Rebuilding a1985 cr500... got some questions

Sounds about right. Great work...your gonna love that big cushy beast.

An update guys. Bike runs great but my led bit the dust. Let me elaborate. Going for my first night ride with my powerdynamo ac
--> rectified and regulated dc to led setup and its working fine at first. Then out of the blue the light dies. So I go home and pull the light bar and power directly to it does nothing. I pull apart the led bar to the circuit board and find a diode is fried. In the process I also damaged the circuit board so that light is done. But why did the diode fail? It seems even with the rectifier regulator the voltage got too high when I went wide open throttle that the components in the led fried. So heres my solution: a new and better led bar and handlebar switch and headed here in the mail. I went to radio shack and bought a five dollar full wave bridge rectifier. After some testing on the bike it was outputting dc like it should but at very high voltage spikes I didnt want to throw my old reg/rectifier on because it obviously didnt regulate very well. So I thought I was stuck. But heres the solution I think. I dug through my powerdynamo parts box and I found the original ac regulator that came with the ignition. My plan is to run the ac from the powerdynamo into the regulator to get perfect 12 volt ac then run that into my little rectifer and boom I should get perfect (around) 12 volt dc out. Thats the plan anyway. In my head this seems like the best way to run leds on this kind of bike and ignition. My last set up of running the ac directly into my reg/rectifier worked but then blew when I really got on the gas so I feel that adding the regulator before I rectify it to dc should stop voltage spikes and keep my at 12 volts. Only thing now is where to mount the regulator. Let me kno what you guys think. I am going to test all this together tonite or tomorrow so Ill let you know how it works.

Ok so that did not work. I got perfect voltage out of the ac regulator and then again perfect dc out of my rectifier but my led still fried. Not the lights themselves but i assume an internal component like the last light or a wire melted. Anyways im off to the university of nevada for college so the husky is going to have to wait till i come home for a weekend and i can tear into her. Its been a fun journey guys thanks for all your help and ill be on the forums again soon.

Thank you for your contribution, & we'll be here.......

Hey guys back again with a quick update. After my last headlight attempt failed I tore into her again to check it out. Turns out the light still works, nothing fried inside it, so I didnt loose my nice light. So i think the problem lies in my rectifer or regulator. I will contunue fidling with this issue later. In the meantime, I reattached my number plate so I could go for a ride with some friends. Bike was running great and was shredding as usual. But when I was nearing the top, my foot kept slipping off the peg, and I kept hearing a rattle and when I got to the top the bike sounded a bit hot. I immediately shut her off and noticed that one of the hoses that enters the water pump (the one that leads to the back of the cylinder) had popped off somehow and the hose clamp was rattling. I obviously lost all my coolant and had to roll home. Anyways, no harm done and an easy fix but as to why it happened, I dont know. My pipe is very close and actually kinda in the way of the hose so I think its just mounted crooked. My subframe pipe mount is very homemade so it may have made the pipe press on the hose funny and that may have led to it working its way off. Last time I was running some 265 f boiling point race coolant and the bike was never really boiling over but just for shits and giggles this time around i got some waterless supercoolant that is doesnt boil till 387 f. Hopefully that will squeeze some more power out of her by keeping her nice and cool. Anyways guys, just an update Ill let yall know how shes runs when I get her fixed.

Hey everyone. Rode the 500 for the first time in a while today. I cleaned her up a bit yesterday. Replaced the cracking fuel line, and put the water pump hose back on that had fallen off, and filled her up with some race coolant.fixed my pipe mount too. She ran good. Need to gear her down though, any recommended gearing?Also i hear a fast knocking while on the gas. Quiets down slightly when I press the pipe in but not much. Im just paranoid its internal. I dont think it is though. Im going to try tighteting the pipe more.

probably nothing if it changes pushing on the pipe...just leaking maybe?
what gearing are you running currently?

Im running 13-48 but may try 14-53 or maybe back to what it came with with 13-53. I even have an 11 tooth that would be fun with the 53 tooth rear. Probably wheelie in 6th. 14-48 is way to high, first gear is even to high, but yields an incredible top speed, and the top of the upper gears pull forvever.

try 14-52, it works for me, same basic area, same trees etc.

i try to keep the countershaft sprocket big as possible...the 12 tooths really dont last well on a big bore...i think the quicker a chain makes the turn around the counter the shorter it lasts as well. ive been running 14/52 and it works ok. maybe just a little tall still for woods work, but it could be my tuning.

Im tempted to try the 11-53 just to see how much acceleration i can get out of her. I would be concerned about looping over. On the flipside i almost want to run 14-48. Itd be terrible on trails, but ohh that top speed would be over 120 probably. Ill probably go with 14-53 its what i have.

14/53 will be a winner. with the 11 it will go thru the gears too quickly, and just be hard on the bike.

tuning is important, but the 500 makes so much torque that tuning for down low is the most important

I've been known to run 11 or 12 with a 53 rear. 1st gear is for really tight stuff or not even used. I don't need to go 70+MPH in the dirt. I just like instant tire shredding power. But I'm not racing in long heats or anything. Just play riding. It would wear me out at full race pace.

I have to do some experimenting with the gearing. Good thing the front sprockets are easy to change. My 500 is "tuned" pretty well I think. As for jetting I've never messed with it cause the guy I got it from was in my area. It has no hesitation or bog anywhere in the rpm. I have messed with the timing quite a bit and recently left it where it felt pretty good, just slightly retarded off stock. I might bring it back to stock tho just to be safe.

to be safe? retarding the timing from stock is "whats safe" you will lessen or eliminate kickbacks and decrease the bikes craving for octane at the expense of bottom end power. the 500 has plenty...

yeah I recall you saying those things, but with my timing a bit retarded like it is, warm starting seems more difficult for some reason. so it makes me want to experiment. and also i could have sworn more advanced timing yields better top end because the spark has to go off earlier to keep up with higher rpms. and retarded timing goes off later so its easier on the motor but less power. that's just what i was always told.

disregard my last statement. I did some online research and you're right, advancing timing results in a flat top end. Apparently its different with 4 stroke vs 2 stroke because you have to take into account that the spark is firing every rotation of the crank vs every-other like a 4 stroke, so too advanced timing can melt your piston. Also i read that too advanced timing yields a flat top end because of the flame front entering the pipe at a certain time, therefor changing when it returns to the exhaust port, effecting overall power. Its pretty damn complicated so i dont even know if im explaining it correctly. thanks for your explanation tho i am going to keep my timing where it is. if i change it at all i am going to go back to stock for a baseline, then just retard it less then i have it now, because i want a bit more bottom end power. thanks

gearing will help

if you arent having problems with kick back, and feed it pump premium always, you can run spec timing. it isnt super advanced. if you experience hot start problems you can try leaning the airscrew a quarter or half turn out.