Exhaust issues

Hi guys,

First of all let me introduce myself. I am from Romania and i own a xj650 Seca from 1982. Recently i have removed the exhaust for some cleaning and stuff. The problem is that after fitting and securing the exhaust the header from the first cylinder started leaking (i can feel the exhaust gases coming from the side of the header connection with the engine).
Also the previous owner has crashed the bike resulting in a bend in the 1st cylinder's header and maybe a broken seal.

Can this lead to a worse situation if it isn't fixed immediately (the parts for bikes like there are rare around here) or i can drive it in this state for about a month (the time needed to order and receive the exhaust rings)?

PS: After securely fitting the muffler to the collector pipe the bike started popping on deceleration. I have to go very easy on her when closing the throttle (while driving not on side stand)or i will unleash a thunder storm in the exhaust.

Thank you in advance for any advice

Regards Bogdan

 

there is a seal in the header - sometimes hard to see for the carbon but it is a large washer type of seal. Take it out and examine. If in good shape you can use some high temperature sealer on it. If not replace it. It is a fairly common size and should be available.

 

Actually, your supposed to replace the exhaust seals everytime you remove/install the headers. I have re-used the old ones with success, but you have to make sure you get a good tiight fit. In the case of a bent header however, I would replace those seals to get them to seal.

 

thank you for your answers but i have to wait approximately two weeks to get them (dealer or ebay), so will it be safe to drive the bike in this condition (could it cause any damage to the engine besides the poor performance?).

Cheers
Bogdan

 

If it's leaking at the pipe/head joint you could damage a valve.

 

uh. how?

just curious, because people say this constantly about cars too and it could hardly be further from the truth....

 

I would take one of the crush gaskets to an auto parts store and see if they can match them up with ones from an automobile (Nissan, Honda or Toyota maybe?) I found some for my Honda Shadow that are a direct replacement for the Honda gaskets and they are less than 1/2 the price. I think I paid $2 or $3 each and Honda wanted $12 each. I never priced the yamaha ones however, but I'll be willing to bet you can get them cheaper somewhere else.

 

i am also curious about this because this is my daily rider and i really cannot let it go down.

 

The only thing I can figure is that if it's a bad enough leak, it could cause a lean condition, which can lead to a whole host of issues, valvetrain included... The common myth with cars is that little or no backpressure (be it from wide open pipes, or in the case of every performance engine I've built, open headers) will allow your valves to bend, but this is just not the case. I don't know when or how that particular tidbit of false information came about, but it's rampant in the drag racing world.

 

The myth is "backpressure," but that's a whole different discussion.

If you have an exhaust leak THAT close to a valve, an exhaust valve mind you, it can get enough COLD air rammed in there at speed to cause the valve to be unevenly heated/cooled and possibly stick or bend. It happened to me before I didn't just make it up.

 

Ok guys. I leave it be then until i can get my hands of the exhaust gaskets. Also i need to fix the header itself because it appears to be bent.
Thanks allot for the advices

 

No disrespect intended fitz, thats why i asked =) I figured you had first-hand experience and could clarify it for me. That makes perfect sense.

 

No offense taken my friend. It was another of those lessons learned "the hard way." The whole reason I posted is to hopefully save somebody else from learning the same way.

Remember the old adage about "if I only knew then what I know now..."

Like the "P" position below "lock" on the ignition switch...

Like the little marks that tell you a nut is REVERSE THREADED...

Like ALWAYS use a torque wrench especially threading steel into alumnium...

Like why they invented anti-seize compound...

Like what happens if you overtorque an o-ring sealed fitting...

Unfortunately none of these apply to women...

 

This indicates a lean condition, possibly from the exhaust leak, not sure how bad it is.
Once the leak is corrected if it still does this check into your tuning of the carbs.

 

Hey guys. i have asked my dad to help me with the headers as the were not straight and after fixing them - they weren't in line - the popping is gone. Still i have a hissing from near the headers as if the exhaust gas still leaks. The popping is gone and the bike pulls hard but the hissing is pretty annoying.

The exhaust is an after market model that was bought from Germany and when i removed it it had no crush gaskets whatsoever. My question is: "There are any after market exhaust systems that don't use crush gaskets to seal?"

Thx a lot guys,

Bogdan