Just put a keyster kit through the carbs on my 89 3LN1, including new float needles, jets, emulsion tubes, needles. Not sure why but the seemingly accepted float height of 16mm was far too lean for my bike. Dropped it to 15mm, then 14mm and soon will be dropping another 1mm to 13mm. At 16mm it was pretty much unrideable, 15mm major hesitation coming off low revs or after changing gears, 14mm almost perfect with a hint of hesitation so hopefully 13mm is spot on. Maybe I'm just measuring the float height incorrectly or something else is up the **** However when the float height was 16mm the fuel level was around 9.something mm above the casting mark on the carb.
Have you got the needle circlips in the centre position? Above that is leaner and below that is richer.
Needle circlips in the middle position, with the two small shims under the centre 2 carb needles to raise it half a notch. I'm happy with how it runs just thought it was interesting Sent from my LG-H815 using Tapatalk
The float height is measured when the tang just touches the tip of the float valve needle. The spring loaded tip should not compress.
Also note that the float housing is held in position by the float bowl. To measure float height it is often advisable to reverse the bowl so you can use it to hold the float assembly fully home or remove the o-ring whilst setting the height. An example
pilot system set correctly? this sounds perplexing as the specs state 9.2mm fuel height for a 3LN1, 10.5mm for a 3ln3 onwards IIRC. Did you install the keyster kits to remedy intermittent chugging? If so, the other issue notwithstanding, did it cure the chugging? I've got 4 full sets for my carbs also, yet to install them though, one thing I did notice was that the needles aren't stamped with an I.D.
The pilot screws are at 2 turns out as stated in the manual (I think). Bike ran well before, except for being a bit thirsty for my liking, put the kits through just for the sake of it really Ill remeasure using that method maelstrom cheers
Before you drop or adjust the float level's again, I think 3 full turn's out is the base mixture screw setting, then warm up the bike to operating temperature and adjust them from there Turn in to lean and out to richen, and drop the idle speed if needed after adjusting each carby Make sure the airbox etc is fitted, air filter etc too I'm guessing running them at 2 turn's out is making it too lean, and would be causing your hesitation off idle
Rechecked the floats, the tip definetly wasn't compressed when I'm measuring, however the float hinge has a bit of play. Anyhow dropped the float level another mm and reset the pilot screws to 3 turns and she's mint Sent from my LG-H815 using Tapatalk
Well it is all good information. As more owners report their results the better for all. I know Ruckusman had new genuine Yamaha float needles in his 250 so that is another variable that we need to note.
The keyster needles also felt like the spring was a tad stronger, again another variable Sent from my LG-H815 using Tapatalk
When I used the keyster repair kit items on my carbs they were far different from OEM, I had to clean the OEM components and put them back in because the keyster components were way off the mark. That's just my 2 cents.
Is it okay if i check the float levels with the tangs resting on theh float valve but not compressing it or do we need to position the carbs as they would sit on the bike and then measure?? Lol confusing
In all my years of working on motorcycles I have never seen a float tang that was not parallel to the float arms. It is a function of design that the engineers would do this. Having a 'bent' tang would add to manufacturing complexity and introduce another possibility for error. Of course this is not to say that such a float assembly does not exist.
