phm 40 ms carb fuel/air mixture settings

[david Harris]

hi
basically, exactly what the title says ;-)
just got my sm610 up and running, done about 30 miles and the spark plug is black and has carbon deposit on it. I have found out this is the air/fuel mixture wrong but cant find any info on setting the idling screw and mixture screw, can anyone help me please.? im sure you guys think this is really easy, and probably it is but if you dont know...... "ya dont know"........
Also at a constant speed (not particularly fast speed, general traffic) it seemed to be quite "jumpy", i think its miss firing, is this also related to the mixture settings?
I have set the valves spot on according to Georges recommendation, so happy with that.
any help would be greatly appreciated please.
cheers everyone.
dave

 

[DaveM]

Hi,

I suggest you start by removing the carby and give it a good clean, this is essential.

Write down all the jet numbers there is a idle jet, intermediate jet and a main jet.

It seems the intermediate jet may be a little rich from the factory which is why they surge just

off idle about 1/8 to 1/4 throttle.

Turn the carby upside down and make sure the float arms are horizontal with the body.

My bike surges just off idle so it is most noticeable when I am just cruising along with traffic,

when it is transitioning from the idle jet (# 62) to the intermediate jet ( #60).

What clip is the needle on I was told the second clip position from the top ( third from the top

being stock ) but now have mine on the very top clip position, which has stopped a lot of the

surging at part throttle. It still surges a little bit but with research this is normal for a Dellorto

phm 40 ms.

Has your air box been modified by having the holes I think there a six of them in the cover

drilled out and has the muffler had the factory restrictor taken out?

With the TE 570 with modified air box and exhaust restrictor removed the recommendation is

stock 62 idle jet, stock 60 starting jet and 170 main ( stock main is 175).

The stock idle jet in mine seems to be a little rich and I only have the mixture screw out a half of

a turn.

I have the idle screw set to idle a little faster but this makes for easier starting.

With this jetting I am finding it is accelerating very quickly through the gears and pulls strongly

in top gear.

I nearly forgot on the carby the choke ( fuel enrichment circuit ) valve has a rubber end which you

can take off and turn over to make sure it is sealing.

I unbolted the plate and blew through it to make sure it is sealing, if it is not sealing you will get

a over rich situation, I hope this makes sense?

Cheers,
DaveM

 

[david Harris]

Thanks a lot dave M, I will take the carb off this afternoon (sunday morning 10 am here in uk ) and have a look and get back to you.
It kinda runs but if you accelerate hard it jumps like crazy,
Cheers buddy
Dave

 

[david Harris]

hi DaveM
stripped the carby and it was pretty clean. the floats are separate and move freely, the float arms were a little off from being parallel with the body of the carby but i have set that right now.
This is what i have (really sorry but i didnt want to describe something wrong and give you the wrong information so i thought it would be clearer putting it on an image, please see link)

http://imageshack.us/photo/my-images/845/phm40.jpg/

just getting confused with the descriptions
i think they are:
needle jet k32
starting jet 60
idle jet 70
main jet 195
atomizer AB264

float needle valve 300
I have written the values next to the parts on the image ( see link)

the needle is on the top/first clip from the top
the air box has not been modified as far as i know and is standard (you can see from my avatar, as this is the actual bike in question)
the mufflers (there are two) have NOT been modified either, again, as far as i can see. if i look down the end that connects to the main pipe i can see a round filter looking thingy **************************************** if thats it....
cant find what you mean about the choke seal as the diagram i have found, #26 seems to point to something else.
Would you recommend changing any of the needle or jets etc and if so would you mind giving me your opinion/advise as i would be more than happy to buy new to get it running. i will buy a new gasket set anyway but will wait for your reply to see if i need to buy any thing else.
thanks mate for your help, very much appreciated.
look forward to your reply.
cheers.
Dave

 

[DaveM]

Hi Dave,

I have been away a few days and have only now got back, I was hoping someone else might have been able to help you.

The page I am looking at now is www.dellorto.co.uk. go to motorcycle carbys then phm parts.

