Pod filter carb tuning

You lowered the needle clip/raised the needle one position? You have not taken it to redline yet?

Once I get my new coils I will let you know how my setup works. There are too many variables for me to bother listing my current setup.

Are the '81 carbs different from the '78? Yours is SOHC, right?

 

Do you have brass floats or rubber? Do you have o-rings/washers in your idle mix screws?

And you're SOHC, right?

Redline on my '78 is 9,250 rpms.

 

Weird, I wonder if my tach is original or if it was replaced at some point. Could it be that the redline was reduced for reliability reasons? Someone must know!

My redline starts at 9,250 and goes all the way to 12,000!

I also believe my stock mains are 137.5; it's crazy that you're not lean with such small mains.

 

9000 is the red line. Some of the earlier bikes are 9250. With my 80 carbs I use the 77-79 5Z1 needles and the x-4 needle jet they are richer and are adjustable unlike the 80-82 ones.

 

Thought I would share my setup. 1977 XS360. Original pilot was 17.5 and main was 135. I'm running Uni pods and a 2-1 exhaust with a Kerker canister. I now have a 20 pilot and 145 main. The needle was raised one slot and the mixture screws are out about 3 turns. Everything runs great, smooth at every throttle position.
I originally bought a jet kit on ebay because I didn't have time to figure out the jetting and I couldn't find pilot jets anywhere. The kit did not even include pilot jets and the mains they sent me were way too big. Finally have it running right.

 

What jet kit did you buy ?

 

I was wondering, would elevation have an effect on the jets I would need to purchase? I currently have 135 mains and 42.5 pilots but was just thinking of buying the same according to the this thread. I live in Salt Lake City, UT, and I'm probably riding at 8000 elevation. I know CHKM8 is located in Minnesota and we vary in elevation.
Also when you guys mention +1 or +2 on main or pilot what do you mean by that? Thanks!

 

The jet sizes go up in increments of 2.5

40, 42.5, 45, 47.5, etc.

+1 would be 1 increment higher than stock. Stock pilot jets are usually 42.5, so saying +1 means get the next larger size which happens to be 45 in this scenario. Saying +2 would refer to 2 sizes up; 47.5 in this example.

If we don't know what your exact jet size is, as in the mains because they vary a lot by year, we might just say go +1. You figure out what size you have an get the next larger one.

 

Thanks! I tried this but used 142.5 mains as I didn't have any 135s, it's much better, the PO had 55 for pilots and 155 for mains. The response is now super smooth right through the revs/throttle positions, it does break up at 7.5 K, like it's lean, should I go larger on the mains and/or raise the needle?

 

What needle clip are you on now. 77-79 carbs used third as factory. The 80-82 are nonadjustable and would need shims. 7.5k is more of an off needle and more main rpms.

 

I'm on the 2nd from the bottom, I've had a few sets of 80 and 81 carbs and they've all had adjustable needles, maybe they're different for the Canadian models?
It was breaking up much more wide open at around 6.5k

 

Try third as the fourth maybe to rich. Have you synced with a manometer?

 

What pods are you using. If you have emgos that maybe your problem. If they are on you factory H-pipe then that is not so bad but directly on the carbs that is not good. Uni's or REAL k&n filters (long and round ones) will tune much better. Just using the H-pipe helps a lot.

 

cool, I'll see if I can find a set of H pipes in my parts bins, I've been planning on ordering a set of Unis too

 

finally got some unis, my goodness what a difference, no more sputtering, the flat spot seems to have disappeared, I only checked on my short ride to work this morning