Tuning a DT 250 2 cycle Mikuni carburetor

Tuning a DT 250 2 cycle Mikuni carburetor

Now that the engine starts, I need to get it running right.

The Yamaha DT 250 Enduro starts and idles o.k. and the low rpm response is
at best 'all right' . But when I crank on the throttle the bike just doesent
pull like it should. At about 3500-4000 rpm the power band flattens out...
feels like it's starving for fuel.

Does anyone have the specs for initial setting for these 2 cycle carbs? Float
setting, number of turns for idle and high speed jets. Techniques?

Another symptom is that the plug fouls quickly. If I burn off the soot on the
plug with a propane troch is starts instantly. But after just one or two runs
the plug is again so fouled it wont start. Is there an adjsustment for
richness?

Thanks,
Dave

--
Message posted via http :// www .motorcyclekb,com

Re: Tuning a DT 250 2 cycle Mikuni carburetor

"graybeard via MotorcycleKB,com " <u42342@uwe> wrote:

> Now that the engine starts, I need to get it running right.
>
> The Yamaha DT 250 Enduro starts and idles o.k. and the low rpm response is
> at best 'all right' . But when I crank on the throttle the bike just doesent
> pull like it should. At about 3500-4000 rpm the power band flattens out...
> feels like it's starving for fuel.
>
> Does anyone have the specs for initial setting for these 2 cycle carbs? Float
> setting, number of turns for idle and high speed jets. Techniques?
>
> Another symptom is that the plug fouls quickly. If I burn off the soot on the
> plug with a propane troch is starts instantly. But after just one or two runs
> the plug is again so fouled it wont start. Is there an adjsustment for
> richness?
>
This is where you spend a few bucks on a secondhand manual, to find the
correct settings.

--
BMW K1100LT Ducati 750SS Honda CB400F, SL125 & SH50
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....
chateau dot murray at idnet dot com

Re: Tuning a DT 250 2 cycle Mikuni carburetor

"graybeard via MotorcycleKB,com " <u42342@uwe> wrote in message
news:819c3f8b96031@uwe...
> Now that the engine starts, I need to get it running right.
>
> The Yamaha DT 250 Enduro starts and idles o.k. and the low rpm response
> is
> at best 'all right' . But when I crank on the throttle the bike just
> doesent
> pull like it should. At about 3500-4000 rpm the power band flattens out...
> feels like it's starving for fuel.
>
> Does anyone have the specs for initial setting for these 2 cycle carbs?
> Float
> setting, number of turns for idle and high speed jets. Techniques?
>
> Another symptom is that the plug fouls quickly. If I burn off the soot on
> the
> plug with a propane troch is starts instantly. But after just one or two
> runs
> the plug is again so fouled it wont start. Is there an adjsustment for
> richness?
>
> Thanks,
> Dave
>
> --
> Message posted via http :// www .motorcyclekb,com
>


You are not really going to get the expert help you need here. These guys
mean well however most don't have a clue on how these old Yamaha Enduros
work.

For the best help, join us over at www .yamahaenduro,com

Tom

Re: Tuning a DT 250 2 cycle Mikuni carburetor

SC Tom <tkimberly@socal.rr,com > wrote:

>
> You are not really going to get the expert help you need here. These guys
> mean well however most don't have a clue on how these old Yamaha Enduros
> work.

You man, like this old guy who recommended checking the spark plug first
and the coil/HT lead second, and who scored a bullseye?


--
BMW K1100LT Ducati 750SS Honda CB400F, SL125 & SH50
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....
chateau dot murray at idnet dot com

Re: Tuning a DT 250 2 cycle Mikuni carburetor

"The Older Gentleman" <totallydeadmailbox@yahoo.co.uk> wrote in message
news:1ieb75s.1weabbkodaqrkN%totallydeadmailbox@yahoo.co.uk...
> SC Tom <tkimberly@socal.rr,com > wrote:
>
>>
>> You are not really going to get the expert help you need here. These guys
>> mean well however most don't have a clue on how these old Yamaha Enduros
>> work.
>
> You man, like this old guy who recommended checking the spark plug first
> and the coil/HT lead second, and who scored a bullseye?
>
>
> --
> BMW K1100LT Ducati 750SS Honda CB400F, SL125 & SH50
> GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
> BOF#30 WUSS#5 The bells, the bells.....
> chateau dot murray at idnet dot com


Who is "You man"?

I see you still think your the knowledge base of all things motorcycles.

If the person posting really wants to get his bike running right and learn
how to do it with the least amount of mistakes, he should ask those who work
on these bikes every day.

Also please keep the name calling to a minimum, there are children visiting
here.

Tom

Re: Tuning a DT 250 2 cycle Mikuni carburetor

SC Tom <tkimberly@socal.rr,com > wrote:

> "The Older Gentleman" <totallydeadmailbox@yahoo.co.uk> wrote in message
> news:1ieb75s.1weabbkodaqrkN%totallydeadmailbox@yahoo.co.uk...
> > SC Tom <tkimberly@socal.rr,com > wrote:
> >
> >>
> >> You are not really going to get the expert help you need here. These guys
> >> mean well however most don't have a clue on how these old Yamaha Enduros
> >> work.
> >
> > You man, like this old guy who recommended checking the spark plug first
> > and the coil/HT lead second, and who scored a bullseye?
> >
> >
> > --
> > BMW K1100LT Ducati 750SS Honda CB400F, SL125 & SH50
> > GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
> > BOF#30 WUSS#5 The bells, the bells.....
> > chateau dot murray at idnet dot com
>
>
See this above? It's a sig. Try to snip it.


