Help routing fuel pump system to carb!!!

[Krispy]

Hey guys,
I am kinda new to the Karting world. I bought a kart frame and put a 2003 KTM 125sx Motor on it and i am having trouble/getting confused on how to rout the fuel lines between the fuel pump, tank, and carb. Can someone PLEASE give me some kind of diagram or picture how to run lines so i dont flood the carb or starve it? I have looked on youtube and some people are saying drill a hole in the reed box?

 

[chancer]

Here is thread with a fuel pump. I copied this for mine. But they are NOT the same style motor as yours. ??? best I got for ya
http://www.diygokarts.com/vb/showthread.php?t=28416&highlight=db30+trike&page=3

 

[landuse]

Welcome to the forum!!

 

[itsid]

Welcome Krispy,
routing fuel lines is pretty straight forward..
if you looks closely the fuel pump will have some arrows indicating the fuel flow.
the line coming from the tank should see the arrow pointing into the pump;
the line from the carb should see the one pointing away from the pump.

On pulse pumps,
there is a third connecor, that's used to get the engines pulse signal;

See if you have a coresponding nipple on your intake manifold, that way you could grab a pulse directly from there; if you don't you could either use KTMs electric pump (which is likely the way I'd go) or modify your manifold... or you'll have to find a different option I cannot think of atm.
[EDIT]
Models with exhaust control from 2002 on should have a hole drilled in the left hand side cover plate for crankcase ventilation.. maybe you could grab the signal from there
[/EoE]

Wait for Desertduler to chime in, he's not only our local two stroke guru, he's also a dirtbike racer, and if he hadn't HAD a KTM 125sx in the past, he surely rode one maybe even repaired one for a friend


'sid

 

[Krispy]

No that motor looks like a 1 speed lawnmower motor or the type of motor you get from Harbour Freight. Mine is actually a dirtbike motor. Thank you tho!

---------- Post added at 09:17 AM ---------- Previous post was at 09:13 AM ----------

itsid,

that is where i get confused with the whole drilling a hole into cover plate. Is there a video or a picture i can reference from? I am a very good visual learner

 

[itsid]

do not drill a hole (you shouldn't need to!)

Post a pic of your engine (not a pic of a 'close match' off the internet!)
especially the left hand side...

Then I can see if the cover I had in mind is actually there (i.e. your's has exhaust control)
and if it's already equipped with a ventilation.

And then I can circle it for you to see.

'sid

 

[Krispy]

sorry for the late upload but here is MY carb.

i know its dirty..

 

[itsid]

sorry for the late upload but here is MY carb.

i know its dirty..

Here's my question:

[...]
Post a pic of your engine [...]
especially the left hand side...
[...]

you need to read every word.. I moved the highlight a little...

I'm not interested at all atm in your carb, it's the exhaust side of the cylinder I'm interested in
(I even said I'm looking for the exhaust control ..right?)

So it not only took long, it was also pointless I'm afraid.

'sid

 

[Krispy]

Dang man sorry. Here's the pictures of the motor. Like i said I'm new to this.

 

[itsid]

Dang man sorry. Here's the pictures of the motor. Like i said I'm new to this.

No problem

here you go:


that's the crankcase ventilation on the side cover I was talking about earlier;
the end of that hose should be open (maybe ends in a small oil catcher)

Anyways, you can without harm remove the hose from the elbow;
and with a running engine and your thumb check if it pulses..
if, just reattach the hose and attach the other end to the pulse signal port of the fuel pump..

No hole drilled.. pump working.. done!

'sid

 

[Krispy]

Ok cool man thank you! Now I have a question about the hydraulic clutch. I know I have a Magura but idk what model type. I need to buy the lever itself and don't have the old one to reference looks. Can I get some help with exactly what lever I need? I'll post pics below.

I bought what the guy at KTM told me but it looks to be the wrong size?

 

[itsid]

let's keep that to your other thread

'sid

 

[Desertduler]

Howdy, you can remove the reed valve assembly and seal off the crankcase inlet with rags and drill and tap a 1/8 inch pipe threaded hole in the location that I have circled in red or anywhere on that flat area in the reed valve inlet port as it will give you a crankcase pulse signal in that location. I would use a brass 1/8 inch x 1/4 bung fitting and use Teflon tape as a thread sealant. After I installed the fitting I would check the inlet and file flush any of the fitting which was protruding in the inlet as so that the reed valve block can be reinstalled in the engine. I have some concerns about the amount of dirt that is in the air horn of your carburetor, by chance has this engine had a gauze type filter on it like a K&N air filter? Or has it had a foam air filter on it without any oil applied to the foam air filter?

 

[itsid]

Ah thanks for stopping by Bret!

So you're saying the ventilation thingamabob on the side cover isn't producing a strong enough pulse?

Since -to me- drilling a hole when you don't actually need to, seems to be the second best thing to do

'sid

 

[Desertduler]

Ah thanks for stopping by Bret!

