I have 3 little "nipple" on the inlet of the carburator, on the head side.

Two are cap off, but the one on the cylinder 4 is open.



I removed the carb to clean them because I have a crank no-start.
Do I need to cap this off ?

Thanks

 

Those are the ports used when syncing the carbs. They have to be capped or the bike will not run correctly. Cylinder #1 has a screw instead of a cap but it has to be there also.

 

Thanks a lot !!

I will check for the cylinder one for sure,

It started to get worste and worste since I put too much oil in the K&N filter, and now it won't start. I think it's a good thing to clean it, but can this be the reason it started to get worste and worste

 

You're welcome. Without those capped off you have a giant vacuum leak and the bike will run erratically and very lean.

 

Thanks again! Can't wait to try it, also, do you know a good post to help me clean my carb ? I found one but it was for F2.

 

Ignore last message, I just found the Service Manual

 

The principals are the same. There are some great YouTube videos also. I'm not sure if he still has a channel or not but there was a guy called mrmaxstorey who has some awesome how to videos

 

If I run it like that without knowing for a "long" time, can I damaged this cylinder because it was running lean ?

 

There's also a member on here called idodirt. He's a f3 brainiac. He has some great carb posts.