2007 Royal Star Venture

[rayzar52]

• carbs sinked and adjusted ,
•  
• starts and idles well ,
•  
• but has a stumblewhen cool ,
•  
• seems to go when it get realy warmed up or hard on the throttle. any ideas hard on the throttle 
•  

Item prefix:  carbs sinked and adjusted 

[M61A1MECH]

Check to see if the air boxes have been modified of if there are K&N filters installed. 

On my 2007 when I modified the airboxes, that is cut the holes larger, I  had a stumble on hard acceleration, I shimmed the needles, see the tech section for doing this, when I put K&N filters on the stumble came back and I had to re-shim the needles, that mostly got rid of it. The only way I got rid of it was to purchase a used pair of unmodified air boxes from Ebay.

May not be your problem, but easy to check for.

Also check that the diaphragms in the carbs are not damaged, some times they get pin holes in them

[N3FOL]

These machines like to run well when warmed up really good.  

[videoarizona]

Mine has done that since day 1. Cold blooded beastie 

I haven't concerned myself with it, just ride slow till she warms up. Only a few minutes for me...

[N3FOL]

I'm riding my '07 this week.  Even though the weather has been warmer during the days, the early morning rides are cooler.  I still remember the day I bought my '07 with only 3 miles on her and the shop mechanic told me as I was about to leave...he said, "Warm it up really good and don't lug the engine."

Edited May 29, 2023 by N3FOL

[ascaife01]

I have a 2007 RSV.  Once when I had the two front lowers removed, I rode down the road and the bike began to stumble, falter and almost shut off.  I quickly turned around and attempted to diagnose my perceived "carb" related problem.  After several attempts to locate, I simply placed the lowers back on and it ran fine.  My point is that the airflow was more direct on the breather when the lowers were removed and this was the cause of the stumble.  Getting too much air (or direct air) can cause the issue.

Edited June 13, 2023 by ascaife01

[N3FOL]

Interesting observation on the lowers.  FWIW, I don't intend to remove them at all whatever the season is.  Ride safe.  

[videoarizona]

Interesting. Agreed that air flow can be an issue.