Headcover fit from new models? Update!
 

Do the headcover from 1998mod fit my 93mod, what changes was made on the next engine? Is it any point changing only headcover or is it best changing cylinder/headcover in one unit for best fit?

The Rocker box and head should be replaced as a matched pair. I know some on eBay sell them separate, but this is not good. The cam bearing function is the combination of the two and should be matching to assure a proper clearance. You "MIGHT" be able to get by, but do you want to take a chance?

My opinion, I am sure others will jump in...

I do not know if the 89 head will fit the later model.

Yep what Steve said , the head and cover go together unless you remachine the bores together like I had to on one of mine. I'm sure quite a few can be swapped around, depending on how Yamaha original located the parts when machining them, but it would be a crap shoot.

Still have the oil leak huh? Maybe it's the head itself that has a flaw.

Ok i understand, yep leaking never stop. The strange thing is that i have located it to be beetween front and rear screw left side at the plug cap. I really dont see how only this small area can be uneven, stupid me came just now came up with the idea of measure if there is a gap when cover is on without sealent. How much can the sealent fill up?

I don't have a solution short of replacing the head and rockerbox as a pair but I had a similar problem with an 82 HONDA XL500. I understand this is quite common with that model as they do not have enough bolts to evenly hold the rocker box in place. I tried several times using different sealer, letting it sit for days to dry and NOTHING solved it. I later sold it on and next owner replaced the head and rocker box to solve it....

Steve

Sort of sounding like maybe the faces are not flat or at some point in past its had something jammed in to lever it off maybe?
If you can find someone clever they maybe able to machine the mating faces of the head and camhousing flat then take the bore then bolt both together and remachine the hole the camshaft runs in to the correct size..
Alternatively the machinist may say 'what are you sodding around with bloody old rubbish for?'....trouble is some of this bloody old rubbish tends to keep working long after some newer stuff has deceased..
I'd say your options are machining or another head and cam housing..

Never have been any problem with leak before, bike has 35000km and the only reason i did the seal because of the O ring leaked on the side of cover. I had an idea, what if i just put minimum of sealent around the cover and add some more where the leak problem is? Just thinking adding even around gives no help in a problem area, does it sound way out? Or maybe iam wrong and there problem is a high spot that makes the seal go away in that area, next time i will put the cover back and try to get feeler gauge in there and check clearance.

A feeler gauge should let you know what your dealing with. It's just weird that one of the sealants didn't fix it, the oil isn't pressurized up there so it is just flung or running past that area. Nothing should be forcing it out.:confused1:

Ok, have been out for hours and testing, checking every 15min around the engine with paper all around. And i think i have found the reason, the oil never came out on idle, i think i found a crack. Its strange that oil can come out in the top like that, but i guess in high speed it get sucked out. Oil was coming down to the sealent at the same spot every time when riding down hill, so i have fooled myself thinking its the sealent..

My big question now is, can i clean up this and use dremel to grind a little. Then use the alu stick over the area? please dont tell me i have to take cover off for welding? Iam just happy now for finding the leak:D:D

http://s18.postimg.org/dwosdkr21/DSC_0006.jpg
foto upload

http://s7.postimg.org/qx26thl2j/DSC_0008.jpg
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Take the mount plate off to gain good access to the area and grind a "V" groove the length of the crack on fill it all with JB Weld.

A true TIG aluminum welded fix would be best(take the cover offdoh), but the JB may just work.

I would have thought a leak from that area would show up in the back side of the cap not up by the front, sure there isn't more of a crack on the other side of that area?

Yeah the TIG was my fear hehe. I have the alustick so i think i give it a try, i have grinded i little as you see in pict just to check if its deeper. First it looked like just crack in top surface, isnt it strange that so mch oil can come out in the top of the cover after 2hours riding?

Is this possible to do on the cover?
https://www.youtube.com/watch?v=hHvrE1Cd5Eg

That is a stress point, the engine mount is flexing the crack, more so at speed. This means that you will have to have it professionally welded, hopefully it will not warp. If this were not a stressed area, you could seal it with JB weld. Expect the worst. Hope for the best. I expect a good heli arc welder can "fix" it. He may grind out a "V" as well, It would be best if you can soak the cover in solvent to get as much oil out as you can. If not, oil will try and seep out of the crack during welding, not good.

Steve

So you dont think that the alu stick can fix this? When we talk about heat, what is best for this, heat up to 350degrees for alustick or do TIG? Dont want anything else to get damaged, iam thinking its best doing this job with cover on engine so it wont bend heating.

This is the Alustick

http://www.ebay.com/sch/i.html?_sop=...ardweld&_frs=1

And how thick is alu at the point i want to fix? Seems strange if its only my engine that its happend to, hope someone else have done the repair.

Since this is a stress point, NOTHING short of a full aluminum weld will be strong enough. Engine torque will keep breaking the glue or weak weld. I don't think you can weld it on the engine due to the heat involved and the oil. You will most likely have to completely dismantle the rocker box, remove all the parts and seals as it will get very hot from the welding. Hopefully if the welder is good, he will preheat the whole piece then weld it and let it cool naturally, hopefully it will not warp.

Ok i understand, but what you mean by stresspoint? I think i will try with the wizard weld, this i can do with nothing removed. The temp on a TIG weld is extreme and iam more scared to damage the cover than not getting sealed. This engine monting is only for stability, its not like the engine is hanging after this monting. I was out riding now and had one hand on the engine on different rpm, cant even feel vibration.