phukin dellorto

Hi there carburator-wizards.

I've been struggling with my -02 fe650's carburattor for a quite long time. Seems like it just refuses to run well. no matter what i do, it seems to run too rich.

the jetting is:

pilot jet: 33
main jet: 195
needle: k51 2nd clip from the top
needle jet: dr 272
the jet under the needle valve: 300
choke jet: 70 (used to be 55 but it broke and i just found this one)

Is there any reason in the jetting why it seems to run rich? The choke jet only affects the starting when the choke is on, right? I bought a mixture meter and when the bike is idling the mixture seems to be just a little bit too rich to get the bike started with e-start. At the instant i touch the throttle the mixture gets way too rich. I can even screw the mixture screw fully closed and the bike still runs I managed to get the bike started with e-start when the engine was warm and i had the mixture screw opened for ½ turns. All the parts needed to get the bike started have been upgraded already. (r6 starter, battery, newer and modded auto decomp-stuff, double grounding )

could the gas level be too high or what?

help is highly appreciated

regards,

Jerry

I would drop the needle that last notch and see what it does. I am running the same specs in my 98 600 except for a 170 main jet. No problems and runs strong. E-start takes off 1st spin of the motor. My plug still comes out black and I may drop my needle to the last clip and see what it does but right now I am too lazy to pull it apart.

Put this in your browser and see what comes up, it may help
Dellorto Motorcycle Carburetor Tuning Guide

Which jet are you refering to as the jet under the needle valve?

http://www.bevelheaven.com/Products/dellorto/phm.htm

It is very common for the needle and needle jet to wear causing a difficult to correct low speed circuit rich condition.

Also many have installed an Idle Emulsion Tube which goes under the pilot jet to help with starting as all carbs did not come with one. Dellorto part # 11651.

Run a search on Idle Eulsion Tube and CDI Jet to dig up the old posts on this subject.

http://www.husaberg.org/index.php?name=PNphpBB2&file=viewtopic&t=2569&highlight=cdi


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From "The Doc"


CARBURATION
Blow the carb out and check the fuel screw still has a washer and 'O' ring on the end. The float level can be checked by laying the carb on the open face and checking when the float valve closes. At the moment of closing the arms should be parallel to the gasket line for the floatbowl.


Dell orto - Jetting - VITAL
The carb suffers from a worn atomiser and needle. Its undetectable to the naked eye or under a magnifying glass. Just change them! CHANGE THEM IF THEY AREN'T NEW TO YOU! With that done a 33 or 35PJ work on all models. The choke jet at #45 - too big and a #40 should be fitted c/w new 'O' ring.


Dell orto - missing CD jet?
Some Dell Ortos may be missing this jet tube.


Sticking float - Dell orto
Sometimes the float will stick in either the open or closed position. Remove the floatbowl and check for the pivot rod sticking out or bent tabs etc. In the one piece floats you should check by laying the float on a flat surface for unsymetrical floats when looking from behind.

Sometimes water will enter via the breather pipes and stall the engine. See also below. Drop the floatbowl and look for water residue.

Sticking float valve - Dell orto
The floats operate an arm that pivots up and down, near the centre of the arm is a small pin that looks like a plumb bob with a black rubberised tip. The float valve can sometimes get debris on it and stick open flooding the carb.

Choke - identify the correct choke jet - FCR (Dell orto is similar)
Work out what choke jet you need. This area is overlooked simply because the principles of the choke and the jet required aren't understood.

The dell orto carb has a choke jet that can get blocked - especially if the carb and steed haven't been used for a couple of months. It will need cleaning out and should be held up to the light. The hole should be quite large and the trouble is that after cleaning it may be no better. At least .5mm wide is how it should look.

The important thing is to LISTEN TO THE ENGINE. This is something that few people do. they ***** coz it doesn't start yet the engine is trying to tell them something!

The reason we have fun with carbs is because it's the LAST thing we fettle and whilst everything else has a setting: the carb REACTS TO THE ENGINE. And that is the fascination and why it is so hard to help people!

This is what i look for when i start a bike;

Lean on choke The bike is a ***** to start, takes 30 kicks, each time it starts it runs a little longer until after 5 minutes it runs fine but you daren't touch the throttle yet!

Slightly lean on choke The bike starts and judders for anything up to 10 seconds before it builds and builds up revs then revs like an ***** compared to starting! This bike will never 8-stroke and you can go to the loo/tog up ready, lock the garage - the lot-it ain't gonna stall!

