rear exhaust is leaking, what is the best way to fix?

Started by coinsrus, June 11, 2018, 01:32:53 AM

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coinsrus

Been a while since I have been here.  Bike is running good, starts easy, Got rid of the gel cell bat and put in a featherweight lithium battery.  Now it starts easy and no problems with power.  Still haven't put the fairing on yet. I've got this problem with the rear exhaust it won't stop leaking.  Could use some help.  Thanks

Walt_M.

Good that you have the battery under control. Some people worry about the lithium batteries but I have one in my RZ, no problem for over 4 years. As for your exhaust leak, it could be a couple of things. If it's leaking at the exhaust port, you can get new crush gaskets. Yamaha may still stock them but one of the forum members, Blake, got a hundred of them and will let you have them for shipping. If the leak is at the junction, which is more likely, you will have to find serviceable replacement washers. They get flame cut very quickly if they come loose and will never stop leaking. They are NLA new and you will have to source used ones that are not flame cut. Happy hunting. 
Whale oil beef hooked!

cvincer


You don't say where the leak is, but I presume at the  'Y'  fitting for the rear cylinder.

I cured my problems at this joint by using  High Temp (red) silicon sealer.

Rikugun

For reference, this is what the parts in question look like. The part that Walt referenced as being no longer available is marked "A". If the joint has been loose and leaking, the chrome rings marked "D" may also be damaged.

Part "E" fits into the head and there is a crush washer ahead of it which is not pictured. That crush gasket may still be available new but not the other.
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

fret not

I recall John Clemens explaining his method of eliminating leaks.  He said to leave things a bit loose but all parts in place, block the muffler up against the bottom of the under side of the bike and THEN tighten all the joints and connections.  This is good advice for most things that have various connections and joints.
Retired, on the downhill slide. . . . . . . . still feels like going uphill!

QBS

After Johns' advice is followed, run the bike to fully hot and let cool.  Then retighten the long clamping allen head screws until they make a single snapping sound.  Then stop attempting to turn them.  Ride the bike as normal and repeat this procedure until the screws refuse to snap.  This will ensure that the clamping assembly is fully tightened.  My thinking in doing this is that I think that when the clamping system is really tight, the vibration and hot cold cycling can't cause the assemblys parts to rub against each other and allow the copper rings to loose their seal, which then leads to fatal silver disc flame cutting.

coinsrus

Thanks for your help guys! Its leaking where the ring marked A is.  I have tried to find those and no good so far.  Maybe  I will have to  try cvincer's  High Temp (red) silicon sealer.  Also loosen the exhaust system as fret not says, then retighten (as qbs suggested) it up and hope for the best keep my eye out for those donut gaskets.

coinsrus

Does anyone have the dimensions of the copper rings?  The nla marked "A".

Rikugun

The critical dimension is a tight fit on the OD of the "Wye pipe" - not marked in the picture but hopefully self explanatory.  :)  Measure the OD and look for a good fit. If the other dimensions are similar to the stock part hopefully it will work. EDIT: I think the ID of the copper rings may be about 25mm.

There was a member who made his own from copper wire of an appropriate diameter but I can't remember who and how he sealed the free ends. Anybody recall?
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

jefferson

A friend of mine found some copper rings at the auto parts store that worked. Just took a little bit of detective work.

coinsrus

Just wanted to let you guys know that I found those copper rings on ebay. Item #192340847071.  I was burned once before on these through ebay, so I didn't want to say anything till I have them in my hand.  Well I was happy to see they were right.
His page say he has more then 10 as of today. (7/01/2018)  So if anyone needs these, now is a good time to get them.  They were a little pricey, 17.95 a ring but shipping was good at 3.95.  He says they are nos, new old stock and he shows them in there original package, but when I got the one I ordered it was in a zip lock bag but it doesn't look like it has ever been installed, so I think they are good.  I only got one to make sure that he was selling the right thing.  Now that I know they are right I just ordered 3 more.  Two for the bike and two spares.  When you compare the new one to an old one they are a little fatter then the old one.  That's why I don't think they have ever been installed, they haven't been compressed down yet.  Maybe this will help others at rov to get some new stock on a nla item.
Hope this helps,
Mark

Rikugun

Based on the price I'd say the seller knows how rare and important they are. Glad you found them and hopefully this will correct the leak.
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

QBS

Coinsrus, thank you very much for the part resource referral.  Please keep us posted about your exhaust leak repair.

coinsrus

#13
I finally got the new gaskets from ebay on the bike, and I have no leaks now.  Those gaskets did work very well.  The old gaskets are just worn down, and to small work.  The new ones are bigger around, so when you tighten up the flange, the gasket can crush and fill the space.  I took some pix so you could see the difference.  The one with the flanges touching has the old gasket in it, and the pic. with the flanges not touching has the new ones in it.  So it is easy to see the difference.  hope this helps with anyone with this problem.