OzVMX Forum
Marque Remarks => Kawasaki => Topic started by: BMC on March 14, 2014, 03:57:59 pm
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Hi everyone
i brought i KDX 175 1981 for $790 and its all there, ive had some problems over the mouths i have had it with a top-end rebuild done dew to the fact of my carb that it is making it over rev, what i am really asking does anyone have a spare carb for it because im not running the bike without a replacement of a carb or a carb rebuild kit can anyone help?
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i got a carby you can have or go http://www.mikunioz.com/index.html get new one 200$you just got to work out what the juts are if you get stuk i can look in my carby to find jet size
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Maaate what can go wrong with a carb?? have you got the needle stuck when putting the slide thingy in which holds the slide up at half throttle?
is the manifold cracked and sucking air, is the slide badly worn with brass showing through?
does the slide go "thunk" when shut the throttle, should make a solid noise if its closing all the way.....cable isn't hung up on the top adjuster???
has this helped you?
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well basically my carb hasn't been rebuilt before so everything in it is just worn, i am the seconded owner of the bike and thats what the original owner told me
everything is shutting when the throttle is moved there is a noise but its not as load as the pe one, which i do understand there a completely different bike ?, there are no cracks in it so it not sucking in air, i havnt put the slide in wrong
but the slide is showing brass
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the carbs would be very similar but the noise on closing depends on the air filter a bit so it will be different.
If the slide is showing brass, its worn so maybe look at getting a new carb, will solve any problems you have with that one.
But! over revving is usually due to air getting in that's not supposed to be there or an adjustment is wrong.
have you set the idle mixture screw out about 2.5 turn? (little brass screw on the side of the carb) turn it in till it stops (gently!) then wind it out 2 and a half turns.
you idle speed screw isn't screwed in too far? (that's the one with a spring on it) and it should be adjusted so the bike idles nicely at about 800 rpm (not to slow and not too fast) it just pushes the slide up a bit as you screw it in. so wind it out a couple of turns and see if the revs drop quicker... but it should stall if the screw is wound right out.
get the bike going and spray wd 40 all over the manifold and carb to airbox joins and see if the revs change (airleak test)
good luck
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just buy a new one
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need to check that's its the actual problem before spending$$ I reckon.
Although its been "rebuilt" it may have leaking engine seals, gaskets who knows... why rebuild then sell for a song? Sum ting wong for sure...
if he could try a good carb first may eliminate these suspects....
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It must be a common problem. My KDX175 does the same thing. Haven't had a chance to look at it yet but the first thing I will do is strip and clean the carbie. Only started it once since I bought it for $600.00
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Over revving??
What exactly is that?
Once had a girlfriend who told me her car was revving too high, couldn’t work out what the hell she was on about until I drove it and then found out the clutch was slipping.
Another dopey teenager also told me his car was revving too high, after driving it I found out that the T bar linkage was out of sync and his car was stuck in second gear so yes at 100 Kph it was revving too high.
I can’t foresee the carby causing the need to rebuild the motor unless it was running lean.
Do you mean idling too high? This in itself won’t wear out the motor but it is often a sign that you have an air leak which will cause dramas
‘Revving on’ is usually caused by a leaky base gasket, crank seal or inlet manifold which will cause it to run lean which can lead to an engine rebuild.
My carby has brass showing and replacing the carby is on my list of things to do but it’s not going to cause the engine to stuff up.
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my dad said it could be running lean, but as soon as i start it, it would scream and i just dont want to have to rebuild again after what happend ive made sure there were no cracks or leaks in the carby it self, im going to try and tune it all up again,
a question what does everyone that has a kdx 175 run there fuel at like 20:1 ? i was running mine at 28:1 ?
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the engine has had new seals and gaskets put in aswell
also with the float in the carby i am missing the spring would that also be a problem?
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Where are you, what town or city?
Peter B
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run a good oil like motul at 32: 1, will be fine for the dx.
You can buy motorex at $30 a litre but run it up to 60:1 for less smoke and cleaner burn.
(I run it at 75:1)
if you don't know what oil it is, 25 or 32: 1 should be fine
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There will be a hundred different opinions on oil ratio but you can run from 20:1 to 40:1 without major dramas
i am missing the spring would that also be a problem?
What spring? The spring on top of the slide?
That will make it scream as the slide will just stick where ever it wants once air is sucking past it.
If your talking about some other spring then I would advise you take the airbox off (3 bolts and a hose clamp) and see that the slide does actually return to the bottom.
Slide not returning to the bottom is pretty much the only thing that will have it screaming
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Just because you replaced the seals doesn't mean there are no air leaks. The only way to check is to do a leak test on the motor. See if it holds air pressure for say 5 minutes. Seal the exhaust and intake and pump it up to 5 or 6 psi and see if it will hold. Engine racing when started sounds like may have got an air leak somewhere. When it warms up do the revs drop? This is assuming the carb is set with a sensible idle screw position.