The rubber seal you need to check is on the choke piston (52) which seals in the choke housing (55).

Cheers,
Dave.

 

[DaveM]

Hi Dave,

Try this link for a manual http://husqvarnaoutlet.com/repair_manuals.

Cheers,
Dave.

 

[DaveM]

Hi Dave,

This dellorto manual is interesting http://www.ducatimeccanica.com/dellorto_guide/dellorto.html , see section 3.6.5, selection of main jet seems to be indicating your main jet is too big.

Try to download a spare parts list for your bike, what year is by the way? and go back to stock jetting, all the parts lists 98,99,2000,2001 I could find the carby should have a 62 idle jet and a 175 main jet.

Cheers,
Dave.

 

[david Harris]

hi Dave
cheers for the reply and the links.
Fyi, the bike was registered early feb '98, so most likely, really a 1997 model.
I've just ordered the correct jets to take the carb back to stock settings and a new float/needle valve also a new gasket set.
i have checked the choke plunger and the seal is "shot it"....... so ordered a choke service kit also (including choke plunger).
the float arms were not horizontal with the body when held upside down so i have set that also.(mine has the separate floats also)
My main jet was #195 and the idle jet was a #70, and as you correctly pointed out these should be #175 and #62 so hopefully this should make a big difference along with the knew choke plunger seal.

With the tank and carb off, i noticed a small leak on the rocker cover/seal so i have took that off and thought i would look at the rocker arm shafts whilst this was off........ WOW.... i am glad i did , the rocker shafts were REALLY worn,(worst part up to 4 thou) so i have located some new ones and have them on order along with new bushes, but these have to come from Italy and was told it could take a week or so . Could this wear in the shafts also contribute to the miss firing ??? (obviously i understand the valve timings would be out)
I will re post as soon as i get all the new parts in and the bike back together, but could be a couple of weeks waiting for them (will put it back together as soon as i get them, cant wait to get the new stuff in it )
cheers
keep you informed.
Dave

 

[DaveM]

Hi Dave,

Glad to hear you are getting on top of everything, the leaking choke plunger seal will give you an over rich problem straight away.

I did the same as you are doing, went back to stock jetting, made sure the choke plunger seal was sealing, I did this by prying it out and turning it over, the float level was way out so corrected it as per the Dellorto manual.

I had my magneto and flywheel bench tested, the flywheel weights had not moved but the stator windings were not making the correct spark.

I paid just as much getting the stator rewound as I could have bought a new one of E-bay,bugger!

I have read that valve clearances are critical to good starting, so the worn rocker shafts may be causing you starting problems also.

I was hoping someone else may have an opinion as I am not a mechanic.

Cheers,
Dave.

 

[DaveM]

Hi Dave,

More info for you, with the research I did on my bike, if the muffler packing is gone, this can effect jetting as well.

I disassembled my muffler and it had no packing at all left.

After repacking the muffler it is super quiet but has a nice deep throaty roar, I love it.

I researched on You Tube for information about muffler packing and found one for 4 strokes by Yamaha Pitmans who are here in Adelaide, a well known and respected dealership.

They said 4 strokes are hard on the muffler packing and to use a layer of steel wool first and then a layer of muffler packing over the steel wool.

I got the steel wool from the local hardware store it came in a box, it is in a roll, the roll is 70 mm ( 2.75" ) wide.

There was fine, medium and coarse, I thought the medium looked the best.

I hope they know what they are talking about but it seemed reasonable to me and the steel wool is a lot cheaper than muffler packing.

This will give you something to do while you are waiting for your parts.

Cheers,
Dave.

 

[DaveM]

Hi Dave,

More info for you, the Husky 4 strokes with a Dellorto have there own starting procedure, I am not making it up, this was posted here by someone else.

Here it is,

(1) Ignition off.

(2) Choke on.

(3) Kick through 5 times.

(4) Ignition on.

(5) Choke off.

(6) The engine should have stopped rotating just before top dead centre, if the auto decomp is working properly, you are ready to start the engine, even kicking these motors takes time to learn, you are really just pushing it through with a strong push, not kicking like a madman like I first was.

