84 CR500 Rebuild

[BrianPaul69]

Sorry it's taken so long to post an update, life just seems to come at me from every direction sometimes. Here is a pic of the nearly finished bike. It turned out pretty good all things considered.



After the last ride there were a few little things I needed to change and one that I thought really didn't matter but later found out that it did.

That little strap on the front number plate that goes to the cross bar on the handlebars, well my number plate didn't have it on there. It seems that its there for a reason and that reason is to keep the damn front brake hose from going behind the number plate every time the bike hits some whoops or goes off a jump.

I changed the rear sprocket to the 48 tooth and it helped a lot. Maybe motocross would be better suited for the 51 or 52 tooth but for open area riding the 48 tooth worked great. It still tops out fast but any smaller I think it would really hurt the low end gearing on the tight stuff.

I also picked up a used M5B 140/80-18 rear tire that I haven't got on yet. Its got about 1/3 life worn off it but that might help with the funny feeling they have when they are new. Those huge lugs make the back end sort of wander around a bit but when you open the throttle and need it to bite there's nothing like it.

I'm having some trouble with my PJ carb also. It seems that the choke / idle adjustment keeps screwing back down on me. I picked up a used 40mm PWK that I'm going to try and if nothing else at least the idle screw will stay where I put it.

I really wanted to test this bike out with some higher octane fuel BUT turns out the gas station that was selling it locally ran out and now all their pumps have a little sign "no gas". Before doing any other head work I wanted to see if that would cure the low throttle ping.

Last but surely not least I bought some FMF silencer packing but still haven't had a chance to dig into it yet. When I packed it the first time I was under the impression that it shouldn't be packed really tight thinking too tight would make silencer pretty much like a solid unit and not quiet things down. Everywhere I looked they say pack it as tight as it can be stuffed in there. I'll give it another shot and see what happens.

The last thing I can advise is after every ride check your motor mount bolts. I lost the bottom engine bolt last time out and it could be that I just didn't have it tight but I'm pretty sure I did. A little thread locker probably wouldn't hurt either.

If we don't get any rain tomorrow I might try to head out to the ATV park Saturday and see how it goes. I ran across a few guys on YZF 450's out there last time and I don't even bother with the quads anymore. I know there are people that have the new 450's and I guess to be polite I'm sure they run good. As far as the 450's that I have met up with there wasn't a single one that has put up more than a 2 second fight before I blew past them. I have no doubt that on a motocross track the old technology would not be able to compete with the newest bikes but get them out in a nice open area and its like an old dog chewing on a new bone so to speak.

[mightyhammer]

Brian, do you have an airport anywhere close to where you live? I take my 5 gal. jug over to mine from time to time and fill it with av-gas. Its like 6 bux a gallon, but it is 110 octane and "NO" metanol/ethanol whatever added. Might be worth a trip!

[BrianPaul69]

I use to run AV gas when I lived up north but it was 100 low lead not 110. I'm not sure what they sell here in North Carolina. I might have to check into it because the Citgo doesn't look like they're coming back.

[Rot Box]

Awesome! Good looking bike you have there looks like all the effort really paid off

What I found with my 84 is no matter where I set the stock needle I had lean ping or rich blubber and no happy median. The pilot circuit on the PE was also a roller coaster ride. Once I got it to where it would actually start decent when cold it was too lean when warm--ugh. Ultimately I decided to ditch the PE and never look back. When I had a PJ I used a stock needle from a 91 CR500 and richened up the pilot and man did it run good! That carb alone transformed the bike. I now have a 39.5mm PWK but I haven't had a chance to tune it in yet... Hoping it will be even better.

[BrianPaul69]

Thank you for the kind words. This bike has been the most difficult one I have resurrected so far. From everything I read I just decided to skip over the PE carb altogether. The PJ does work great but mine is from a 95 CR500 and pretty worn. The stupid choke / idle adjustment keeps screwing back in and the bike always wants to stall. I bought a brand new 39.5mm PWK for my 95 and right out of the box it works flawlessly. Very clean crisp throttle response and pulls like crazy all the way from idle to top end.

Well, my plan was to get a nice 39mm or 39.5mm PWK for the 84 and as finances have it I had to buy used. It was said to be a 39mm and turned out to be a 40mm. No biggie, I just jetted the PWK like the PJ carb that worked great but the PWK was a mess. The 65 pilot was way too much and the DGH needle that was in it didn't work either. It was so rich at idle the air screw was unresponsive and I had to screw the idle screw all the way in and it still wouldn't idle. There must be big differences in the circuits between the PJ and PWK carbs for it to be off that bad.

Thinking about it more cranking the idle screw all the way in only worsened the problem. Screwing in the idle screw lifts up the slide giving not only more air but more fuel. Anyway I messed with it for a few hours and just couldn't get it right. I decided to just pull the 39.5mm PWK off my 95 and see what was in it. Turns out it had a 55 pilot, CEJ Needle (middle clip position) with a #6 slide and a 175 main jet. Since the 40mm PWK also had a #6 slide I just swapped them out and gave it the same jetting. It fired up on one kick, the air screw was working but it was still blubbering at WOT. By this time the sun was going down and I could see a patrol car showing up in the near future so I called it a night.

