1970 T100

click · Feb 16, 2013

Hi Lads,

Getting to the final stages of a restoration on a 1970 T100 Triumph.

The engine was rebuilt by SRM in Wales.

I'm trying to start the engine, it's giving a little burble but won't catch.

I've checked the static timing, tapets and there's a new 626 Amal premiere carb fitted (I also put the old carb on just to try but it still won't start)

I have fuel & spark but no start???

Any advice on what else to check?

Many Thanks

Kevin

daveh · Feb 16, 2013

Hi Kevin,

Good compression?
Fresh petrol?
You have a spark, but is it a fat, blue spark - on both cylinders?
Fresh plugs?
After it fires a few times, what do the plugs look like when you take them out - are they very wet (too much juice), dry (not enough)?
After it fires a few times, are both headers warm or just one? It might not be firing well on both cylinders.

Did it run OK with the old carb?

It might not be getting enough juice - try squirting some petrol into the carb mouth.

Even though you know your Triumphs, double check timing. Electronic or points ignition?

Just a few thoughts on what to check to begin with. No doubt others will add more.

Some pics would be good!

Dave

click · Feb 16, 2013

daveh said:
Hi Kevin,

Good compression?
Fresh petrol?
You have a spark, but is it a fat, blue spark - on both cylinders?
Fresh plugs?
After it fires a few times, what do the plugs look like when you take them out - are they very wet (too much juice), dry (not enough)?
After it fires a few times, are both headers warm or just one? It might not be firing well on both cylinders.

Did it run OK with the old carb?

It might not be getting enough juice - try squirting some petrol into the carb mouth.

Even though you know your Triumphs, double check timing. Electronic or points ignition?

Just a few thoughts on what to check to begin with. No doubt others will add more.

Some pics would be good!

Dave

Hi Dave,

Good to hear from you.

My incorrect presumption was SRM built engine one or two kicks & away it will go! I need to get my methodical-analytical head on and start problem solving.

Your list really helps.

Many Thanks

Kevin

Snorton74 · Feb 16, 2013

Do you have to prime the crankshaft with oil on rebuilt Triumphs? Just curious.

click · Feb 16, 2013

Snorton74 said:
Do you have to prime the crankshaft with oil on rebuilt Triumphs? Just curious.

SRM recommend you do this. Remove oil pressure switch & pump oil into feed oil line until oil appears then replace oil pressure switch.

Continue pumping to help prime crankshaft.

You can also pump some oil into the rocker box inlets & exhaust which will also prime the sump.

This is what I've done.

If/when!! I get the engine running and I see oil returning into the oil tank I'll cover the return with my finger as this forces more oil into the oil feed for the head.

Kevin

Matt Spencer · Feb 16, 2013

Fuel
Air
Spark .

Thats it
Then theres cam timing , Electrickery , etc . etc .

If its Boyer , is the battery fully charged .
Gnatty little machines , Daytonas. And you can bore them to 72 mm. ( .040 over 650 pistons ) fitbig valves , & 30 mm carbs & ports .

8)

Sounds like the Ign. timings OUT . Hoes the Spark ? Healthy .

Triton Thrasher · Feb 17, 2013

Don't just half-tickle the carb. Flood it copiously and kickstart it with a tiny throttle opening.

grandpaul · Feb 17, 2013

Swap the electronic ignition wires - black/yellow & black/white.

Should fire right up.

acotrel · Feb 17, 2013

Most likely plugs, however they usually allow the motor to cough once , then never fire again. I think it is something to do with the interaction between old carbon and the fuel when the motor hasn't run for years. If it burbles every time you kick it over, it is probably a fuel problem, have you had the carburettors apart and checked that the float needles are free and unobstructed ? If it was ignition timing, the motor will still usually run, but if it is too far advanced it will kick back when you try t o start it, if it is retarded, it will be loud and possibly only backfire out the exhausts.
All you need to do is hold your mouth the right way and keep repeating 'I am the master' ! - Don't cop any shit from it, it's only a motorcycle.

click · Feb 17, 2013

Hi Lads,

I really appreciate all the hint's & tips you have given me.

I hope to work on the 'beast' on Weds, I'll post an update + some pics (I know you REALLY like pics :mrgreen: )

All the best

Kevin

Matt Spencer · Feb 17, 2013

" Don't just half-tickle the carb. Flood it copiously and kickstart it with a tiny throttle opening. "

" Swap the electronic ignition wires - black/yellow & black/white.

Should fire right up. "

Hope its got air cleaners ( Flame Traps ) Seen one ' Fire Right Up ' regularly , to the point of makeing a habbit of it .

Not to worry , usually managed to put it out before it did any serious damadge . Keep a Fire Extinguisher handy , parhaps .

click · Feb 18, 2013

grandpaul said:
Swap the electronic ignition wires - black/yellow & black/white.

Should fire right up.

Grandpaul, if I could email a pint of Guinness to you I would

Fair play, I swapped the bullet connectors down at the EI plate (Pazon) and it fired up first time :mrgreen:

I have the bike in another chaps workshop who did the wiring for me and it was driving him more nuts than me why the bike would not start!!

Can somebody explain why this worked? Is there something further up the chain no connected correctly? coils?

Once again, many thanks to everybody who gave some hints & tips, especially Grandpaul

Some pics of how the bike is now, not completely finished but not long to go now :mrgreen:

daveh · Feb 18, 2013

Well done, Paul - you've been there before, I think!

Kevin - thanks for the pics. Looks like it's coming along grand. Is it an original Irish bike or an import?

Dave

click · Feb 18, 2013

daveh said:
Well done, Paul - you've been there before, I think!

Kevin - thanks for the pics. Looks like it's coming along grand. Is it an original Irish bike or an import?

Dave

Hi Dave,

Original Irish bike, ex. Garda, it was my very first bike and my only means of transport for about 8 years, toured Ireland, the UK & Europe.

This one is a keeper, hope to be pottering around on it into my very old age :mrgreen:

It won't be a trailer queen, I'm rebuilding it to ride, I'm sure the 'classic' crowd would turn their nose up at some of the mods, you know the type!! :roll:

Kevin

850cmndo · Feb 18, 2013

No nose here. Gimme gimme. I like it. Nice work.

click · Feb 20, 2013

grandpaul said:
Swap the electronic ignition wires - black/yellow & black/white.

Should fire right up.

As I said earlier this solution worked, first kick & off she went.

I'm not sure why this worked? anybody want to explain the theory behind this :mrgreen: Is it something further up the chain (coils) that's wired incorrectly?

Thanks

Kevin

grandpaul · Feb 20, 2013

Some (all?) systems can be run clockwise and/or anti-clockwise. Depending on the bike used on, setup, and timing, reversing the wires changes everything.

It's all black magic, i just know that's ALWAYS the first thing to check if the bike doesn't start immediately, but seems to sputter or backfire.

L.A.B. · Feb 20, 2013

click said:
I'm not sure why this worked? anybody want to explain the theory behind this :mrgreen: Is it something further up the chain (coils) that's wired incorrectly?

Not the coils, only that the wires (Black/White & Black/Yellow) must have been crossed somewhere between the pickup plate and the Boyer box which results in the system not firing at the correct crank position.

http://www.tioc.org/boyer/boyertestnewweb.htm - 'Timing Plate Wires'

click · Feb 20, 2013

Hi Lads,

Thanks for the replies.

My fuzzy brain is slightly less fuzzy :mrgreen:

1970 T100

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daveh

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Snorton74

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Matt Spencer

Triton Thrasher

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acotrel

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