Replacing exhaust, smoke & backfiring....

[wirelessguy]

Some quick questions for the group.

My V&H 4-1 Street was rusted out and I've got a used V&H sidewinder in.
The megaphone with the sidewinder needs to be hammered out, so in the meantime I just fixed the existing street exhaust on for testing.

I tightened down the header but I'm not sure if it is in tight enough or seated right. After having something of a time getting the bike started (for the first time in about two weeks) I let her try to idle and she crept to 2000rpm (where I was 3500+ with choke on before the exhaust replacement).

When I shut the engine down I did see wisps of smoke coming out of the top of the header where it mounts into the engine. I had not replaced the seals but perhaps that might be wise considering I don't know what the PO did.

I assume the back pressure and mix is off and that could be why I did get one backfire while she was on. I wasn't able to twist the mix screw but I'm thinking that might be premature anyhow.

Anyone out there replace their exhaust? Any suggestions for me? I don't want to tighten too much but I do want to ensure it's mated properly.

Thanks.

Quick photo...

[spyug]

Well it sounds like you don't have the head pipes in right or you are missing the gaskets as there shouldn't be any leakage of exhaust.....duh (sorry you knew that of course). The backfiring is also an indicator of air infiltration from the exhaust side.

The V&H are going to run even leaner than stock exhausts so I think you may need to fatten up the jets to balance, unless of course the PO did that. You didn't mention the state of the carbs so I'd suggest that if not done already they be stripped dipped and fresh o-rings installed. No point in trying to tune the carbs if they are gungy inside and not performing correctly.

I wouldn't waste time trying to make things work with the stock system unless you intend on going that way. Install the V&H and clean and setup the carbs for them otherwise you're doing the work twice and likely going to get yourself frustrated.

Let us know how it works out.

Good luck,
Spyug

[wirelessguy]

Thanks for the reply. I'll go ahead and add exhaust gaskets to my laundry list of to-do items.

To answer the most important question, yes, this bike is turning into a sizable winter project for me and the carb job is on the list.

I've removed most of the panels, purchased a front fender and replacement gas tank (though my existing tank is fine) and will either do a paint job as careful as possible or try to farm it out if I can find someone capable that won't charge more than my bike is worth.

Carb job was going to be my main todo item but small things creep up, the rusted exhaust took me by surprise. The new exhaust apparently needs some sort of custom bracket made. To top it off, I'll need to bend or relocate the foot brake. Add in a new set of tired and poss, brake pads, & stainless cable and I just might be most of the way there.