Exhaust Back Pressure

[fl9018]

I recently finished rebuilding a 84" panhead with a CV carburetor and stock ignition system of points and condenser. At the time of start up I had a free flowing exhaust system on it. Since then I put on 600 trouble free miles. Over the winter I installed a replica stock exhaust system that is considerably quieter than the previous exhaust set up. As it stands now, it pops when cold, stalls out at a stop and it stubborn to restart when stalled. My question is, do I need to re-jet the carb because of the increased back pressure?

[RooDog]

Got pictures of both exhausts?

[awander]

If you went from open pipes to a "stock" system with a muffler, chances are you do need to change the carburetor settings.

[fl9018]

Here are the pics as requested.

[RooDog]

Only 1/2 the pics... What does the "stock " pipe look like?
Are those over sized 2" pipes?

[panheadrider1961]

If uncertain easy test would be take off muffler if symptoms gone back to drawing board

[fl9018]

Here is a larger picture (hopefully) of my bike with the current exhaust set-up. Stock and custom are the 1-3/4" diameter pipes. I may have to try running it without the muffler to narrow down the symptoms. Good idea.

[nifty]

My 2c, check for intake leaks including block-off vac-cap & diaphragm of CV, then re-adjust/re-jet if and as required

Nifty

[Andygears]

Check back over the points & timing, with 600 miles, breaking in, they may have moved or pitted. And you may have a little too much advance for the milder exhaust.

Andygears

[fl9018]

Thanks for all the tips. I did check the points and timing. I checked for vacuum leaks. What I discovered is the there was some sediment in the float bowl which put me onto the path of the pilot and main jet. After cleaning all these items, I put it it all back together. The moment of truth came when it fired up on one kick and without popping. After taking a brief ride getting it up to temp, I shut it off to re-start. It fired up on one kick. Amazing how a piece of crud can ruin a day.

[texasbobber]

That's a good looking motorcycle. How is your CV carb jetted, on the 84" panhead?

[RooDog]

I ran a CV on my 90 inch Shovelhead and it did well. I don't remember the jetting.
....RooDog....

[kitabel]

There is no back pressure at idle