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Post by godfella691981 on Jun 19, 2014 19:12:25 GMT -5
I have a 2010 Tomos Nitro 150, right now the body has about 7,500 miles on it, the engine has around 1,000 on it since I fixed it. For some reason when you let up on the throttle it backfires out the exhaust, recently I have replaced the head, the intake valve, head gasket and rings. Since fixing the bike it has done this, the carburetor does not have an air/fuel mixture screw on it just the idle control screw. I have also replaced the air filter and checked the intake and vacuum hoses for leaks, it has no leaks.
What would cause it to do this? Would the valve gaps not being adjusted correctly make this happen? Could the exhaust valve be to loose?
Any help would be appreciated, this is my only means of transportation and I ride year round.
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Post by creaseuk on Jun 19, 2014 20:41:09 GMT -5
If it backfires on the over-run there is an iar leak in the exhaust system.
Did you repalce the exhaust gasket when you rebuilt the motor?
If not, the original get crushed and when you re-fit the exhaust it sometimes doesn't seat properly.
Get a NCY gasket off ebay for $3, they cover the whole exhaust outlet.
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Post by godfella691981 on Jun 19, 2014 22:25:24 GMT -5
The exhaust is not leaking. I replaced the gasket and I can cover the exhaust tip and the engine dies.
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Post by alleyoop on Jun 19, 2014 22:39:06 GMT -5
Well it is running lean on de-cel, does your carb have a ACV valve on the right side of the carb by the throttle cable side? Alleyoop  |
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Post by godfella691981 on Jun 19, 2014 23:58:31 GMT -5
Yes, It does have an ACV valve, what can I do with that?
I had someone tell me awhile back that was an accelerator pump
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Post by geh3333 on Jun 20, 2014 15:48:04 GMT -5
An accelerator pump is on the bottom right side of the carb if looking at it from the rear .
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Post by jerseyboy on Jun 20, 2014 15:58:26 GMT -5
Mine don't have an accelerator pump that I know about???
I saw the ACV with vac line but thats it???
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Post by godfella691981 on Jun 21, 2014 12:53:17 GMT -5
alleyoop, I have the valve on the side of my carb should I just take it apart and clean it
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Post by alleyoop on Jun 21, 2014 13:10:05 GMT -5
First make sure the Vacuum hose going to the ACV valve has no rips in it. Also make sure your air filter is attached and there are no cracks on the tubing. Also the idle should be around 1500-1800 whereever it idles the smoothest low idle will also cause lean condition on de-cel.
Alleyoop
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Post by godfella691981 on Jun 23, 2014 5:17:40 GMT -5
None of the vacuum lines have holes in them I replaced them all last summer.
My idle varies, normally it's around 1800, but then sometimes it idles really low, it doesn't matter how it idles it still backfires.
Another thing I have a question about, why is that when one headlight lo beam goes out they will come on for 2 seconds then shut off? And I have bought new headlights but all I can find are 35/35, their supposed to be brighter but the stock 25/25 were and I can't find them
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Post by alleyoop on Jun 23, 2014 16:32:55 GMT -5
If the idle bounces it is to LEAN turn the FUEL RATIO MIXTURE screw Counter Clockwise 1/4 at a time wait 10 seconds or so to allow the motor to catch up with the new setting. Adjusting the Fuel ratio screw you want to get the highest IDLE out of it. Once that is done then you can lower the IDLE DOWN using the IDLE SPEED SCREW. Alleyoop itistheride.boards.net/thread/1637/bouncing-rpms-idle |
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Post by godfella691981 on Jul 3, 2014 2:43:33 GMT -5
Alleyoop> There is no fuel mixture screw on the carburetor. Also I took the cover off today to get a better look at the carb and I don't have an ACV valve on the side.
I'm only getting between 60 and 75 miles on a tank of fuel with in town riding, is that good or bad?
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Post by godfella691981 on Jul 10, 2014 19:13:08 GMT -5
Just an update, I got around to checking my valves and the intake valve was around .002, i set it to .005 and now ive got more power and its not backfiring anymore.
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..BAD TO THE BONE..
