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Discussion Starter · #1 ·
About went crazy trying to time a customers 450 today/yesterday.
Basically, the ignition timing was advanced even with the timing plate turned all the way CCW(counter clockwise). 10-15 degrees to advanced. The timing difference between the cylinders was not an issue. Points gap set to .016". Indicated dwell on a 4cyl. meter at approx. 25 degrees.
Maybe I'm missing something very obvious, but it appears as if the exhaust cam needed to be turned back a tooth. If that was the case, the bike wouldn't even run, right?
I've lived with 450's for a decade and feel I have a decent handle on setting the timing, both statically and dynamically. But this one....ahhhhhh!!!!!
I compared another timing plate, both looked OK and very similar. The new points set is from Sudco. Didn't look at the manufacturer. I will in the morning. My personal machine has Daiichi points and setting the timing is easy cheesy. Maybe the points dimensions/specs are the issue?
I wondered if the advance locator pin was buggered up, but it was good. Maybe the springs were weak and allowing advance to occur at idle. So I installed another advance unit and was able to just barely get it to the LF and F marks. But the plate is still fully CCW.
Haven't pulled the cam covers yet to check cam timing.
The bike does run with the present situation and it sounds good. Under the strobe light, the timing marks are were they should be at idle and correspond to a static timing check.
What gives? Any words of wisdom please, or a new Rx for timing madness.

Thanks,
NE
 

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Sensei
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Take two aspirin, check cam to crank timing, Check cam chain tensioner, and send the doctors' consultation fee to me in the morning..... :lol:
BTW ....Why are you even concerned with DWELL?...Is it a non-stock cam?
I ALWAYS start with a LEFT point gap of .014... The right one will fall as it may, as long as within specs...I always check it, but have never set it.....
.....Some aftermarket points will NEVER time in correctly......
 

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Discussion Starter · #3 ·
Steve, I'll send you a wooden nickel this Sunday.
Cam chain tension is set at LH TDC.
I check the dwell on both sets of points to get an idea of how far it's outta whack. Then find a medium point for both sets where the timing and dwell is fairly close.
Can you expand on the issue of some aftermarket points not allowing the timing to be set properly? Brands?
Thanks again. I'm probably over thinking this.

NE
 

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Did you take the advancer apart? It's possible to put it back together 180 deg out which will give you that type of problem.
 

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Discussion Starter · #5 ·
Made sure both advancers were the same. Did pop the second one apart to lube it. Upon reassembly, made sure the line on the center carrier matched the dimple on the points cam. All that business lined up with the indexing slot on the backside.
Just counted teeth on a cam. 30 teeth. 360/30 is 12. 12 degrees is generally what the plate seemed to be off.
Is cam timing being off one tooth enough for the engine to still run and not bend any valves?
How would a twelve degree retarded exhaust cam run?
Deep thoughts...

NE
 

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Easiest answer is to pop off the covers and check cam (to crank) timing.... IF either cam is off the indexes won't both align at LTDC...( or both cams could be timed to each other, but NOT to the crank)....IF ALL THREE INDEXES DO ALIGN, bad/improper/out of spec points or plate.... If they DON'T, remove tensioner and "skip" the chain so they do....
Attempting to "time-in" the points is useless if the cam timing is off....
 

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Have you checked teh springs on the advancer mine were completly flacid but the only became apparant when it was running and advaned almost immiedatly. I managed to source a new pair from a spring manufactirer as a sample (FOC) all round win there.
 

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A "1 tooth" off situation (intake advanced, or exhaust retarded ) could possibly allow rotation without bending valves.... Essentially, a cam with differing duration goes part way there.....That's why I asked if it was a stock cam set.......
 

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Discussion Starter · #9 ·
Well, looks like the exhaust cam is retarded two teeth. Onto the intake.....

NE
 

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Discussion Starter · #11 ·
And the intake is off by the same amount as the exhaust.
Now I gotta get things moved back to the correct relationship.
Removed the upper pulley shaft to allow the chain to move up whilst trying to jump a tooth. Didn't happen.
It is possible to jump the chain, right? I found a thread here where Mr. 66sprint explains the process.

"Remove both valve covers and the dyno cover.....Take off the chain tensioner assembly.... Take off the "teardrop" shaped plate on the top of the engine, and carefully push a smaller diameter "axle" for the top guide wheel to "sit" on..(a small screwdriver works well).... (basicly, you are allowing it to lift as the chain tightens) ... pull two links up in a "V" and catch the pin in the cog left empty by the pin that's now at the point of the "V"......"skip" the rest of the "slack" links down the cog..... Repeat until you have the correct alignment, insert the correct top-guide wheel pivot and secure it with the phillips screw.... Reinstall tensioner.... Remember to verify BOTH camshafts positions/alignment with respect to the crankshaft."

This is to be done at the end of the exhaust stroke on #1 cylinder?
Really don't want to undo the chain.

NE
 

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Sensei
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It's done at LT on the crank... IF you can find a way to "hold" the crankshaft at that alignment it helps...(Friend, c-clamp, etc.....)
 

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Thanks for the "save" Bill......Sorry group, I had a brain fart.....

Align the LT mark on the crank (rotor) with the index pointer line (where the cam marks are closest to being at/on their marks)......Skip chain or whatever is required to place both camshaft marks on their indices......double-check all three alignments after tension re-applied.....
 

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66Sprint said:
Thanks for the "save" Bill......Sorry group, I had a brain fart.....
Yuk, yuk - that particular twist seems to be your nemesis, Steve.

Don't feel bad - I went to school for 18 years, can't seem to get it through my head that 6x7=42, NOT 43.
I know it's 42, but when my hand gets involved, it writes out 43.
God only knows how many test questions I screwed up over the years because of that, and math was always my best subject!!
Even to this day I catch myself making the same stoopid mistake........

Must be some dead brain cells in that particular neural pathway.......the price of a mis-spent life I guess.

"So it kills brain cells - it only kills the weak ones though !!" (Fat Freddy's Cat)
 

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Yep...LOL.... My brain is DEFINATELY defective (worn out maybe?...But HOW?... Certainly not from overuse!)....LMAO!
 

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Discussion Starter · #17 ·
OK, got it timed correctly. Ended up having to remove the intake cam caps to allow enough slack to move the chain around.

1- Place the engine at 90 degrees CCW past ignition LH TDC.This is where the cam lobes are not against any followers. Same position as setting the cam chain tension.
2- Remove(in this order) cam tensioner, top pulley shaft and intake cam caps. Be sure to keep the eccentric shafts in their place within the head. Point the tiny marks on the end of the eccentric shafts up. This appears to be the point of most follower clearance.
3- Do your chain fiddling. Be sure to be very methodical here. A piece of masking tape with an arrow showing the direction you want the cam to go stuck to the frame helps keep your(my) frazzledness at bay. Keeping the top pulley in a suitable position for chain slackness was a constant chore.
4- Re-assemble in reverse order. Very carefully turn the engine over, keeping an eye out for piston/valve interference. Set the engine at LH TDC for valve timing. That is one crank revolution past ignition TDC. Hopefully you're good to go. If not, do it again. :eek:
Reluctance of the caps to slide in easily was due to the eccentrics having turned and lessening the follower/cam clearance.

Thanks for all the help guys.
NE
 
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