The 570 is my first 4 stroke Husqvarna, with the work I have done to it and using this starting procedure, I can kick start the bike standing next to it and kicking with my right foot, which I think is not a bad effort as I am only 5 foot 7 inches.

I have kick started the 570 wearing thongs just to prove a point, but I cannot recommend it.

Cheers,
Dave.

 

[david Harris]

hi Dave
Thanks again mate for the info, really appreciate the guidance.
when i did get it running it was an absolute B*****d to start, and i prayed i didnt stall it whilst out on the road.
im only 5' 8" but do have a bit more "weight" to put behind the kick which after reading the start procedure, is not needed .
i will look at the exhaust packing and do as you suggest as i haven't touched this myself but did notice a "round filter" inside the bottom part of both exhausts, but didnt touch/modify it at all just put it on....... sounds really nice though

When I finally get it running right, at least i will have a base line to work with and can then start to try and improve its performance.
will keep you informed.
cheers mate
Dave

 

[david Harris]

hi, just an update..everything back, valve settings spot on, stock carb jets etc and settings.....
after 20 minutes of continuous kicking, it fired up and ran, a bit lumpy at first but evened that out and left running for about 30 mins on tick over giving it an odd blast now and then....turned it off to get my helmet and gear on and now WILL NOT START at all........ from hot or the next day from cold..... just wont fire up..... now got a left leg like Arnold Schwarzenegger...
tried the main jet needle on 3rd clip as standard, then 2nd and finally top one with still no joy.
when it ran it sounded pretty good, could it be the stator windings, magnets ???? i dont know enough about it to commit to buying a new stator to try as they are obviously not cheap.
just dont know what to do next.......... apart from sell it or torch it......
thanks for any help offered.
dave.
or its "husqvarna sm610 for sale".......

 

[DaveM]

Hi Dave,

Remove the plug, lay it on the head and kick over, is it sparking?

If it is sparking, look closely at the spark kernel is it a strong blue colour? or does it have yellow tinges around the edges?

Yellow tinges mean weak magneto.

Did you adjust the mixture screw as per the manual?

Cheers,
Dave.

 

[david Harris]

Hi Dave
The spark isn't a strong blue, I fact it looked quite faint so couldn't really see if it had any yellow tinges to it so I have took the stator off and found a company who can test it for me and re wind it if needed so have sent it off to them today. £10 to test and £80 to rewind and £180 for new if they cant rewind that particular one...."bet i've got the one that cant be rewound"......just got to wait now...
I adjusted the mixture screw to the manual but obviouy couldn't start it.......
Fingers crossed they find something, don't mind paying as long as it sorts it.......
Let you know as soon as I get it back...... We don't have much of a summer here so the days are ticking by with no bike riding:-(
Cheers again for the input, appreciated :-)
Dave

 

[DaveM]

Hi Dave,

I have read somewhere that 1995 was the first year for the Ducati ignition, I hope someone else can confirm this.

The Ducati ignition is known for poor windings and also a habit of the magnet belt in the flywheel shifting, you should have this checked as well.

After some more reading it seems 1997 was the only year that the 610 was not built so that would then definitely make yours a 98 model.

Cheers,
Dave.

 

[david Harris]

Hi Dave
I have just had a call from the people doing my stator, apparently the "high speed" coil/winding was down considerably and would affect the timing at higher revs, the low speed ok, so they are rewinding it for me. They have checked the stator cover magnets and found only one to be down( lower reading) than the rest (all the others have the same reading)BUT did say this could be correct as they say some stators have this 1x lower rated magnet for timing reasons/settings ..... I don't know if this is correct, hopefully somebody out there can confirm this for me.
Anyway, hopefully will have this back for the weekend so I can try it and get back to you.
Cheers
Dave

 

[david Harris]

Fitted the newly wound stator.......... And .......... F******G thing still won't start.......
that's it really, still won't start don't know what else to say or do .....

