Mod: Straight manifolds on an Ambo

[TodkaVonic]

I saw a photo online of a heavily modified ambassador with straight manifolds. It kinda spoke to me. I liked the continuous line: velocity stack to carb to manifold to engine. And then, still in that line, exhaust out the front and swoosh! Back again below, but parallel, to the mufflers. It works.

I looked around and sourced a pair of straight manifolds from a vendor in Germany. I asked specifically if they would fit my VHB 29 carbs, oh, yes, no problem. So of course they did not fit. It�s never easy. Long story short, the outer diameter of the manifold needs to be 35mm to fit the carb sleeves my carbs are fitted with. The straight manifolds had an OD of 37mm. There used to be a Dellorto sleeve that would have accepted a 37mm OD manifold, but is long since discontinued. Options included having a machine shop modify the manifolds, making bespoke sleeves out of some sort of plastic, or finding some 35mm OD straight manifolds.

More internet searching and I found another straight manifold option for VHB carbs, also from Germany... and also 37mm. Boo! But the vendor was willing, for a fee, to shave off a couple mm. Yay! And these looked to be a lot nicer than the others anyway. They are aluminum with an access screw for synchronization too. Perfect.

Here she is all back together and running nicely.

[Turin]

Were those manifolds maybe intended for some bigger carbs? It's common practice to fit 36mm carbies to small valve heads (as long as you port the intakes  to remove ant lip).

[Antietam Classic Cycle]

Were those manifolds maybe intended for some bigger carbs? It's common practice to fit 36mm carbies to small valve heads (as long as you port the intakes  to remove ant lip).

They were meant for VHB 30s.

[TodkaVonic]

They were meant for VHB 30s.

Indeed. Do you foresee a problem with me using them on vhb29 carbs?

[AJ Huff]

Pretty!

-AJ

[Antietam Classic Cycle]

Indeed. Do you foresee a problem with me using them on vhb29 carbs?

No. There's a slight difference in inner diameter, but not enough to matter.

[Lesman]

Love the carbs/manifolds. Is it cool to hyjack your thread?
Did you paint your rear drive and transmission cases? What is your seat? What are your seat mounts?
What are your mufflers?

Is the sound of the carbs opening...loud? Your bike is really clean.

Best Regards,
Les

[TodkaVonic]

Love the carbs/manifolds. Is it cool to hyjack your thread?
Did you paint your rear drive and transmission cases? What is your seat? What are your seat mounts?
What are your mufflers?

Is the sound of the carbs opening...loud? Your bike is really clean.

Best Regards,
Les

Thanks Les! It turned into more of a cutting-out refurb than anything else. The ambassador is so pretty to begin with that taking elements away from it, even to tidy it up, wasn�t something I did lightly...and believe me there are parts (like the center stand) which I wish I could put back on :(

Did I paint the rear drive? No. I cleaned it then buffed it for hours and hours. I had the rear fork powder coated matte black.
The seat is from Harley Davidson, um, I think a knuckhead? I looked just now and I think it�s part 52004-25. There are new and reproduction models all over the net. The important thing was that the moumting bolt distance matched the Ambo. The seat mounts, at the rear, are simple hardware store chrome spacers. At the front, I used a seat mount/hinge made by TC bros (sku 106-0002) which you can attach to the frame through the existing mounting/pivot point.
The mufflers are from MGCYCLE. They�re the Mistral slashbacks. Not cheap, but they sound fantastic.

As for the carb sound, it�s not appreciably different now with the straight manifolds than it was with the original curved ones. I can�t really comment on their sound vs the non-velocity stack/more oem filtered set-up since I basically bought the bike, rode it home, and took it all apart.

Glad to answer (or try to answer) any additional questions you may have!

Nate

[Fireflyr]

I really didn't need to see this at this point in my build.  The PO of my Eldorado had said that he had built a bobber Ambassador and I was having a hard time picturing it.  You've done a great job!  I tried the straight intakes on my PHF30 / T3 and the filters ended up in my shins.  I eventually went with a pair of angled intakes but lost the ability to use the stock sidecovers.  It's amazing how one mod can have a compounded affect.
Interesting that to get that look nothing had to be chopped.  It's all reversible if you change your mind.  Beautiful bike.