Spot-on The bike runs at medium high revs for at least 30-40 seconds before starting to 8-stroke mildly. It should run straight away at high revs and not build up. The revs should stay the same for over a minute before perhaps 8-stroking mildly and losing revs-it shouldn't stall. it shouldn't 8-stroke any sooner. The problem here for the Dell orto is that one jet may start the bike and then it 8-strokes quickly while the next jet down means 5 kicks to start it but a controlled warm-up. The keihin isn't too bad.

Slightly rich on choke Bike starts well everytime, maybe first kick everytime but you need to blip the throttle or the revs might drop and it might stall, similarly, you have to turn the choke off quickly or it will stall. You have to be near the machine! 8-strokes within 10 seconds.

Rich on choke Bike starts fine but within 2 or 3 seconds it 8-strokes.

On the keihin carb even the MJ affects starting-seriously! so every mod you make has a knock on effect.

Different choke jets are available from yamaha but you can't get them from keihin themselves for some reason (well it used to be like that!) so yamaha are the boys!

I have several choke jets and i used to always be swopping them out. everytime you change the needle straight (very last suffix letter) you will affect the starting.

With the dell ortos the starting is really just the effect of the choke jet combined with the slide cutaway and PJ. that's why it's a lot harder to understand but not necassarily a problem in itself.

So next time listen to your engine!!

Im in pretty much the same position.

I have a new needle and have ordered a couple of needle jets from Eurocarb.

Then hopefully I will be finally sorted.

Dazza

Thanks for the help! I'll check if i have the cdi jet or not tomorrow. If i have one, does it have a specific size or is it just one size?

- Jerry

there's only 1 CD1 jet to choose from and you will have one in it. suggest that you should have a 190MJ in and that you should be on C2 and not C3. yes you should have a new atomiser and needle to be sure (DR272 and K51) but i would suggest that you have the float height wrong and that you need to check for crooked and bent tabs etc, i had this trouble once and i did the lot, the whole lot, i flattened and straightened the float arm twice and still the bike was horrible. so i put a new float arm in and it was cured there and then!

the other thing to check is the tiny 'O' ring is still on the end of the fuel screw.

you should really run a #40 choke jet with a new 'O' ring on it.

regards

Taffy

.

is fuel screw the same thing as mixture screw?

.

Did all the things mentioned here without any results. Still keeps firing in the exhaust pipe when i break with the motor. I'm starting to give up hope. Does anyone have a keihin fcr for sell? does it fit straight into my -02 machine ?

Re: .

Zeri- said:

Did all the things mentioned here without any results. Still keeps firing in the exhaust pipe when i break with the motor. I'm starting to give up hope. Does anyone have a keihin fcr for sell? does it fit straight into my -02 machine ?

Click to expand...

If it is backfiring during decelleration be sure all the exhaust joints are sealed with a high temp silicone sealant or exhaust sealant then begin increasing the size of the pilot jet until the popping stops.

Yes the fuel screw is the same as the mixture screw.

.

Increasing? And i thought it means that theres too much fuel to be burnt if it does that. It is weird since the bike did not use to do that before. After i tried different sleades it started to do that. could it be because of ****** advance in ignition? I thought tried to change it to both ways but there was basically no difference at all

Re: .

Zeri- said:

Did all the things mentioned here without any results

Click to expand...

So you have:

Replaced your needle and seat
Replaced your needle
Replaced your needle jet
Confirmed your start circuit isnt leaking through (I blanked mine off with a gasket)
Confirmed your float level is correct (I am running mine slightly lower)
Confirmed your float doesnt fill up with fuel (mine had a hole in it)
Confirmed your valve clearance is correct

Where is your O2 sensor mounted?

Dazza

RE: Re: .

Vavles ?

RE: Re: .

Oh, He said that.
Rubber sleeve cracks/holes ?

.

I have changed the needle and the jet under it. also checked for cracks in the sleeve -> nothing. i lowered the fuel level so that the fork is straight. no holes in the floats either. needle jet should be fine, too. have not changed it though.

If you havent changed the needle jet , do it. While it does not seem like a big deal I was very surprised when I changed my DR272. You can really see how much it wears when you put it next to a new one.

From what I have read having your valve clearance incorrect can make the bike act lean or rich.

I dont completely agree but as a fault finding/tuning exercise IMO it should be on the list of things to check.

.

schultzy
Posted: Aug 16, 2009 - 06:39 AM

If you havent changed the needle jet , do it. While it does not seem like a big deal I was very surprised when I changed my DR272. You can really see how much it wears when you put it next to a new one.

Click to expand...

Are you now talking about the small valve under the fork-thing which has like a small rubber tip? I've checked my valve clearance but maybe i should do it again.