How to advance timing

[AustinPhoenix]

Can somebody tell me how to advance the timing on our bikes? If it's in the service manual, just tell me which part and I'll look it up. I have an electronic copy that's HUGE and it drains my computer to a snail's crawl. It's a pain to go through it unless I know which section to look at.

Thanks!

[boyat68]

AustinPhoenix:

The 80G/80SG had special bolts that held the timing plate and Pickup Coil Assembly on. Those bolts were put in due to EPA concerns and have to be drilled out The procedure can be found in section 10-4 through 10-6 of the 80G/80SG Supplementary of the Yamaha manual. You may want to check and see if your machine has those bolts. Someone past replaced them with standard metric allen head bolts but I don't know which ones.

[AustinPhoenix]

drilling out bolts?!

That sounds fun and dangerous. lol Thanks!

[TADracer]

Special bolts aside its just like any other motor. Timing light on #1 cylinder (#4 is OK too since it is a wasted spark) then start motor, set idle at 1100 +/-, then check the timing that it fires on the F mark on the timing wheel. The book says if you want to adjust to shut off the motor and make a slight move (clockwise retards and counter clockwise advances) then start up and re check until its right. I just loosen both bolts and then snug one so that I can move the pickup coil plate witht he motor running and watch the pointer. Then remove the vacuum advance (if you have one) and plug the nipple on the #2 carb then bring revs up to 5000+/- and your mechanical timing should be 31 degrees (for a special) or 36 degrees for others.

Having said all this, If you want to really set your timing accurately, install a degree wheel and a pointer and find true TDC with a piston stop. Now when your timing light hits the mark you want you are really there. The slop in the timing plate alone can be as much as 5 degrees.

[xschop]

advance

I know advancing the timing will give a better throttle response, but will it also increase fuel efficiency, MPG'S? Maybe allow for better performance out of the lower Octanes?

[AustinPhoenix]

fuel effeciency

Chop,

I'm not advancing it. I'm actually delaying or retarding the timing.

Advancing the timing, from my understanding allows more of the fuel to be combusted. It gives more power, but I think you do it so you can pump more fuel into the cylinder...thus reducing efficency. I know some racers that advanced their timing so they can run an alcohol fuel mix. Maybe some XSives have tried or heard of people that tried this around those pumps that have 10% ethanol in the fuel (ie. Houston).

In a "perfect" engine, combustion would happen at or near TDC so that the engine's rotation would be as uninhibited as possible. However, because gasoline is a slow burning fuel, we begin ignition and combustion on the upstroke of compression which makes the head, pistons, valves, etc...basically the entire head hotter than it needs to, and we lose energy because of it. We also reduce the life of our components.

Dunno if this would be worth saving a few extra bucks if it costs you more in the long haul.

From what I've read on your posts though Chop, you can figure out how to mod just about anything on our bikes. Anything to get me up from 32mpg to around 40 or 45 would be MUCH appreciated!!

[oseaghdha]

Spark Timing

Advancing the timing will actually burn the fuel/air charge more completely. This does not mean you can cram more in. The intake stroke will only pull so much fuel/air in. Bigger jets will only make it too rich.

It will increase spark knock, so you want to have higher octane. It will also make it a little harder on the starter motor.

Ideally, you want to fire the charge when the piston is still compressing. This results in more complete combustion and increased cylinder pressures= more force on the power stroke.

Higher pressures produce increased oxides of nitrogen, which is evil smog., and increased rod bearing forces.

Obviously, you can't just crank in more spark timing indefinately. I am talking about maybe 3 or 4 degrees you can play with.

Rule of thumb is 1 degree added to stock for every 1000' above sea level plus or minus whatever your particular engine likes.

Also, more initial timing = more total timing which is really what it's all about because the total timing is probably all in by 3000RPM anyway.
YMMV

[xschop]

timing for better MPG's

I don't want to cram more fuel down the hatch, just burn it more efficiently for better power and fuel economy. I just posted in another thread that a coil upgrade does miracles for power and fuel efficiency....I have a set of ZRX11 coils that will go on my next build to test out......REPLACEABLE WIRES!....shhh

[AustinPhoenix]

Hot rodders

It makes it harder to start because you're making the engine work against itself up to a certain RPM range. The dealership I used to work at had a race team. I'm just relaying what I learned there about being able to use different fuels, more fuel, etc etc after advancing the timing because that's what we did.

Those cars would pop and sputter and sound like complete booty until you hammered the throttle....then the ground would shake.

Chop...I'm going to have to check out your thread!

[xschop]

the Jewels in question

[xs11jack]

The usual stuff

Where do you get the coils and how much do they cost?????

[skids]

Re: the Jewels in question

I can see why you might be interested in changing the plug wires!

Originally posted by xschop

[TopCatGr58]

Hey Chop,

Those coils are very similar in appearance to the MikesXS coils that are in the Tech Tips....FOLKS, Please scroll down from the MAIN FORUM PAGE to find them, there are many new ones that are NOT linked from the LEFT HAND COLUMN LINKS!!

They also provide for replaceable wires, that's why I went with them even though my OEM's were working just fine, because I wanted to put on some GREEN wires. They are HIGH OUTPUT rated at 35Kvolt, and are very economical vs. the higher priced brands like Accel and Dyna! It's your money!
T.C.

PS, the vacuum advance of OUR MACHINES provides for increased timing during reduced loads, like cruising....max being something like 52 degrees!! The max timing is around 36 degrees at 4750 rpm which includes the 10 degrees static and 26 degrees via the cent. adv. The Vac. adv can provide a max of 16 degrees more, but doubtful that it actually attains that much!

[xschop]

coils

mine were $38 shipped to my business.

[Bigleo]

Retarding the timing is not a great idea, it will result in the fuel air mixture not burning completely by the bottom of the power stroke. This causes a still burning air fuel mixture to be forced past the exhaust valves. you are running a definite risk of burning the exhaust valves. You will also be down on power, so generally you will open the throttle more to make up for it, so the motor runs even hotter. And lastly if any fuel is still burning in the exhaust pipe when an adjacent cylinder is in the over lap period where the exhaust and intake are open at the same time you will get backfires out the carburetor. Not a good idea on a diaphragm type carb. One more thing your gas mileage will suffer.
Leo