Anyway I'm heading in the right direction. I'm going to try a 172 main and I need to pick up another CEJ needle. With this big bore air cooled monster I really want to take my time with the jetting. I almost lost it once due to lean jetting when I first fired it up with the PJ carb and again this past weekend when I shut the gas off trying to empty the carb a little before another jet swap. I don't recommend ever doing that. Thankfully the bike was on the stand and I was on the bike.

Here's the scenario. The bike was running real rich and probably had excess fuel in the crankcase. When I shut the gas off I was ready to hit the kill switch to shut her down. Turns out that once the engine hits a certain rpm the kill switch is useless. All I could think was to pop it in gear and I used the rear brake to shut the engine off. Scared the shit right outta me.

This little incident was actually what clued me in to just how rich the bike was running and got me thinking about the whole slide / needle position / idle screw situation. Anyway, I'll keep everyone posted on the PWK jetting, hopefully I can get a few more hours this weekend to mess with it..

[Rot Box]

Thats the point I'm at right now I have no doubt that the PWK will rock on an 84 but it takes a lot of tinkering to get to that point when you have to start from scratch jetting wise lol. The needle is the hard part everything else is downhill from there...

I need to get off my ass and tune mine in! I'll keep an eye here to see what you find, and if I figure something out that works good I'll post up Good luck,

Andrew

[BrianPaul69]

Ok, I finally got the pictures of the compression release valve in the head.


With the shroud off and looking straight at the head you can't even see the valve.




Sort of tough to get the camera in there but now you can see it.




Not much better a view just a little closer




And there it is from the pipe side.




With the shrouds on you can just slip your hand behind the left side shroud and click it down. Usually one kick after its warmed up is all you need. Sometimes I don't even bother with the valve, I mostly use it when its cold to get it started.

[BrianPaul69]

Looks good.
How did you match the paint?
Gonna ride it or race any AHRMA events?

I wanted to reply to this and figured if I put it at the end more people would see it. I found the member who was selling the Flash Red Powder Coat and I wanted to share that with all of you just in case you are looking to go that route. Looking back I would have preferred powder coat over paint.


Here is the post with the person who was selling the Flash Red Powder.

http://www.bannedcr500riders.com/board/ ... hp?t=12147

He also says he has other factory colors as well.

In case something happens to the link you can just shoot him a PM on here. His ID is dogger315

[BrianPaul69]

It's been a while but the last updates I have for the old 84 really helped. I got a new intake setup for my 95 and found a cheap Rad Valve on e-bay so I put the 39.5mm PWK on with it. I then took the 38mm PJ carb and put it on my 83 CR480 and was so happy to get the PE carb off it. No matter what I did with the PE it was just a headache and I never could get it jetted properly. I even experimented with VForce3 reeds and they made the bike very hard to start and took away the bottom end grunt. With the Rad Valve and 39.5 PWK it was actually fun to ride. I do have a set of 87 forks with the disc brake setup but don't have time to rebuild them and do the swap. The 84 forks need to go at some point because they are a little dangerous if they take a hard hit. The only crazy problem I had with this bike was about an hour into riding the engine started to die out like it was running out of gas or something but I had half a tank. I was worried that maybe it was over heating or something got in the carb and was blocking a jet. I packed it up for the day and when I got a chance pulled the carb and cleaned it. It was spotless. I took it for another ride around by my house and it seemed to run fine until I really put the hammer down and it started the same thing again. I limped it home so I didn't hurt anything and decided to pull the plug and see what that says. I look in there and the rubber plug boot was up a bit higher than it should be. I touched it and sure enough it was loose. When I took it off the plug I noticed threads. Humm... threads? Sure enough the stupid screw on spark plug tip unscrewed and everything was just bouncing around under there. First the bottom engine bolt now this. Its about a full time job just keeping the bolts and things from falling off on these big vibrators. Anyway, tightened the tip back on and all seems to be good again with the old girl.

I'll be starting a new thread to post up the build pics of the 83 CR480 as time permits.

[Tharrell]

Hey Brian,
Nice bike.
I see you have an old Yamaha endure too.
I have a complete '70 AT1 if you want it.
I have a bunch of Yamaha endure stuff laying around.
Too many projects that will never get done.
ATMX
MX125
LT1
parts from a 1968 DT1, etc....

[BrianPaul69]

Hello Tharrell glad you liked the build and moms old DT1. That bike has been in the family nearly since it was new. At one point it was moms only transportation. A cop pulled he over once because I was on the bike with her as you can see in the one pic and he told her "Hey lady are you trying to kill that kid?" Can't remember what mom said she told him but I'm sure he turned and left.

We have to talk about the AT1 and parts that you want to let go of. God my wife will probably kill me but I just love these old bikes. I have a 72 Yamaha JT2 and 2 little Yamaha GT 80's (I think ones a 73 and the other is an 80 ) that I haven't started on yet but still I'm interested.

I just looked you up on the map and we are about 4 hour apart BUT wow it looks like you are in awesome riding territory up there Riding sort of sucks here in the Wilmington area. PM me your phone number and we can talk. Thanks and take care