As some know Im working on a 1989 CBR600 Hurricane. I did a bench sync of the carbs this weekend. This is what I did....
I used a .009 guitar string to adjust the number 3 butterfly opening. Then followed all the outboard carbs to follow spec using the adjustments between them. Doing number 4, then 2 then 1. After that I turned all A/F screws out to 3 1/2. It is clear that someone else has been in the carbs on cyl 3 & 4 because there are tool marks inside the bowls and number 4 was sealed with RTV. I did my best to clean out the jets but I think some new jets, to match the aftermarket exhaust I will be putting on is in order just for good measure.
However after all my tinkering the bike only fired up on cyl 1 and 2.
I pulled the plugs on 3 & 4 to verify it has spark. Its got great spark and the plugs are new. It also looks like the plugs have never received any fuel. As far as I can tell it *sounds* like it has compression and I will verify this over the weekend with a compression test.
Since the cams are driven from the center how often do they break on the right or left side? Im also thinking that if I drop the engine and take the valve cover off. I can see if the intake cam is broken on 3 & 4.
I also have a quick question. I noticed that there are machine screw holes without screws in them on the intake side of the block... I took pictures and if you follow the red lines you will see what I'm talking about. When I crank the bike, sometimes, it feels like there is air coming out of these but when it is running it doesnt. should I worry?
CAUTION... RUST Take measures to prep your eyes.... lol


Thoughts?
I used a .009 guitar string to adjust the number 3 butterfly opening. Then followed all the outboard carbs to follow spec using the adjustments between them. Doing number 4, then 2 then 1. After that I turned all A/F screws out to 3 1/2. It is clear that someone else has been in the carbs on cyl 3 & 4 because there are tool marks inside the bowls and number 4 was sealed with RTV. I did my best to clean out the jets but I think some new jets, to match the aftermarket exhaust I will be putting on is in order just for good measure.
However after all my tinkering the bike only fired up on cyl 1 and 2.
I pulled the plugs on 3 & 4 to verify it has spark. Its got great spark and the plugs are new. It also looks like the plugs have never received any fuel. As far as I can tell it *sounds* like it has compression and I will verify this over the weekend with a compression test.
Since the cams are driven from the center how often do they break on the right or left side? Im also thinking that if I drop the engine and take the valve cover off. I can see if the intake cam is broken on 3 & 4.
I also have a quick question. I noticed that there are machine screw holes without screws in them on the intake side of the block... I took pictures and if you follow the red lines you will see what I'm talking about. When I crank the bike, sometimes, it feels like there is air coming out of these but when it is running it doesnt. should I worry?
CAUTION... RUST Take measures to prep your eyes.... lol


Thoughts?