I ran into a problem with my bike. It started running like crap at the end of last season, and I found out the intake was leaking between the manifold and the cylinder heads. I tested it by spraying ether based dieselstart at the manifold, and it was clear it leaked there. So I got hold of some new o-rings, and changed them. It didn't help, so now I've ordered some original ones from Yamaha. But I tried a few times, sometimes with leaks on the front cylinder and sometimes on the rear. But no matter which one was leaking, it was the rear one that shot long yellow flames out of the exhaust. I think I might have other issues too? Am I right? Does my carb need a finetuning too?
Any advice would be much appreciated, thanks

1st have to get rid of leaks before ya dive into carb. Use a little hymalar sealer . when you put the screws in, make sure none bind, very important,//// hand tighten in a criss cross pattern to shoulder of manifold. jiggle the manifold a hair if ya have to to keep from binding. once there, tighten by 1/4 turn at a time.

Thanks for your reply

My plan is to get rid of the intake leak first. I tried with sealer too, but still leaks. I really don't get it? And I checked the manifold ain't warped at the flanges - I'm nearly at my wit's end...
The original o-rings are just to make sure that THEY are what they are supposed to be...

But will an intake leak cause flames out of the exhaust? And always the rear - no matter which leaks?

Hairline cracked manifold maybe?

Thanks for your reply

I have checked that - no leaks when I spray dieselstart on the manifold - only between the manifold and head

remove the AIS if it is not done. could also be caused by an exhaust leak too.

The AIS is gone

I can't rule out the exhaust leak, but they've been on for 4 years? And I know for a fact, that I have an intake leak?

Like Erbman said, work on that leak first. It took me more than a few tries to get my leak fixed. You need to surface the flanges and then use Permatex Hylomar, not just any sealer. I'll paste a couple of other post below to give you some more info.

A Curt post on surfacing flanges...
"New manifold or not SURFACE THE FLANGES. The surface on stock manifolds suck use 300-400 wet or dry paper with cutting oil on the paper. Tape a 8x11 sheet to a perfectly flat surface like a glass table top or granite counter top. (Or a 12" square piece of tile. B Hold the flange that goes to the head FLAT and move in a figure 8 pattern until you see all the surface is shinny. Do both flanges and the wash clean with dish liquid and hot water dry the manifold and reinstall. The flange surface will look as good as the surface on the head so just make sure they are all real clean."

An old post by me...
"My advice on using the Hylomar: Spread it on the manifold flanges then lightly on the heads but don't assemble right away. Let it sit for 20-30 mins to let the solvent evaporate. Then put your o-rings into the grooves and bolt on the manifold. Be very careful putting the manifold in place. There's not a lot of room and the o-rings can slide out of the grooves. And don't over tighten the manifold screws. Snug them in an alternating pattern a little at a time. I bought the Hylomar at the local Oreillys Auto Parts."

Good luck!

Thanks for your reply

Do you have a link for the Permatex Hylomar? I need to see what it is to track it down over here in Denmark

The surfacing could very well be part of my problem? But I just figured that the o-ring IS the gasket/sealer, so that is supposed to do the trick? Of course the flanges are not supposed to be covered with junk, but not really there to seal?

manser wrote:
Thanks for your reply

Do you have a link for the Permatex Hylomar? I need to see what it is to track it down over here in Denmark

The surfacing could very well be part of my problem? But I just figured that the o-ring IS the gasket/sealer, so that is supposed to do the trick? Of course the flanges are not supposed to be covered with junk, but not really there to seal?

http://www.hylomarsealant.com/?kc=6NbrC&tsid=googleppc&gclid=CNOu69249qcCFQat7QodBRtMDA