Hi, I have a problem with my Mk 1 Speed triple only running on 2 cylinders, mileage 11K. The problem is on No 1 ( left side ). I have had the Carbs cleaned and re built, also tried another set of Carbs, swapped the coils round and tried another coil,if you pull the wires of the coil with the bike running, 2&3 alters the engine note No 1 does nothing. Changed the spark plug, plug shows good spark when held on cylinder head. Checked the valve clearance and all OK. Going to do a compression test next, need to find an adapter for my gauge to fit plug treads first. Pat
I am probably talking pure crap,usually do,but I see there appears to be a T piece in the fuel line on the spare parts diagram. could it be that there is a blockage to that cylinder even though the others are clear? you seem to have covered pretty much everything else Love speedies, have you posted any pics??
Thanks for the replies,having trouble getting 12mm adapter for my compression gauge locally so have had to order one of EBay. Going to make up a "leak down" adapter and try that while I wait. The inline fuel filter is clear to all Carbs, have tried spare set of carbs as well. There is no petrol or coolant in the oil,can see crown of piston down plug hole,looks ok. The plug comes out wet, but don't smell like petrol although I could be mistaken. Thinking could be head gasket? Pat
it could be a faulty plug lead I had that with my trophy, I would of thought you would have some sort of contamination in the oil if it was a head gasket. Keith
like I said before i talk a load of crap I know but have you tried running in the prime position on the fuel tap. thnking it may be a vacuum and/or flow problem and this could rule it out. also I see you have changed the coil but have you checked you have power going to the coil, there may be a fault in the wiring
Ok Pat have you got a timing light ? if you have connect it up and check the light pulse if that is ok then it looks like you will have to check the compression, I take it you have tried another sparking plug just in case ? Keith
I am running the bike on the bench using an auxiliary tank connected straight to both fuel lines, so don't think it's a flow or vacuum problem, have tried a new set of plugs. Compression seems good. Checked wires from coils to igniter box all readings ok no broken wires.Power to all coils ok. Just put the bike back together, started straight away, ticking over perfect on all 3,but then after about 5mins it drops out on No 1 cylinder again? Tomorrow I am going to try a spare igniter box,to see if that's the problem. This one as really got me baffled, anymore suggestions much appreciated, thanks for all the replies. Pat
Hi Pat that still sounds like a coil breaking down when it is warm or the the ECU ? have you changed the ignition sensor ? just a thought, I got so fed up trying to find a similar fault with my 900 trophy only on no two cyl, I changed the lot and it has been fine since, but I still think it was a coil/lead problem in my case, Where are you Pat, are you near to Kings Lynn by any chance. Keith
Hi Keith, I am near Mansfield in Notts. The first thing I suspected was the coil, but I have tried several spare coils, including swapping No 1 over with No 3 cylinder which I know works ok. I have a spare ECU coming over later today, to give a try. Never considered the ignition sensor, would that not effect all cylinders and not just one? Will have a look at it if I get no joy with the ECU. Thanks Pat
I thought the sensor would cause probs on all cylinders too but it is worth a punt. I think as it is now intermittent,ie you had it running well, now it isnt, it is more likely to be an electrical problem though.
Yes you are possibly right Pat and sprintdave but you now need to check everything and odd things do happen I have know ignition sensors to play up and do odd things, by the way even if you do not replace it, check the gap between that and the rotor it can effect the pulse to the coils, I think we can rule out the coils themselves as you have swapped with known good ones, You are a bit far away for me to pop over and give you a hand Pat sorry it was just a thought. Keith
Dear all, I'd be very interested in finding out the outcome of Pats no1 cylinder problem as I think I have a similar problem going on with my 95 T Bird. I had fual leaking into the air filter when the bike was left to stand for a while after forgetting to turn off the fual tap. Not sure if this is related. Anyway the No1 cylinder started dropping out intermittently at first and has now gone altogether. Thanks for any help...
I'm not sure so don't shoot me, but fuel finding it's way into the airfilter is often a sign of carb floats sticking.
well this is a bit odd you seem to have checked everything but if the compression is ok it must be electrical something is breaking down when it warms up a bit, I agree with thebiglad re fuel in the airbox but it could be because that cyl is not firing ? but you mention the plug is sparking when earthed on the head are you sure the spark plug lead is ok ? try a known good one and a known good plug, Lets us know how you get on with the other ECU when it arrives. Keith
Thank you so much for your help. Took the tank off tonight and checked the plugs on no one. It was sparking ok but the lead as it joined one of the three small black boxes attached to the frame under the tank was shorting out onto the frame. I presume they are coils???. Checked no 3 and nothing coming out of that at all. So there I think lies the problem. Guess I just change that box. Do you think while I'm at it might be a good idea to change all three boxes and all leads.
If I understand you correctly you have issues on No.1 and No. 3. If there's no spark at all on 3 then I would be checking the security of the leads, if they are OK then get a new coil. On No.1 it sounds like the insulation on the lead is breaking down. Check to see if there are any obvious faults on the lead - if in any doubt, replace.
you say one of the small black boxes (the coils) were shorting out, was it the coil shorting out or the lead ? either way you will have to replace the coil or lead that is shorting out as for No 3 cyl that could be just a coil and will need replacing if the lead is ok, try and work out what you need because the coils are expensive as are the leads I replaced mine with second parts from Triumphant and National Triumph and the coil new from ebay and as I recall about £50 for one and all three leads s/h from the two people I have mentioned cost £60 but you can almost double those prices from Triumphs. Keith
Looks like there is a set of 3 coils and leads on National Triumph at the moment - £68.00 if I remember rightly.
