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Discussion Starter · #22 ·
Of course I would tell you.
Wifey and I went skiing last couple days and have not had time to mess with bike. Internet was a little spotty also. I will read thru all the responses again and let you all know what I find.
 

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I went thru both carbs. I cleaned all the crud out, blew air through every hole. Cleaned out fuel tank, verified good flow throughout all the new hoses into the carbs. New 91 octane zero ethanol fuel. Starts on 1st kick every time now. Idles well. on the test rides, it will not go over 30 mph. It starts cutting out. I let off of the throttle, and all is good again. Is this a timing issue? If so, will someone educate me on how to adjust it? Any other suggestions on what could be causing this?

From your description I can tell you that this is not a fuel related issue. I trust you are not an idiot and that you have reassembled the carbs correctly. The bike would probably not start otherwise and it certainly would not idle correctly if the issue was with the carbs.


Your issue is ignition related, most likely your ignition coils or possibly the spark plugs.


If you are running NGK plugs then don't, always use Champion plugs in older Triumph engines. The Champion plugs have a more suitable heat range than the NGK equivalents.



I would replace all of the basic ignition components, plugs, leads and coil/s. If you are running points make sure they are cleaned and properly gapped and timed. If you are running an electronic ignition (boyer) then make sure the battery is in good condition and the zener diode or electronic rectifier is in good condition and functioning properly.


With the engine running at ~2000 rpm, check the battery voltage, it should not be more than 15.2 volts (zener) or less than 13.5 volts (rectifier). If the voltage is higher or lower, replace the zener diode or electronic rectifier.


If you happen to be running a magneto, then it is time to have it rebuilt.
 

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Hi,

If you are running NGK plugs then don't,
Apart from a brief experiment with Nippon Denso in one Honda in the 1980's, I've run NGK's exclusively in all my bikes since about 1978 or 1979. Never a problem; however, I do make sure I buy from a reputable dealer.

replace the zener diode
Very difficult to buy verifiably-good Zeners. :(

Hth.

Regards,
 

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Discussion Starter · #25 ·
I have to work this weekend, but hopefully I can spend some time to mess with the bike. I'll start with Peg's suggestions and go from there. I'll also go back thru the carbs again to see if I missed anything. I'll be sure to look at the choke a little closer also!
Also, I have had the bike for less than 1 month. It had this same issue before I touched the carbs.
Thanks for all of the replies. I'll let you know what I find.
 

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Do you have an in-line aftermarket petrol filter?. These symptoms duplicate a problem on a mates bike. After cleaning out the tank the fine brown internal patina (rust) that formed as it dried blocked a visibly perfect filter upon first fill up.
When the demand for fuel increased the bike would start cutting out from insufficient fuel supply. As soon as the throttle was closed and the bike ran at a lower speed requiring less fuel so ran perfectly


.
 

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Hi Dan,

How does one check ignition
First establish whether it's carburation or electrics (ignition).

As "Peg" advised, mark (dab of paint? Magic marker?) the throttle housing where you can see it when riding the bike; mark the grip beside the throttle housing corresponding to 1/4, 1/2, 3/4 and WOT.

Go for a test ride. If it misfires, note twistgrip position, gear and rpm; change gear and note twistgrip position and rpm. If the misfire's at the same twistgrip position in different gears, it's carburation; if the misfire's at the same rpm in different gears, it's electrics.

Hth.

Regards,
 

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These problems and the answers are always interesting...From a life time of riding junk bikes and driving junk cars/trucks I can say if the engine starts instantly and idles well you can eliminate all sorts of potential mechanical problems..If it has points you can pretty much eliminate charging system issues, especially if it hasn't needed a battery charging...If it misfires unevenly or backfires out the exhaust it may be ignition, if it just bogs down more evenly or spits out the cabs it may be fuel/carb related...The "choke" in the on position is possible but that will make for a crappy idle, yes?
 

