Install tdc and set timing boyer bransden etc

[dwaynemcfarlane]

Hey guys.
Ive been all over the internet searching for a manual for installing tdc and timing etc for boyer bransden. Would be nice with a manual similar to The XS650 Garage Carburetor Guide

( http://www.amckayltd.com/carbguide.pdf )
Any links ?

 

[XSLeo]

Finding TDC is te same with any igition.
On these bikes if you have the stock rotor and stator it's easy, just line up the marks. If you have an aftermarket alternator then you need to use a piston stop to find TDC. Once TDC is found then you can mark that on your alternator. From that mark you can calculate where the idle timing mark and full advance mark should be.
Once you find TDC install the ignition as the instructions from the ignition manufacturer.
That should get it to start and run. Once running use the other marks to set your timing.
Not that hard to do.
I think Hugh at HHB has stickers that go on the case under the alternator cover that has all the timing marks you need printed on it. If you get one of these stickers put it on the case, find TDC, place mark on rotor to coninside with TDC on the sticker. Then you don't need to calculate the other marks.
Leo

 

[Jan_P]

I have used a wooden stick inserted in the spark plug hole to find the TDC
When no marks on the rotor
It is Tricky but doable .I think I got that from a Clymer Manual

 

[arcticXS]

I get tired just listening to what you have done.

I have used a wooden stick inserted in the spark plug hole to find the TDC
When no marks on the rotor
It is Tricky but doable .I think I got that from a Clymer Manual

Doable, but not very exact. Even when using a dial gauge in a central spark plug hole, like when timing a 2 stroke, there is a little bit of minimal piston movement around TDC.
A piston stop, combined with a degree wheel bolted to the LH end of the crank, will give a more precise reading.
I would advise to do this with the cylinder at the end of the compression stroke, to avoid any potential for interfering with the valves. If the stop hits the piston at 30 to 45 degrees BTDC/ATDC, one should be both safe and sufficiently exact. If one gets a reading of, say 40 BTDC and 50 ATDC , then TDC is when the degree wheel reads 5 degrees ATDC. Pretty sure there are multiple cam timing videos on YouTube that covers finding TDC, and much more.

 

[Jan_P]

Yes Yes
artcicXS of course is right I usually is a strict rule follower as per Service manual
And stock but I got a rotor rewound without marks.
Perhaps of interest ..When I Started ..I knew one that adjusted his timing by " Ear "
Triumph Bonneville 1968 It sounded suspect then
The rationale was that back then Auto mechanics that had worked with the same brand for 5 -10 -15 years
fex VOLVO
They could hear on the engine Knocking and Throttle response when it was right I don't think they even used a strobe light.
It was lover rpm and lower power.
But as with every profession after a couple of years .. they get the Know How ..
And if not satisfied one could go back to the shop ---Newer heard that happen though.
So I am not recommending it but if a wooden stick is used some more adjusting afterwards can be needed.
For Boyer one then moves the triggering magnet relative to cam ( and crank ).
XS650 is difficult to start if the ignition is off so that is a safety feature not getting to far of the mark .
I believe. One besides the other aspects get a signal there .. When the sweat after Kicking starts flowing

 

[grizld1]

There are several fine threads on TDC location, and the search function on this site works very well indeed. But if you have the OE stator in place you can use the factory marks. The Boyer ignition is not initially timed at TDC. It is initially set with the timing marks at full advance using the paint mark on the ignition rotor, then checked with a strobe. If you have lost the installation instructions, you can find them on the Boyer Bransden web site. Google for it.

Another method for setting initial timing is to remove and ground the plugs with a timing light connected to one plug wire, spin the motor with the electric start, and set timing to the retard mark (~15*BTDC). Then reinstall the plugs, start the motor, and set timing so that when you rev the motor, timing advances no farther than the full advance mark (40*BTDC). Most of us prefer to set timing at full advance in the range of 36* to 38* BTDC.

 

[GLJ]

Another method for setting initial timing is to remove and ground the plugs with a timing light connected to one plug wire, spin the motor with the electric start, and set timing to the retard mark (~15*BTDC).

Damn good idea. Never thought of that! Good day learned something.

 

[bosco659]

Finding TDC is te same with any igition.
On these bikes if you have the stock rotor and stator it's easy, just line up the marks. If you have an aftermarket alternator then you need to use a piston stop to find TDC. Once TDC is found then you can mark that on your alternator. From that mark you can calculate where the idle timing mark and full advance mark should be.
Once you find TDC install the ignition as the instructions from the ignition manufacturer.
That should get it to start and run. Once running use the other marks to set your timing.
Not that hard to do.
I think Hugh at HHB has stickers that go on the case under the alternator cover that has all the timing marks you need printed on it. If you get one of these stickers put it on the case, find TDC, place mark on rotor to coninside with TDC on the sticker. Then you don't need to calculate the other marks.
Leo

Just did that this winter. Piston stop; degree wheel; Hugh’s sticker and a blob of red paint completed the task. Super easy to see with the timing light now. Ignore the etched TDC on the rotor, from the PO.