B750 - odd low speed 'misfire' |
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Andrew_C
Senior Member Joined: 14 May 2014 Location: Hampshire Status: Offline Points: 298 |
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Posted: 17 Sep 2017 at 17:58 |
OOK - scenario.
At 2500 rpm ish, the bike is misbehaving. Not really a misfire, but a hesitation. High speed it seems fine. One pipe (nearside) looks bluer. ISTR from my spannering days long ago this indicates that cylinder is running hot. Plugs look OK, the other side maybe a bit sootier around the insulator, but tips look the same. Any thoughts about where I should be looking first? I have got a cable and Guzzidiag. |
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Brian UK
Moderator Group Joined: 13 May 2014 Location: Surrey Status: Offline Points: 17641 |
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Firstly put some injector cleaner in the tank, be generous. See if that improves it over a few miles.
Next I would check the balance of the throttle bodies. |
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Brian.
Better 5 minutes late in this world than years early in the next. |
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Andrew_C
Senior Member Joined: 14 May 2014 Location: Hampshire Status: Offline Points: 298 |
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Ta. I'll give that a whirl.
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Andyb
Senior Member Joined: 02 Jul 2016 Location: Nottinghamshire Status: Offline Points: 602 |
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My 750B always had a flat spot, but a little higher up the rev range, at around 4000rpm. Never sorted it out, which was a shame as it ruined the bike for me. The later V7 with 1 TB is much better.
AndyB Edited by Andyb - 18 Sep 2017 at 09:25 |
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Andrew_C
Senior Member Joined: 14 May 2014 Location: Hampshire Status: Offline Points: 298 |
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Nah, not a flat spot. A definite fault.
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theoneandonly
Senior Member Joined: 24 Jul 2014 Location: london Status: Offline Points: 661 |
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empty the tank , there will be water , check plug caps for resistance , unplug lambda sensor add contact cleaner , make/break 5 times , make/break tps connector .
take for a good (15 miles ) thrash then plug it into someones diagnostics , see if lambda is working .
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https://www.facebook.com/BaldricksWorkshop
http://baldricksworkshop.co.uk/ motorcycle slut, if it has wheels and an engine , i will ride it . |
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Andrew_C
Senior Member Joined: 14 May 2014 Location: Hampshire Status: Offline Points: 298 |
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Thanks Brian! |
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Brian UK
Moderator Group Joined: 13 May 2014 Location: Surrey Status: Offline Points: 17641 |
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Guess how I knew that.
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Brian.
Better 5 minutes late in this world than years early in the next. |
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Andrew_C
Senior Member Joined: 14 May 2014 Location: Hampshire Status: Offline Points: 298 |
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Hmmm... having ridden to work today, I'm not so sure it is fixed. I'll give it a bit longer, but it does seem to be low speed, when cold that is a problem. Just went out on country main roads on Sunday; in traffic this afternoon.
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rapheal
Senior Member Joined: 13 Nov 2014 Location: west country Status: Offline Points: 573 |
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Mine used to do that, I think its something to do with the way the bike is set up for the emissions, it turns the fuel off, I fitted one of those magic gadgets from the dark lord, result a much smoother motorcycle, and better pick up from low revs
also worth checking are the plug caps, and the threaded adaptors on the plugs, these coem loose with the vibration for some reason, I nipped mine up and crimped them a bit
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Andrew_C
Senior Member Joined: 14 May 2014 Location: Hampshire Status: Offline Points: 298 |
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Nope. This is above and beyond the normal V twin "lumpy at low speed" feeling. That I've fixed with a Finbau thingy.
Don't think it's the caps on the plugs either; I've had them out to look at the colour. |
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Mike H
Senior Member Joined: 21 May 2014 Location: East Anglia Status: Offline Points: 8733 |
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Have you done this:
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"Chicken nuggets don't dance on a Tuesday."
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Andrew_C
Senior Member Joined: 14 May 2014 Location: Hampshire Status: Offline Points: 298 |
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Some of it, yes. Lambda stuff fiddled with adding FF gizmo. I'll look for water and knackered plug leads, TPS etc. I've got the GuzziDiag tool. |
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