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Discussion Starter #1
I have spark on both plugs. I have gas. I have new battery.

Amal carbs are not tuned yet. I am trying to get the bike to fire first.

I was able to get it to start up for 2-3 seconds and then died.

Where should I start trouble shooting?

[ This message was edited by: tokarz33 on 2006-12-06 19:16 ]
 

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Tokarz,

try the following:

1) check carbs are set up properly - 1.5 turns out from full in for idle mixture "air screws", and ensure they are exactly aligned when slides are fully open (by adjusting cables to each carb)

2) check balance tube between intake manifolds has no leaks

3) check for air leaks around intake manifolds - broken gaskets or o-rings.

4) check choke (air slides) are not fully down (on) - choke cables should be tight to hold slides up (choke off)

5) check the bolt that hold the choke lever bracket on the LHS intake manifold is not loose or missing.

6) give it plenty of tickler on both sides before you kick.

7) check battery voltage - did you bench charge it for 8 hours at <1 amp before installing it in bike?

My guess is it's a combination of carbs not being set up yet, timing a little bit off, and not enough tickler.

Pete
 

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Discussion Starter #3
1) Did it.
2) Looks ok
3) Looks ok
4) I am not using a choke
5) I am not using a choke
6) Always
7) Horn is loud and strong. So battery is good.


To give a little more history, I replaced the rings last week. Put everything back together. Did the valve adjustment. I have the cables dialed in so now the carb sliders rest lower which will make the bike idle lower.

One thing I did not do is smear some exhaust sealer putty on the header pipes where they connect to the head. Could have a leak there.
 

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Discussion Starter #4
Just checked the valves again. Everything is lined up correctly.

Its not even popping or backfiring. Its not even trying to start.

Is there a way to tell if its getting enough gas? May I am starving it.
 

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What does the spark look like? Blue, and makes a snapping sound? Or yellow and quiet? Plugs new?
Do you have a compression guage? If not, put your thumb over a plug hole, press down firmly, and give it a good kick...you should feel heat on your thumb and it should vigorously blow your thumb off the hole.
With the ignition off, tickle the carb and kick the engine over to get the fuel into the cylinder. Do the other side. Ignition on and kick.
I set the idle mix screw for initial start up at one revolution out. Turns to me are 180 degrees. So, to avoid confusion, I'll use the word "revolution".
 

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On 2006-12-07 12:57, tokarz33 wrote:
Is there a way to tell if its getting enough gas? May I am starving it.
i'm nowhere near as smart as some of these other guys, but in my experience it's tough to flood these things. so err on the side of drowning. that "tickle, kick (ignition off), re-tickle, kick (iginition on)" procedure that mecchanica reccomends works for me.

12 volts at the battery. hot spark, good wiring. idle screws in then out per manual or other instructions. if the battery's hot, sparks are strong and consistent, and you're slobbering gas out of the carbs, then what? timing? air leaks somewhere between carb and cylinders? bird nest in the intake manifold? good luck. don't hurt your knee.

[ This message was edited by: johnnypence on 2006-12-07 14:50 ]
 

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I once put my rings in upside down..very little compression...Do the plugs get very 'Sooty' and wet?
Have you drunk enough beer and thoughtfully sucked on a pencil...To be serious though, if it started before you did the rings then the timing is still fine, I'd be looking at the carbs, cos they came off too.
Cheers
BonnieT
 

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Discussion Starter #8
Well, I have some good news....

I rechecked the valves and they appeared to be tight, too tight. So I loosened them back to .004(E) and .002(I). Which is what the book says. I swore I had them at that before.

Decided to get more gas and poured in a gallon.

Everything back together, tickled the carbs till they were dripping strong....and gave it a kick....

It roared back to life with just one kick. Did some light tuning of the carbs so it would idle.

I think adjusting the valves helped and making sure there was more than enough gas was the key. I really believe I was starving the carbs or at least one.

Thank you for everyones help. Watch for my next posting about valve chatter.
 

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The two and four thou. settings are for 650 engines with stock cams. The 77 uses a higher lift and longer duration inlet cam using STD. radius tappets, and a weird weenie exhaust cam which uses R tappets. The settings for the 77 should be .006" on the INTAKE and .008" for the EXHAUST. Yes, more for the exhaust than the intake.
 

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Discussion Starter #10
Haynes clearly states......

.004(E) and .002(I)

Sure they could be wrong.
 

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Per the Triumph Workshop mnual the settings for the T140 750 including 1977's shoud be:
Intake .008
Exhaust .006
This has always seemed backwards to me as I would think you would have more heat on the exhaust side and bigger clearances there same as the 650. But this is what the factory recommends. Also on the sticker under the seat.
 

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Right, I got it backwards, the larger is for the inlet, smaller for the exhaust, opposite from what you would think. That is because of the exhaust profile and the flatter R tappets in the exhaust side and the more agressive Thruxton profile and higher lift on the inlet cam.

[ This message was edited by: Mecchanica on 2006-12-08 15:18 ]
 

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My Haynes says the same htown,
Intake 8 thou, Exhaust 6 thou.

Tokarz, for engine specs, you need to be lookin' at Chapter 9 in the Haynes, not chapter 1.
 

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Discussion Starter #15
OzBloke,

Ha, you are right. I have been reading the wrong section. I will wear the idiot sticker for a day.

No problem, I will make the adjustment.

.006 for Exhaust
.008 for Inlet

I guess I will read the back half of the manual now. :hammer:
 

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tokarz,

Don't forget to re-torque the head after you've run it for a little while. After you've re-torqued the head, you'll need to re-check the valve clearances again. This is possibly why the valve clearances "tightened up" before....?
 
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