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Discussion Starter · #29 ·
Update

No work this weekend, so let's see what we can get done! I did get a chance on New Year's Day to fool around with it for a couple hours.
So to start off - the tach is bad (jumps all over the place) and the odometer is falling out of whatever holds it in place. I will send them both off to that place back east (Nosinger?) for repair. So the bottom line here is that I cannot answer your questions about rpm when thing start to go bad. The timing light that I use on my car has a tach built into the back of it. I've never hooked it up to a bike and the positive ground thing I am not clear on. Question - which plug wire do I clip to? Do the other leads go to red and black battery terminals?
I pulled the air cleaners and see that one of the choke slides is sitting lower than the other. After reading thru a few other posts on this forum, I decided that the choke was not needed anyway, so I just removed the slides completely and pulled the cable all the way to the top. It appears that it was not a good decision because now while it still starts instantly and idles well, giving any throttle at all makes it cut out and it will die if given too much.
So my job for this evening is to put the choke slides back in and adjust.
Ive read Bushmans carb tuning secrets. I'll read it again and see where I end up.
(http://www.jba.bc.ca/Bushmans Carb Tuning.html)
Posting good pictures from my iPad is still a struggle for me. If someone can educate me to not post them upside down or turned sideways, it would be helpful. Look close and you can see one slide sitting lower than the other.
Bonus points for all those who spot the fuel line issue!
 

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the tach is bad (jumps all over the place)
I have found that a ‘jumping’ tacho is more likely to be a cable fault than a tacho head fault, it might be worth inspecting and lubricating the drive cable first, the square drive end should not rounded off.

The timing light that I use on my car has a tach built into the back of it. I've never hooked it up to a bike and the positive ground thing I am not clear on.
Do not worry about the bike setup, just look at the battery, red timing light wire to the + battery terminal, black timing light wire to the - battery terminal.
If you have points fitted then left ht lead times the left side and right ht lead times the right side, if you have electronic ignition then you only need to set the timing once and can use either ht lead.
The timing marks on the alternator should line up when you rev the engine to 3500 rpm, (not at idle speed)

Some people remove the choke slides altogether, but I believe they seal the cable hole to prevent air being drawn down, other leave the choke in but permanently fix it in the top position but remove the cable.

The carb slides can be held out of sync in two ways, the cable and the throttle stop screw. An easy way to set this is:
1) slacken the cable right off so there is excessive play at the throttle-maybe 1/2" before the cable takes up the slack.
2) First to set the throttle stops—screw out the throttle stop/tickover screws as far as they will go
3) take two pieces of thin wire (thin welding rod is ideal) about 6" long, wedge one under each throttle slide.
4) turn the throttle stop screws in on one carb until you just see the rod twitch, do the same on the other carb. The throttle stop screws are now synced, mark with a sharpie the position screw slot is on each carb.
5) Now to set the cables, very slowly turn the twistgrip while watching both rods, they should move together, if one moves first, adjust the cable on the other carb using the screw adjuster on the other carb to shorten the other cable.
(In your photo I can see one fully down, on the carb top plate) set the adjusters on top of the carbs until the rods ‘twitch’ at the same time. Cables are now synchronised and the locknuts tightened.
6) set the tickover, the throttle stop screws are synchronised but you need to lift the slides so the engine will idle.
When you move one screw, make sure you move the other screw exactly the same amount- as a basic setting screw in each throttle stop 3/4 of a turn, and start the engine-the engine will most likely stall when you let the throttle off, if it does -screw in another 1/4 turn on both screws-try starting the engine again. When you get it to idle, set the tickover speed—the secret to this is move each screw the same amount each time.
7) Go back to the handlebar and adjust the cable slack at the handlebar to 3/16", check at full steering lock each way.

