setting floats

I'm having a hell of a time trying to set the floats on my carb. They're a Hitachi set for a 1981 xj 650. I've spent hours and hours trying set them. I started with the guess and check method then switched to using a set of calipers. Even with the calipers I'm having no luck, sometimes I can move the paddle up and the fuel level will increase others it will decrease. I'm endlessly going back and forth! Do you have any tips for setting these floats?

 

when you move the tab up towards the top of carb float sits lower = lower gas level

I use my caliper to measure the tab distance so that when i bend it I know how far I moved it
also measure float height before and after adjustment it will give you an idea on how much change you have done with the tab bend

what I mean is if your float is 1 mm closer to the top of the carb your fuel level is about 1 mm higher
which would mean the second float measurement is lower that the first.

and this is the hardest part of the carb rebuild



Setting the fuel levels

 

Are you using the clear tube to see the level?

What was your initial setting?

 

Yes I am using clear tube, initially they were all half full so approximately 13mm from the bottom of the carb body. Manual I have says 3mm +/-1mm from bottom edge of carb body

 

How I set mine turn carb upside down ( shinny cups down) take a 6 inch scale with metric markings measure the forward tip on the float from the base of carb Without gasket set to 17mm . Flip over put bowls back on fill and check level should be close to 3mm , may not be science , but my bike runs like new .

 

Initial setting is 17.5mm.....

 

Any chance your floats are upside down?

 

What are you using for you fuel supply?

 

I read the guide that XJ550H linked before I started, big help. I recommend checking it out if you're trying to set floats.

I emailed chacal for new jets and floats because i thought maybe I had deformed them and messed up the shape of the hole for the pin. I have a bad tendency to "throw parts at it" when I get frustrated. Since I had seen an o-ring in some of the ebay rebuild kits on ebay I asked him what this was for (idle air mixture screw replacement). He said, "I know that those (and many similar kits on eBay,, etc.) are cheap, but I know who makes them, and the needle/seat that comes with them are not really correct for the HSC32 or 33 series carbs, and you'll end up with float valves that will leak! We used to carry that manufacturer's kits until we discovered that they aren't really right for these carbs, I have no idea why they still offer them, it was a real nightmare for us. I decided to swap out the seemingly brand new jets with the floats and jets from a spare carb." **By the way, if you're looking for parts this is a great example of why you should buy from vendors on this sight rather than ebay"

So when I got home from work I swapped out the seemingly brand new jets that Ive been struggling with in the carb that Im going to be using with the old jets and floats from a spare carb. I had already robbed two floats from my parts carb so I am going to have to redo their spacing, but the other two sets were adjusted perfectly.

When checking fuel levels on the two bowls that measured adequately after the swap I noticed that the fuel flowed smoothly and had more of an abrupt stop as the floats reached their stopping point. With the jets that appeared to be brand new it would take 5 to 30 seconds for the fuel level to top out.

I believe that the jets that I have been having trouble with are to blame for erratic fuel level when trying to set the floats to the proper level.

Im going to go start fooling with the two floats that still need adjustment to see if I make any head way. Definitely going to try out the method of measuring the floats upside down!

Im having trouble with lights too so I might post another thread about such in the near future

 

Yes, those incorrect fuel inlet needles/seats are longer than the stock types, and what I think happens is that the needle can "seize" within the seat bore on it's way up (trying to close) and thus the inlet valve may never shut off. I think the extra length of the needle affects the geometry of the whole affair and you get a RANDOM overflow situation..............it took us the longest time to figure this out before we found a more suitable supplier (all of this happened about 5-6 years ago.....and like I said in the message to nilla, I don't know why the original mfg. hasn't corrected this issue, we told them about the problem (multiple times, too) a long time ago.........

 

A couple of years ago I had a XV750 virago been setting since 84 4500 miles bought it for 400$ .... carbs looked like peanut butter , got 2 K&L overhaul kits with jets...back cylinder pipe would glow orange, would cut out when slowing down . Burtnt up 2 starters (Virago curse) was reading in maual the kits I had had 122 jets...fine for 84 and up...BUT 83 and down used front cylinder 124 rear 132.... put new jets in and holy cow it ran great pulled like a freight train... just sounded like a box of gravel rolling around when starting. Learned a few tricks on the starter lol.