Rexxis
Almost there...
I'm trying to jet my carbs for open intake/open exhaust plus a 750 kit and not having much success.
Early on I had no clue when it came to tuning carbs so all my jetting changes were going off of what I read on this forum. I had no baseline to start with bc my bike never ran before all the modifications were made. Carbs have been completely rebuilt using www.amckayltd.com/carbguide.pdf and are super clean inside. Everything has been given the once over, even needle jet o-rings and butterfly shaft seals replaced(OEM shaft seals)
When I first pulled my carbs apart, they had 135 mains and 27.5 pilots in them so I assumed they were the '78-'79 bs38's. To deal with my mods, I started bumping up on the pilots and mains and got it running decent with some bogging coming off the pilots through the early midrange but then it cleaned up and ran good the more I twisted. I didn't run it all the way to the top so I don't know if it ran strong at WOT or not. At that point I was using #30 pilots, with a #140 main.. I was 1 up on the pilots and 2 up on the mains, needles in slot 3, right in the middle. I don't remember where I had my mix screws, probably at factory for late 38's though, 2 1/4 out I'd bet.
But then 5twins tells me that my carbs are a set from '76-'77 and the man knows what he's talkin' abt so I start over, this time I went with original pilots (25) and two up on the mains(127.5) and leaned my needle a step(slot 2) with my mix screws 1 1/2 turns out. Now I can barely even get her to start, have to kick her 10-15 times.
I'm not running a tach and I pulled the internals early in my build, wish I hadn't done that. Hindsight is 20/20 and now I know to keep the tach useable till she's running strong, then you can take it off if you want.
Also, my carb gaskets are glued to the head but aren't glued to the manifolds(JBM's) b/c I have to take the manifolds off to get my carbs out. This could be an air leak but I haven't checked yet bc the f*@%er currently won't start. Is glueing the gasket to the manifolds a necessity or can I get by until everything is running strong? I don't know what else to do bc I am having to repeatedly take my carbs on and off and I can't afford new gaskets every time and I definitely can't scrape gaskets at every change and keep my sanity.
Looks like I might go back to the 30/140 set-up and try it with the clip in slot two this time, maybe that will help my previous midrange problem. I don't know though bc my plugs were black as night when looking at them while trying this setup, albeit my clip was still in slot three then. Anybody have any insight they can share?
I have been trying to get this thing tuned for two weeks now. This isn't even fun any more.
I'm wondering how does one tell the difference between '77 and '78 carbs just by looking?
Has anybody ran open intake and exhaust w the 750 kit? If so, what's your jetting???
Thanks guys.
Early on I had no clue when it came to tuning carbs so all my jetting changes were going off of what I read on this forum. I had no baseline to start with bc my bike never ran before all the modifications were made. Carbs have been completely rebuilt using www.amckayltd.com/carbguide.pdf and are super clean inside. Everything has been given the once over, even needle jet o-rings and butterfly shaft seals replaced(OEM shaft seals)
When I first pulled my carbs apart, they had 135 mains and 27.5 pilots in them so I assumed they were the '78-'79 bs38's. To deal with my mods, I started bumping up on the pilots and mains and got it running decent with some bogging coming off the pilots through the early midrange but then it cleaned up and ran good the more I twisted. I didn't run it all the way to the top so I don't know if it ran strong at WOT or not. At that point I was using #30 pilots, with a #140 main.. I was 1 up on the pilots and 2 up on the mains, needles in slot 3, right in the middle. I don't remember where I had my mix screws, probably at factory for late 38's though, 2 1/4 out I'd bet.
But then 5twins tells me that my carbs are a set from '76-'77 and the man knows what he's talkin' abt so I start over, this time I went with original pilots (25) and two up on the mains(127.5) and leaned my needle a step(slot 2) with my mix screws 1 1/2 turns out. Now I can barely even get her to start, have to kick her 10-15 times.
Here's the thread: http://www.xs650.com/forum/showthread.php?t=21117That's not a '78-'79 carb set. From the looks of it, it's a '76-'77 set.
I'm not running a tach and I pulled the internals early in my build, wish I hadn't done that. Hindsight is 20/20 and now I know to keep the tach useable till she's running strong, then you can take it off if you want.
Also, my carb gaskets are glued to the head but aren't glued to the manifolds(JBM's) b/c I have to take the manifolds off to get my carbs out. This could be an air leak but I haven't checked yet bc the f*@%er currently won't start. Is glueing the gasket to the manifolds a necessity or can I get by until everything is running strong? I don't know what else to do bc I am having to repeatedly take my carbs on and off and I can't afford new gaskets every time and I definitely can't scrape gaskets at every change and keep my sanity.
Looks like I might go back to the 30/140 set-up and try it with the clip in slot two this time, maybe that will help my previous midrange problem. I don't know though bc my plugs were black as night when looking at them while trying this setup, albeit my clip was still in slot three then. Anybody have any insight they can share?
I have been trying to get this thing tuned for two weeks now. This isn't even fun any more.
I'm wondering how does one tell the difference between '77 and '78 carbs just by looking?
Has anybody ran open intake and exhaust w the 750 kit? If so, what's your jetting???
Thanks guys.