers, if the way you have them in now it doesn't rattle, that it is correct.
 
john zibell said:
Jesse, find someone near you that has done a valve adjustment before and can teach you how to do it. It doesn't have to be on you particular machine, but something similar will do. From the questions you are asking you need help. Writing the procedure would take pages for someone at your skill level, but can easily be explained/shown in person. As for the running issues, very difficult to diagnose over the internet. For the exhaust spacers, if the way you have them in now it doesn't rattle, that it is correct.
Click to expand...

Thanks John, actually I've done one before just not on this bike. I took an engine rebuild class about a year ago where I tore down and rebuilt a small Ninja 250 engine. I'm just a very visual person and couldn't find an image from the front of the bike of what was being adjusted. I should have checked my notes before I sent that though as I discovered the alternator nut is what I need to rotate (according to http://www.webbikeworld.com/Motorcycle-technical-articles/guzzi/valve-adjustment.htm).

Thanks for clarifying about the spacers, just knocks that off my checklist of possible causes to my problem.
 
Replaced the spark plugs and adjusted the valves. Went for a test ride and it's still an issue. Back to the drawing board.
 
You might want to have Todd check the reflash. Also have you checked your spark plug wires as Ben suggested?
 
Fuel map has been well proven over and over. Likely not the problem, but I'm happy to be of help for any needed adjustments.
 
In the UK I had this exact problem with my V7II (2015), bought from new and soon had intermittent misbehaving: variable idling, loss of power (especially at low revs), turn throttle then power suddenly comes back in a rush, over revving at idling (sometimes revs by itself to over 4000rpm), occasionally cuts out. Other times (maybe 70% of the time) was fine. Often seemed to clear itself after fully warming up or opening the throttle on a long stretch so i put up with it for some time.

Took it back to my dealer last year who reflashed and replaced the plug leads at the same time as doing the 600 mile first service. At first it seemed better but still not right and recently got worse (some quite hairy trips to work an a bike kangaorooing through town, not a good look).

So phoned my dealer again who phoned MG Technical (in the UK I think) who said that they had produced a new ECU flash last October for idling problems. Still sceptical I took the bike in and 20 mins later am riding out on what feels like a totally different bike, buttery smooth power delivery, the bike I had hoped I bought. Haven't put more than about 75 miles on her over 2 trips so still monitoring it but the problem does seem to be solved.

I'm no mechanic but I always suspected the fuel mapping as a mechanical problem would surely less likely be so intermittent and it just felt something was playing around with the fuel delivery.

Btw, dealer also said they have never had problems with the throttle bodies/O2 sensors on the V7s.

Hope this might help...
 
Jesse P said:
Replaced the spark plugs and adjusted the valves. Went for a test ride and it's still an issue. Back to the drawing board.
Click to expand...
Jesse- Was this issue ever resolved on your end? Were you able to diagnose the problem? 6 year old thread, what are the chances, ja!
 
Jesse P said:
@Nico Bollini honestly I can't remember, sadly I haven't been riding in quite some time but I can't recall having any issues the last time I rode.
Click to expand...
Thanks for the response Jesse, appreciate the time. Taking it in to Todd is always the answer but I want to get my bearings first and learn myself.
 
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