KX Riders
Maintenance & Technical => KX500 Original => Topic started by: gowen on November 23, 2004, 05:01:48 PM
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I've installed a PVL ignition, which is a little inner rotating flywheel and is a whole new ignition and I have a question about setting the timing, maybe Cam or Doordie or anybody!! can help.
PVL recommends the ignition setting to be set at 2.2mm-2.4mm before top dead center. Well, I used a dial indicator and set the mark at 2.3mm (.090in). It is a little harder to start, but has good revs and get this! The vibes are waaaaaay down!!!!!!! Anyway, for my question, they say in the manual that modified engines need to be retarded from the above figures. Now, is retarding the ignition going from a 2.3mm to 2.4mm or the other way? Also, does anybody have any clue as to how much I should retard? I'm very lost in this process and just plan to just play with it, but should I start by retarding the timing or advancing it? I favor the topend.
Thanks
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getting closer to TDC retards the timing. So 2.3 -> 2.2
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gowen,
Paul is right!
I will check up what timing you should use.
Don?t overadvance it ,you can ruin the engine!
The teory is so low advance as possibly. :wink:
//doordie
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Doordie, that would be awesome if you could do that! Thanks! Penton Imports told me the exact opposite. They also said, that all the modifications I will need to further advance it. Is this true? Or retard it? I remember on the stock ignition that I retarted the timing to bring up the top-end. Thanks doordie
Gabe
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gowen,
Alt 1:
A=Cos(P2+R2-L2)/2*P*R
A=ignition advance in degrees
R=Stroke divided by 2 in (mm)
L=conrod length (mm)
P=R+L-T
Alt 2:
T=ignition timing in (mm)
T=L+R*(I-Cos A)- "ROT"(don?t know word) L2-(R*Sin A)2
This is the formulas!
At 5000 rpm stock timing is about 17 degrees ,then fall back to XX degrees to it reach max rpm.(Don?t know what KX500-CDI have for set-up programed).
I will not say what you should use for timing,will not be responsbility! :oops:
Start at low advance and step up in 0,1mm and run it and check
if it runs better.Then when you have reach the best performance,fall back a little and see if you loss Hp.
My advice is to use the least of amount of advance conducive to peak performance.
Good luck! :twisted:
//doordie
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Thanks Doordie, I will be taking tomarrow to work with the timing. Went from jetting to timing now. :-) I need to find me a degree wheel.
Now, the formula I will be using is the Alt 2. Cause I do not have a degree wheel. :-( Just a dial indicator.
T=L+R*(I-Cos A)- "ROT"(don?t know word) L2-(R*Sin A)2
I'm unsure of the "ROT", but if I can find that missing forumla. :-) Would you happen to know the connection rod length? I don't have anything that has measurements besides tearing down the motor? It is a Hot Rod, but is stock length. Thanks
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Gabe,
If you have access (of know someone) who has a CAD program, for an easy degree wheel you can draw one, print it on a large self adhesive label (8.5x11 avery) and stick it a piece of tin (or even cardboard or an old CD if the hole is not too bid). Over the years, i've made a few of these and they work quite well. Heck you can just glue the paper on if you have no label. If you're stuck, drop me a pm and I can email you mine (6") in a pdf or autocad. You could print it off at home. As far as timing, Doordie and Paul are correct. Think that as your piston approaches TDC the sooner the ign fires before the piston gets to TDC, the more advanced it is (the timing), therefore as you reduce to 2.2mm the piston is closer to TDC when the ign fires, hence retarded. Modified 4-strokes like more advance, 2-stokes not necessarily - take a few tests to find the best setting. Although I always thought that retarding was better for bottom end power but likely depends on the engine. Have fun. I have too much snow to test anything now. Rebuild season. Cam.
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Gabe,
One more thing. You might want to stay fairly close to the PVL specs. Too much advance can torch a hole through the piston really fast. You don't get much warning either. Bike kicks over quite easily afterwards though (Ha Ha). Cam.
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gowen,
Conrod lenght is 145 mm.
I think the word I mean is "squere rot" ,sorry if wrong spelling! :oops:
T=2.3mm (example)
P=R+L-T=43+145-2.3=185.7mm
R=86/2=43mm
L=145mm
Now YOU calculate it!
//doordie
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Hi Doordie, thanks, that helps alot and I understand now. I have a question though, I now run into a problem I never did with the stock ignition, the kick starter now kicks back on me while trying to start it. Is this normal? What does this mean? Thanks
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gowen,
Ask any preowner of old (before1984)Husky 488cr with motoplat rotor-ignitionsystem.Many broken wrists :lol: :lol: :lol:
Yes, that?s a problem you have to live with. :cry:
Many vintagebikers here start the bike with pulling first, so it?s more easy
to start it when warm close to race.
Little "inertiaweight" reduce the helping rotating force with a rotor.
(I have reduce the stock flywheel weight only,good for revving on iceroadracing but spinns the backwheel more easy though). :wink:
//doordie
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Well, just a small update on the timing. I did reduce the kick backs by retarding the timing. It's been fun, but now I'm running into another problem, it is a pain to start! I just replaced my kickstarter last year and now it is bent a little outward and it is now slipping slightly from the kick backs. When I get it started and it is HOT it is still hard to start, just as hard as cold. There is no way anybody could live with this bad starting on the KX. I will reinstall the stock ignition if that is the case. But, I will try to advance it tomarrow and see if that helps. Was wearing my riding boots (AXO RC5) and now have a huge bruise on the bottom of my foot from kicking. A little discusting. :-( Cam, a degree wheel would be awesome! my e-mail is gabeowen@earthlink.net
I'm also thinking I should go with a EIX plug instead of a ES plug. I will try tomarrow if my lower foot doesn't hurt as bad as it does now. :-) Any thoughts?