The carbs should be synchronised fairly close, enough for the bike to run quite nicely (once your problem is resolved), you can further fine tune from this point later if you wish.
Note: (I have assumed that the standard throttle cables are fitted, with one cable to the twistgrip, and a splitter box to that has two cables to tha carburettors)

One thing not mentioned- is beacause you inherited the problem, do not assume the previous owner has everything correct- he might have bolted the wrong carbs to your bike—check needles type, clip positions, jet sizes and throttle cutaway number are all correct according to the Triumph manual.

In your photo I can see the fuel filters, these might be blocking flow. To check this:
1) fit the tank and half fill it, put the petrol cap on.
2) remove both drain plugs at the bottom of each float bowl.
3) put a measuring jug underneath
4) open the main fuel tap only, you should get 300ml (1/2 pint UK, or 0.6 pint USA) flow in one minute
5) close the main fuel tap and repeat with the reserve tap.
6) if the flow rate is slow, try again with the petrol cap off the tank-in case the vent hole is blocked.
7) if the flow rate is still slow try again with the in line filters removed.

Best regards
Peg.
 

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Discussion Starter · #32 ·
I have found that a ‘jumping’ tacho is more likely to be a cable fault than a tacho head fault, it might be worth inspecting and lubricating the drive cable first, the square drive end should not rounded off.


Do not worry about the bike setup, just look at the battery, red timing light wire to the + battery terminal, black timing light wire to the - battery terminal.
If you have points fitted then left ht lead times the left side and right ht lead times the right side, if you have electronic ignition then you only need to set the timing once and can use either ht lead.
The timing marks on the alternator should line up when you rev the engine to 3500 rpm, (not at idle speed)

Some people remove the choke slides altogether, but I believe they seal the cable hole to prevent air being drawn down, other leave the choke in but permanently fix it in the top position but remove the cable.

The carb slides can be held out of sync in two ways, the cable and the throttle stop screw. An easy way to set this is:
1) slacken the cable right off so there is excessive play at the throttle-maybe 1/2" before the cable takes up the slack.
2) First to set the throttle stops—screw out the throttle stop/tickover screws as far as they will go
3) take two pieces of thin wire (thin welding rod is ideal) about 6" long, wedge one under each throttle slide.
4) turn the throttle stop screws in on one carb until you just see the rod twitch, do the same on the other carb. The throttle stop screws are now synced, mark with a sharpie the position screw slot is on each carb.
5) Now to set the cables, very slowly turn the twistgrip while watching both rods, they should move together, if one moves first, adjust the cable on the other carb using the screw adjuster on the other carb to shorten the other cable.
(In your photo I can see one fully down, on the carb top plate) set the adjusters on top of the carbs until the rods ‘twitch’ at the same time. Cables are now synchronised and the locknuts tightened.
6) set the tickover, the throttle stop screws are synchronised but you need to lift the slides so the engine will idle.
When you move one screw, make sure you move the other screw exactly the same amount- as a basic setting screw in each throttle stop 3/4 of a turn, and start the engine-the engine will most likely stall when you let the throttle off, if it does -screw in another 1/4 turn on both screws-try starting the engine again. When you get it to idle, set the tickover speed—the secret to this is move each screw the same amount each time.
7) Go back to the handlebar and adjust the cable slack at the handlebar to 3/16", check at full steering lock each way.

The carbs should be synchronised fairly close, enough for the bike to run quite nicely (once your problem is resolved), you can further fine tune from this point later if you wish.
Note: (I have assumed that the standard throttle cables are fitted, with one cable to the twistgrip, and a splitter box to that has two cables to tha carburettors)

One thing not mentioned- is beacause you inherited the problem, do not assume the previous owner has everything correct- he might have bolted the wrong carbs to your bike—check needles type, clip positions, jet sizes and throttle cutaway number are all correct according to the Triumph manual.

In your photo I can see the fuel filters, these might be blocking flow. To check this:
1) fit the tank and half fill it, put the petrol cap on.
2) remove both drain plugs at the bottom of each float bowl.
3) put a measuring jug underneath
4) open the main fuel tap only, you should get 300ml (1/2 pint UK, or 0.6 pint USA) flow in one minute
5) close the main fuel tap and repeat with the reserve tap.
6) if the flow rate is slow, try again with the petrol cap off the tank-in case the vent hole is blocked.
7) if the flow rate is still slow try again with the in line filters removed.

