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Old 07-28-2008, 09:22 PM   #16
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I would check to see if the piston is scored on the side .

Check to see if you are getting tank slop , add a fuel filter in line with the pressure hose from the pipe.. if you are getting the flame out on the corner at the end of the straight ...

Check to see if your brake shoes are not binding onto your fly wheel..

Check the chassis braces , if they have come loose the chassis will cause the clutch bell and C Diff to bind ...

Crank Case cracks are common on the OS

Rear bearing faliure is common on the OS

Rod faliure is common on the OS

Check these faults ..

any debris in the HSN or fuel line can cause this ..

Hope these help..
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Old 07-28-2008, 09:23 PM   #17
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Quote:
Originally Posted by jpalessi View Post
+1 this is a common problem with the v spec..
What plug are you running?, What state are you in?, What pipe?, What carb stack? If theres no leaks, it's either your setup/tune
P3 Plugs only
JP-3 Pipe
Running in Arizona at the Nitro Pit
Stock Carb Stack.. the bigger opening


Well... I just checked the clutch and the clutch looks really good. All springs working fine, very little ware.

I looked in the exhaust hole at the top of the piston and it's shiney looking as new, so no build up.

I looked close at the exterior of the case with a bright flashlight and didn't see cracks... I'll have to look inside if cleaning the needles and replaces the exhaust seals don't work.

I'm going to order new pipe seals first. When you put the pipe on there is enough slop you can wiggle it side to side, so I hope thats the problem. However not many here seems to think that is the cause of my symtoms and that has me worried.

Quote:
My first thought was "con rod." Check the con rod bushing for slop, even though you only have a gallon on it. (Break in is hard on them!) They're only like $25-30 for the V-SPEC, so it isn't a huge cost to replace if that IS the issue.
How do you check the con rod for slop?

I'm timid about doing surgery on my engine as I am new, but I have to start somewhere and I do want to learn all there is to know.


Suggestions??
On what steps I should take to begin my troubleshooting... ideally from easy solutions to the more difficult I assume?



Thanks everyone I really think the people on this forum awsome.
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Old 07-28-2008, 09:49 PM   #18
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Quote:
Originally Posted by Don Duct View Post
P3 Plugs only
JP-3 Pipe
Running in Arizona at the Nitro Pit
Stock Carb Stack.. the bigger opening


Well... I just checked the clutch and the clutch looks really good. All springs working fine, very little ware.

I looked in the exhaust hole at the top of the piston and it's shiney looking as new, so no build up.

I looked close at the exterior of the case with a bright flashlight and didn't see cracks... I'll have to look inside if cleaning the needles and replaces the exhaust seals don't work.

I'm going to order new pipe seals first. When you put the pipe on there is enough slop you can wiggle it side to side, so I hope thats the problem. However not many here seems to think that is the cause of my symtoms and that has me worried.



How do you check the con rod for slop?

I'm timid about doing surgery on my engine as I am new, but I have to start somewhere and I do want to learn all there is to know.


Suggestions??
On what steps I should take to begin my troubleshooting... ideally from easy solutions to the more difficult I assume?



Thanks everyone I really think the people on this forum awsome.
you prob need to lean out the bottom end about a 1/4 turn. I always ran my v specs about 230 -255.. it sounds to me like your loading up on the infield and even more at idle. Leave the idle at 1-1/2 turns from fully closed and then lean the bottom end to stabilize the idle. Out in AZ you should prob run a OS P4 plug, it's colder then the P3. so running the P4 you'll also require a leaner setting. Good luck.
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Old 07-29-2008, 12:31 AM   #19
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Rich LSN sounds like something to dig into.

Last edited by desertbird; 07-29-2008 at 08:30 AM.
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Old 07-29-2008, 06:13 PM   #20
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dont box tune!!!
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Old 07-29-2008, 08:19 PM   #21
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Quote:
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dont box tune!!!
Yup, not good. Best to tune on the track.

It was running rich at the bottom end. Leaned that out quite a bit. After full throttle it kicks down to a nice idle after 6 seconds. Before when the bottom end was rich it took 15 seconds to kick down to a level idle.

I just ordered new gaskets. Should be here in a week or so. I'll let everyone know what I find out.

-Don
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Old 07-29-2008, 08:37 PM   #22
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Don,

Seal the carb and the back plate, reset your needle to stock settings and start the tune over. Sometimes that's all it takes.

Did you check the front bearing to see if there is any leaks?

I'll be at the pit on Saturday and we can tune it then.