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When you unscrew the top of the carby, is there a long spring inside that pushes on the top of the slide ??
It should be trapped between the slide and the top cap with the throttle cable running through the middle.
Lets try this approach first .....
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we may need to walk thru the basics here and see if we can sort this out. it shouldn't scream. a detailed how to fit the slide correctly may be an idea.
A guy on café husky recently described the embarrassing mo when he realised the slide wasn't in right and it fired first kick.....he was still jumping and shaking two days later after having to pull the plug cap off :o ;D
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(http://images.cmsnl.com/img/partslists/kawasaki-1981-kdx175-a2-kdx175-carburetor-kdx175-a2_bigkar046446912_1f56.gif)
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okay yes the spring is there, and yes when its warmed up it still reving to high
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‘16021’ from the parts list is the idle screw adjustment, is it screwed all the way in tight? It shouldn’t be, it may even have the wrong size screw which may be too long!!
As I said earlier, take the airbox off and see where the slide is sitting then take a picture and post it here
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Its getting too much air from some source
Things to check.
is throttle cable kinked bent sticky too sharp an angle ?
is slide seating all the way?
is idle screw set correctly or too far in ?
Is carb correctly assembled and complete?
Is rubber boot cracked correctly installed?
are all intake flanges tight and leak free (wd40 test)
they are the basics and perhaps more info is required.
you mention a missing spring . which spring would that be?
I'm leaning to the theory that if one part is missing then maybe another is. or the idle screw is turned in too far or cable isn't allowing the slide to seat correctly.
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couple of simple things to try Cam,
part no 16021..screw it out 1turn.
part no 16014. screw it in till it stops (gently)then back out 1and a 1/2 turns
see if that helps
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okay so i have adjusted it to that 80-85 husky and i can see a defference in it i can have it idleing but as soon as i give it abit it will revv right up and it doesnt turn off when i use the engine stop or the igneation key ether, so i have to stall it so it will turn off
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you either have a massive air leak somewhere that is leaning the mix out so much it is "dieseling" and continue to run even with no spark. or your carb slide is hanging up in the throat.
for an air leak, my guess would be the main engine seals, either behind the flywheel or behind the primary dve gear under the clutch cover. if the bike is blowing heaps of smoke, its the primary dve side seal as it will also suck oil in.
pull the flywheel cover off and see if there is oily gunk in there just to check.
can you see into the carby throat to check the slide is hitting rock bottom every time?
the fact that you can idle it then it screams is a bit weird but reed valve gaskets can suck and blow as can the carb rubber boot to reed block. if it has a split in it. it can seal nicely till you hit the throttle and the vacuum opens up the crack letting a heap of air in.
it has to be an air leak. I just don't think you've found it yet.
But wait!! there's more .....
also check the fuel tap is letting enough fuel out...... I wonder if the jets are blocked enough to give that running out of fuel rev out....???
may pay to undo the big nut on the bottom of the carb bowl and see if fuel runs out everywhere (not on the lawn!). take it off carefully and look inside it to see if its clean or cruddy as its like a trap for water and dirt.
Turn the fuel tap on and make sure a good trickle of fuel is pouring out everywhere. that will eliminate stuck needle or floats.
have a look at the main jet (little brass thing sticking out the bottom of the bowl (92063) and see if its clean brass looking or covered in fungussy stuff.
if its cruddy looking and there is junk in the bottom of the big nut, you need to pull the carb off and get it cleaned. it could be blocking the fuel which will make it like an air leak.
have a look at all that!
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Sticky slide?
Frayed throttle cable?
Throttle tube sticking on handlebars?
Kill switch disconnected?
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okay so when i had it tuned how you said to 80-85 husky it also wasnt hitting the power banned ? now i had a look now at the carby its haveing the little tickle come out so nothing is blocked in it, ive made sure that the engine seals are fine and the brackets are tight
the kill swith is connected it was fine before the top in rebuild that i had done, im starting to think ill need a new carby because even before i had my rebuild done it was like this when it got close to blowing up, day one it was fine but had the over revv and then it just got worse or time now it does it all the time ?
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How do you know it wasn’t hitting the ‘banned’? Were you riding it with a sticky throttle? You must be one of these youngsters looking for some extreme riding ;D
There is nothing in a carby that can wear out that can cause it to rev wildly.
The revving will be caused by either an air leak or the slide in the carby not returning to the bottom
You need to check to see what this slide is doing by watching it as you turn the throttle and release (while engine is stopped)
Waste of time to replace the carby to find out your problem is a frayed throttle cable.
You also need to remove the spark plug to check that there is no spark when you are holding the kill switch down
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yeah i am young but i love my old bikes, ill go and have a look at the carby today and see what the go is and ill let you know
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enjoy the bike and fixing it as you will learn so much for future years while all your mates are buried in an x box. live the dream!
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.... ive made sure that the engine seals are fine.....
Tells us how you made sure. What did you do?