Ok to remove head nuts without removing cams [Head Gasket Leaking]

[trbig]

The manual for these bikes are only good for certain bits of information otherwise they are worthless in my opinion. If you want a good running bike for years to come, math is something you need to become good with. People may disagree with me. But math is what will make fuel/ ratios correct, engines not leak , timing to be correct, gravity fed fuel correct , back pressure amounts correct and finally a bike to ride true.

What exactly makes you think the manuals are worthless? Not having a clue with math will still let you adjust a carb. Math has very little to do with whether an engine leaks. The manual shows how to measure things to make sure they are true, but that's not really math. Math has nothing to do with timing, unless you are meaning to be able to count two dots/lines and a timing mark? I can see some add/subtract measurements to see if a bike is straight or not, but it's not like it's rocket science using a piece of string.

Now granted, I haven't done hundreds of motors, but I've never seen or heard of "Porous" engine blocks before unless they had a crack in them or it was just a flaw. Having an engineering degree won't fix his head gasket, but following simple directions in the manual probably will.

[D0wn5h1ft]

I think I may have found my issue. Looking back at the pictures I took it seems the mating surfaces between the head and the cylinders was a far cry from as clean as it needed to be. One of the POs did the "trick" where he used aluminum paint to "seal" the head gasket. There was a significant amount of this left and I got the "ah f*** it, that's good enough" attitude with it. Probably the culprit for my leaking and low compression .

As far as resurfacing, decking, porting, or whatever it's called for my cylinders and heads is it a difficult thing to do. I know if the surfaces are uneven I have to bring it to my local machine shop to have them square off the cylinder/head surface on the mill. It there a way of possibly sanding off the old residue or will the sanding cause the surface to become uneven?

I can also post this question in a new thread to keep things organized for future generations searching for the same problem if need be.

[MaximPhil]

Hi Downshift,
If you did not clean the mating surfaces before re assembly then you will most likely never get it to seal properly. sad to say you will need to do the job over this time with attention to detail.
Many say you can reuse a gasket but if it were me I would start with a new gasket. Once a leak path has been found it is very difficult to get a good seal.

Phil

[D0wn5h1ft]

Edit: The real reason I didn't get too aggressive, I guess, is that in the cylmer manual it warned against damaging the cylinder/head mating surface. I just don't know what's too tough and what's not enough.

Here you can see what I'm talking about.



You can see the old silver paint left behind. It wasn't nearly as bad as that after I scraped the loose stuff away but I assume it has to be nearly pristine?

[D0wn5h1ft]

Hi Downshift,
If you did not clean the mating surfaces before re assembly then you will most likely never get it to seal properly. sad to say you will need to do the job over this time with attention to detail.
Many say you can reuse a gasket but if it were me I would start with a new gasket. Once a leak path has been found it is very difficult to get a good seal.

Phil

How do I go about cleaning the surface properly without damaging it? The more specific questions are in the post right before yours.

[MaximPhil]

Pristine is a good word for it. VERY Carefully with a gasket scraper. Almost any tool you use will be harder than the soft aluminum so extreme care has to be taken. In the case of paint perhaps a solvent wash would help?
Phil

[trbig]

Is it silver paint or is the old gasket just delaminating? Dremmel has a sanding wheel that has multiple flaps of sandpaper that does a really nice job without being too aggressive, but there'll still be a bit of scraping around the studs. I put all the pistons at halfway and stuff rags in the cylinders to help keep bits and sand out.

The main thing you're looking for is the metal rings in the gasket to seal around the compression chamber. If there's a lot of garbage in there, it'll make that gasket too thick and keep the rings from getting a tight seal. Of course the gasket also holds back oil, but just around the cam chain galley.

I have reused head gaskets many times, but if they become delaminated and bent like that, they're junk.

[D0wn5h1ft]

I definitely did not put that one back in there. I used one I got from IanMac. As far as cleaning the mating surface I did some reading online and got myself some acetone, scotchbrite pads, a plastic surface cleaner tool (convenient right?), and razor blade to use very very very carefully if needed. I'm about to throw on my work pants now and get the heads off again and I'll post pics of the surfaces before I put it together if I have any doubts.

[skids]

Good on you! You will be hapy with the results.

[Outster3]

What exactly makes you think the manuals are worthless? Not having a clue with math will still let you adjust a carb. Math has very little to do with whether an engine leaks. The manual shows how to measure things to make sure they are true, but that's not really math. Math has nothing to do with timing, unless you are meaning to be able to count two dots/lines and a timing mark? I can see some add/subtract measurements to see if a bike is straight or not, but it's not like it's rocket science using a piece of string.

Now granted, I haven't done hundreds of motors, but I've never seen or heard of "Porous" engine blocks before unless they had a crack in them or it was just a flaw. Having an engineering degree won't fix his head gasket, but following simple directions in the manual probably will.

Let correct myself. Math is pretty general statement. Numbers is a better way. Needing to know numbers, geometry is for bike frame straightness (rake, soft vs hard tail, mono vs duel shock set up, etc) you can use a string to center your bike but unless you know what straight is, you can still "dog track" to left or right.
Timing. 10 % advanced TDC, -10 % retarded TDC, 1% marks in between. Math being used for various adjustments. Such as when boring ( without math this process is useless). Valve lash adjustment. Valve spring tension due to lack of rocker arms. Carb adjustment, such as replacing jets, unless you just put any jet that will fit versus doing the math to figure what jets you should put in depending on what mods you have done. You will never true up your carbs without figuring out the absolute pressure (atmosphere), vaccum if set up, OHC replacement, increasing size.
Compression ring size, increase or decrease in size, depending on piston change or stock. I could on and on. I've never built a motor or a bike without a mic (internally/external), level, measuring tape.
Aluminum is a porous metal. Which is a reason you can not weld with certain types of weld. Or you will get aluminum foaming (a break down if the molecular structure of the metal). You can pit it with a screw driver due to it being so soft .
The manuals are outdated and written for the ideal situation mechanic not the average back yard mechanic. If you are not familiar with engines I would not attempt the engine rebuild only using this manual for guidance. Good for specs ? Yes.

[ViperRon]

Exacto makes a flat square edge blade that allows you to get low and flat with the surface when scrapping material to clean the surface. One other important issue I have seen people leave the washers off under head bolts and this can greatly effect the torque effect on the head so make sure you have the thick washers under the head bolts.

[D0wn5h1ft]

Got the heads off and started working on the cylinder surface first. Went at it with the scotchbrite pad and some acetone and I definitely see the difference. The surface is bright and shiny now compared to that dull silver color the old gasket left behind. It's going to take a bunch of elbow grease and time to get both the cylinders and head looking good but I think it'll be worth the time in the long run.

[trbig]

Something satisfying about hard work, but there's also satisfaction in powered tools...

[IanDMacDonald]

Something satisfying about hard work

I thought this said something else . . .

[D0wn5h1ft]

Couldn't get it perfect because the graphite from the old gasket was really baked on but it's a least a smooth surface now. Put the heads back together and poof no more head gasket leak. Now if I could only explain why it won't start...