<-=- Club Bevel Heaven -=->

Sorry Hashashan - I should be more careful! Apologies.

To identify the parts I'm talking about, have a look at the Darmah SD parts manual on Steve's main site.

To do this, go http://www.bevelheaven.com/ , then from the list on the left, select 'Manuals Index' (under 'Technical Information'). Then scroll down to '900 SD Darmah Spare Parts Catalog' and click on 'Here'. Then select 'TAV09 - Carburetor'.

The mixture screw is numbered 12 on the drawing. They look like this


Now, it may be that this screw is not adjustable on your bike. This is because the carbs were changed on later Darmahs because of new emissions control regulations.

The enricher piston is numbered 16. You cannot see the rubber seal that sits in the bottom of it - it does not come as a separate part. But it looks like this

ok, much clearer now
yeah the mixture screw is adjustable and i adjusted it the best I could.

about the enricher(choke as I call it) what do you mean when you say that the marks of the enricher are on the seals? Ill look at them once again, I can change them just in case. It actually could be the problem but wouldn't I see a yellow spark in the color-tune then?
my best bet is that I have a faulty ignition. I need to find a stroboscope now

Hashashan

given your ealier post about how performance has deteriorated significantly over a relatively short period time this is not normally a characteristic of an electrics problem.

I'd strongly recommend doing a compression test before spending any time on getting electrics tested.

The other reason for doing compression test first is if you have problems with piston rings sealing &/or valves properly seating then those problems really complicate trying to sort out any carburettor problems.

Mick

hashashan wrote: ... and I adjusted it the best I could.

How many turns out, Hashashan? It should be +/- 1 turn out. The reason I ask is that it's possible to mask a leaky enricher and/or other carburettor faults with this screw. In this case, the bike seems fine at idle, but in fact it's all wrong over the rest of the range.

hashashan wrote: ... about the enricher (choke as I call it)

Yeh, that's what it's commonly called. But just be aware that the Dell'Orto system isn't a choke. A choke works by reducing the amount of air entering the engine. In contrast, the Dell'Orto system works by increasing the amount of fuel. So you can see why it may be of importance in your situation :-).

hashashan wrote: ... what do you mean when you say that the marks of the enricher are on the seals?

The rubber seal that's in the bottom of the little piston sits on top of the enricher jet. Over time, this leaves an impression in the rubber in the shape of a round ring. It will look like this ...


If the rubber seal goes hard - which they do - the seal is lost, and excess fuel will flow into the engine at all throttle openings, even with the choke lever closed.

hashashan wrote: It actually could be the problem but wouldn't I see a yellow spark in the color-tune then?

Not if it's being masked by an adjustment on the mixture screw ....

hashashan wrote: ...my best bet is that I have a faulty ignition

I gotta agree with Mick. Me, I would do a compression test first.

Ciao

Craig

Well the first thing I would do is replace the the "choke" plungers with new ones for $20 and ensure that the cables weren't holding them up (like give them 3mm of free play). Before I fitted the new plungers, I'd get a soft wooden dowel and run it around the enricher void to ensure there was no impediment to the plunger sealing. I wouldn't mess with electricts until you eliminate this because it is a pretty common issue that aligns with your symptoms.

Kev

+-1 turnout? yo mean it is supposed to be nearly closed?
I turned it half way out ... that is about 3-4 turns from fully closed position. I guess this is not normal .....
and I will check the thing with the enricher seal in the next few days ... if that is the problem I owe all you guys a beer when u come to Israel :D

There is no point messing with the idle mixture or anything else until you confirm the enrincher ciruit isn't leaking. Look at that first.

Lay ya London to a brick...

Convential wisdom is staring position for tuning is 2 - 2/1/2 turns out from all the way in (with new o-rings)

Kev

hashashan wrote: +/-1 turnout? You mean it is supposed to be nearly closed?

Yes! Anything more than 2 turns and you should start be suspicious ...

hashashan wrote: I turned it half way out ... that is about 3-4 turns from fully closed position. I guess this is not normal .....

No! Basically, you are allowing too much air/fuel mixture thru the idle circuit. And this circuit is in operation, to a greater or lesser degree, at ALL throttle openings, not just at idle. I'll add something about this below - see the paragraph with the **.

Also, Kev makes a good point. You can get a build-up of hardened fuel deposits on the top of the enricher jets. So, when you remove the enricher pistons, have a good look down the chambers that they come out of and make sure the top of the enricher jets are clean. They must be able to give a good surface for the rubber seal in the pistons to seal against. You'll easily see what I'm talking about when you get there.

hashashan wrote: ... and I will check the thing with the enricher seal in the next few days ... if that is the problem I owe all you guys a beer when u come to Israel :D

Well, let's hope this is all it is. Carbs are precision instruments, required to measure out finely balanced amounts of fuel and air while putting up with dust, motion, changing temperatures, crap fuel etc etc. So they do need looking after, especially at the age they're all at now.

--------------------------------------------------------------------
** Ok, back to the mixture screw 'problem'. The most common cause of this is a little difficult to explain, but here goes ...

At the entrance of the carb, i.e. the end that the air filter fits on to, you will see, below the throat of the carb, some small drillings. One of these supplies air to the idle circuit and, because it is rather small, it often gets partially blocked by fuel deposits. This is especially true with modern fuel which evaporates more quickly than the old stuff .

These deposits can be very tough and hard to remove. Do NOT stick anything steel down the drilling. It is stepped inside and you could wreck it.

The best solution is to put the carb in an ultrasonic cleaner - the thing jewellers and opticians use. Otherwise, spray carb cleaner, possibly with a little help from a fine nylon or brass brush or wire, can clear any deposits, altho' it may take some time.
--------------------------------------------------------------------

Anyway, try with the enrichers first and let us know how you get on ...

P.s. At some point, you may decide to simply send your carbs off to someone who knows what they are doing for a full overhaul. Steve Allen offers this service. Or you might decide to buy new ones. I see you were talking about fitting 40mms; but, unless you also fit Contis (or similar) silencers, you won't gain much. And, while you will gain some top speed, you will also lose torque at most riding speeds.

In many people's opinion, a better compromise is 36mm carbs - which Steve can supply, btw.

Ciao

Craig

well due to lack of cash I will first try to deal with the problem by fixing the carbs.
and I do have a conti with 2 into 1 pipes. as a matter of fact I wanted to put a super trapp exhaust but still didnt find one for a reasonable price.

i had a pile of main jets and went out got up to say 90 mph pulled the clutch in and cut the engine stopped took the plugs out to see what colour they were tried another until i had the right main jet
mucked round with the needle and position of the circlip went tried a few pilot jets to get it to idle nice sorta boom bap pah boom bah ah boom bang boom until until it all ran sweet.

finally took off the carbie and took a picture of the piston
take a look at this:

the piston is nothing like the one that is in the shop or on the pictures. is there one like this in the shop? or is it just in such bad shape that it looks different?
also the rubber seems quite stiff but not too much .. it is somewhat elastic.

That's in as sad shape as I've seen. Replace them for as much as 20 bucks then start your tuning.

Kev

are you saying that those used to be flat?

yes, they did.

Kev

what do I do about replacing enricher rubbers on lever flip enrichers