ideally it would be good to borrow/try one first just to confirm problem/cross it off the checklist. Can't see any s/hand at the mo Loz. Does anyone know how different PF1C characteristics are? I see you E.... (and one other) are selling this for a price it would be worth having a punt at. Not sure why the PF3C warrants a price 2 and a half times as much..
The other is +£17 postage + 20% vat and import duty Of course I can supply one to try if returned undamaged, clean with all packaging - but it would be easier if someone local could swap one over if possible to test? £40.00 + £3.90 post (small parcel unfortunately) - here to help fellow subscribers as it's where my business was born :Finger:
Was told only pf3c will work. Theres a car pattern one thats similar with holes instead of slots. I filed out the holes into slots but the trigger hole is different also, so that was nfg. Someone on here built a step motor + reader to test tps and checked mine with a readout graph via post for a drink.
0v-5v- at two terminals check the voltage coming back from the third when twisting the throttle. ifit's a common problem hack an old loom and keep it for checking the resistance.of the t.p.s. rent it oot. anyhoo why go looking for the awkward faults first? 1hr checking the basics will illuminate/diagnose many faults on these basic engine management systems.
was only just walking for a bit down that avenue fin - nothing cast in stone dude/not suggesting Loz even pursue that yet. I would go checking all ignition related connectors for loose-ness/corrosion first because I am tight and you know I would already : )))))
it's a common fault (with people) think of the complicated unlikely faults first? same with mot's people get right stressed about them. looking at the basics, vacuum pipes and insulators, plugs and leads (narrows down cylinders) condition of connections. although a bit guilty of it myself, especially with fiats. instead of following a diagnostic procedure you start jumping the gun to save time and money.
So some findings ... Spark plug check: Rear plug was sooty, the front plug looks, uh, oily? on one bit of the electrode, the rest of it looked a healthy brown. Maybe I dribbled on it taking out the front one. The resistance across electrodes was very high, beyond the accuracy of my multi-meter. I assume this is correct. The indications of fuel available for combustion at the plugs leads me to believe the issue is electrical rather than fuelling. It might be that the rear plug is fouling/misfiring or some other issue to do with delivering spark. Fuel line condition/injectors/etc: I checked for bubbles in the tank when the fuel pump primed - no bubbles. Injectors ... no idea. I know that these were gummed up prior to the bike being put back on the road but they responded well to clean at the time and I was getting exemplary fuelling up until a few weeks ago. Electrical connections: I'm not convinced that the battery connections, +ve and -ve both, were sufficiently tightened the last time I tinkered with it. Now corrected. Starter solenoid connections are tight. I have cleaned the 3-wire connectors for the TPS unit and the ignition pickup sensor. Voltages: I'm reading 13.5V at 2000rpm, just as Keith suggested. The TPS voltage across the red/white and yellow wires is about 4.5V. I was unable to obtain any reading via the third terminal (regarding what finm said). TPS: I couldn't see any issue with the way it was mounted. Beyond that, I'd need some hands-on guidance on how to diagnose/deal with it. I will say that the PCIII registers opening and closing of the throttle in an entirely consistent fashion. At the end of doing not very much at all, I revved the crap out of the little thing. Throttle response was crisp, non-hesitant and frustratingly awesome. It seems the issues are when the engine is under load and most pronounced when in 5th gear, which makes me think it's some sort of ignition/crank sensor thing that's at the heart of it. However, I need to take the bike out tomorrow to see whether just faffing about with it has changed or improved matters. I checked tyre pressure while I was tinkering. They were down to about 1.7 bar front and back, but those Michelin things are so crap I hadn't even noticed. The SportSmarts and M7RRs on my 999 tell me the instant they have dropped more than 0.1 bar. Adjusted the chain, too, that was a little on the slack side so hopefully this will tidy up low-speed work. Oh, and I had the chance to use my lovely new Halfords Advanced toolkit - it gave me a happy, it's ni-i-ice.
