i have 2012 kx500af timbersled and I need some help with setting up the timing for the new pvl ignition I got. it has a raised comporession head, porting, and running 100ll gas. I have a gauge but I need to know in mm before tdc where to set the flywheel. pvl does not have a keyway like stock. people are saying 14-19deg btdc but I need to know what that is converted in mm before tdc. anyone have any input?
kx 500 timing
- Thread starter Pbeaud01
- Start date
This sounds like a question for Portgrinder, maybe pm him.
M5
M5
Assuming the stroke (86mm) and the con rod length (145mm) numbers I found on the internet are correct, and that your bike is still stock relative to those numbers...
14deg BTDC is 1.65mm
19deg BTDC is 3.02mm
14deg BTDC is 1.65mm
19deg BTDC is 3.02mm
P
portgrinder
Well-known member
The stock recomendations for the penton ignition leave alot of power on the table. IF you want to run better fuel. my engine is not stock, but below is how it responded on dyno
The after about 4000rpm the plug fires basically at the timing mark on the stator. might be a degree less at 8000 rpm but not much. before 4000rpm it tapers down like a normal ignition curve.
so the best we found was 22.5mm from the factory mark measuring along the circumference of the stator. did some math and figured out every 1.1mm is 1 degree .
going back to 17.8mm you're down about 6hp over a 1000rpm range.
at 14.6mm youre way off the mark. down over 10.
it will barely run when its set at TDC
didn't advance any more than 20.45 deg. thought we had gained enough. we likely could have though.
This is running c12, checking plugs, fuel flow, egts. all that good stuff. use at your own risk. Mine's staying at 20.45 though. going down to 100 octane it will tick in the midrange.
The after about 4000rpm the plug fires basically at the timing mark on the stator. might be a degree less at 8000 rpm but not much. before 4000rpm it tapers down like a normal ignition curve.
so the best we found was 22.5mm from the factory mark measuring along the circumference of the stator. did some math and figured out every 1.1mm is 1 degree .
going back to 17.8mm you're down about 6hp over a 1000rpm range.
at 14.6mm youre way off the mark. down over 10.
it will barely run when its set at TDC
didn't advance any more than 20.45 deg. thought we had gained enough. we likely could have though.
This is running c12, checking plugs, fuel flow, egts. all that good stuff. use at your own risk. Mine's staying at 20.45 though. going down to 100 octane it will tick in the midrange.
port grinder thank you for the info. I am using a dial indicator gauge and measuring the mm of advancement that the top of the piston sits before tdc. The PVL manual said 1.8-2.2 mm before tdc. Im wondering how your numbers convert to those measurements. The manual sais raised compression will need less advancement but i don't want to be losing hp. the pvl ignition doesn't have a keyway so basically you have to set the timing by getting the piston where you want it in mm before tic and the bolting the flywheel on to the crank shaft
We set up a PVL on my friends KX. There are many
ways to do the job I guess, but heres what we did. Use your dial indicator to find TDC.Then make a mark on the flywheel and the case that line up.
Then slap a degree wheel on and adjust the flywheel to the timing you want in degrees before TDC. Now it is in the ballpark and will run and any further adjustments can be made with a timing light and your TDC marks. Your timing light needs a dial on it so you can use the TDC marks.
The whole process is kind of a P.I.A.
The 100 W stator is kinda nice, I guess.
I love simplicity so I skipped the PVL thing and added a 35 w winding to the stock stator.
Thats enough power to run my EGT gauge and
an LED light.
Good luck!
ways to do the job I guess, but heres what we did. Use your dial indicator to find TDC.Then make a mark on the flywheel and the case that line up.
Then slap a degree wheel on and adjust the flywheel to the timing you want in degrees before TDC. Now it is in the ballpark and will run and any further adjustments can be made with a timing light and your TDC marks. Your timing light needs a dial on it so you can use the TDC marks.
The whole process is kind of a P.I.A.
The 100 W stator is kinda nice, I guess.
I love simplicity so I skipped the PVL thing and added a 35 w winding to the stock stator.
Thats enough power to run my EGT gauge and
an LED light.
Good luck!
20.45 deg BTDC is 3.49mm.
krust i appreciate your efforts but i think setting the piston timing at 3.49mm before tdc seems to be a little to much advancement. they don't recommend anything over 2.2mm and that is on the edge according to pvl. here is what it said in pvl manual.
Section 4: TIMING SPECIFICATIONS: Engine timing is directly related to the compression of the engine. The higher the compression, the less advance (as in advance of the piston’s arrival at top dead center or highest position) can be used for the timing position. To get more bottom end, advance the timing from the recommended range. Since the exhaust pipe, carburetor, cylinder porting, and cylinder head design are all tied to the amount of heat that an engine makes, they must be taken into consideration when setting the engine’s timing. It’s all about heat that is generated in the engine’s combustion chamber. An engine burning a specific fuel can only tolerate a certain amount of heat, and all of the above mentioned factors are related to this heat. Since the ignition timing and its effect on that heat are directly related to the engine’s longevity, it is critical that you get it right. Too much and you toast the engine, too little and you are giving up horsepower. Gasoline and alcohol (methanol) have different figures due to their burn characteristics. Generally, alcohol burns slower than gasoline and needs more heat. This can be accomplished in one of two ways - advance the timing or up the compression. You still can only have so much heat for the engine to operate. The following timing specifications are offered only as a starting point guideline! To determine whether your system is Analog or Digital, compare your part numbers to those listed in the PVL Components Testing Chart on page 4 of these instructions.


