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| flatspot nightmare https://www.ausmini.com/forums/viewtopic.php?f=2&t=52396 |
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| Author: | roleyfoley [ Wed Apr 22, 2009 5:39 pm ] |
| Post subject: | flatspot nightmare |
hey guys ive got a 65 deluxe with a 998 and 1 1/2" SU im sorry to repost but i think ive tried most of the stuff thats been posted. Im trying to get rid of a big flatspot in my accerating, its low down in all gears , so it makes taking off a nightmare, whenever i go to take off i put my foot down and it just lurches and coughs and splutters. Pulling out the choke makes it work fine. Is this something to do with the tuning? we have recently put in a new 123 dissy, plugs and leads, i checked the oil in the dash pot and its up to the top of the little bobly bit on the end of the stick Any help would be greatly greatly apprecieated |
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| Author: | scotta_74 [ Wed Apr 22, 2009 5:46 pm ] |
| Post subject: | |
MIne had a similar problem and I found it was sucking air because of a worn throttle shaft. Is there any movement in the throttle shaft? |
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| Author: | roleyfoley [ Wed Apr 22, 2009 5:51 pm ] |
| Post subject: | |
sorry to be a complete noob. But how would i test it? |
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| Author: | micowen [ Wed Apr 22, 2009 5:59 pm ] |
| Post subject: | |
Dont be sorry for being a noob. I am one and proud of it. I have asked and read topics on here and had absolutly no idea what people are talking about. I say "yes, I understand", then go to work and ask for the translation. By the way, what is a lay shaft, and what is a cam with spider gears? Love minis to death, but have no idea technicaly! I bend, weld and paint things for a living! |
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| Author: | roleyfoley [ Wed Apr 22, 2009 6:09 pm ] |
| Post subject: | |
ok i just figured out what the throttle shaft was and checked it and it seems to be tight i tried wiggling it and pulling it and no movement |
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| Author: | Tombo [ Wed Apr 22, 2009 6:09 pm ] |
| Post subject: | |
roleyfoley wrote: sorry to be a complete noob. But how would i test it?
Grab either end of the throttle shaft and try to wobble it about, if you can feel movement then it will be leaking air in. If pulling the choke helps then it might simply be running lean, a dyno tune would sort that out and get you some more power at the same time 
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| Author: | roleyfoley [ Wed Apr 22, 2009 6:18 pm ] |
| Post subject: | |
cool thanks all, might have to go see the dyno guy my dad knows again, i think this might be a bit over my head |
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| Author: | Gadgets mini [ Wed Apr 22, 2009 6:23 pm ] |
| Post subject: | |
what sort of oil are you using in the Dashpot?? it might be a bit thick seeing its getting colder in Canberra
I use 3 in 1 oil in my dashpot and it works fine has this issue started in the last couple of weeks if so that when it started to get colder and the oil in the dash pot may be a bit more Viscious
to check for a worn throttle shaft with the engine running spray some WD40 throught the little red straw onto both sides of the shaft if the revs increase its sucking the wd40 through and it is fuelling the engine
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| Author: | Dylans Clubby [ Wed Apr 22, 2009 6:24 pm ] |
| Post subject: | |
the throttle shaft is a part of the carb. take the air filter off, you should see an axle going through the body of the carb, just before the manifold. this is the throttle shaft. to see if it has play, grab hold of it and try to wriggle it about. if it wriggles, it is loose. it is only supposed to spin, like an axle. try and get your hands on an SU tuning book, and see if you can remedy if it is running lean (check the spark plugs, i think it is white deposits that mean it is running lean? don't quote me on that though) how old is your fuel filter? i had similar problems, changed the fuel filter and all was well (but pulling the choke didn't fix mine...) |
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| Author: | Dylans Clubby [ Wed Apr 22, 2009 6:26 pm ] |
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roleyfoley wrote: ok i just figured out what the throttle shaft was and checked it and it seems to be tight i tried wiggling it and pulling it and no movement
ok that is good 
next, see if you are running lean. also, check the timing. you may need to tune the dizzy |
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| Author: | roleyfoley [ Wed Apr 22, 2009 6:27 pm ] |
| Post subject: | |
Gadgets mini wrote: what sort of oil are you using in the Dashpot??
it might be a bit thick seeing its getting colder in Canberra I use 3 in 1 oil in my dashpot and it works fine has this issue started in the last couple of weeks if so that when it started to get colder and the oil in the dash pot may be a bit more Viscious yer thats the other bit i forgot to mention it seems to be really bad on cold days, even when the engine says its warm but i always take the car to the tuner in the arvo and its never a problem Thanks heaps i think you got it. this question is dumb i know but is 3 in 1 oil avliable at just any old auto store supercheap etc? |
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| Author: | Gadgets mini [ Wed Apr 22, 2009 6:29 pm ] |
| Post subject: | |
3 in 1 is the light weight sewing machine type oil you should be able to get it at Woollies or Coles
BTW there used to be a guru of SU's working at Dyno tune Braddon not sure if he is still there give them a ring i think his name was Phil, brad or even Steve  
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| Author: | roleyfoley [ Wed Apr 22, 2009 6:37 pm ] |
| Post subject: | |
oh yer dad knows the guys at powertune in philip so if all fails there ill give them ago . and thanks again everyone, the help on here is amazing |
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| Author: | BALLISTIC [ Wed Apr 22, 2009 7:23 pm ] |
| Post subject: | |
Sewing machine oil may be abit thin, I use dextron 3 auto trans fluid. Fill it up to the top of the piston tube......you will see the lip. |
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| Author: | roleyfoley [ Wed Apr 22, 2009 7:46 pm ] |
| Post subject: | |
Dylan's Clubby wrote: roleyfoley wrote: ok i just figured out what the throttle shaft was and checked it and it seems to be tight i tried wiggling it and pulling it and no movement ok that is good next, see if you are running lean. also, check the timing. you may need to tune the dizzy i got the service manual for my bday and was reading through it and it said that if you pull the piston up about .8mm and if it looses power/stalls its lean so i started riching it up by turning it anti-clockwise, but i turned it a lot and this still happened, also the flat spot seem to have moved a bit higher up the rev range so now i can take off but if i put the throttle down semi hardish it goes flat so i kinda stopped playing with it scared i might end up with a huge flat spot and something going really wrong. also how do i go about getting the oil currently in the dash pot out? |
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