Carburetor setup

[BobAndren]

Hello Folks, I guess that I'd classify as a new member as having only visited the site about 7 years ago to verify that the CB750 I was about to buy was indeed a '69 sandcast model.  Indeed it was and the bike, a total mess,  was put in the restoration queue. Two years ago, it had moved close to the front so I pulled (or rather dropped) the motor and sent it up to Vic World to work his magic. I might add that the machine is in SoCal, where I spend the Winter/Spring months so I only get 6 months per year to work on the projects out here. The rest of the year is spent in Rhode Island, where another set of bike projects are to be found.  Anyway, the motor returned last "season" and by then, I'd disassembled the rest of the bike and sent various parts out for painting, powder coating, plating, polishing, etc plus ordered up numerous needed parts.  Normally, we'd be back in RI by now but Mr Covid has made the prospect of travel somewhat unpleasant still so we're still in SoCal.  This, however, has allowed me to begin the enjoyable process of re-assembling the motorcycle (with nice clean, shiny refurbished or new parts).  The bike sits now as a rolling chassis.  The carb bodies are assembled and mounted as a bank on that long bracket , with the chokes connected.  Now, I want to set the throttle stop screws.  The workshop manual says the following: "Adjust the throttle stop screw to align the "T" mark to the index mark stamped on the carburetor body. Perform adjustment on all carburetors."  That's all well and good but one can align the marks every revolution of the throttle stop screw. Can someone clarify this for me. Also, another question.  I've found just about all of the parts I've needed from JT Marks, David Silver, or Yamiya.  Are there other parts sources that I should be aware of?    Thanks, Bob Andren

[kp]

Welcome Bob and enjoy the reading. Lots of info here for sure. Also good to see another sandcast recovered.
In relation to parts purchases, I believe Yamiya is way cheaper than anyone only issue is he doesn't have everything needed so next port of call for me is Partzilla Webike in Japan and of course eBay. The rest of them you can take your pick really but remember that a good number of genuine Honda parts are not like the originals. Examples are cables, pan head screws, peg/kick start rubbers and the like. I know it's not always easy but try and keep the original parts and restore them is my only thought or at least keep them for comparison. Mark's 97 and Sam's builds are a good start for any restorer. Later

[Sam]

Hi Bob!

The manual's comment about aligning the T-mark is really only to get you started. The better way to get going with the carbs i to bench sync them and then dial them in on the bike when it is running. Perhaps you have already bench synced carbs before. If not, the general idea to to put everything at their factory settings and to get the slides as equal as possible between the carbs. The common way to do that is to use a drill bit to measure the resting slide height (the distance between the carb body and the slide when the throttle is at the closed position) and repeat for all carbs resulting in the slides being set the same on each carb. Within reason, it doesnt matter what size bit you use. a 1/16 or 3/32 bit would be fine. Once you get the carbs on the bike and perform the sync on them, you can dial them in more exactly. Totally ok if your bench syncing results in an engine running at too high of an RPM. Just lower each slide by the same amount and then get them synced.

These carbs are tricky until they aren't!

You have three excellent parts sources listed there. If those three or ebay dont work, you can always reach out to the community here to get help finding the part you are looking for.

Welcome to the forum!

[jaka]

Hi!
CMS in Holland has lots of parts too!