Nice to hear a fellow Triumph man from my neck of the woods. Had the same bike before I left the country. Had many other makes over the years, but somehow always come back to Trumpets. Cheers mucker. Putnam Valley NY.
I once had an intermittent slight misfire on my T140V, it was mildly irritating when it did it under load, but when it was idling, it would be running ok then suddenly stop. I fitted new plugs, new needles in the mk1s, cleaned out the pilot jets, made numerous air screw adjustments, but it was still there. I tested the resistance on the coils, both ok. After much head scratching, to confirm it was an ignition fault I connected up my strobe and watched the flashes at idle. Now and again, it would miss a flash or 2, and sometimes cut out. As I live quite close to Boyer Bransden's factory near Maidstone, I took the ignition module to them for testing and that was ok too. I'd already checked the ends of the HT leads to make sure they had clean connections, but they were the only thing left, so I fitted new leads and caps - problem solved.
thats going to be a big relief if a replacement coil eliminates the stumble off idle. Funny how we get so fixated with the fuel or the ignition or electrics etc that we don't even consider other possibilities until we have exhausted the first idea that we had.
Alright John, I hope it is just the coil, thinking about it though every single carb setup I had done made no difference what so ever in the stumble, you are right about being fixated on one thing,. Then I found the other chap online who had the same problem who solved his issue with a new coil. That got me to rip mine out and check them and find the one faulty. Now we have to wait and see if the new coil fixes it, Tuesday Ii should get them.
@@OldBiker thats the great thing about the Net isn't it. No matter what information or advice you need ,....someone somewhere in the World has had the same issue and usually found a solution. I often wonder how we ever managed to do anything before the internet. ! I have to say though if it were me I'd think seriously about sticking a Electronic ignition on the Triumph for total reliability and consistent timing and advance. I've had a Boyer on my XS650 for 8 years now and there is a lot to be said for being able to go out to the shed and fire the engine up on the button and never ever have any ignition issues . You watch.... now that I have said that it won't start tomorrow now .lol
Ya got it going yet? Make sure where your header pipe joins the silencer is sealed with rtv and clamped tight... Fixed the flat spot off idle on my twin mk2s
Hi Bill yeah I solved the problem in the end completely by blocking the link pipe (later vid) so the bike uses each silencer separately, there was never enough back pressure with the link pipe open but now the bike runs like it should and has tons of power from the minute you crack open the throttle, no stumbling what so ever and I'm well chuffed with the performance.
@@OldBiker you might want to look around for brass screw on tops for the the mk2s as the throttle cables will eventually pull through the plastic threads putting out the sync... Bike looks neat
A gammy coil as yours tested should mean only one cylinder is capable of firing (the one connected with the good coil). Does not explain your stumble when accelerating...as bike would run very rough at all rpm with constantly low (50%) power output. On my Norton Commando with OEM Amal twin carbs, a stumble from idle to 1/8 or 1/4 throttle roll-on usually indicates a lean condition. Only the idle circuit and needle jet are operating at this throttle position, so ignore main jetting sizes etc. Richening the idle mixture Air screw and running with needle raised/needle clip in lowest needle notch seems to cure it on my bike. Although I've had a worn needle jet/or worn needle or both that gave a very bad stumble from idle to small throttle roll on (like when leaving a traffic light etc). Unsure how much of this will apply to your non-stock carbs.
The coils are wired in series ( Live +Coil- Link wire +Coil- Earth) so if one coil breaks down I'm getting half the power, half the power = very weak spark prone to flooding when the throttle is opened hence the stumble.
Nice to hear a fellow Triumph man from my neck of the woods. Had the same bike before I left the country. Had many other makes over the years, but somehow always come back to Trumpets. Cheers mucker. Putnam Valley NY.
I once had an intermittent slight misfire on my T140V, it was mildly irritating when it did it under load, but when it was idling, it would be running ok then suddenly stop. I fitted new plugs, new needles in the mk1s, cleaned out the pilot jets, made numerous air screw adjustments, but it was still there. I tested the resistance on the coils, both ok. After much head scratching, to confirm it was an ignition fault I connected up my strobe and watched the flashes at idle. Now and again, it would miss a flash or 2, and sometimes cut out. As I live quite close to Boyer Bransden's factory near Maidstone, I took the ignition module to them for testing and that was ok too. I'd already checked the ends of the HT leads to make sure they had clean connections, but they were the only thing left, so I fitted new leads and caps - problem solved.
Ignore that, replayed it, realised you were already on 200k !
We've all seen the movie mate, old bikes, say no more
It is an old known that two thirds of the carb problems are ignition problems
good luck ,
Try putting the meter on the next range up on resistance and see what it reads
thats going to be a big relief if a replacement coil eliminates the stumble off idle.
Funny how we get so fixated with the fuel or the ignition or electrics etc that we don't even consider other possibilities until we have exhausted the first idea that we had.
Alright John, I hope it is just the coil, thinking about it though every single carb setup I had done made no difference what so ever in the stumble, you are right about being fixated on one thing,. Then I found the other chap online who had the same problem who solved his issue with a new coil. That got me to rip mine out and check them and find the one faulty. Now we have to wait and see if the new coil fixes it, Tuesday Ii should get them.
@@OldBiker thats the great thing about the Net isn't it. No matter what information or advice you need ,....someone somewhere in the World has had the same issue and usually found a solution.
I often wonder how we ever managed to do anything before the internet. ! I have to say though if it were me I'd think seriously about sticking a Electronic ignition on the Triumph for total reliability and consistent timing and advance. I've had a Boyer on my XS650 for 8 years now and there is a lot to be said for being able to go out to the shed and fire the engine up on the button and never ever have any ignition issues .
You watch.... now that I have said that it won't start tomorrow now .lol
Ya got it going yet? Make sure where your header pipe joins the silencer is sealed with rtv and clamped tight... Fixed the flat spot off idle on my twin mk2s
Hi Bill yeah I solved the problem in the end completely by blocking the link pipe (later vid) so the bike uses each silencer separately, there was never enough back pressure with the link pipe open but now the bike runs like it should and has tons of power from the minute you crack open the throttle, no stumbling what so ever and I'm well chuffed with the performance.
@@OldBiker you might want to look around for brass screw on tops for the the mk2s as the throttle cables will eventually pull through the plastic threads putting out the sync...
Bike looks neat
A gammy coil as yours tested should mean only one cylinder is capable of firing (the one connected with the good coil). Does not explain your stumble when accelerating...as bike would run very rough at all rpm with constantly low (50%) power output.
On my Norton Commando with OEM Amal twin carbs, a stumble from idle to 1/8 or 1/4 throttle roll-on usually indicates a lean condition. Only the idle circuit and needle jet are operating at this throttle position, so ignore main jetting sizes etc. Richening the idle mixture Air screw and running with needle raised/needle clip in lowest needle notch seems to cure it on my bike. Although I've had a worn needle jet/or worn needle or both that gave a very bad stumble from idle to small throttle roll on (like when leaving a traffic light etc). Unsure how much of this will apply to your non-stock carbs.
The coils are wired in series ( Live +Coil- Link wire +Coil- Earth) so if one coil breaks down I'm getting half the power, half the power = very weak spark prone to flooding when the throttle is opened hence the stumble.
process of illimination, good job
The gap is not critical as long as the filter seals on the side cover.....DUH!!