carb hiccups

[Downer]

hey guys im getting carb hiccups when im in third fourth and fifth gear but only giving it about 1/4 throttle it sounds to me that i need to up the pilot one more can someone confirm this? i have bs38 one up on pilot 135 main and needle leaned one notch thanx again

 

[Downer]

Bump to the top

 

[Downer]

No one? 5 twins I know you gotta cure? Thanx in advance

 

[5twins]

Dialing in carbs is all about experimenting. Sure, try a larger pilot. I've dialed in a bunch of sets but here's what it takes to do that .....

If you're running straight pipes (which I think you are), you may never get it dialed in perfectly. Straight pipes just look good, they don't work very well. They rob low end and midrange power and, as I mentioned, can be very difficult to tune for. Before changing jets again, you might try moving the needle again. Try both directions, a step leaner and a step richer, to see what happens. That may point you in the right direction as far as choosing jet sizes goes.

 

[Downer]

Ok cool and thanx I'll give it a go I was just wondering if it was unheard of of going two up on pilots cause most threads people only go up one and get good results thanx again

 

[Derek]

Ok cool and thanx I'll give it a go I was just wondering if it was unheard of of going two up on pilots cause most threads people only go up one and get good results thanx again

What do you're plugs look like? What are you running for air filters?

These need to be considered also.

~ Derek

 

[Downer]

Uni filters and plugs look pretty good a little lean on the left just got rid of my popping on decel by screwing my air/ fuel screw out two turns so I guess I'm making a little progress the hiccups don't really affect much just trying to fine tune I guess

 

[5twins]

No, it's not unheard of to need two sizes up on the pilots, but as you mentioned, one size up works most of the time. Your stock mix screw setting is 1.5 turns out. The fact you need 2 turns, a richer setting, could be telling you a larger pilot is called for. Like I said, dialing in carbs is all about experimenting. I tried one, two, and three sizes up on my pilots when I was dialing the carbs in. Two sizes up was good until I rebuilt and ported the head. Then the bike liked one size up better.

 

[ippytattoo]

Not to hijack the thread but I started down the road of adapting carbs from a 2004 EX500 to my 81 xs. I had read several posts about it being a possibility with very little jetting changes. In fact one post I read said they went up 1 on the pilots and 1 or 2 down on the mains and it was running great. My endeavors have proven to be a little more complicated as of right now I am at 1 up on the pilots, 3 up on the mains and the needles shimmed 1mm. So every setup is going to be different and the only way to get it right is trial and error. Good luck and happy tuning.