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Old 12-20-2008, 09:55 PM   #61
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Originally Posted by butch man View Post
To do a basic rod check take the back plate off, put the crank pin to either left or right side ,hold the flywheel & try to move the rod up & down on the crank pin. If you see the rod is sloppy on the pin its bad.By sloppy I mean if you can decern movement between the 2 or you see oil/fuel squeeze out between the 2 thats too much. Of course being a v-spec it could also be a worn crank pin. Think of it this way,at 40,000rpm the rod goes up at balistic speed,comes to a dead stop,then is jerked down about a hundred times in the time it takes you to blink. It dont take a lot of slop to cause problem in that scenario. You also said you took the motor completely apart, did the rod just fall off the crank pin by when you turned the motor on its ass or did you have to actually have to pull the rod off the crank. Off & on with no resistance is bad. I have no idea if thats your problem just awnsering your how to ?
Thanks butch man will def check that when i get a chance.

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Are you sure the long side of the piston skirt is facing the exhaust?
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Hi jonro

Generally a Vspec if ok is the easiest engine to tune and just runs like a swiss watch. You do however get the problem ones. Yours is a problem engine.

Personall I work on lots of engines and have sorted out most of them. Some you just use a paperweight.

IMO I think from what you described the carb is your problem. Remember a nitro engine is just metal put together. To get it to perform and run well thats where the carb comes in. You confirmed no issues with bearings etc.
Check under the carb for the black metal rubber coated washer. remove you carb and try another carb. This will immediately tell you a story.
Also importantly, Vspec are sensitive to fuel. Ensure good qaulity fuel as a starter. Ive seen many guys struggle with Vspecs only to discover that they were using bad fuel.

Hope this helps.
JB
Unfortunately i don't have another carb apart from the one that's in my grp, so i cant perform that test. But i will be ordering a different brand of fuel and will def try that. TY for the help.

This may sound crazy, but every time i try and tune this engine i always put the needles back at factory settings and start from there. This time i will do the same but instead of leaning the LSN as normal i will go the other way and try richening it, hey? anythings worth a try at this point.

Thanks for all the reply's, you fella's have been a big help. Keep em coming if you think of any more.

I actually think the V-spec is a very well designed and all around fantastic engine but i think O.S has poor QC because these engine are so massed produced. Im tempted to buy another one but im scared of getting another dud.

Just watching this video: http://www.youtube.com/watch?v=L9JSzc5UVW8 and seeing what these engine are capable of even in a TRUGGY makes me wanna hit the buy now button, but eh cant risk the 300 especially in this day and age with the economy the way it it.
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Last edited by Jonro; 12-20-2008 at 10:21 PM.
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Old 12-21-2008, 06:39 AM   #62
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Running nitrotane 30% with a os2060 pipe my carb settings are 2 1/4 out-HSN, flush to 1/4 turn in from flush -MID, and 1/2 turn in from flush -LSN. I didn't read all the replies so i might repeat something. Replace the fuel and pressure lines and try another tank if you have one. Take the pipe off, put your thumb on the end that goes on the engine, blow thru the outlet and make sure air comes out the pressure nipple ok. A fellow racer had this issue and it drove us nuts til he found it.
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Old 12-24-2008, 12:02 AM   #63
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Running nitrotane 30% with a os2060 pipe my carb settings are 2 1/4 out-HSN, flush to 1/4 turn in from flush -MID, and 1/2 turn in from flush -LSN. I didn't read all the replies so i might repeat something. Replace the fuel and pressure lines and try another tank if you have one. Take the pipe off, put your thumb on the end that goes on the engine, blow thru the outlet and make sure air comes out the pressure nipple ok. A fellow racer had this issue and it drove us nuts til he found it.
Thanks for the help.

Could a badly leaking but smooth running front bearing be the cause of a non existent bottom end/no response when tuning the LSN?
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Old 12-24-2008, 04:54 AM   #64
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if you have a bad front bearing it will make the motor run on the lean side, you would have to fatten it up on the top to get the temp down, which could cause the bottom to be like you described
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Old 12-24-2008, 05:47 AM   #65
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does it start off bogging or mid tank. yup, sounds like typical v-spec. lsn flush, and richen the top, lean to max performance till it bogs then back out to the last non-boggind spot. set idle with stop screw. if its hesitating on the bottom the hsn is lean a few hours. if it won't idle and fattens up open up idle stop all the way then back it down after a few runs where it idles consistent for 10 seconds then drops to 4 stroke. seen it many times. its cool cause with a shorter pressure line you can tune it to lean bog at the end of the tank every time. but just richen the hsn a bit for now and open up idle.
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Old 12-26-2008, 03:41 AM   #66
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Ok i pulled the engine down again and yes there is allot of play between the rod and crank pin. The brass bit in the rod is almost worn away, how can i tell if just changing out the rod for a new one will help or if the crank pin is worn too much also? The engine still has good top end and good compression so is it normal for the rod to wear so quick?

