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Re: Hard Starting Triumph 650
tiger_cub #783435 09/04/19 1:08 pm
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Originally Posted by tiger_cub
Is it confirmed that the Boyer won't spark just being turned slowly?

Yes.

Also, you will "get a spark" wherever the timing is set. It just might not be a timed spark.

Last edited by Nick H; 09/04/19 1:20 pm.

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Re: Hard Starting Triumph 650
tiger_cub #783437 09/04/19 1:21 pm
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1968 T120R
1972 T120RV
Any advice given is without a warranty expressed or implied.
Re: Hard Starting Triumph 650
tiger_cub #785292 09/24/19 6:09 am
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I have now got the Boyer strobe timed, a messy job despite trying to get all the oil off the primary first! the comments I made above refer to there being only an intermittent or no spark when the motor is turned over very slowly. It remains rough when first started, although it will start 2nd or 3rd kick. The slide I discovered is a 3 1/2, not a 3 as I thought, however I don't think this is a particular issue, I do have an air filter fitted. I have ordered a #19 pilot jet as suggested above, hopefully this will help further.


1966 Triumph Thunderville
1970 TR6C
1972 TR6C
Re: Hard Starting Triumph 650
tiger_cub #785315 09/24/19 11:52 am
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You can set the timing with a strobe and a special disc on the camshaft. This works ok on Boyer, as well. Here it is in action. I have marked the disc with a triangle pointer to see more clearly. The engine has reached full advance and the points have lined up. I had set the timing at 36 degrees but have since returned to 38.

[Linked Image from live.staticflickr.com]


Last edited by dave jones; 09/24/19 11:54 am.
Re: Hard Starting Triumph 650
dave jones #785337 09/24/19 6:01 pm
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Originally Posted by tiger_cub
... first! the comments I made above refer to there being only an intermittent or no spark when the motor is turned over very slowly


Transistor boxes and there triggers have certain idiosyncrasies .
when powered up ... but in standby ,
the box may not fire ... when turned over too slowly .

.. the 2 rotor magnets must pass the pickup coils with a certain amount of angular velocity
to signal the box to start working .
it doesnt take much ... but it has to be enough .
you can take a refrigerator magnet , stuck on the end of a pencil
and wag it back and forth over the pickup ... and it will wake up and fire the plugs . .. just like the rotor does when its spinning.
but
a stationary magnet alone wont do it
and the magnets proximity to the pickup won't do it either .
its the added velocity of the magnetic field
that adds the extra bit that produces enough signal to wake the transistor box .

on the other hand ,
if the 2 free air sparks produced are not equal ,
like one spark is intermittent and one is good ... this is usually a coil , spark plug wire or spark plug problem ... not a transistor box problem.

if your coils must be wrapped in insulation to make them work ... they are on the edge of failure .

this is a new build , right ?
it sounds like maybe the bike is getting easier to start as its getting broken in .

Re: Hard Starting Triumph 650
tiger_cub #787292 10/17/19 5:23 am
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I finally received my new #19 pilot jet in the post. I started the bike up after 2/3 kicks and warmed it up to normal temp. I then swapped the jets (easy on the Premier) and did a readjustment of the idle settings (very slight turn only required). Test ride was fine. The next day it started first kick from cold and although requiring careful low throttle opening for about the first 30 seconds, ran OK. I would say that it is now what I would call 'normal' for a bike that doesn't have a choke fitted.


1966 Triumph Thunderville
1970 TR6C
1972 TR6C
Re: Hard Starting Triumph 650
tiger_cub #787345 10/17/19 11:24 pm
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Hi tiger_cub, That sounds about right. I find cold start in garage, usually no choke, back out of garage immediately, then close garage door with pocket remote. Put into gear & drive away.

Gentle throttle is needed for addition 30 seconds at 70f, or longer as it gets colder in winter. If I crank throttle it will fall on its face. Using choke will allow bike to take throttle very well cold. Of course doesn't help idle at all. Will not hardly idle cold unless I give throttle (there is no provision for cold fast idle on these carbs). Takes about 2-3 miles riding to get reliable idle after start up depending on temp. 70f + is 2 miles ish. If in 20-30s f. I can take 4-5 miles of city riding to get reliable idle. I find this normal. Bikes that idle well cold without holding throttle are running too rich in my experience or will idle too fast heat soaked after 15-20 miles.

Sounds like you are good. With California fuel we need to tickle to start bike when heat soaked as fuel boils so easily. On 110f day the fuel will boil after about 5-10 long stop lights in congested city traffic. So you need to blip throttle often & hold idle very high. Even 2000 sometimes. The motor gets smoking hot, but that's what we need to do. If you let it die, very hard to restart. Not good in middle of busy intersection.
Don


1973 Tiger 750
Re: Hard Starting Triumph 650
tiger_cub #787470 10/19/19 6:20 am
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110 degrees I'm staying home in the AC!
Even at 90 degrees I'm only riding modern, water-cooled bikes. No sense both of us being abused by the heat.


Stepping on others doesn't make you stand tall.

71 A65L "Zelda"
92 BMW K100rs "Gustav"
72 T120V cafe project "Mr. Jim"
72 T150V "Wotan"
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