2010 Problem (cam cover leak)

I'm not sure why you would think that would be a fix for your problem at all. The gasket around the plug hole is torn down the center as a result of too little clearance between the cover and head when bolted down, causing the gasket to compress to an excess and split.

I agree, I did the same thing as him initially because I had read it on here that it was "the" fix, but ended up ripping another gasket in 20 hr's or so. This last time I just torqued the valve cover bolts a little less to take off some pressure. Seems to be lasting longer now but not a sure fix until i get more hours on the bike. Both times the gasket failed it was very warm out as well.

Ok I repaired my valve cover gasket. Here is what I know. My gasket was torn in 2 spots, 1- around the spark plug, 2- The bridge piece between breather and valve train. I was at a friends house and did not right down the exact #s, so sorry for that, but I did take a digital caliper to the old gasket, my new gasket and my friends new gasket that was bought some time ago. My torn gasket and my friends new but purchased some time ago gasket measured approx. 5.15mm thick at spark plug circle. My new bought this week gasket measured 4.8 ishmm thick at the spark plug circle. Also my new purchased this week gasket has a different part # than my friends purchased some time ago gasket. So it seems Yamaha is aware of the problem and has produced a gasket that is thinner in hopes that it will not squish out under pressure. I have run the bike but not ridden it yet, so far so good.:thumbsup: On a side note, I would think torque has little to do with the problem as the bolts are shouldered...:smirk:

t I did take a digital caliper to the old gasket, my new gasket and my friends new gasket that was bought some time ago. My torn gasket and my friends new but purchased some time ago gasket measured approx. 5.15mm thick at spark plug circle. My new bought this week gasket measured 4.8 ishmm thick at the spark plug circle. Also my new purchased this week gasket has a different part # than my friends purchased some time ago gasket. So it seems Yamaha is aware of the problem and has produced a gasket that is thinner in hopes that it will not squish out under pressure.

The old (5.15mm thick) part number is 3D-11193-00-00, and the new part number (4.85mm) is 3D-11193-00-01. Looking at online fiche, the old part # has been superseded with the new, thinner, gasket.

Edited by andy250
spelling

I checked it today and it does have a little tear in it im going to order a new gasket tomorrow.

I'm not sure why you would think that would be a fix for your problem at all. The gasket around the plug hole is torn down the center as a result of too little clearance between the cover and head when bolted down, causing the gasket to compress to an excess and split.

Gray,

After the initial failure the bike had another 50 hours put on it and the same mod has been done on three other yz 450's (2 2010's & 1 2011) with no failures.

I think that the failure is due to excessive heat in that area as the area that failed on the first bike was directly in the path of the spray off the inboard exhaust cam lobe and with more airflow in the valve cover there would be less heat.

I didn't invent the mod, I was told by an engine builder that this was the thing to do, regardless the mod would not cause any problems if it were not successful so what is the harm?

I know it works, this is my last post on the subject.

Gray,

After the initial failure the bike had another 50 hours put on it and the same mod has been done on three other yz 450's (2 2010's & 1 2011) with no failures.

I think that the failure is due to excessive heat in that area as the area that failed on the first bike was directly in the path of the spray off the inboard exhaust cam lobe and with more airflow in the valve cover there would be less heat.

I didn't invent the mod, I was told by an engine builder that this was the thing to do, regardless the mod would not cause any problems if it were not successful so what is the harm?

I know it works, this is my last post on the subject.

Very well, but the mod you did reduces the efficacy of the baffling placed in the crankcase vent path to cure the tendency that the older models had to blow oil out of the breather, so it directly interferes with an engineered improvement.

In any case, the gasket shown was obviously split from excess compression, based on my professional experience with this king of thing, the info Andy posted below bears that out. You haven't had a recurrence of the problem because your new gasket cured it.

The old (5.15mm thick) part number is 3D-11193-00-00, and the new part number (4.85mm) is 3D-11193-00-01. Looking at online fiche, the old part # been superseded with the new, thinner, gasket.

Same issue for me. My 3rd just blew. Onto my fourth. Whats up with this?. Not every bike has the issue, as my mates 450f has had no probs. Any ideas why some are giving out?. It cant be the gaskets (bad batch etc), as it would have a wider impact. My mechanic has checked that everything is square, no sharp edges etc, and everything is torqed correctly. Even tried the silicon sealant to be sure. Still no fix. Its now a very expensive problem.....My last one blew in near freezing conditions in the rain, so im not sure that heat has anything to do with it. Has anyone in Australia had any luck getting Yamaha to provide a new gasket.?

Same issue for me. My 3rd just blew. Onto my fourth. Whats up with this?. Not every bike has the issue, as my mates 450f has had no probs. Any ideas why some are giving out?. It cant be the gaskets (bad batch etc), as it would have a wider impact. My mechanic has checked that everything is square, no sharp edges etc, and everything is torqed correctly. Even tried the silicon sealant to be sure. Still no fix. Its now a very expensive problem.....My last one blew in near freezing conditions in the rain, so im not sure that heat has anything to do with it. Has anyone in Australia had any luck getting Yamaha to provide a new gasket.?

When buying replacement gaskets, are you getting the new, thinner version?

Be sure that next time you get the 3D-11193-01-00, NOT the 3D-11193-00-00.

(maybe the replacement gaskets you've bought were the old p/n; thicker and more prone to failure . . .)

Edited by grayracer513
correction of part number

Yeah. Thats a possability. I havnt checked the part number in the past, but will onthe next one....

The updated gasket will have 2 ribs on the gasket instead of three.

mine just let go at about 30 hours...

Same around 30 hours started noticing oil spitting from the hole on the right side of the cylinder. Does anyone have the part number for the gasket?

I looked it up and the part number is 33D-11193-01-00

Any 2011's with this problem? I'll check out my gasket when I go to check the valves next time.

i have 2011 50+ hrs no leaks except the fork seal which have been done twice.

so has anyone had the problem with the new part number gasket or a 2011?

well, I got some good news today, Yamaha has agreed to cover the repair for me.

just got done dropping my bike off at my dealer..

Mine just went too at 47hrs. Yamaha admitted the fault but said 47hrs was too many to repair at their cost so the dealership i got the bike through came to the party and gave me the gasket!!

The cover is bolted down with 3 bolts which have shoulders on them so that they can only run down so far. This allows the bolts to be run down and tightened in a solid, metal-to-metal manner while the clamping force on the gasket is specifically limited. The problem was that the original gasket was too thick, or the bolt shoulders too short, or the cover machined wrong, however you want to see it, but anyway, the gasket ended up being clamped too tightly and was splitting from the pressure.

Yamaha could have cured this in a number of different ways, but they chose retooling the gasket because that fix could also be retrofit to all the previously built units as well, and would be the first thing someone who was not aware of the problem history would replace if they found it on their own.

Be sure the replacement gasket has the current PN: 33D-11193-01-00

I did the repair myself i was a little worried about it but its still holding together. Now 5th gear is going out had it at Sharps Motorsports in Amarillo Tx for 2 months and the only thing they did to it was put new grips and a chain and sprocket. Probably the worst service ive ever had im just going to have one of my mechanic buddies do it. He is going to play with the engine a little and make it go extra fast cant wait till its done!!!

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