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Discussion Starter · #1 ·
Hi guys,

I have searched as ever but not found anything, to be honest I’m unsure how to even Google it!

Basically I’m timing my 1949 FL with manual advance distributor by the book, step by step exactly as it says and every time I get it done and go to check it by rotating the engine one full turn, as in the book, I check in the timing window and the flywheel mark has moved.
I start with flywheel timing mark just inside the right side of the window, time it up and make one full rotation, check the mark in the window and it’s right in the middle, rotate it again and it’s right by the left hand edge.

Someone, please, what the hell is going on? Am I mis-interpreting the book? Is my bike cursed? I am just about at my whits end.

I had the engine rebuilt by one of the best in the UK and finished building the bike about 6 weeks ago and so far I have got it running a couple of times and done a total of about 15 miles in 4 short test rides but now I’ve got nothing.

Pushrods are adjusted correctly, I have spark, battery is charged and I know the mikuni carb on there runs. I have a linkert to swap over but unsure if it runs so want to get it all good on a carb I know works before testing the linkert.

I’m sorry for the essay, I’m sure I’ve forgotten useful information…
 

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why are you doing the timing if it ran?
 

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If you are using a test light or meter on the points, the mark moves because each single revolution of the engine changes the points cam lobe that is activating the points. The front lobe is thinner than the rear and the mark moves in the window as a result. Nothing to worry about as long as you are timing on the correct cam lobe for the correct cylinder.
 

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Discussion Starter · #5 ·
Seems by “one revolution” I maybe meant two?
I’m rotating the engine enough to give one full rotation on the distributor cam lobe, right to where the points were about to open as when setting the timing initially.
 

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Mark the point cam lobe that you are timing on. Make sure that it is the correct lobe for the cylinder that you are timing, and make sure that cylinder is on compression stroke. Start from scratch and do it all again. I'm confident you'll find your answer.
 

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Discussion Starter · #7 ·
Im using the narrow lobe to time the front cylinder, ensuring I’m on the compression stroke by spinning the pushrods. I’ve timed it from scratch like 10 times today and on the last one I noticed the flywheel moving.
earlier in the day I did get it to pop a few times immediately after timing and then not again till retiming, which would make sense if for some bizarre reason the flywheel isn’t making even rotations?
 

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Are you making sure that the advance mechanism is turned to full advance while you set timing? It sounds like you may have a worn out timer assy. The bushings and/or shaft may be worn to the point that there is too much slop to give consistent settings, or maybe the worm gears are worn. Have you replaced the capacitor? At least twice? (I have seen brand new ones bad from the box.)
 

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Back to basics. In your initial post you say that you are rotating the engine one full turn after setting the timing, and that you find the mark in a different place in the window. What are you using as your reference to determine "one full turn"?
 

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How are you turning the engine over and are the plugs out while turning it? Back wheel in gear blocked up off the ground to turn the engine. You maybe just going past the mark trying to get it.
 

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Discussion Starter · #12 ·
Back to basics. In your initial post you say that you are rotating the engine one full turn after setting the timing, and that you find the mark in a different place in the window. What are you using as your reference to determine "one full turn"?
The point at which the points are about to open with the points follower lining up with the timing mark on the cam lobe is my reference for a full turn

How are you turning the engine over and are the plugs out while turning it? Back wheel in gear blocked up off the ground to turn the engine. You maybe just going past the mark trying to get it.
At this point I’m turning the engine with the kicker, can’t actually remember if I had the plugs in when I noticed, I may have done. I’m definitely going past my mark, I’m turning it in minuscule increments with the kicker until my timing light glows telling me the points are about to open
 

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Personally, I've never been able to use the kicker to turn an engine over with that kind of finesse. For timing I lift the rear wheel, put the trans in 3rd gear, and bump the wheel, with the plugs out. This lets you go forward and backward with the engine. You've got to understand that the difference between the mark in the center of the window and on the left side of it is only a couple of degrees. It most certainly isn't enough to keep the engine from running. Seems to me like you've got something else going on there. What coil are you running? Are you sure it's good? What voltage are you getting from your battery to the coil? Are there any loose connections in the electrical system? Is it getting fuel? Etc.
 

