Carb tune done with Cobra Slip ons

[sdt354]

Ok. Little update. Finally got some main jets and time to install a set. I bought 147.5s and 145s. Installed the 147.5s yesterday and ran out of time to test drive it. Had to leave for work. I just took the bike for a ride and it still does the same thing and I really feel that it is worse. Having a hard time understanding how/why there is no improvement. Seeing as I went down 2 jet sizes. Gonna let the bike cool down to pull the plugs and check the color of them before I head to bed for work. I will install and try out the 145s. But after what I seen with the 147.5s my hopes aren't high.

I think your concentrating on the wrong circuit. The off idle and mid range seem to be issues. 147.5 mains should be fine. Maybe better with 145's, but not an issue at 3-5k. All slides are moving freely? Diaphragms in good shape and in the groove correctly. Slides aren't previously drilled out? I'm wondering if the bike had a different set of carbs, or a removed stage 1-7 kit, shortly before you bought it?

 

[ItsDuckie]

Slides move freely and are installed correctly and diaphragms are in good shape. How would I be able to tell if it previously had a stage 1 or 7 kit installed? As I've stated. Bike idles great. Runs fine up to 45mph in fifth gear. 50mph+ and 5k+ rpm is where it studders and lunges. Not sure if it clears up past like 8krpm as I am already doing like 75-80mph at that point. I will admit I did not sync the carbs after I installed the 147.5 mains. I will do that when weather isn't so crappy and see if that changes anything.

 

[ItsDuckie]

Well, figured I would shot a quick update. Haven't really had a lot of time lately to fully devote time to the bike. Took a few minutes today to check wet float levels. Leveled the bike with a couple boards under the kickstand. (No lift right now) Used about a 4 inch piece of tube and lined the end of the clear tube with the line on the carb for all 4. Looks like they are all about 2-4MM to high. Looks like the dry float setting may not be a good ref. point for my max. So looks like I will have to start the painstaking task of setting the wet float level. I am hoping I can just take the carbs apart. Position carbs so the float is just on the valve the bend up the tab 2 maybe 3 MM more and it will be good. Does anyone have any objections to that idea?

Thanks
David

 

[ItsDuckie]

Another update. I got around to changing the mains again while at work last night. Dropped them down to 145s. Tried to take the bike on the highway and could barely manage 65mph. Got off on the first exit. Pulled over and stuff a rag in one half of the "V" on the air box. Rode it around on the roads a bit, then got back on the highway. The studdering is gone.... I can take the darn thing all the way to 95 with no problems. So What The Heck..... Guess I should have gone the other way with main jets?

 

[Traumahawk]

It sounds like your getting too much air. I wonder if someone changed the primary air jets before you bought the bike?

 

[ItsDuckie]

I am pretty sure all jet sizes are what the book says my year should have. It is a stock bike (as far as I know) except for an OEM style KN filter and the cobra slip ons.


And please excuse my ignorance. But I thought the PAJs were only idle circuit and up to when the slides moves? The point at which the slides begin to move and beyond is where I was having my problems. Bike ran perfect 3.5k and below.

 

[ItsDuckie]

To eliminate the rag and get this thing running without it. Should I go up a couple sizes from the stock 152.5 to 157.5 or at least 155? I am sorry for all this, carbs are just not my thing really. Guess I should look for "Carburetors for Dummies". Haha