Tom
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Old 07-29-2008, 09:40 PM   #23
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Check to make sure there's not any debris floating around in your pipe like a piece of the gasket your going to replace. I've seen that happen, it will cause random flamouts like you described.
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Old 07-30-2008, 12:48 AM   #24
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Quote:
Originally Posted by Don Duct View Post
P3 Plugs only
JP-3 Pipe
Running in Arizona at the Nitro Pit
Stock Carb Stack.. the bigger opening


Well... I just checked the clutch and the clutch looks really good. All springs working fine, very little ware.

I looked in the exhaust hole at the top of the piston and it's shiney looking as new, so no build up.

I looked close at the exterior of the case with a bright flashlight and didn't see cracks... I'll have to look inside if cleaning the needles and replaces the exhaust seals don't work.

I'm going to order new pipe seals first. When you put the pipe on there is enough slop you can wiggle it side to side, so I hope thats the problem. However not many here seems to think that is the cause of my symtoms and that has me worried.



How do you check the con rod for slop?

I'm timid about doing surgery on my engine as I am new, but I have to start somewhere and I do want to learn all there is to know.


Suggestions??
On what steps I should take to begin my troubleshooting... ideally from easy solutions to the more difficult I assume?



Thanks everyone I really think the people on this forum awsome.
Well make sure your idle set screw is isn't turning and moving on you. Slamming the slide shut killing the motor. I had an OS I used a small amount of thread lock on cause the screw would rotate on its own. Then I second the idea too that,
the clutch shoes are dragging too and intermittently killing your motor. Change the bearings maybe they are oblong and you cant tell and the bell is wobbling ??
Oh and Off topic here but something I do, keep a roll of plumbers Teflon tape in your box, has been a life saver for me when the seals get loose and you don't have another set of manifold and pipe seals around. Just wrap the existing seal to a nice snug fit.
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Old 07-30-2008, 03:52 AM   #25
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dont bother with anything else just replace the rod and i bet your problems will be solved. when the vspec rod gets slop it causes the engine to flame out. replace the rod seal the backplate and you should be good to go
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Old 07-30-2008, 05:00 AM   #26
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shim your engine to 0.9mm and use a p3 plug and your problems will be fixed.there is no way you have alot of slop on the conrod after a simple gallon.
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Old 07-30-2008, 10:40 AM   #27
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it might not be the motor at all did you check the tank for any cracks on it ormaybe youre fuelline is ripped somewhere my friends motor was doing the same thing and it turned out his tank was broken .
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Old 08-16-2008, 01:32 AM   #28
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Well everyone, I wanted to give you an update on the actual cause...

A few of you said hairline crack... and if you did you would be correct.

CWalters described it DEAD ON. I just didn't have the trained eye to see it before.

I want to thank everyone here, and a special thanks to the crew at the Nitro Pit who are such a great bunch of people willing to spend time and help out. www.nitropit.com

The guys at the Nitro pit was able to find the crack and show me what it looked like. It was exactly where CWalters said it was...


Quote:
Originally Posted by cwalters View Post
Funny how you describe your problems with your VSpec... Mine gave me the same issues and all at pretty bad times. I tried a new tank, fuel line, plug, pipe and exhaust gaskets and still had the same problems.

Found a hairline crack in the engine case above the motor mounting tab on the side. Very visible on the inside of the engine but hard to see on the outside. Problems started at the 1 gallon mark, but I spent the entire next half gallon trying to diagnose the problem.

Problem #2 is that O.S. doesn't seem to want to stand behind the issue. I've heard that they have a new updated engine case now and carb. Mine is the previous (with the longer backplate screws).

Leaves me a little disturbed, now I've got a brand new Vspec that is useless without a new $100 case... But check that, I almost needed a magnifying glass to see mine...
I also did find out that there is a chance OS will replace my case. A few guys at the Nitro Pit had cracked cases with little as a gallon though them and OS did replace their case. I'm going to give it a try and I will let you know if they did replace the case for me.

-Don
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Old 08-16-2008, 07:37 AM   #29
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Sorry to hear that Don. You should have a new case, so this shouldn't been a problem.

Anyway, if you need a motor until you get a new one, you can run one of mine.

Tom
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Old 08-16-2008, 08:51 AM   #30
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That is the reason i stopped running OS motors. I had 3, 2 vspec and 1 speed get the crack in 1 piece motor mounts.

I am surprised now one mentioned an obvious possibility. FUEL. you live in AZ, as i live in NV. the heat were we live kills fuel.
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