I also have a MRT GRP that has close to the same amount of wear on the rod end but it runs like a swiss watch, so eh i duno... I don't know weather ill bother with this engine as i could end up replacing the rod and it wont fix a thing.
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Old 12-26-2008, 11:10 PM   #67
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You can always do what I did. Buy the rod then find you need a new crank.HaHa. I had never heard of a crank pin wearing till my OS took a crap. Some shop on e-bay sells v-spec cranks from time to time for $55 US+$12 shipping + 3-4 week delivery. Is the run time & power worth the hassle? Right at 3 bills for the new ninja at carolinas right now or a hair over 2 for a Jammin almost anywhere on line.

http://www.carolinasrc.com/webstore/...idproduct=9820

http://www.amainhobbies.com/product_...ducts_id/11200
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Old 12-26-2008, 11:19 PM   #68
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Hmm
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Old 12-26-2008, 11:53 PM   #69
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Originally Posted by motomanpat View Post
How new is this engine? Did you buy it brand new and you are having this issue? If it is used at all it could be the rod. In my Vspec I had a similar problem but it was at about the 2 gallon mark.My rod started going away(I didn't know it at the time) and I was having a really hard time getting my low end to be right but it still ran and was pretty good down the straight but it kept stalling out and then I started tuning the mid,still no good! After that I went to a playday and was still having the same tuning issue so I started tuning again and then I heard a pop and it locked up. The bottom of the rod where the copper bushing is was totally trashed. Not sure if this is the same issue but if your motor has been used at all then it is something to think about since you still have pinch. Hope that helps!!!!!!!!!!!!!!!
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Originally Posted by Jonro View Post
Ok i pulled the engine down again and yes there is allot of play between the rod and crank pin. The brass bit in the rod is almost worn away, how can i tell if just changing out the rod for a new one will help or if the crank pin is worn too much also? The engine still has good top end and good compression so is it normal for the rod to wear so quick?

I also have a MRT GRP that has close to the same amount of wear on the rod end but it runs like a swiss watch, so eh i duno... I don't know weather ill bother with this engine as i could end up replacing the rod and it wont fix a thing.


Ok first and foremost I would like to let you know that in the original V-Spec the connecting rod does not have a lubrication hole going to that bushing add that to the break in process which is pretty hard on the rod.I have also heard that it is a good idea to replace the rod after break-in. You need to get a Vernier Caliper and measure the crank pin in a few different spots to see how out of round it is. I can't remember but I think it needs to be no greater than .01 difference between all measurements(Maybe someone could chime in with the correct tolerance) If it is still within the Spec the crank is still useable. I would suggest to you that if it is in spec and you decide that you want to buy a rod buy a Speed rod as there is a lubrication hole going to the bushing! So how does the backplate look? Heavy scoring?
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Old 12-27-2008, 02:26 AM   #70
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You can always do what I did. Buy the rod then find you need a new crank.HaHa. I had never heard of a crank pin wearing till my OS took a crap. Some shop on e-bay sells v-spec cranks from time to time for $55 US+$12 shipping + 3-4 week delivery. Is the run time & power worth the hassle? Right at 3 bills for the new ninja at carolinas right now or a hair over 2 for a Jammin almost anywhere on line.

http://www.carolinasrc.com/webstore/...idproduct=9820

http://www.amainhobbies.com/product_...ducts_id/11200
The new ninja/O.S engine has a coated crank pin to reduce wear on it, am i correct?

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Originally Posted by motomanpat View Post

Ok first and foremost I would like to let you know that in the original V-Spec the connecting rod does not have a lubrication hole going to that bushing add that to the break in process which is pretty hard on the rod.I have also heard that it is a good idea to replace the rod after break-in. You need to get a Vernier Caliper and measure the crank pin in a few different spots to see how out of round it is. I can't remember but I think it needs to be no greater than .01 difference between all measurements(Maybe someone could chime in with the correct tolerance) If it is still within the Spec the crank is still useable. I would suggest to you that if it is in spec and you decide that you want to buy a rod buy a Speed rod as there is a lubrication hole going to the bushing! So how does the backplate look? Heavy scoring?
Yes yes lots of marks on the back plate... what does this mean?
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Old 12-27-2008, 08:05 AM   #71
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The new ninja/O.S engine has a coated crank pin to reduce wear on it, am i correct?



Yes yes lots of marks on the back plate... what does this mean?
Correct the ninja has a DLC coated crankshaft. Simmilar to the speed crank just without the pressed in slugs.
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Old 12-27-2008, 03:37 PM   #72
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i wonder if your exhaust is the problem..maybe its blocked somewhere and causing too much tank pressure?

could you try a different exhaust?
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Old 01-01-2009, 09:47 AM   #73
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Anyone run the O.S. pipe on the V-spec yet??? Im trying to figure out the diff. between the 2050 and the 2060.???? Which one is better for 1/8 buggy...thanks for your help
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Old 01-01-2009, 10:04 AM   #74
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the 2060 will be smoother and the 2050 will have more bottom. I haven't run either but thats what I hear.
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Old 01-02-2009, 02:43 AM   #75
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Need some advice. Is it recommended to place the extra shim included in the os speed, and aside from the os 2060 pipe are there any other pipes that is suitable for this engine? Tnx
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