Head gasket leak has apparently been issue all along

Been battling my colortune showing lean on 3 cylinders no matter what I do. Replaced manifold gaskets today and still no difference. Ive used propane and carb cleaner all over the carbs and boots and cannot find an air leak, but upon spraying the head gasket area the bike idles up. At some point in the past a previous owner looks to have started a head removal, as a nut in the rear is missing and two washers under the domed top nuts are gone, so I'm pretty damn sure this is the result of that previous attempt.

I did first attempt to re torque the nuts, and replaced the missing bolt, but it had no affect, still getting too much air. Can't figute out how to upload pics off the iPhone, so I'll try putting them in my profile. The gasket surface is a bit dirty, the piston heads needs cleaned, but the front head studs are quite rusty and the sleeves around them are crumbling. Is this "normal" on a bike this old with 36k miles? Gonna start the process of cleaning while waiting for the new gaskets.

Compression test showed:

#1 - 90
#2 - 105
#3 - 120
#4 - 100

Number 3 cylinder is the only one that cooperates with the colortune. Number 1 won't fire until either choke or throttle is used, and 2 and 4 just show blue no matter how rich I set the mixture.

 

You pulled the head? You'll probably want to (at the very least) lap the valves and replace the valve stem seals while you have it apart.

 

Yeah, head is off. Been looking at valve lapping tutorials online. Doesn't appear to be any oil making is past the valve seals, but I'd hate to have it start happening in a couple thousand miles so I figured it'd be good to lap and replace valves seals while the head is off.
The surrounds around the front studs are crumbling apart, and the studs are a bit rusty towards the bottom. This a sign of something, or fairly common with a bike of this age?

 

Had the head checked at a machine shop today; it's warped. Having it machined.

 

Which model do you have? I bought everything (including the stud sleeves) from Chacal/Len when I did a top end rebuild on mine. You'll need a heat source; preferably a heat gun (I carefully used a not recommended bbq grill torch). Some members used electrical shrink wrap. Note: The length of the sleeves are critical to the fitment of the head. I don't remember any of the rear studs getting sleeves. Also, the two oil transfer seals and copper washers must be properly located or the head will leak. Hope this help.

Gary H.

 

Believe it's an H model, but not 100%. I'm in the process of ordering the copper washers, orings and one replacement sleeve from Chacal. I guess I'm not following on the heat gun and shrink wrap. You talking about putting shrink wrap around the studs, under the sleeves?

 

No. The sleeves you get from Chacal will need to be heat shrunk to the studs same as the o.e.m's were. I read in other threads members used shrink wrap in place of the sleeves.

Gary H.

Edit: Over night Seafoam bath and brass brushing works great for removing carbon build-up from valves and pistons.

 

Head gasket installed and the bike fires up and there are no leaks. Compression is consistently 120 on cylinders 1-3, and closer to 130 on cylinder 4, so that's good news at least. I did then put a bit of 20w 50, very slight amount, down each cylinder and rechecked. Compression results shot way up, 210-220 per cylinder. Could this be due simply to the heavy oil I'm using to wet check, or does it also indicate my rings are in needs of maintenance as well?

 

The first compression test was fine. Imo you need to blow some of the oil out the holes then take it for a good spin to burn out the rest (it'll smoke a bit) then re-do the test.

Gary H.