i know this is a common problem, but has anybody ever actually completely cured it? i've tried new needles, viton tipped, super unleaded fuel, but they still stick now and again. tap the floatbowl of the carb and watch bubbles go up the fuel pipe towards the tap. the way i thought of fixing it was epoxy a tiny round magnet - the sort i use in my magnetic screwdriver - under the tang of the floats. even though the tang is brass, the magnet is strong enough to pull the spring pin down, so the float needle lifts off its seat. it works without epoxy on it [yet] and even works with the carb upside down. any other solutions out there? :umm:
cheers, gil.
round magnet fitted under tang - an old one:
(https://i.postimg.cc/x1yvhcx6/reedbuildz94.jpg) (https://postimages.org/)
some needles have small springs that wrap around the tang
I just had to pull the float bowls off my RZV and get my needle valves moving again.
Just put new ones in over a year ago (Mikuni)
Found that they were starting to corrode on the 4 edges of the needle that center the needle.
Cleaned off the corrosion and the bike is running good again.....for now.
Only way I can think to stop it is gas with no Ethanol....?
I have tried sea foam in the gas, and that obviously didn't help...
Same process for sticking float needles and carbs that want to weep fuel through the overflow: I take a q tip and a dab of Simichrome and polish the seat and the float needle valve. Then, I take very fine sand paper (600 grit or up) and polish the fins on the outside of the float needle.
I use Sta-Bil if they are going to sit for more than a couple of months.
Gross ball valves instead of needles. Big upgrade on gammas, might work for you
my year old TM32's will stick on occasion as well. well, the Rh one for soem reason. Its on a premix bike as well. 1st time ive had this issue on new stuff. Ive learned to start the bike then turn the fuel on after its running. the vibrations of the motor usually free it up. :twocents:
My nearly new Tm32s stick on occasion as well.
When they stick and a little vibration frees them up, it is often interference between the side wings (actually linear bearing surfaces) and the inside of the seat. Polishing both and removing any radial scratches should fix it.
Quote from: pidjones on August 06, 2021, 08:17:16 AM
When they stick and a little vibration frees them up, it is often interference between the side wings (actually linear bearing surfaces) and the inside of the seat. Polishing both and removing any radial scratches should fix it.
agreed. i was planning on polishing them up next time i had the carbs off. oddly, it only started happening a few weeks ago and only on the RH side. (for me).
What do you guys do to polish them? Ive heard of semichrome on a q-tip and stick it in a drill?
i just use mothers on a wadded up shop towel (blue) with a small allen wrench in the middle of it for support.
I start with 1200 grit silicon carbide and progress up to 7000 grit using 91% isopropyl to flush and keep the grit cutting. Make sure you polish the needle wings, too.
Grose Jets do work well. Unfortunately they are out of production.
thanks for all the answers and advice. i've sent for some wired float needles, which i know won't fit in my float needle seats, but i've got a set of needle files and plenty of fine grade wet n dry. the annoying thing is now i've got the engine running close to right it's getting to be a pig to start. the joys of nearly 50 year old 2 strokes i suppose :rolleyes:
cheers, gil.
p.s. i tried the magnets and they work perfectly at pulling the float needles down. just wish i could cure this hard to start problem. it did it now and again with the standard ypvs reeds in it and i thought the new dual stage carbon reeds would cure it - but no.