Engine Displacement in Standard Form*


Analog System(BTDC)
Millimeters / Thousandths*
Millimeters x .039 = Thousandths

Open Class Engines
2.2 to 2.4 mm = 85 – 93th
Modified engines (higher compression) will need to use timing that is retarded from the above figures. **Engine, carburetor or pipe modifications necessitate experimenting with the timing.
Section 4: TIMING SPECIFICATIONS: Engine timing is directly related to the compression of the engine. The higher the compression, the less advance (as in advance of the piston’s arrival at top dead center or highest position) can be used for the timing position. To get more bottom end, advance the timing from the recommended range. Since the exhaust pipe, carburetor, cylinder porting, and cylinder head design are all tied to the amount of heat that an engine makes, they must be taken into consideration when setting the engine’s timing. It’s all about heat that is generated in the engine’s combustion chamber. An engine burning a specific fuel can only tolerate a certain amount of heat, and all of the above mentioned factors are related to this heat. Since the ignition timing and its effect on that heat are directly related to the engine’s longevity, it is critical that you get it right. Too much and you toast the engine, too little and you are giving up horsepower. Gasoline and alcohol (methanol) have different figures due to their burn characteristics. Generally, alcohol burns slower than gasoline and needs more heat. This can be accomplished in one of two ways - advance the timing or up the compression. You still can only have so much heat for the engine to operate. The following timing specifications are offered only as a starting point guideline! To determine whether your system is Analog or Digital, compare your part numbers to those listed in the PVL Components Testing Chart on page 4 of these instructions.


Engine Displacement in Standard Form*


Analog System(BTDC)
Millimeters / Thousandths*
Millimeters x .039 = Thousandths

Open Class Engines
2.2 to 2.4 mm = 85 – 93th
Modified engines (higher compression) will need to use timing that is retarded from the above figures. **Engine, carburetor or pipe modifications necessitate experimenting with the timing.
I'm not advocating you set your timing at any certain value. I've never worked on a KX500. Hell, I've only ridden one once. It scared the crap out of me back when I was a noob at the dunes. Just trying to answer your question of how those timing angles relate to piston movement. The geometry is what it is.
Hope you get it up and running strong.
Hope you get it up and running strong.
P
portgrinder
Well-known member
To get max power you gotta adjust it waaaaay past what they say. If that scares you, then don't.
hammer it on there real tight. mine slipped once
P
portgrinder
Well-known member
few more things on the penton....
the rubber gromet that it comes with is not the greatest. water gets in. just found out the hard way they dont like water. got mine real hot and it let go. no spark.
seal it up real good with your fave gasket make of choice and check it often. i put a drain plug in the bottom of mine.
mine survived 3 years with water in it many times. this last time though there was about 300ml in there. guess that was enough.
also the mount that the coil comes with will crack over time. mine was 0.080 thick and i mounted it to the head stay. made it 3yrs before it cracked in half. keep an eye on that.
the rubber gromet that it comes with is not the greatest. water gets in. just found out the hard way they dont like water. got mine real hot and it let go. no spark.
seal it up real good with your fave gasket make of choice and check it often. i put a drain plug in the bottom of mine.
mine survived 3 years with water in it many times. this last time though there was about 300ml in there. guess that was enough.
also the mount that the coil comes with will crack over time. mine was 0.080 thick and i mounted it to the head stay. made it 3yrs before it cracked in half. keep an eye on that.
Thanks for the info port grinder. How many mm dos you set yours up before tdc? I don't want anything crazy or to be on the edge like yours because my fuel is not as good as yours and I have also raised the compression
