The Kat is POPPING badly

[79XS11F]

I just got back from a quick 10 KM test run with the 750 Katana and WOW .. she is really backfiring badly on down shifts and when the throttle is let off quickly. I am very sure this is going to prove to be exhaust system leaks because the system is a "slip" together setup. The type that uses springs to hold the sections together.
So for those who also have similar set ups .. What are you doing to seal the header pipes to the exhaust port pieces and same question for between the header pipes section and the muffler?
Rob

[olebiker]

I thought that when a bike does that it means that there is more fuel in the exhaust than there should be.

[79XS11F]

That can also happen ole biker but this bike is running a 4 into 1 header with no carb changes. I would hazard to guess that if anything it is likely running lean.
I need to seal the exhaust system up before I move on to the next step in finding the cause. If I have to I will wrap the joints with heavy alloy tape and see what happens.

On a different note .. WOW ... make that WOW!!! . .what a scrunched up position to be in to ride this bike. i was sure bot hips were going to pop out of the sockets LOL LOL. The bike sounds NICE but has NOTHING over my 11 in the acceleration department.
Rob

[AlanB]

Hi Rob,

It can be difficult to seal the collector, but usually, if you get the joint at the head sealed, the popping is not too bad.

AlanB

[olebiker]

Rob that is kinda cool to think that the Katana is not gonna wipe out your 11.

[79XS11F]

Originally posted by AlanB
Hi Rob,

It can be difficult to seal the collector, but usually, if you get the joint at the head sealed, the popping is not too bad.

AlanB

Hey Allen .. The way these pipe hook up at the head is that they have separate collars that bolt onto the head with gaskets and then the header pipes slid into those collars. That's where the worst of the leaking is happening.
Rob

[79XS11F]

Originally posted by olebiker
Rob that is kinda cool to think that the Katana is not gonna wipe out your 11.

Not the restored 11 and not the hopped one that's for sure.
Rob

[AlanB]

Hi Rob,

We ran that style of pipes on our race Laverdas, and they were a bitch to seal!..... We had a roll of "tarry, asbestos string"...... I have no idea what it was originally meant for, or where we got it, but that did an OK job; it was wound into the groove in the collar and then the pipe pushed in.

We also tended to use twists of lock-wire across the top of the springs to pull it tight into place. Half the trick is making sure that the pipe is pulled evenly into the head; most pipes have the springs only on the top, so the bottom is not held.

Best of luck!

AlanB

[egsols]

Hey Rob,

I've got a 4 into 1 Jardine on my '79. I was having a similar problem with the pipes leaking at the collector. Thought about sealing with clamps or tape or paste. Didn't need to. Apparently the pipes should have gone into the collector a lot more then they were.

What I ended doing was loosening all of the headers off at the head. This allowed me to refit the pipes into the collector. I got them all to go in a lot further. Once I was happy I had them in as far as they could go I retorqued the header bolts.

The difference was like night and day!