XS400 needles in my BS34's?

[kazdika]

I wasn't going to start a new thread but after reading and reading I'm still kinda stumped.

I guess I should start off with the details:
81 xs650 with BS34's
pods and exhaust
140 mains
45 pilots
mixture screw 2.5 turns out
Needles: Adjustable needles i think from an xs400. Moved needles up one notch (richer)

I think i have xs400 adjustable needles and not Canadian needles from mikes because according to the carb guide they are identical to the stock needles but result in a leaner upper midrange. Does anyone else have experience running xs400 needles?

So after riding and tuning and riding and tuning, my bike is still running too lean. Plugs are white. And it seems like its lacking power in the mid to top end. I bought a set of Canadian jet needles and needle jets but didn't install them because the needle clip fits too loose. The Canadian needle is narrower where the clips fits than the current needles i have. Ill probably end up buying new clips from mikes unless its ok that they are loose?

Anyways I installed 145 mains but never took er out on the road yet. I thought after all these adjustment I should start getting some color on my plugs. Just wanting to know if anyone else had similar problems as I'm having or had any advise.

Thanks

 

[5twins]

What is the number stamped on the needles you have and are they adjustable?

 

[kazdika]

Never noticed any number but I just took it apart again and seen 5IX11 on the needle and 336 Y-0 on the needle jet. F@ck me I shoulda looked I'm the first place!

So now I know I have the Canadian needle jet and jet needle, with the needle one notch up, why is it still lean?

The Canadian needles in my carb compared to mikes Canadian needles are slightly different. Same numbers, size and shape but different size of clip spacing.

My pic is not that clear. Mikes needle is on bottom

 

[5twins]

Yes, it looks like you have the genuine Canadian needles and needle jets. It's possible Mike's are reproductions and that's why your genuine Mikuni e-clip fits loosely in the slots. The section of needle above the clip slots does look different on the two but that part isn't important. It does sometimes vary between needles of the same number, even on genuine Mikuni needles. It doesn't do any fuel metering so apparently they aren't concerned about making it exact from needle to needle.

The needles shouldn't be the cause of your lean running. I would look for other causes like air leaks or improperly set floats. The BS34s are very picky about their float level settings. Your '81 should have the plastic floats. I would make sure they're set to 22mm at the most. Any more will make things leaner.

 

[kazdika]

Thanks 5twins.

Yes i forgot to mention i already set my plastic floats to 22mm, and rechecked them just to make sure. I shouldn't have any air leaks but ill check again.

 

[5twins]

When you measure your floats, you should take two measurements, one from each side. In other words, measure each "bulb". I've encountered quite a few float assemblies that are racked or twisted on their pivot bracket. This puts one "bulb" higher than the other. It's a simple matter to twist them back and make them equal again but you won't know if you have the problem unless you measure from both sides. If they are off and you only measured from one side, what you think your fuel level is probably isn't where it's really at.

 

[XSLeo]

You say "moved the needle up one slot"
Moving the clip up one slot would drop the needle, leaning the mix, moving the clip down one slot, lifts the needle, richening the mix.
So did you move the needle up or the clip up?
Leo

 

[aldo5468]

Always good to remember that 22mm is exactly 7/8" - it's really easy to pick up an inch scale instead of a metric one - not sayin' that I've ever done that, but ....

 

[kazdika]

Thanks everyone

I will check my floats to see if they are twisted. When I measured the floats it was from the inside of the gasket surface to the top of the float. And made sure that the pin wasn't compressed when I measured

I richened the needle. I raised the Needle up one, or in other words, lowered the clip down one.

I just had surgery on my leg the other day so ill give an update when I can get back out to the shop.

 

[XSLeo]

7/8 inch is .875 inches. 22mm is .86614 inches. Not exactly the same but close enough.
Leo