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Griso broke - help!

rebus

rebus

Cruisin' Guzzisti
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Apr 25, 2009
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2008 Griso 1100. Bit of background, but not sure if any of it is relevant to the current problem. Bike has covered 6600 miles and was serviced at 6000 miles with updated maps installed at the same time. Only mechanical problem I've had since owning it is a recent faulty oil pressure sensor, which I replaced myself and cured the oil warning lights and service icons it had produced on the dash. I only mentioned this because its the first serious bit of spannering I've done on the bike since owning it. It's never given me any problems before and has only ever needed routine maintenance and servicing which has been carried out at the dealer. I admit I did struggle with the sender unit (getting it in and out) because of the tight clearances between the bottom of the alternator and the left hand cylinder, so I'm concerned that I may have disrupted something that has caused my current problem.

Sorry about the waffle - on to the problem at hand! Left home Friday lunchtime for an overnight trip on the bike and it rode faultlessly on Friday and was parked up overnight outside our accommodation. Saturday morning, the bike didn't start on its usual one-push of the button and took a further two attempts and a bit of throttle to get it started, which is unusual but I put it down to the fact that it had rained overnight so it was a cold damp start. Once started, the bike was hunting on tick-over between 1000 and 2000 rpm and wouldn't settle into its usual steady 1200rpm. Again I put this down to it being out in the rain overnight, and the bike rode fine Saturday morning although the tick over issue didn't settle down even after we'd got a few miles under our belts. Stopped for lunch later in the day, with exactly the same issues on start-up, but other than the tick over issues the bike was still running fine. Then when we got back onto some fairly open road after lunch I opened the bike up and it immediately began to run very rough, so much so that I immediately rolled the throttle off, the engine died and we coasted to the side of the road. I was able to restart it, but only by holding the throttle half-way open; it was running very rough and as soon as I allowed it to drop below 2000rpm it immediately cut out. The bike was unrideable and we had to be trailered home. Subsequently I've removed both outer plugs (my first thoughts were that it was a spark issue) - both plugs were soaking wet and black with oil, although I am getting spark at both plugs. I Haven't removed the inner plugs but they appear to be firing as when I cycle it through the starting process to check the spark with the outer plugs removed I am getting combustion, evident from the inner plugs through the outer plug hole. Absurdly it makes no difference to the bike's running if both the external spark plugs are disconnected.

My mechanical skills are limited to what I've already done. I've removed the tank again to make sure that I didn't inadvertently damaged or disconnected anything when sorting out the oil sender - everything is connected and nothing has come adrift. Fuel lines are all secure; fuel injectors not disturbed and there are no ECU error codes logged when I scroll through the diagnostics on the dash. I really am stumped! Any help, thoughts, suggestions would be appreciated - sorry for the long ramble but I wanted to put down the bike's recent history in case it was relevant to the current problem or rang any bells with anyone.
Cheers
Stu
 
Do you have access to VDSTS? I'd like to get some TPS readings at closed and partial throttle. I faulty TPS could cause an over rich condition.
 
Hi John
Thanks for the reply. Afraid I don't have access to any diagnostic software, although as far as I'm aware the TPS was reset less than 600 miles ago when I had it serviced and the maps were updated. I specifically asked them to reset the TPS and was told this would be done as a map update would require it.
Thanks
Stu
 
Hi Pete.
Iv"e gone through The diagnostics. ECU errors dash errors ETC But nothing is being shown, just 0 after every ECU code
 
Well its unlikely that anything is really 'Broken' then. If it was you'd be getting some code thrown up.

It is also highly improbable that you would have a mechanical failure on both cylinders that would allow oil into the combustion chambers so the etness is almost certainly fuel left over from when the mixture isn't combusting.

The obvious culprit in a case like this would seem to be the TPS. You'll need to connect the bike up to Navigator/Axone/VDSTS or whatever and then with the ignition on but engine off open and close the throttle to see if the TPS signal is moving smoothly. If it suddenly jumps to amuch higher reading or the oltage/degrees reading isn't linear then the TPS is 'Donal Ducked', probably worth giving the contacts on its plug a good clean anyway.

Another less likely possibility given the way its behaving is that the engine temperature or air temperature sensors are giving false info to the ECU their readings can be ascertained with the diagnostic sofware as well.

As for running with the outer plugs disconnected? As long as the HT lead that should be connected to the non-working plug can arc to earth somehow the other plug will still spark. its just that the spark will be a bit late for a single plug engine. The main reason for twin plugging on the last of the pushrod engines is to improve the burn and reduce emissions rather than enhance performance. With a twin spark arrangement though the sparks both go off a few degrees later than with a single plug engine as with two ignition points in the chamber the burn is faster and the pressure rise quicker so to keep maximum pressure in the combustion chamber at the right time, (Just after the piston has passed TDC basically.) the ignition point is retarded. It IS important though that if the HT leads are not on the plugs that they be earthed somewhere. The two HT leads are both ends of the secondary winding of the coil and when the magnetic field from the primary collapses it creates a LOT of voltage in the secondary and it REALLY wants to complete its circuit. If the inner plug is still firing then the current is still finding its ay back to 'Earth' and it obviously isn't being too fussy about how it goes about it! Not good for the coils or the ECU! Beware!!!!

Pete
 
Thanks for the reply Pete
I will contact the dealer once they are open after the bank holiday here and arrange to have it trailered in. Hopefully it will be a easy enough fix for them to sort. my main worry was that i may have inadvertently done something to cause the problem. So much for my plans to spend my week off out and about on the bike :(

Many thanks for your help with this

Stu.
 
I had exactly the same symptoms on my 2006 Triumph Tiger. Fortunately I did get an error code that made diagnosis a bit easier. The code was low voltage to the TPS. In the case of my Tiger, the ignition switch had been replaced and apparantly one of the the pins in the Molex style connectors didn't seat properly when it was plugged in. Disassembly of the connectors, cleaning and application of new dielectric grease cured the problem. I would check any connectors in the proximity of the service work that you performed and make sure all connections are well seated and there are no high resistance points at the pins.
 
Just to update all those that replied, It was a faulty TPS causing the problems. Mark at Twiggers told me its the first one he's had to replace on a Griso in a long time . Thanks for all the kind offers of help and the advice, much appreciated.

Cheers

Stu
 
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