So you're saying the ventilation thingamabob on the side cover isn't producing a strong enough pulse?

Since -to me- drilling a hole when you don't actually need to, seems to be the second best thing to do

'sid

That hose is the vent for the transmission, the crankcase is separate from the transmission on a two stroke, the place that I have indicated is under the reed valve petals and will have a direct pulse signal from the crankcase to run his fuel pump but I would keep the impulse line as short as possible and as small as possible because as you might remember I have pointed it out before in another post how the impulse line volume running a fuel pump has an effect on crankcase compression ratios and can effect performance on a two stroke but two strokes are supposed to be simple right?

 

[Desertduler]

Look at this right side crankcase half for his engine and notice the location that I have indicated.

 

[itsid]

That hose is the vent for the transmission, the crankcase is separate from the transmission ...

That cannot be correct Bret!
(or the KTM manual is wrong)


See? it says crank case ventilation, the only reason I suggested that in the first place.
that blackish dot.. it says "(15)" (the exact elbow I pointed to)

...I would keep the impulse line as short as possible and as small as possible ...

good point.
So mounting the fuel pump closer to the seat (front of the engine) instead of closer to the carb (rear of the engine)
is a good idea then
The tank itself is right under the steering hoop I assume as usual on shifter karts.

Oh a tank with an internal pump is not a good idea in this case...

...two strokes are supposed to be simple right?

less moving parts perhaps.. simple... hehe.. IDK

'sid

 

[Desertduler]

Dude, that is correct! that vent line has nothing to do with the crankcase of the engine, there is a exhaust valve flyweight governor that is ran off of the crankshaft that has linkage that runs up through the side cover and into the cylinder head and the vent from the trans is right where I told you it is! How many KTM two stroke engines have you had apart? Maybe you ought to take one apart and see for yourself as I have many times! Not to grandstand my friend but I have built and owned many and still have one. This is why I do not reply to a lot of threads because it is a waist of my time because someone has to question your answers without facts or thinking that they have to be right, you are totally incorrect and just because the KTM parts manual calls it one thing I am telling you from having the SOB in my hands many times! I think that I have had enough of this site and I will find something else to do and not waist my time trying to give advise to someone who wants to argue with me about something they are speculating about! I am out of here lock my threads as I will not be adding anything to them and I can tell you one thing when I say something that is what I mean.

 

[Poboy kartman]

Whoa!!!! We'red that come from? Alex did say unless the manual was wrong. Don't leave....we appreciate your knowledge and imput.

 

[itsid]

... question your answers without facts or thinking that they have to be right, you are totally incorrect and just because the KTM parts manual calls it one thing I am telling you from having the SOB in my hands many times!

Bret, what do you think why I asked you to drop by and take a look?

What have I said in the PM??
may I quote myself?

I think I got it covered.. but KTM two strokes....
I'd rather have your opinion as well for obvious reasons

or further up...

Wait for Desertduler to chime in, he's not only our local two stroke guru, he's also a dirtbike racer, and if he hadn't HAD a KTM 125sx in the past, he surely rode one maybe even repaired one for a friend

Yes I asked you to verify that again...
but without facts buddy?
An official KTM 125cc repair manual, what else can I refer to NOT having an identical KTM crankcase to pop open?

What do you think?
If I thought I'd know more than you about this very engine I'd ever asked you to come by just for me to prove you wrong?
Now you're starting to P!%% me off!
I now do have the feeling you realized the 125 is too different from your 300 and I was correct;
then flipped because of that!?..

I think that I have had enough of this site and ...... when I say something that is what I mean.

Bret (I still honestly call you) my friend,
we had that exact conversation about two years ago, remember?

'sid



[EDIT]

Wow.. took the last 60 minutes to load and check nearly all different manuals from both the 125cc and the 300cc KTMs! (very different engines, mainly because of very different exhaust control)

even checked all inside shots of any 125/200cc KTM i could find
There is NO WAY that side cover is venting the transmission;
NO FLYING WAY!!

exactly nothing in front of the crankshaft or above the lower edge of the intake is even ABLE to vent the transmission! (not without a hose)
even the clutch is sealed away!

So yes, I'm sure that side cover is ventilating the crank case just as stated in this manual (and all the other 125cc manuals covering a 2002 or later engine)


[EDIT II]
Krispy, I'm sorry;
I'd like to ask you to just see if you get a signal from that elbow up there (should take you no longer than a minute to test)
and if you don't all the manuals I've seen are incorrect and I truely missed some vein in the crank case castings that indeed vent the transmission and cancel out the crank case ventilation for whatever reason.
In which case you will indeed have to drill as Bret suggested.

I think it's at least highly unlikely by now, but it's still Bret, the guy I ask (this time with an extraordinary result as you can see) when I'm out of ideas or uncertain about two strokes.