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Discussion Starter · #14 ·
I sort of knock the kicker so it makes only tiny movement on the engine, it’s the way I was shown so stuck with it. I will try jacking the bike and turning the engine with the wheel in gear.

I’m running a fairly standard 12v coil which shows good health. Battery is the same, fuel delivery fine, no loose connections, plugs, ht leads etc all fine.

i understand the timing marks movement in a single instance isn’t a worry, my concern is that it’s moving forward with every revolution effectively untiming the bike. Maybe that’s impossible!
 

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use the rear wheel to turn it or pull the primary cover & use a wrench or socket to turn it, an old buddy, RT rip buddy), had a steering wheel with a socket off of it & a degree wheel to turn motors for the timing, I personally run a belt & have a degree wheel on the front pully so I dont even need to remove the timing plug or look at the crank mark, glass pushrod tubes as well so no removing to see if your on front cylinder compression stroke.... no oil leaks either as nothing come off to set it
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I sort of knock the kicker so it makes only tiny movement on the engine, it’s the way I was shown so stuck with it. I will try jacking the bike and turning the engine with the wheel in gear.

I’m running a fairly standard 12v coil which shows good health. Battery is the same, fuel delivery fine, no loose connections, plugs, ht leads etc all fine.

i understand the timing marks movement in a single instance isn’t a worry, my concern is that it’s moving forward with every revolution effectively untiming the bike. Maybe that’s impossible!
If everything is tight, the only way that would be possible would be for the gears to be wrong somehow. If the sprocket shaft was spinning in the flywheel it wouldn't affect that, the pinion shaft can't spin due to the key, unless it's missing. I can't imagine how that could happen, but I suppose it's possible. Maybe the gear is moving on the bottom of the timer shaft? Something isn't right for sure. Try turning the engine over multiple times, stopping each time at the same timing mark position on the flywheel, and taking pics of the points cam position. Always with the timer fully advanced.
 

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Discussion Starter · #17 ·
Thanks man will do that today and report back. Something is definitely off, hopefully it’s me, haha. Timer gear is fine, if anything it’s a tiny bit tight to spin by hand but there’s zero play on it.
 

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Discussion Starter · #18 ·
OKAY... its running, still no idea what the flywheel weirdness was about fuck it it ticks over now.

new question though, how much should one be retarding the timing to start? i've found that if i retard all the way i get nothing, but bike starts pretty easy retarded about half way. is there a set amount of movement any timer should have? i suppose my fear is if it's starting halfway retarded, then is it fully advanced when the timer is pushed against the stop?
i expect the answer is that it varies bike to bike depending on parts, wear, etc but i want to be sure before i try and run in the engine and kill it because it's horribly out of time.
that all said, it start easy and ticks over nice when i advance, so feels right to me...

thanks
 

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Do you have your timer connected to a cable so that it can be operated from the handlebars, or are you moving it by grabbing it by hand and twisting? You are correct that optimum advance for a particular engine is determined by a lot of factors. Compression ratio, cam specs, fuel, heck even humidity in the air if you want to get that technical about it. (racing is the only good reason to get that finicky though) You said that this is a recent build, so you want to break it in easy. Keeping max advance just a bit back from full will prevent pre-detonation while running a few break in miles. After getting it broken in, you can start advancing the timing a degree or so at a time till it starts to run worse, then bring it back a bit. That is how I usually fine tune mine when I want to get that picky about it.
 

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Discussion Starter · #20 ·
I’m grabbing the timer itself, it’s a chopper so that’s fine for me.
inwas told to to take it easy for 100 miles, change oil, take it easy-ish for another 500 miles, change oil and then have at it. I’ll add keeping just off full advance to that then!

thanks mate really appreciate all your help
 
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