O.S. .21 VZB VSpec
06-06-2007, 06:14 AM
#1
O.S. .21 VZB VSpec
Hi all,
I have an OS Vspec, the engine ran just fine but occasionally stalls, so during the last buggy clean-up, I dismantled the air filter and tuned pipe, clean the outer engine thoroughly...and re-adjust the throttle opening at idling.
Today I had a run of the buggy and the engine starts without problem at first crank, but no matter how I tune the engine, occasionally it stalls too...I re-read the Vspec manual and it covers on how to reset the high-speed needle to factory setting which is on the richer side...
How do I know the factory setting of the Mixture Control Screw and Metering needle? I'd prefer I can re-tune the setting to something more stable at idling.
thanks
I have an OS Vspec, the engine ran just fine but occasionally stalls, so during the last buggy clean-up, I dismantled the air filter and tuned pipe, clean the outer engine thoroughly...and re-adjust the throttle opening at idling.
Today I had a run of the buggy and the engine starts without problem at first crank, but no matter how I tune the engine, occasionally it stalls too...I re-read the Vspec manual and it covers on how to reset the high-speed needle to factory setting which is on the richer side...
How do I know the factory setting of the Mixture Control Screw and Metering needle? I'd prefer I can re-tune the setting to something more stable at idling.
thanks
06-06-2007, 06:23 AM
#2
Tech Adept
mabey try a new glow plug
06-06-2007, 06:32 AM
#3
I had the exact same problem about a week or two ago. I was convinct it was an air leak so I replaced all the o-rings in the carb and motor back plate but it still would stall after about a minute of running. No matter what I changed the high or low speed needle too. It turns out that the mid-speed needle (mixture control needle) has to be set dead on before the others can be adjusted. Now even thought the OS manual says make the screw head flush with the carb body and then turn it in 1 complete turn, I found mine only runs when the head of the screw is flush with the body of the carb. Also I sealed the motor backplate and carb with gasket sealant to be sure that was and issue. Finally got my motor to run until it could come up to temp, then adjusted my high and low speed needles to optimium tune.
Hope this helps some.
Michael Bunker
Hope this helps some.
Michael Bunker
Last edited by mbunker; 06-06-2007 at 06:35 AM. Reason: spelling
06-06-2007, 09:19 AM
#4
06-06-2007, 09:22 AM
#5
I had the exact same problem about a week or two ago. I was convinct it was an air leak so I replaced all the o-rings in the carb and motor back plate but it still would stall after about a minute of running. No matter what I changed the high or low speed needle too. It turns out that the mid-speed needle (mixture control needle) has to be set dead on before the others can be adjusted. Now even thought the OS manual says make the screw head flush with the carb body and then turn it in 1 complete turn, I found mine only runs when the head of the screw is flush with the body of the carb. Also I sealed the motor backplate and carb with gasket sealant to be sure that was and issue. Finally got my motor to run until it could come up to temp, then adjusted my high and low speed needles to optimium tune.
Hope this helps some.
Michael Bunker
Hope this helps some.
Michael Bunker
06-06-2007, 04:35 PM
#6
Tech Regular
a racer at the last club meet had the same problem and got it fixed with a mach 21 carb(my v-spec done a main bearing with only 10 litres and now i`ll only use novarossi)
06-08-2007, 02:41 AM
#7
Most likely to be the main bearing!
06-08-2007, 06:47 AM
#8
Oh ya, I replaced the front and rear bearing too with TKO units from A-main but it was still having the problem after they were replaced. So unless you hear any bad noises coming from your bearings, I would continue to check the metering needle position.
Michael
Michael
Last edited by mbunker; 06-08-2007 at 06:53 AM. Reason: added
06-11-2007, 06:25 AM
#9
I run a V-Spec and have none of these problems whatsoever, on initial start up motor runs rich and i manually rev it to warm it up pre race, once up to temp it runs fine nice and clean and will sit and idle for 40+ sec without a hiccup, if you turn in the mid speed jet remember to turn out the bottom jet the exact same amount or it will run lean, once set i have hardly touched it at all just seems to run and run, a couple of guys have built basic rolling roads using small freight rollers 40-70mm dia (more drag with bigger roller) which seem quite good for getting engine in ball park for settings, if in doubt richen everything up a good full turn and start again you never know 
06-11-2007, 01:36 PM
#10
When the main bearing goes on a V-spec you will hear a rattle when the engine is idling, sounds like a screw is loose kind of. If you have no strange noise then keep looing at the carb tune.
06-11-2007, 04:18 PM
#11
You're going to need a whole new carb. On my v-spec carb, the side that the HSN is on would twist like the seal was broken and that sounds like your problem. It would run fine and just stall out of the blue, so I put an rb carb on it and it runs great now.
06-13-2007, 05:45 AM
#13
I usually tune on power and smoke. Some engines just run a little hotter. I usually don't even blink at 260.
06-14-2007, 06:12 AM
#14
Patric, What fuel are you running. I have recently got alot of guys switched over to Rocket Science 30%, Much cooler temps than most fuels and better engine life........You get what you pay for........Why spend a ton on a great mill only to run poor fuel thru.......Rocket Science=220 with my v specs!!!!!!
