Smoothbore identification

BlackStar wrote:

...BTW I checked with Sudco this May on the jet block gaskets. They assured me they had them both via email and over the phone. It may be worth checking again?

Thank you for posting that information!

I don't think you will have luck finding the jet block gaskets at Sudco. If you find any, please advise as I was understanding they are not available and haven't been for years.

The issue with identifying smoothbores has come up a zillion times. From the side, they look pretty much like non-accelerator pump VM26s... If you have them off the bike, you will see additional castings on the intake side venturi edge that are unique to 29 smoothbores. The castings don't actually do anything... just look different. MOST smoothbores have a large drain plug on the bottom but some don't... those that don't have bowls that look about like a VM26.

The jet block that has been touted as a feature isn't really visible when the carbs are on the bike. If you raise the slides with the airbox or airfilters off, and take a look AND you know what you are looking for, you can spot the block inside the venturi. It ain't easy to see. I will attach a pic of a VM29 where you can see the large drains on the bottom and the extra casted holes on the intake venturi edge.

The VM33 is pretty unique looking and as Arai60 said, these carbs are hard to mistake. They have black painted caps held on by two screws and the caps are not shaped like other VM carbs. The bowls have large drains and there are extra (unnecessary) holes cast into the intake venturi. The carb bodies look a bit different as well since the sync mechanism is a different type than other VM carbs... they were NOT based on other VM carb designs as the 29s were... I need to take some good pics of the 33s as these will be on our website soon. The pic shown below is not some that came through our shop... just a pic I found.

Patton wrote:

BlackStar wrote:

...BTW I checked with Sudco this May on the jet block gaskets. They assured me they had them both via email and over the phone. It may be worth checking again?

Thank you for posting that information!

All I'm saying is that this is what I was told by Sudco. I did not confirm by ordering, but I did have them open the diagram and confirm because I heard they were not available. I decided to sell the carbs and go a different way (RS34's). Hopefully somebody can confirm this.

Damn! The piece of crap parts bike I bought a little while back has smoothbores!!!!! Thought they looked like it in the pictures but wasn't sure. Checked and sure enough. Need cleaned but looks like the bike just paid for itself.

The first pic is a Std. VM series carbs throat bore. Where the slide fits there is a concave area that disrupts the flow.
The second pic is a VM29 Smoothbore. The jet block fits inside the slide and smooths out the flow at the slide area.
Fish

The VM 29 smoothbore throat area.

thanks for all the info guys does anyone have a 29 smoothbore that has a good jet block in it. I have a set and am trying to locate one for parts, thanks keith