Coils loose?

[Welshguzzi]

I'm having a recurrent problem with my 2002 Le Mans: Within the last 18 months, I've broken down twice, and just made it home once with some drama with what appears to be the same problem: The bike starts to lose power and I get loads of back fires and ominous popping: so far I've changed the HT leads, plugs, new inlet manifold rubbers. Also, I put on a new reg/rec and charging seems to be OK.

 

I have just checked the low and high tension resistances across the coils, which are 0 ohms and 3.2 kilohms respectively. Would I be right in thinking that the coils are mounted on a floating bracket? There doesn't seem to be an obvious way of bolting it to the frame - there are just 3 rubber mounting lugs which locate against the frame. Or should they be glued on.......?

 

So I'm really stuck - I thought that the rubber manifold was the problem as the left hand one was split about 1/3 of it's circumference next to the clip, but when I started up this morning, it was behaving in the same old way, although during the week it was absolutely fine when i started it in the garage.

 

I'm leaning towards a fuelling problem - I'm going to change the filter, although there are only 15000 miles on the clock, so it should be OK.

 

Beginning to get down-hearted - the weather is great in the UK........

 

 

[czakky]

The coils are just mounted on those rubber "puck" things mine fell off long ago so they are now held on by the nest of wires and fuel lines/a couple zip-ties. Not sure about that resistance reading.

 

After 15k you should take a look at that filter and replace/wash if reusable.

 

When was the last time you did a basic tune-up? TPS, balance TBs, valve check?

 

Next I'd check that fuel filter at only 15k miles it could have had some old fuel strangling the system.

[Welshguzzi]

Valves clearances are fine - checked them this week.

 

What confuses me is the intermittent nature of it - if the filter was clogged up, then I would expect it to play up all the time surely? It looks as if it was replaced in 2008 or 2009 as it's date stamped, so it's probably only done 7-8000 miles.

 

It's over a year since I bought the bike from a dealer, so the TPS and TB's may need checking, but it's got to run first!!!

[czakky]

If it were me i would change fuel filter, do a tune up, run an injector cleaner then rebalance TBs.

[docc]

If it were me i would change fuel filter, do a tune up, run an injector cleaner then rebalance TBs.

+1 on that for a starting point.

 

The loose coils are not likely the culprit, yet I'm not sure how to test them properly. Have a look also at the Tank Off Maintenance Checklist for other issues and how to reattach or replace the coil mounts.

[fotoguzzi]

Have you checked the battery connections? and the ground wire from the battery?

[Kiwi_Roy]

What you describe sounds very much like the symptoms of a dirty ignition switch or the side stand switch playing up.

Next time it happens flick the ignition switch a few times if it improves it's the switch for sure.

You can check it for resistance, see Note 4 of attached.

 

It's easy to clean just drop the contacts off and you can unplug it just under the tank.

 

If the side stand switch is still wired you can test bypass it by wrapping a strand of bare wire around the 30 and 87 pin of middle relay (TP-b to TP-c)

 

[Welshguzzi]

So far, I've checked and cleaned the block connector for the S/S switch - it looked OK but you can never tell.... the bike now starts and runs OK, but it was running last week but then stuck 2 fingers up at me at the weekend, so that may or may not have been the answer. I'll take it for a local run tomorrow and see what happens - I live at the bottom of a hill so I can always coast home.....

 

Intermittent faults - dontcha just love 'em

 

One suggestion has been the butterfly settings in the TB's - any thoughts? It was somebody who had experienced very similar symptoms to mine.

[docc]

One suggestion has been the butterfly settings in the TB's - any thoughts?

Definitely. It's worth working through the full tune-up: TPS Set-up and Throttle Balance Tuning

 

Next, per Kiwi_Roy: clean the ignition switch and inspect its connections.

 

Also, inspect the 30 amp charging/regulator fuse for signs of heat failure.

[Welshguzzi]

Ah yes, the ignition switch..... is it easy to dismantle in situ? Not keen on a strip-down of the dashboard

[docc]

I went searching for that procedure and never found it posted. I can't remember actually doing it, but it was not difficult on the Sport. Not sure how much that changes with the LeMans fairing . . .

[Kiwi_Roy]

If the switch has too much resistance the ECU relay starts to drop out which plays havoc with the ECU and causes backfiring, next time it plays up flick the switch a few times to see if it changes.

The switch on mine was quite easy to remove, 2 large screws up underneath, you just remove the black part, the key stays in situ.

I told a friend to remove his and he found one of the wires had broken off.

 

If you don't want to pull it off at least measure the contact resistance, Note 4 on the comic I posted back up a bit 

Disconnect battery negative, pull relay 3, measure Ohms from fuse 6 & 7 to contact 30 in the relay socket, I just went and checked mine, it read 1.5 Ohms and dropped to 1.1 after I worked it a couple of times, when this bike had symptoms similar to yours it read over 18 Ohms.

It should measure

 

To check the safety circuit

If you have an electric petcock attach a small lamp from there to the chassis, tape it to the bars where you can see it while riding, it should never flicker, if it does there's the problem in the safety circuit. (Ignition switch, Sidestand  circuit, kill switch) 

[Welshguzzi]

Just tried to get the ignition switch apart - the barrel appears to be fairly secure - I didn't want to force the tabs on the side tto much in case I broke it.

 

I also ran the resistance test you described - either my multimeter isn't sensitive enough or I've done it wrong, as there was not a flicker from the meter when I put it across the relay socket and fuses 5 and 6, tried with fuses both in and out.

 

At the moment, the bike starts every time I hit the button, but a bit nervous about riding it

[docc]

I wasn't getting the resistance readings either. Until I disconnected the negative to the battery and turned the switch on. I went from the outboard fuse 6 connector (fuse out) to the outboard relay connector: 0.8 Ohms.

 

As I recall, the ignition switch drops out the bottom of the triple clamp after taking out these two screws:

 

[Welshguzzi]

Right, with the ignition ON, I get zero resistance when I did that test. Good or not so?

I managed to release the base of the ignition switch, but it's fairly firmly sealed - I'm a bit wary about trying to prize it apart as I don't want to damage it. When I broke down I tried to start the bike a number of times and turned the ignition on and off quite a lot without any success, so I'm hoping it's probably OK.......