Best regards
Peg.
Good info. Thanks Peg

Ill let you know what I find.
 

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Discussion Starter · #34 ·
Put choke slides back in and raised them all the way up and locked them in place. Followed suggestions from Peg and others on how to synchronize the carbs. Wanted the test ride, but too much ice and snow on the roads today.
Thanks for all the suggestions. I will let you know where it ends up.
 

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Hi Dan,

Wanted the test ride, but too much ice and snow on the roads today.
When you test ride, follow the advice to ascertain basically whether the misfire is carburation or ignition/electrics, something you've so far failed to do despite advice - all the faffing with the carbs. will progress absolutely nowhere towards finding the cause of the misfire if the cause isn't carburation?

tach is bad (jumps all over the place)
I cannot answer your questions about rpm when thing start to go bad.
You don't need to:-

As "Peg" advised, mark (dab of paint? Magic marker?) the throttle housing where you can see it when riding the bike; mark the grip beside the throttle housing corresponding to 1/4, 1/2, 3/4 and WOT.

... test ride. If it misfires, note twistgrip position, gear and rpm; change gear and note twistgrip position and rpm.
"If the misfire's at the same twistgrip position in different gears, it's carburation"; the actual rpm is irrelevant but, having changed gear, the tach needle will be "jump[ing] all over" a different area of the tach? Changing to a different gear again will have the tach needle in another area of the tach?

The timing light that I use on my car has a tach built into the back of it.
which plug wire do I clip to? Do the other leads go to red and black battery terminals?
As "Peg" posted, Red wire to battery +ve, Black wire to battery -ve.

However, the rpm the timing light shows depends on your car's engine and which HT lead you clip it to on the car; electronic tach readings depends on the number of HT pulses it picks up through the HT clip. For example:-

. assuming the car engine is 4-stroke, if it has a distributor, the HT lead to the distributor will have two pulses per (crankshaft) rpm if it's 4-cylinder, three pulses per rpm if it's 6-cylinder, four pulses per rpm if it's 8-cylinder;

. but any HT lead to a plug will only have one pulse every two rpm.

. If the bike has points, either HT lead will also only have one pulse every two rpm. But if it has electronic ignition, both HT leads have one pulse every rpm.

. Unless it's a cheap timing light, it'll have a switch to set so the tach indicates the correct rpm for the number of HT pulses.

Nevertheless, what are you planning to do with this timing light? Take it on the test ride and look at it if/when the engine misfires?

Btw, I see several posters have asked whether the bike has points or electronic ignition; I can't find your answer?

Hth.

Regards,
 

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Hi Dan,
I forgot to mention something I sometimes do with the timing light.
If I suspect an ignition misfire, or have a misfire on one cylinder that I am not certain of side that is faulty, I connect up the timing light and observe the timing maks, first one side then the other. If the timing marks ‘jump’ about all over the place then I strongly suspect an ignition fault.
However; this is not a 100% foolproof method, spark plug/cap faults are not taken into account. Also while rpm related ignition faults can show up, load based ignition faults might not as full load is only achieved while riding.
It is better as an indicator of an ignition working properly, ‘steady’ timing marks from tickover to 5000 rpm, and also when you ‘snap’ the throttle open give a fair idea that you have reasonable ignition pulses.
I will say once again it is not 100% foolproof.

Regards
Peg.
 

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Discussion Starter · #38 ·
Resolved!

Roads are clear and I'm off work this weekend. I went through the steps of synchronizing the slides, played with air screws and idle. Went for a test ride and it appears to have resolved the problem. Runs very well now. Lots more white smoke now than it had before. I'll save that issue for another time.
Thanks to all for the help / suggestions. Now I cant wait for spring so I can go and enjoy it.
 
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