500 ramblings...

[Louis Mielke]

ok so I've got the 500 all torn down again. Working on rebuild. I had a terrible time with the cooling at TF. The rads kept getting pressurized and blowing the coolant out. well after pulling the head off and looking at the head gasket I'm pretty sure I know why.

No1 my head gasket was blown.

No2 i did have the wrong gasket. Got the correct one and not only is it 3 times as thick but the water port holes are drastically different. Not sure if it will make a difference but who knows. While I have it torn down I'm gonna lap the gasket surface. My head was milled before I put the thing together but I never bother with the jug so I guess I'm pulling the studs out of the cylinder...blah...

I'm just very glad I didn't really push the thing at TF or I might have had more than just a head gasket to replace. Would have sucked to hydro lock the thing.

Sadly this doesn't explain why it keep blowing the base gasket out from under the jug no matter how many times I retorque it.

I'd also like to take time to thank KTM for making the 85sx, because just as a few others on the board have, I have also aquired a set of inverted forks for the 500 (thanks to billy among others) So now I'm working on the front end conversion also. Should drop the whole bike another 2 inches once I go to 20" tires in the rear and helpy hanlding alot. I'm pretty sure I'm gonna go with 0 rake in the tripples leaving jsut the rake in the headtube.

Looking at my head it kinda confirms my thoughts that the bike was running real rich at TF, I know its gonna be hard to tell since i was burning the coolant too but the jug and piston top are coated black as night. My first thought was that it would run lean since I have no lid on my air box but that doesn't seem to be the case. I think I'm gonna start by going down on the pilot jet to start with as the bike just really seemed real burbly at idle and on the low end. (course I've always been told 2 strokes shouldn't idle but I'm sorry I gota have at least a little idle)I also had alot of pipe spooge which is why I'm also leaning towards pilot jet.

Over all the bike didn't run too bad for having a new carb pulled out of the box thrown on it last second. Set the screws as best I could and loaded it on the truck.

[Red Rider]

Those forks look familiar. Welcome to the club!

[Billy Golightly]

That must have been a gasket for the old 84(?) aircooled engine. On the base of the cyl...it or the cases might be warped. We know it definetly got hot a few times there at haspin, maybe it got hot enough to warp it.


Also, I bought my second set of KTM forks the other night

[Louis Mielke]

Heh,i guess it is a club eh? lol

As far as the head gasket, no, it came out of a gasket kit that was marked 88-01 so I don't beleive it was from an 84.

Warpage of the cases, that could be the case but I don't believe so honestly. I was having the problem when I first started the engine a week or two before trikefest. Thats actually the second gasket. I will say though that this gasket lasted almost three weeks where the first one blew out both sides in less than a day. Right now its only blown out on the right hand side. I'm gonna send the cylinder back to the accustart guy and have him move the water spigot further back on the side of the cyilinder so I may have him check the base and gasket surface of the cylinder for me. He seems to know what he's doing as far as machine work, that or he talks a big game.

As far as the caes...*shiver* I really don't wanna pull that crank back out...ugg... I'll see what I can do to check the surfaces with it still in. blah.

another thought, my cylinder is on its last bore, I'm wondering if that is causeing any heat transfer issues. dunno. I've been looking at aftermarket radiators an honestly don't think the cost is justifiable. I'm gonna get the head gasket straightened out first and see if I still have a problem before I do anything else. I am however gonna get my set of Ronnies super coolers installed and try some of that water wetter/ or engine ice.

Another note, as much as I love the look of my fueltank its deffinitly rubbing in afew spots. I gota get that figured out or I'm gonna develop a leak. I may have to go to stock style tank. I will say though I'm wondering if the "scoops" on that oversized tank arn't really scooping much air.

I'm also seriously thinking about a 13ounce flywheel weight. All the CR500 boards tend to agree the weight really helps these motors chuck like a tank for woods riding.

heh Saw you over at Larry's board billy. Doing a little recon too huh? lol
Man its funny but I getting excited all over again about this project. I was fairly please with it at TF and now I'm kinda getting stoaked about getting it dropped down lower and getting it running right.

Oh and lucky duck on the new set of KTM forks. I'm seriously considering trying out a set of CR80 forks on my 250r since they are more plentiful. I maybe able to reuse my bored out clamps from the 500 for the 80 forks,

[Darius1502]

Louis,

Fellow big bore rider here KTM 550 two stroke. Your 500 should idle if its jetted right.

