Changed shock...new problem

[Oldie]

Had a decent run today on my 1100 and then popped into a mates to get a hand changing my front shock. Slid the tank back to get at the top nut etc and the job was done without fuss.

Starts to ride home and the bike is only (or at least, mainly) firing on one cyclinder. The R/H one aint working. Checked that the throttle cables hadn't been dislodged and both were fine.

Had to get back and put the bike away so not had a chance to check for spark etc but I was wondering whether it is likely that something could have been dislodged or nipped under the tank when refitting it. Something obvious that a noob wouldn't think of? Cheers

 

[ppgser]

Reseat the throttle cables and all should be restored.

 

[Steptoe]

Reseat the throttle cables and all should be restored.

Check both the throttle pulley wheels fully return. The cables can become dislodged at the splitter box end, where you can't see them.

 

[Oldie]

Yes, both pulley wheels fully opening and closing as per normal and no cables dislodged.

 

[Flipfly]

I think the Coil is nestled under there somewhere, could you have pulled the HT lead??

Sounds like a cable issue to me, but that's the only other thing I can think of.

 

[davegs]

Yes, both pulley wheels fully opening and closing as per normal and no cables dislodged.

Just flog it quick.

 

[Oldie]

I think the Coil is nestled under there somewhere, could you have pulled the HT lead??

Sounds like a cable issue to me, but that's the only other thing I can think of.

Mmmmm, that's what I'm thinking myself. I just nipped out for a quick look and noticed that the HT lead had popped out of the little clip on the TB, so that might suggest that it has an issue "further up" the line. Tank off again when I get a chance..

 

[Oldie]

Needing further help on this one chaps

Started to work through some basic checks to see why R/H not firing.

Firstly, I put a new plug in to see if that worked. Started engine but, as before, only the left cylinder fired up. Had a look at the plug and it was slightly wet and still very new looking, so assume some amount of fuel getting through.

Therefore thought that it might be the HT lead, so took both leads off and re-attached the "good" one to the R/H side. Bike failed to start at all, so neither the new plug nor HT lead to blame, I assume. (edit - I've just realised that I never checked the plug for a spark )

Am I right in thinking that it might be the coil? (can one side be fine and the other knackered?) or should my next job be to check the spray pattern?

Finally, I did the valves the other week and the bike was running fine. Could I have failed to tighten up the rockers properly, or something else? Ta!

 

[Ian J Hartley]

Take both plugs out and connect to HT leads. Earth the plugs and check for spark. If both spark HT OK.

If only one sparks, swop plugs and recheck. If the fault transfers, it's the plug. If fault the same. Swop the HT leads at the ignition coil and recheck.

If fault transfers, it's the HT lead, if fault the same it's the coil.

This should help diagnose basic HT fault.

 

[Oldie]

Thanks Ian

I managed to borrow my mate's diagnostic tool and the only reading I can get appears to be a Hall Sensor fault, although I'm not 100% confident that I'm using it properly as I actually got two different HS fault codes (a bit beyound me now).

Anyway, time for some more reading. However, I'm still surprised that this all happened just after removing the tank - maybe I've disrupted the wiring from the Hall Sensor to the Motronic unit

Onwards and upwards

 

[Oldie]

Just bought a used coil - soon have a brand new bike at this rate

 

[Oldie]

I installed my replacement coil today. I was sure that this was the main issue as I had the erratic tach symptoms and a bit of a crackling/shorting sound before.

Bike burst into life but then it would lose power, with very pronounced tacho jumping and that shorting sound again, possibly in the general vicinity of the ABS/ Motronic unit. In fact, without starting the bike, just switching the ignition on, you hear the fuel pump prime and then, after a few seconds there is the shorting sound and the pump re-primes. Anyone recognise these symptoms ?

 

[Keith Chapman]

A jumping tacho points to a hall sensor fault.

 

[davegs]

Tacho

This sounds like a hall sensor, check the wiring at the sensor. do a search on here plenty of info about this.

 

[Oldie]

Thanks guys. Does that tie in with the shorting sound at all?

Edit: I'm now fairly sure that the shorting noise is coming from the hall sensor. If so, does that signify that the wiring has probably been fried over the years?

 

[davegs]

Thanks guys. Does that tie in with the shorting sound at all?

Edit: I'm now fairly sure that the shorting noise is coming from the hall sensor. If so, does that signify that the wiring has probably been fried over the years?

As I said in my post do a search as you wont be the first to suffer from this prob.

 

[Ian J Hartley]

All your symptoms point to a hall sensor fault, but as this all started after you refitted your tank, that's the first place to start, you might have trapped a cable either shorting it to the tank or the frame. Lift the tank and have a good look around for evidence of shorting. Pay particular attention to connectors. The contacts corrode with age and just by disturbing them slightly may result in a poor connection causing your problem.

If you find nothing obvious, then disconnect the hall sensor connector, check the contacts for corrosion and clean if possible. Sometimes making and breaking a connector a few times is enough to clear any corrosion on the contacts enough to give a good connection. You can also check the condition of the wiring of the hall sensors by removing the alternator belt cover.

 

[Ian J Hartley]

Some useful info links

http://users.rcn.com/dehager/service/oilhead_hall_sensors.pdf

http://users.rcn.com/dehager/service/oilhead_timing_box.pdf

 

[Oldie]

Thanks again for all the input.

I've now looked at hundreds of posts (plus links) and the weight of evidence certainly points to the HES.

I guess that a new one is not a bad idea anyway (£160) which will take my total investment in the bike up to £2250 (£400 in parts) and I'm still comfortable with that. Together with the previous owner, the bike has had new wheels, discs, clutch, starter, battery, coil, exhaust, front shock and other maintenance items. I've managed about 1000 miles on it over the winter and it's a lot of fun, so I can take a bit of pain. Bit of a learning experience too

Cheers

 

[Oldie]

Managed to clear some room in the garage and get the bike away from the wall. I can now start to look at a few things without.

Firstly, I'm getting a spark from the "bad" cylinder, which I wasn't expecting. Seems to be a relatively strong spark too. Still, I can't ignore the shorting noise - something obviously wrong in the wiring dept.

Back to my checklist then - timing issue, fuelling issue, maybe the valves? I'm sure that I'll get there eventually. Next report should hopefully be more positive