[bang]
i have a '99 Monster 750 (with 39FCRs, K&N, cut airbox, ignitech box, dyna coils, and high-mount DP pipes). i am chasing an intermittent
poor running problem where 1 cylinder quits firing (don't know which one, because usually by the time i get home, it's running on both
again). this only happens after the bike has been running 10 or 15 minutes, so i'm starting to think it's heat and not fuel related. anyone
ever seen the ignition pickups go intermittently bad when warm? i've replaced everthing else in the ingition path (box, coils, plugs, wires).
next step is to pull the left side cover and look for a kinked/broken wire or something. i'm thinking of pulling the pickups to the bench,
put a meter on them and hit them with a heat gun, sound like a plan?
all suggestions welcome, i've been chasing this for 15 months now. good think i have other bikes to ride! [moto]
jimh
duvall, wa
Did you check the wires where they exit the case?
I've heard of some failures there that might cause an intermittent problem.
If not that I think your plan is a good one.
In case you don't know you will be looking for 93-95 OHMs. They can be replaced one at a time if you can find one. I scribed a line on the bracket and case for reference when I did mine. For the timing.
I had a pick up go on mine last year, I don't remember which cylinder. The pick up at fault would go from 95 ohms to infinity at about 180o when heated in water if I remember correctly. Better control with a water than a heat gun. I replaced the set since they both have been through the same torture and Ducati sells it as a complete bolt on set, but if you want to replace just the one you can try here:
http://www.electrexworld.co.uk/p8-pickup-pulse-coil-ducati-twins-electrical-parts-for-motorcycles-electrex-world-9413-0.html (http://www.electrexworld.co.uk/p8-pickup-pulse-coil-ducati-twins-electrical-parts-for-motorcycles-electrex-world-9413-0.html)
Do confirm it is the pick up first. It can also be a coil or ignition module. Easiest way to find out on the road is determine which cylinder is misfiring, then switch modules oops you have an Ignitech box) and coils one at a time. Did Ignatech give you any troubleshooting info?
You may have already eliminated a kinked or otherwise plugged fuel tank vent. It can cause a tank vacuum after running for awhile that keeps the fuel pump from delivering enough fuel.
thanks for all the suggestions, guys. yep, i've checked the tank vent, rode it home with the cap open last weekend, still ran like shit.
i'll check the wires to the pickups, and thanks for the hot water tip, that sounds much better. i'm assuming that under normal
running, they aren't likely to get much over about 230 250 degrees F, right? and if one's failing it's failing much lower than that,
since i've been riding in 50 degree weather, with oil temps around 70-80 degrees C.
onward!
Not very scientific, but have you tried moving the wires and connectors coming from the pickups and where they go to the ignitech unit while the bike is running? I had some bad wiring on my bike that would cause intermittent firing problems. They weren't as bad as what you describe (actually the bike wouldn't fire at all at first), but they were very similar and they didn't show up until I started moving wires around (as you would have done when installing the ignitech unit).
I'm not sure how the ignitech wires up, but I would check all those around it by moving them, bending them, etc. while the bike is idling to see if you get any change. At least do that before you pull the cover because I was ready to pull my cover and check the pick-ups before I discovered the bad connections by complete accident.
Factory service manuals call that " the wiggle test". [laugh]
+1 on the wiggle test.
Also check wiring round R side steering stem for wear/shorts.
I had similar problems (but only when warm and only at idle) and it was just a badly adjusted pick-up sensor gap.
So check that while you're checking for loose wires, etc.
ok, folks, where is the smiley for 'major f'ing egg on face'?
through this whole episode, i've been very confused by the fact that when the bike fails to run, it
'feels' like its out of fuel, but it didn't happen when you'd normally think, it happened at cruise,
not at hard running.
somewhere on this board i saw a recommendation for 'testing the fuel pump': put the output hose in a
can, crank/run the engine, you should get a fair bit of fuel, even with the hose held up by the fuel tank.
tried that last night, got almost nothing, a dribble. pulled the pump, took it apart, looked fine. as i'm putting
it back, i notice that the rectangular pump that chris sells is symetrical, you can mount it two ways, but one
of those ways is 'backwards': input to carbs and output to tank. I THINK I HAD THE FUEL PUMP IN BACKWARDS!
this is made easier by the hose routing, the hose from the tank actually enters the pump in the front, and the back
connection then loops around and goes to the carbs.
because a monster is MOSTLY gravity fed, it ran a lot of the time, but when the pump had a good strong
vacuum signal (like at cruise), it could fight against the gravity and stop the fuel flow. i put it on the right way, i'll test ride
it tonight and see. if that was the problem, i'll have to mash my forehead in with a sharp rock.
thanks, all!
Closest I found (http://www.sporthoj.com/forum/images/smilies/action-smiley-034.gif)
Thx f sharing, now maybe someone else won`t have to do the same mistake!
We`ve all done stupid things.... ;)
[roll]
good news and bad news: it runs! rode it for 45 minutes and other than the fact that the jetting is messed up,
from my previous attempts to fix this, it ran great! bad news: as noted above, i'm an idiot. good thing i got
this day job, i am so obviously not the next Merlyn Plumlee (may he RIP). oh well.
now to fix the jetting, then i can start thinking about fixing the tach, and gettin' this old girl some new paint.
[moto]
hooray. [thumbsup]