I just bought a 2012 Evo and it runs extremely lean. The pilot screw was set at one half turn out and I turned it to one quarter turn out and it's still lean. (I was told this was a fuel screw, but if I turn it out more than a half turn, it stalls.) I cleaned the carb, the bowl was full of crap, but none of the jets or ports seemed plugged. Put it back together and no improvement. Sprayed some brake cleaner under carb area and it stalled instantly.

After further inspection, I found two screws that hold the center cases together were loose. I cleaned off the case and can see a gap. It appears the center gasket has blown out or got sucked in. So, as a test, I squeezed a whole tube of RTV/silicone in the canal between the reed block and top of case.

I was going to test it today, but ended up with my car in the shop all day because the Toyota dealer can't figure out what's wrong with my radio, another tale of woe.

So, I'm jumping ahead I realize, but there is a question here:

Has anyone heard of this? Is it common?

Do you think I can leave it as is, assumming this works, or is splitting the cases the only way to fix it.

Since I just bought this and it has many issues, I'm going to talk with the previous owners, but it was an "AS IS" sale, so I don't have any expectations.

 

Sounds like you may be on it! See how it runs, but you already know how to fix it right!

Mutual friend Chris and I were immensely helpful laughing at the massive glob of sealant that grew on the back of the engine case.

Thanks Dan (and Chris) it was fun to have a peanut gallery so close by as I Frankensteined my new bike!

I rode it today and it goes great! It's like a whole different bike. So, I guess I'll ride it for a while and see if the bubble gum holds up.

Of course you know, it will let go right in the middle of an event!

Fix it properly ,what you've done won't last,at least it allows you to ride it to see if it needs anything else

I'll send you some high strength  pookey if you need it! The standard stuff may leak!

I'll send you some high strength  pookey if you need it! The standard stuff may leak!

Two rides and still running great. I'm thinking about riding the season and overhauling it next winter. That way I don't lose any riding time and I can fix anything else I break over the season.

CopeMech; what do you use for "High strength pooky"?

I considered liquid steel, but getting that off later will certainly be a nightmare!!!!

Fix it properly ,what you've done won't last,at least it allows you to ride it to see if it needs anything else

Agreed, thanks.

Just for the record, the silicone held up just fine for two and a half months.

I finally fixed it and have all the pictures here:

http://fulltilt.smugmug.com/Auto-Mechanics/2012-Beta-300-Evo-Center-Case/

http://fulltilt.smugmug.com/Auto-Mechanics/2012-Beta-300-Evo-Center-Case/

All the bolts were loose on the center case and it looks like someone has been in there before. So far, nobody will admit to having it apart, but I believe it was the lack of properly tightened bolts that caused the problem.

The centercase bolts on my 2012 300 Evo came loose, too. It happened after I sold it to a good friend of mine.

The centercase bolts on my 2012 300 Evo came loose, too. It happened after I sold it to a good friend of mine.

 

Thanks. Maybe it was common for that year?

 

Good question. I figured it was a weird fluke when it happened on my old bike, so to hear of another one having the same issue is pretty surprising. Owned a ton of motorcycles over the years, never had it happen on anything else.

washing bike before stripping engine must be a thing of the past

washing bike before stripping engine must be a thing of the past

 

That had bugged me too. I would have been scared to death that sand and crud would get somewhere it shouldnt be.