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gowen,
Here is some calculating:
2.4mm=16.9*
2.3mm=16.5*
2.2mm=16.2*
Stock is not 17* at 5000rpm it?s at 6000 rpm! :oops:
Some info about more or less advance:
If you want fast big "hit" in low and midrange adjust for more advance,but it will be more heat and easier to sieze at long straights.
The opposite with less advance with more topend and more "space" to siezing.
So, more advance with many sharp corners,and the opposite with long straights!
Just my idea. :wink:
(We have a good tuner from Finland as member,he will correct me if
I have wrong ideas). :lol:
// doordie who?s waitng for ice. :twisted:
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I guess Doordie mean me :oops:. Eric Gorr is good tuner, not me, but i agree what Doordie said about advance.
Maybe this can help you too:
If diameter of flywheel is 80mm, so circle is 80mm x pi(3,14..) = 251,3mm.
251,3mm / 360degrees = 0,698deg/1mm = 1mm in the circle is 0,688deg.
So 2,4mm in the circle is: 2,4mm * 0,698deg/1mm = 1,6755mm.
I like write and ask more here, but my english, d**n :(
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mun,
Don?t worry,they understand my bad spelling so it?s no problem for you,I promise! :D
Everyone look at his website,and you understand mun can "a lot" of tuning. :wink:
//doordie
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Mun,
Don't worry about your spelling. It's nice to have guys like you and Doordie part of the family. Besides, your English is far better than my Swedish. Last time I was in Stockholm the beer was tasty and the girls were very(very) pretty. Cam.
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Mun,
Don't worry about your spelling. It's nice to have guys like you and Doordie part of the family. Besides, your English is far better than my Swedish.
Seconded :)
It's good to have input from around the world
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Well, I finished working and installing the PVL ignition. I set it at .090 in, and installing a BR8EIX plug, it starts pretty easy now. First off, the power gains are HUGE in the top, and unlike a 125, with full throttle it jumps instantly into the upper RPM range with explosive type power. The power is so huge that I could not even really handle it on hard packed surfaces...I love it! It is a little harder to start due to the fact that the flywheel is about a 1/4th the weight and size of stock, but all that is required is a serious kick and I mean all weight to the kick.
Wow! This has to be the most power I've ever played with! :shock: I will get pictures tomarrow.
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KXcam22,
Swedish girls are not only pretty they are nice to if you "behave"! 8)
The girl on pic?s is a very good rider,does Paris-Dakar to and her name is Maria Sandell from Sweden.
By the way if you go to Sweden ,give me a call,means everybody!
gowen,
You can use some Eter to inject at airbox before first kick to. :wink:
//doordie
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KXcam22,
Swedish girls are not only pretty they are nice to if you "behave"! 8)
The girl on pic?s is a very good rider,does Paris-Dakar to and her name is Maria Sandell from Sweden.
By the way if you go to Sweden ,give me a call,means everybody!
gowen,
You can use some Eter to inject at airbox before first kick to. :wink:
//doordie
From what i learned from another type of bikes if you have an issue with starting the bike it is because the timing...give it try and see..retired the timing to .085 or .08 and see..also if you feel the kicker kick back when you try to fire the bike...i'm sure the timing is too high. go down and see.
(sorry for my english)
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Hey guys, sorry to bring up and old thread but i have just bought a PVL ignition for my 500 and im a bit lost on setting the timing. Can i just set it to the fully retarded position and keep advancing until no more power gains and then go back a bit for safety? Can anyone tell me how to set the timing with maybe a reference to the edge of adjusting slot to center of tightening screw? Or is it best to just buy a dial indicator and try to set it to about 0.090in, 2.85mm? Any help would be much appreciated.
Cheers
Brad
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you will have to check the timing with a dial indcator ... follow the directions from pvl thanks .stewart
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ok cheers, I will get an idicator tomorow.
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ok cheers, I will get an idicator tomorow.
It's a good idea, tough lesson to learn if you do not do it right.. Including 2 broken kick starters and 2 pair of boots. Not including the bruises to my foot in the process. Never start with tennis shoes while testing.
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Hahaha yeah my foot is no stranger to bruises from the ol 5hunge, if i cant start it within 3 good kicks with the tennis shoes i throw in the towel. Another question, do you guys run the tiny little spark plug cap that comes with the PVL kit? I tried following the instructions and stripped the high tension lead about 32mm then i ended up pretty much stuffing it in the cap as best as i could. It doest look like the best of connections. :?
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I used it and it did fine.
Fwiw, when it kicks back it will more than likely break your foot in tennis shoes. I wasn't meaning typical KX500 starting.
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I took mine off and threw it in a box, with no keyway it slipped (at least I think it did) and when it kicked back, broke my foot, the kickstarter shaft and the clutch cover case, suprisingly the kicker didn't break. Now I'm running the 89 ignition, it's about as good and starts way easier.
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So far so good. Haven't had a chance to play with the timing yet (set it to 2.30mm) but is running allot better atm, but that is also due to the fact that my old ignition was stuffed. Had a couple of kickbacks when first starting, scared the bejesus out of me hahaha. But if you kick it with anger it starts nicely 8-)
My clutch has packed it in atm so will give a better report once i have replaced that.