I changed the degree display on my timing gun untill the notch on the pulley lined up with the notch on the cover. Although it is timed to 17degrees at the inspection hole, (with the v groove).
I see now I understand. What was the degree display set to when you timed it through the inspection hole ? (i'm hoping it was 0 rather than 17 ) And to answer your question - the timing at both ends (inspection hole AND crank pulley notch) should be the same. Andy
Timing at the inspection hole (using the v groove) is 17degrees, and at the crank pulley notch end is 30degrees. If I time the inspection hole using the BTDC mark, then this is the same as the crank pulley notch.
I'm a bit confused here, but working at the inspection hole, I think you need to either (not both!) set the gun to 0deg and time against the (18deg) timing mark on the flyweel, or set the gun to 18deg and time against the TDC mark on the flywheel If you're timing against the 18deg before mark, AND have the gun set to 18deg before, you're going to be timing to 36deg before. (For 18deg in all cases, read 16,17,18,19,20, whatever the accuracy is.) -M.
muppet9966, My point was, that your light should be set to 0 degrees - then you should adjust the distributor until the V-groove lines up with the inspection hole pointer. The timing is then set at 17 degrees, because that's where the V-groove is. If you set your light to 17 degrees and then adjust until the V-groove aligns with the inspection hole pointer - you will set the timing to 17 degrees BTDC (because of the light) PLUS 17 degrees or whatever (because of the V-groove). This would give a Total of 30+ degrees at the Crank pulley notch. Hope this; a) Makes sense b) Helps ! Andy
Oh, so using the inspection hole, I need to set the gun to 0degree. Or using the the TDC mark on the flywheel, set the gun to 18degrees. So thats what I've done wrong. That does explain the 30ish degrees I was getting from the crank pulley. I'll try that when I get home. Thanks so much guys. So I hope to get the timing set, therefore I only have the carb left to set. Although I did notice that changing the carb CO level altered the timing slightly. Is this right?
Thats true, although it doesnt seem to be pinking now Also, with the idle speed, do I set it at 1000ish revs when doing the timing? As turning the carb CO mixture down decreases the idle revs.
Correct - the flywheel V-groove is at 17 (ish) degrees BTDC (so you don't need it on the light) The Crank pulley notch is at TDC (so you do need it on the light). What carburettor specification is it ? and what are you adjusting ? Andy
Carb is a webber, and I will be adjusting the CO level (on the front drivers side) and also the idle screw (on the front of the carb)
What model Weber please. There is probably an idle mixture screw (which I think you're calling CO) and an idle speed screw. Set the mixture first (which will affect the CO) and then the idle speed, then re-check the CO. Have you got the correct Haynes manual for the CO/idle speed settings. Andy
Its a Weber is a 32/34 twin progressive carb. Yes you are right, there is an idle mixture screw on the side of the carb (J), and an idle speed screw (H). Yes I do have the correct Haynes manual, CO 0.5% to 1.5% (same as Weber instructions) and idle speed of 950+/- 50rpm. Im assuming I set the timing first, then the carb, as post above?
Thanks alot MKone, Am I right in thinking that looking at (d), the highest engine speed will be adjusting the mixture screw J anticlock wise? If so, this might be why my CO is out, and rich.
Highest idle speed will be obtained when the air/fuel mix is just about 'ideal', so turning the mixture screw either way from this point will lower the idle speed. I believe it will tend to sound rougher/drop faster as you go leaner, so there's a tendency to err on the side of richer, and end up a bit high on the CO. Get it about right by ear, or using your Gunson thingummy, then get it checked properly and finally tweaked at an MOT station. I think you're meant to disconnect the crankcase breather from the airbox in order to get an accurate CO setting. Edit: And I'm pretty confident that you can't change the timing by changing the mixture, so you need to get that right first, or your efforts will be invalidated if you subsequently have to tweak the timing.
Ok cheers guys, I have set the timing and it all seems well. Previously I stumbled on setting the carb, and by the sounds of it, I had always set it too rich. I have currently got it set by ear (and weber instructions) as I havent got a socket set to take my spark plug out to use the gunsons colour tune. It does idle smoothly, although there was abit of white smoke coming out of the exhuast when I reved it high in neutral (this could be crap/unburnt fuel from the cylinders, maybe?) I am still trying to find a decent garage (MOT test centre) to set up the carb. And yep EZ_Pete, changing the carb mixture does not affect the carb, what I was doing was setting the mixture so rich that it lowered the rpm (made the idle unstable) and thus casuing the timing to fluctuate - silly me! We all learn form our mistakes though. EDIT: maybe I had the mixture too lean, as it was set quite far clockwise.
Well guys, I went to 2 random local garages this morning, one said he would charge 30 to set the carb, and the other was alot more helpful and pleasent. He said 'lets have a look', and then spent 1/2 an hour with another mechanic (who seemed to know about carbs) adjusting the carb to obtain 1.2% CO (it was previously at 3.5ish % ). When I asked how much do I owe him, he said dont worry, its free, and gave me his card. And who says you dont get things for free!! Thanks for all your help guys, lets hope that has sorted my high mpg problem. I think I will def be paying that garage a visit when I need to get some work done that I cant do.
