Another VM26 Question(s)

I have read about everything I can get my hands on regarding adjusting these carbs after a rebuild including the service manual and a search here on the forum. My first somewhat unanswered question regards the initial bench sync of the carb slides. When you insert the gap tool to set the slide to bore gap I assume this is done from the engine side of the carb correct? My second question regards doing a second carb sync. If a second slide sync is done the engine would have to be running, so is this accomplished with a CarbTune or vacuum gauge? Lastly (?) a final carb adjustment is made using the Carb Tune and adjusting the pilot screw and when doing this adjustment are you looking for highest rpm? Thanks for any info regarding my questions.

Rick H.

Yes, vacuum sync after the carbs are installed. Carb Tune is the best. Adjust the pilot air screws to achieve the highest idle speed.

Hello,

Answer to First Question: Yes , it is done on the engine side of the carbs. You can also use a wire that is around 1 mm in diameter.
Answer to Second Question: Yes, after doing a bench sync and the engine is still running rough at idle you will need to do a vacuum sync with a warmed up engine. If a good idle is not achieved you might need to check valve clearance and engine compression.
Answer to third Question: I don't fully understand your third question, Sorry.

Please read over this document for more detailed instructions: members.dslextreme.com/users/bikecliff/i.../vm_carb_rebuild.pdf

Ok guys. I think I have it. First step is to bench sync the slides to the bore for initial gap. Second step is to put the carbs on the bike and fire it up, then do the same process you did on the bench, but using a Carb Tune or something similar trying to adjust slides for same reading across the board on Carb Tune correct? Then when that process is completed you go back and adjust pilot screws for highest rpm then adjust main idle screw for final idle. Does this sound about right? For some reason it didn't dawn on me that you re-sync the carb slides on the bike with engine running. I thought it wasn't needed after you bench synced them.

Rick H.

Thanks for the article Your_Boy_Yuriy. Lot of good stuff in it. Going through a "wet test" of the fuel bowl level is having the level about even with the bottom of the carb body acceptable or too high? All the fuel levels about very close to the picture I have attached. Thanks...

Rick H.

Generally, the fuel level is near the bottom of the carb body, as yours is. However, the factory service manual has the correct height listed in it. It would be much less frustrating to get it exactly right now, than to have to pull the carbs again and redo the adjustments.

The level should be 3-4 mm below that edge. They tend to be high for some reason though. Maybe the float needle spring gets weak? Anyway, I adjust them to be in spec because nothing worse than gas spilling on the engine and ground.

So they are all a bit high I take it. I was trying to find a good reference point for the level. I will bring them down a bit.

Rick H.

Rick h I recently built this in about 20 minuets. Mounted the carb rack to it then I set it on my bench and used bar clamps and shims to level the carbs. I just went thru a float level adjustment. Used an old lawnmower tank for fuel supply. And the clear tube to set the floats. Have patience and be extermly careful with fuel. I put a shutoff in the fuel line and filled the bowls, checked the level, drained the bowls, bent the float tang and repeated till all were set. It’s a PITA.