"bike for sale" ;-)
Cheers from a very sad Dave

 

[Up-tite]

Dave
Don't give up Assuming motor is good? valves in spec, piston rings good, ign good.carb clean,
Have a small screw driver handy in your pocket.
Find a long hill with gas on ,choke lever on start rolling down the hill.
Pull clutch and manual decomp lever pull up into 2nd gear,then at the same time slowly release clutch with the de comp pulled the motor will turn over easily now release the decomp should fire,
now it's going to get busy take off the choke, keep it running try to keep it running long enough to get it hot.
Do whatever it takes to keep it running hand on throttle other hand on Idle speed screw to get it to idle with hand off throttle.
Now when it's hot adjust your idle speed to where it's very low, now get the screw driver and start turning the Fuel mix screw in clockwise if it starts to rev back out the Idle speed screw back to the low idle,continue to screw Fuel mix screw in until it wants to drop in idle speed or stumble (getting to lean)
now go the opposite direction on the fuel screw until it stumbles (to rich)
now set the fuel mixture screw between these two points,set your idle speed up to an nice idle (not to high).
Ride it back up the hill, before you shut it off reach down and gently pull back the decomp lever on the rocker cover should have 1mm freeplay in the cable before it touches the rocker can feel this just jumps around in your finger. Might have to adjust these cables.
Shut it off with kill button.

you should have 2 one for the manual and 1for the kicklever if so kick is more critical on adjustment than manual as you just pull it harder.
if you have both the kick one always engages when you kick it. Manual one will just over ride it.

Now just kick it don't look for the hard spot just kick it valve spring pressure rolls the motor back to the start point, no throttle.
If only manual decomp push down on the kick lever until it gets harder to push STOP( all valves are closed and piston is moving up and building compression) don't go to far now pull decomp lever push down on kick lever 1 more inch. What you have done is bleed off comp and moved the piston up further in the stroke. (not kicking a 610 now but more like a 250 or whatever), release decomp bring kick lever back up to the top now it's ready to kick. If everything is right will start and purrr like a kitten.

Learn to listen to it because they will talk to you.
Example after several kicks pull manual decomp throttle WFO kick it thru couple times if you get a back fire thru the exhaust it saying I'm to rich or flooded get it to back fire couple times then kick it.
If nothing it's saying give me some fuel (choke) or no fuel in float bowl.
Has always been a big misconception about kick starting and TDC it's not even close to what is happening if you go to TDC or just past it will never start because would have to go thru 3 more strokes before motor is on comp stroke again.
Set up properly this bike will start by using HAND did it once but have some customers do it all the time just to piss others off.
Later George

 

[david Harris]

hi George
thanks for the reply, very helpful and informative.
have tried to bump start down a hill near me and no joy....so cannot set the carb up.
just turns the engine over but does not try to fire at all, not once.

had someone check the compression and said he could only get 95psi......is this good/bad????? he said he thought he would feel more resistance in the kick start and expected more compression from it.
i don't know and he doesn't know huskys very well but did say there was a good spark and confirmed the valve clearances were spot on.
i haven't touched the timing chain so dont know if this is out, the timing marks on the stator plate are in line.
fuel seems to be getting through but dont really know how to check if it is getting in to the chamber, all i can say is the float bowl is full.
i have fitted new, all jets,seals, etc in the carb checked and double checked that they are set and seated correctly(as these were not to book/factory) and it has ran since then,.... to be precise, after about 20 minutes of continuous kicking, it fired up and ran, a bit lumpy at first but evened that out and i left it running for about 30 mins on tick over giving it an odd blast now and then, sound nice ....turned it off to get my helmet and gear on and that's the last time it ran (nothing has been altered since it ran so cannot really eliminate anything i have done apart from having the stator rewind (high rev coil)........ just wont fire up.....
can it be the compression ? but why would this all of a sudden change?
just so infuriating
unfortunately or "fortunately"... depends how you look at it , i am going on holiday this Sunday 23rd for two weeks to Spain so will not be able to try any thing you might kindly suggest until my return on the 7th July,.... which will drive me mad as i will be itching to get it running as we only have a small window of good weather here in the uk with our sh*tty summers....
tanks again george really appreciate your expertise.
cheers
dave