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Discussion Starter · #1 ·
What is the easiest and most accurate way of finding BTDC without the plunger tool or specialty tools? I just received a new sparx ignition kit and I am having trouble finding the proper setting for BTDC through the crankcase timing plug. There is two notches to look for? How do you know which notch is TDC and BTDC? Any and all help is very much appreciated. Btw.... I have the Haynes manual, and all it shows is how to find TDC.
 

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With a screwdriver in the crankcase timing hole, find the notch for TDC when the RH piston is at the top of its cycle.
Put it into gear...top is easiest I think. (although my gearbox is naff and I can only get 1st and 2nd, at the moment). Turn the rear wheel backwards [carefully, dont jam the driver] until the 38 degrees before TDC [BTDC] notch is found. This is the fully advanced setting.
Presumably you have the fitting instructions here:
http://www.tri-corengland.com/acatalog/Sparx_Electronic_Ignition.pdf
See the alternator picture 10.

It does not really matter if the ignition cycle is 180 degrees out because the sparks are produced on both plugs on every half cycle.
 

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Discussion Starter · #3 ·
Re: BTDC

Thanks Caulky! But that 38 degree mark is what I can't find. The only notch I can find is like an engraved deep horizontal line on the flywheel. (I used the small screwdriver and even the mirror method to look for it) Is there suppose to be an actual hole?:confused: Btw... It is a 1977 t140v 750.
 

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Discussion Starter · #7 ·
Hmmm... Ok, I will have to take a look. And I am guessing I will want the pistons to be just before TDC. Right? Thanks GPZ, I appreciate the help. :)
 

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Discussion Starter · #9 ·
Yeah I tried that, but all I found was a one line indicator or mark . And I have a 77 750 which has the little inspection cap above the Triumph symbol, which has a little nail looking pointer. I will try what you have both suggested and see what happens. Thank you guys for the help!
But one more question (before I go out and start playing with it)... How do you check for spark? By holding the wire close to the plug or something metal, while kicking it over? Or what? Thanks again
 

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I rest the plugs in their caps on top of the cylinder head and kick over.
*You have got 5000 Ohm plug caps I hope?
 

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Discussion Starter · #11 ·
I just tried checking for spark, like you said Caulky (thanks), and I'm getting very little spark. (and I only get spark on the first kick) i have a brand new battery and light are very bright. Also.. I have NGK-R BR8ES spark plugs. Would these plugs cause little to no spark?
 

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It appears that the "R" on NGK plugs means that there is a ceramic resistor built into the plug. [not the plug type...R-*****]
So you wont need a resistor cap.
When kicking over, you should get several good blue sparks.
I can only suggest you check the HT leads and connections.

It occurs to me that your pointer in the inspection cap will line-up with the alternator rotor marks at BTDC, fully advanced.
The rotor on your sparx should align with the hole in the stator diagram 5. If not re-align the rotor without moving the engine.
You can strobe it later for final setting.
 

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Discussion Starter · #14 ·
"HT"... What is that? And what are other possibilities of very little spark? Also... Is the line on the alternator rotor the BTDC line? (mine only has 1 line) I have a feeling that it's not my timing that is giving me trouble, that it's my low spark. :confused: Do you happen to have a picture of what the caps look like? Thanks
 

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When referring to ignition systems HT means high tension. In this case the HT leads are the wires from the coils to the spark plugs.
 

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Discussion Starter · #16 ·
O ok! Thanks Slowpocono. Spark plug wires!! My wires look like they are in excellent shape. (by eye) But I will check them thoroughly tomorrow. Any other recommendations will be appreciated. I tried starting that thing in every rotor position possible. Uughhh.... I am at a stand still. :(
 

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I`ve found that the connection at the coil/plug leads can work loose or just be naff and it really needs to be good.
Mine were so bad that I bought new leads and right-angled connectors...made all the difference.

BTW, after having the head done, I was advised to use Iridium spark plugs...(a bit expensive).
 

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Discussion Starter · #18 ·
Thanks Caulky. Can I buy plug wires and those iridium plugs at any local auto parts store, or do I have to order online? And can I use regular wires for Harleys etc? (sorry.. I've never bought plugs or wires for a motorcycle) Thanks
 
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