R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Nitro Off-Road

Reply
 
Thread Tools Search this Thread
Old 06-06-2007, 06:14 AM   #1
Tech Apprentice
 
Join Date: Apr 2007
Posts: 52
Trader Rating: 4 (100%+)
Default 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
cj.g is offline   Reply With Quote
Old 06-06-2007, 06:23 AM   #2
Tech Adept
 
Join Date: Jun 2006
Posts: 125
Default

mabey try a new glow plug
Garrison is offline   Reply With Quote
Old 06-06-2007, 06:32 AM   #3
Tech Regular
 
mbunker's Avatar
 
Join Date: Mar 2003
Location: Redding, CA
Posts: 427
Trader Rating: 29 (100%+)
Send a message via MSN to mbunker Send a message via Yahoo to mbunker
Default

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

Last edited by mbunker; 06-06-2007 at 06:35 AM. Reason: spelling
mbunker is offline   Reply With Quote
Old 06-06-2007, 09:19 AM   #4
Tech Apprentice
 
Join Date: Apr 2007
Posts: 52
Trader Rating: 4 (100%+)
Default

Quote:
Originally Posted by Garrison View Post
mabey try a new glow plug
tried, new glow plug does not solve the problem...thanks anyway
cj.g is offline   Reply With Quote
Old 06-06-2007, 09:22 AM   #5
Tech Apprentice
 
Join Date: Apr 2007
Posts: 52
Trader Rating: 4 (100%+)
Default

Quote:
Originally Posted by mbunker View Post
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
Thanks Michael, will try it when I run the buggy next time...
cj.g is offline   Reply With Quote
Old 06-06-2007, 04:35 PM   #6
Tech Regular
 
Join Date: Oct 2006
Location: Browns Plains,Queensland
Posts: 484
Default

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)
__________________
www.pinehillsdirtracing.com...MUGEN MBX7R with TEKNO V4 conversion.....TEKIN RX8 GEN2 esc HOBBYWING motor 2200kv.....
pitdog is offline   Reply With Quote
Old 06-08-2007, 02:41 AM   #7
Tech Master
 
vti-chris's Avatar
 
Join Date: Jan 2005
Location: Cyprus
Posts: 1,075
Trader Rating: 3 (100%+)
Default

Most likely to be the main bearing!
vti-chris is offline   Reply With Quote
Old 06-08-2007, 06:47 AM   #8
Tech Regular
 
mbunker's Avatar
 
Join Date: Mar 2003
Location: Redding, CA
Posts: 427
Trader Rating: 29 (100%+)
Send a message via MSN to mbunker Send a message via Yahoo to mbunker
Default

Quote:
Originally Posted by vti-chris View Post
Most likely to be the main bearing!
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

Last edited by mbunker; 06-08-2007 at 06:53 AM. Reason: added
mbunker is offline   Reply With Quote
Old 06-11-2007, 06:25 AM   #9
Tech Addict
 
slow coach's Avatar
 
Join Date: Oct 2003
Location: guernsey C.I.
Posts: 626
Default

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
slow coach is offline   Reply With Quote
Old 06-11-2007, 01:36 PM   #10
Tech Master
 
RBMike's Avatar
 
Join Date: Jan 2007
Location: Santa Clara CA
Posts: 1,264
Default

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.
RBMike is offline   Reply With Quote
Old 06-11-2007, 04:18 PM   #11
Tech Addict
 
associatedguy's Avatar
 
Join Date: Oct 2004
Posts: 714
Trader Rating: 8 (100%+)
Default

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.
associatedguy is offline   Reply With Quote
Old 06-12-2007, 10:17 PM   #12
Tech Addict
 
patrick21x's Avatar
 
Join Date: May 2007
Location: Orange County CA
Posts: 674
Trader Rating: 58 (100%+)
Send a message via Yahoo to patrick21x
Default Optimum running TEMP

My VSpec runs best at 230-250 Deg. Is that too hot, I am worried it is. What are others temp coming in at ? and what are others Neeedle setting at optimun running? Any tips would be greatly Appreciated
patrick21x is offline   Reply With Quote
Old 06-13-2007, 05:45 AM   #13
Tech Elite
 
Join Date: May 2003
Posts: 2,820
Default

I usually tune on power and smoke. Some engines just run a little hotter. I usually don't even blink at 260.
Homer Allman is offline   Reply With Quote
Old 06-14-2007, 06:12 AM   #14
Tech Regular
 
Dan Reino's Avatar
 
Join Date: May 2007
Posts: 411
Trader Rating: 2 (100%+)
Default

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!!!!!!
Dan Reino is offline   Reply With Quote
Old 06-14-2007, 05:35 PM   #15
Tech Elite
 
Jason Halvorson's Avatar
 
Join Date: Apr 2007
Location: Grand Forks ND
Posts: 3,955
Trader Rating: 22 (100%+)
Send a message via AIM to Jason Halvorson Send a message via MSN to Jason Halvorson
Default

boy really pushing that rocket science fuel arnt we????
Jason Halvorson is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
opinions please! which is better the o.s speed vspec or the eb modded vspec? downunder23 Offroad Nitro Engine Forum 23 11-29-2015 02:37 PM
RB .15 VSpec Squackyrc Australia For Sale/Trade 0 08-21-2008 05:23 AM
FS: EB Mod OS Vspec BH R/C Items: For Sale/Trade 4 10-18-2007 07:00 AM
NIB 07 EB Mod VSpec Cyberacer R/C Items: For Sale/Trade 4 09-13-2007 06:51 PM
NIB 07 VSPEC....$245 ckt111 R/C Items: For Sale/Trade 5 08-30-2007 05:38 PM



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off



All times are GMT -7. It is currently 02:03 AM.


Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net