Before wondering about bigger radiators, I would make sure your radiators are flushed out and don't have 'goop' in them.

Second, yes that gasket for the head looks way too restrictive!

Third, is your impeller turning?

Fourth, these CR500's are indestructible. The trouble is with your head I bet. Your compression may be too high and the restrictiveness of that head gasket could be raising the temp. and the pressure of the fluid.

Also this is a last thought: Is your radiator cap correct for you bike year? I don't know for sure if this would matter but I think it does effect the pressure of the system, correct? Or perhaps the boil over point?

[Ryah]

I had an 89cr 500 that had the same issues as yours, except that I had the correct head gasket. They (engine shop) said the bottom of the cases were most likely warped. I had the bottom of the barrel milled flat then used form-a-gasket along with the stock honda gasket and it quit blowing out the base gasket. I second the radiator restriction issue. I sent mine off to this guy. He did a real nice job http://www.motorcycleradiators.com/ . I also got a radiator cap off of a KX500. It had a slightly higher pressure release. I've got a 90cr500 with a weld on weight and it makes all the difference in the world of the bike. It just doesn't want to stall and climbs like a 4 stroke.

[Lomax]

Also, I bought my second set of KTM forks the other night

And your going to sell those to me cheap for the Tri-Z arent you

[metalm0]

A lot of people put the 88-01 gaskets on because they are thinner than the 3 piece I believe? 85-87 gaskets... With thinner gaskets it raises the compression but you are supposed to outline the gaskets and cut them out and what not. Sounds like whoever had it before you just threw it on. Also Lou, you sure thats a 86 jug? Someone might have sanded it off but all the 80s bike came factory with black engines.

Like someone said earlier to check your rads. Look inside and double check if they are scaling or what not. If you want them cleaned up or if they are bent send them to Mylers at www.motorcycleradiators.com

[Louis Mielke]

A lot of people put the 88-01 gaskets on because they are thinner than the 3 piece I believe? 85-87 gaskets... With thinner gaskets it raises the compression but you are supposed to outline the gaskets and cut them out and what not. Sounds like whoever had it before you just threw it on. Also Lou, you sure thats a 86 jug? Someone might have sanded it off but all the 80s bike came factory with black engines.

Like someone said earlier to check your rads. Look inside and double check if they are scaling or what not. If you want them cleaned up or if they are bent send them to Mylers at www.motorcycleradiators.com

Um, yah, I thought by reading through this whole post it was apparent that I rebuilt this engine, maybe not. From the ground up dude, I got the engine from a bone yard, dissasembled the whole thing, glass beaded the whole thing, and then got the lower cases re-powdered. New bearings, new seals, new rod kit, new piston, my jug is on its last bore. I know for a fact its an 86 jug. I specifically sought out the 86 engine cause everyone says they were the meanest year engine. The jug was black when I started with it but I pain stakingly blasted all the black off.

As far as the gasket i'm still not sure on this one. If you look at my new gasket which is suppose to be the right one for my year engine the only water ports that are totally cut open are the two on the front. All the rest have only a hole the size of a coffe stirrer in them. I'm nmot sure if I should open them up or not. Billy do you remember what your head gasket looked like before you put your head on last?

[Billy Golightly]

Yeah, from what I remember it looked like the new one you posted. It was kind of thick. It was an aftermarket Cometic one. I had a Vesrah on before. Actually I think the old head gasket is still in my toolbox, I keep it just for conversation because when you look at it and realize how large the bore on it actually is its a little overwhelming

I would leave the other ports the way they are. All the heat is on the exhaust side of the engine anyways. And, from what I've been reading, the smaller water ports increase the velocity at which the water travels around through the cylinder and keeps it from becoming stagnant and not circulating as well. You might also trying picking up another set of radiators, dont have to be new ones or aftermarket ones. I noticed that the outside tubes on yours were kinda smashed in from it being on its side while it was still a bike. The outside tube on I think its the right side on mine is completely collapsed, and I know thats not helping it. You might want to check into that too.

Haha and yup, I've been to Larry's forum a few times. Theres another really good one (I like it better) www.cr500riders.com I think it is. Pretty knowledgable people there and the guys with the hill climber bikes know just about every trick there is to power.

[KASEY]

i went back to a stock honda gasket in my 500,,, i am also on the last bore and aftermarket gaskets don't hold cause the metal band is not laege enough to seal properly in an .080 over bore,,,, went to honda again and no more issues,,,