Triumphrat

crazypierre

Hi Guys
Bonneville T140V 1979 with Boyer ignition. I get a pinking under full accelleration. I think the timing is out. If it had points, I'd know how to adjust the timing but how do I do it with the Boyer unit? I don't have a strobe light.
Cheers
Pete

OzBloke

Pete,
Did this just start happening? If so, probably not your Boyer - check fuel octane level (try a higher grade of motion lotion, or an octane booster for a tankful to see if it improves). Could also be a lean mixture, or carbon deposits in combustion chamber causing pre-ignition.

If none of these, it's probably ignition timing too advanced, as you suspect. You can move the Boyer coil plate (not the inner one with the magnets on it) slightly clockwise to retard the timing. I find marking the plate and the side of the timing well with a fine black marker allows me to take it back to where it started if I need to, and to judge how far I've moved it.

Other than that, you'll need to borrow a strobe light, or take it to a reputable mechanic.

Good luck, and let us know how you get on.

Ozbloke

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cat

my bsa is doing the same thing w/ a newly installed boyer. a bud and i set the timing w/ a strobe light and it ran fine until it got fully warmed up. i think what i did wrong was set the timing before it was really warmed up. i went for a couple miles before but i don't think that was enough. i'm going to back off the timing a bit and go from there.

timing advance is counter clockwise on the bsas and clockwise on triumphs btw.

pinging can really hurt the engine.

let us know what happens...

cat

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cat

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crazypierre

Thanks Guys,
Well, it could be the fuel-they have removed leaded petrol here and replaced it with lead replacement fuel. But I do seem to recall it was doing this 5 years ago before I put it in storage.
I'll mess with the timing and see what happens.
Peter

oilyboot

Good advice in the previous posts.

Beg, borrow, or rent a strobe, and set the timing according to the Boyer instructions. It is -critical- you do not advance past that point.

Is this a new problem? What have you changed?

Have you ever 'decoked' the combustion chambers?

Are you burning the highest octane pump fuel you can buy?

'Read' the plugs to check carbeuration(sic). A lean mix can also cause 'pinking'.

If it still 'pinks', and retarding the timing just a bit from spec won't help, try an 'octane boost' additive or some leaded avation fuel mixed with your pump gas..

If it still 'pinks' under full acceleration, maybe you should not accelerate so ***** 'fully'.
It is a fine classic motorcycle. Not a Kawasaki krotch kamakazie :wink:

One more unlikely possibility?
If that 'timesert' is too long, and protruding into the combustion chamber at all, it'll get red hot and act like a 'glow plug' in a diesel engine......

crazypierre

Oilyboot
Your comment about the Kawasaki krotch kamakazie did make me laugh! I haven't laughed so much in ages! You are right of course and I have been trying not to twist that throttle too fast.
I think I should get hold of a stobe light and start with trying to set the timing right. I has tried to mess with the timing some time ago and probably did not set it right. Now, off to look for Boyer timing instructions on the internet somewhere.
Pete

papereng

Get a timing light. It's not worth wrecking your motor by guessing. Triumph recommends using an AC powered unit, as opposed to one that's powered from the bike's battery. you can use a "self-powered one as well, which is even handier. I picked up a really nice one from Snap-On (the web site) called a Blue Flash. It's self powered - has 2 D cells - and you just clip it to the spark lead you are setting on. Automatically clips the flash at higher RPM so you can see what's happening easier. Really nice and works very well. I use it on my T140 all the time. Be sure you are setting the timing with the bike revved up tp at least 2500 RPM. :asb:

[ This message was edited by: papereng on 2005-06-06 10:54 ]

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Lee

bclscott

Hi Brian here.
I have a t140v with a boyer ignition unit and I have a strobe light.
One important thing to note, that i found out after many years of trying to solve a similar problem.
whilst playing with the strobe I found that if the two wires from the replacement points (electronic pickups) are connected the wrong way round, the ignition unit retards the ignition as the engine revs increase. this is of course wrong as the ignition timing should advance as the revs increase.
The result of the two wires being the wrong way around is :-
If the timing was set at say 3000 revs (using the strobe) and then under driving conditions, when the throttle is increased and the revs are below 3000rpm then the ingition timing will have been advanced and NOT retarded. This will result in all sorts of engine noise.
Note. as boyer units trigger both spark plugs (only one cylinder will be on the igition stoke), so the engine WILL run, BUT will kbnock like hell at low revs
Hope this hels
Bclscott