When my 750SS started running badly, it was down to a loose alternator nut. It allowed the flywheel to flap around, which damaged one of the pick-ups. Had to get a new pair from Electrex. Not sure if the ie has the same system though...
as i have just discovered it's cool working on your own stuff. the plugs should be open circuit between electrode and threaded part on your highest setting 2000m ohms? and probably about 5k ohms from electrode to top of plug. it all sounds H.T related to me, but again i wont pretend to know their foibles. cant see why an rpm/crank/tdc censor can affect under load but ok at high engine speed. still got it's lamda sensor? can you disconnect and test ride?
swap plugs over or change plugs see what happens had issues with sparkplugs before even new ones ngk R especially I run bosch now
No lambda sensor on my bike. So I went for a quick blat this evening, to test my tinkering and also met up with Chris and Torquepen at Bury Hill. The result was: nice chat with Chris and Stuart, one brief moment of flat-spot under acceleration and the rest of the time the bike performed brilliantly. The steering was good (that'll be the air in the tyres), the low-speed performance was spot-on (that'll be the chain-tightening) and the bike readily accelerated in all gears except for that one instance. Good Goat it was good to be riding a well-behaved 750 again The moral of the story - ask people on the forum and they will give you great ideas and great advice
OK, the gremlins are back, with a vengeance. I would say that the recent monsoon I rode to work in contributed but if I am honest, the issues starting creeping back in during the dry spell. Bike doesn't want to rev past 6k rpm when in gear but in neutral or with the clutch pulled in, it will redline. It will rev higher, the lower the gear it's in. The engine is slightly hesitant to rev in neutral, there's a bit of lag. In gear, the hesitancy is horrible and on the way home today, life-threatening. Staring has been somewhat reluctant of late - normally the bike starts almost before I press the button, it's that eager. My first step is to replace the spark plugs - I've ordered NGK DPR8EA-9 x2 as I think this will suit how the bike is ridden. The current set are of unknown age - it's possible that they are really very old indeed. The HT leads look in fair nick to me so plugs, first.
Is it definitely firing on both cylinders? Being generally right down on power would give you higher revs in low gears. My 750 suffered a loose alternator nut, which allowed the flywheel to wobble, taking out one of the pick ups. Before it totally lost one cylinder though, it would fade and then come back. If it's knocking, it could well be that. Could also be lots of other things of course, let's hope it's just a duff plug.
At times it feels like it's on one cylinder when it's running. The vertical cylinder plug looks like it might be oiling/sooting up a bit compared to the horizontal one.. That said, your experience with the loose alternator nut is a worry. I sometimes think I can hear a knocking but that could simply be my imagination. How straightforward is it for an unskilled owner to check on this issue?
Pretty easy.....ask Chris if you can borrow his Clarke rattle gun.............that will sort the alternator nut out......... ...........it's probably easier to drain the oil; but some people lean the bike over to the right against a wall.........I'm not in favour of that as I have had bikes slip down when I have been working on the other side (an Enfield Bullet was one)....... ...........just unplug the alternator wires where possible; remove the front sprocket cover; clutch slave off if it's the same side as the alternator (not sure if this impedes removal of the cover though).....undo all the allen bolts........about 14 of them.......copy the cover diagram from a parts manual, print it off, then you can push each bolt through the paper so you know which one goes where; remove the cover plate from the centre of the cover; then you might need a cover puller (two M6 bolts and a central one, say M10) or you might be lucky and the cover may come off with some careful tapping with a rubber hammer....... With the cover off you can then see the alternator nut........After I had replaced the starter sprag and had put the flywheel and rotor back on, I used the same sort of rattle gun to tighten the nut as much as possible (bike in 1st gear and rear wheel on the ground) and somehow I also managed to check the torque was correct after that. Check the bearing in alternator cover for play as these can also wear enough to cause a knocking noise......... ........and check the pick-up positions in case they have moved, plus check the air gap. Not that hard really, just bloody laborious......... Use 3 Bond to give you a gasket after having cleaned the crackcase and cover gasket faces. Sorry if I forgot anything.........
Thanks, Al, that seems pretty clear to me. I may end up with a bit of spare time on my hands soon, this will be a good job for then
get stuck in loz. the sense of achievement is immense when carrying out diagnostics. it can also put you in to the depth of despair with a wee measure of depression to go with it.