> Who is "You man"?

Sorry? I don't understand this.

>
> I see you still think your the knowledge base of all things motorcycles.

That'll be 'you're'. And, no, I don't, but I do have quite a lot of
experience. And as has been pointed out, a two-stroke single is the
simplest engine there is, so if it stops running, there are only so many
things to check.

>
> If the person posting really wants to get his bike running right and learn
> how to do it with the least amount of mistakes, he should ask those who work
> on these bikes every day.

Not every day, but certainly every week.

>
> Also please keep the name calling to a minimum, there are children visiting
> here.


What names are you referring to? I don't see any name-calling in what
you've quoted above.

My advice to you is to come off the high horse, and stop acting like a
prat. In the nicest possibly way.


--
BMW K1100LT Ducati 750SS Honda CB400F, SL125 & SH50
chateau dot murray at idnet dot com
"What you're proposing to do will involve a lot of time
and hassle for no tangible benefit."

Re: Tuning a DT 250 2 cycle Mikuni carburetor

"The Older Gentleman" <totallydeadmailbox@yahoo.co.uk> wrote in message
news:1ieckbz.1bxld311yumgqfN%totallydeadmailbox@yahoo.co.uk...
> SC Tom <tkimberly@socal.rr,com > wrote:
>
>> "The Older Gentleman" <totallydeadmailbox@yahoo.co.uk> wrote in message
>> news:1ieb75s.1weabbkodaqrkN%totallydeadmailbox@yahoo.co.uk...
>> > SC Tom <tkimberly@socal.rr,com > wrote:
>> >
>> >>
>> >> You are not really going to get the expert help you need here. These
>> >> guys
>> >> mean well however most don't have a clue on how these old Yamaha
>> >> Enduros
>> >> work.
>> >
>> > You man, like this old guy who recommended checking the spark plug
>> > first
>> > and the coil/HT lead second, and who scored a bullseye?
>> >
>> >
>> > --
>> > BMW K1100LT Ducati 750SS Honda CB400F, SL125 & SH50
>> > GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
>> > BOF#30 WUSS#5 The bells, the bells.....
>> > chateau dot murray at idnet dot com
>>
>>
> See this above? It's a sig. Try to snip it.
>
>
>> Who is "You man"?
>
> Sorry? I don't understand this.
>
>>
>> I see you still think your the knowledge base of all things motorcycles.
>
> That'll be 'you're'. And, no, I don't, but I do have quite a lot of
> experience. And as has been pointed out, a two-stroke single is the
> simplest engine there is, so if it stops running, there are only so many
> things to check.
>
>>
>> If the person posting really wants to get his bike running right and
>> learn
>> how to do it with the least amount of mistakes, he should ask those who
>> work
>> on these bikes every day.
>
> Not every day, but certainly every week.
>
>>
>> Also please keep the name calling to a minimum, there are children
>> visiting
>> here.
>
>
> What names are you referring to? I don't see any name-calling in what
> you've quoted above.
>
> My advice to you is to come off the high horse, and stop acting like a
> prat. In the nicest possibly way.
>
>
> --
> BMW K1100LT Ducati 750SS Honda CB400F, SL125 & SH50
> chateau dot murray at idnet dot com
> "What you're proposing to do will involve a lot of time
> and hassle for no tangible benefit."


How low will you go? Calling the spell check gods to back your position
means you have no valid point to make. As for keeping the name calling down,
it appears you just could not resist one last swipe.

BTW, read your first reply because I still would like to know who "You man"
is referring to (these are your own words).

Have a nice day!

Tom

Re: Tuning a DT 250 2 cycle Mikuni carburetor

On 25 Mar, 14:25, "SC Tom" <tkimbe...@socal.rr,com > wrote:
> "The Older Gentleman" <totallydeadmail...@yahoo.co.uk> wrote in messagenews:1ieckbz.1bxld311yumgqfN%totallydeadmailbox@yahoo.co.uk...
>
>
>
> > SC Tom <tkimbe...@socal.rr,com > wrote:
>
> >> "The Older Gentleman" <totallydeadmail...@yahoo.co.uk> wrote in message
> >>news:1ieb75s.1weabbkodaqrkN%totallydeadmailbox@yahoo.co.uk...
> >> > SC Tom <tkimbe...@socal.rr,com > wrote:
>
> >> >> You are not really going to get the expert help you need here. These
> >> >> guys
> >> >> mean well however most don't have a clue on how these old Yamaha
> >> >> Enduros
> >> >> work.
>
> >> > You man, like this old guy who recommended checking the spark plug
> >> > first
> >> > and the coil/HT lead second, and who scored a bullseye?
>
> >> > --
> >> > BMW K1100LT  Ducati 750SS  Honda CB400F, SL125 & SH50
> >> > GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
> >> > BOF#30 WUSS#5  The bells, the bells.....
> >> > chateau dot murray at idnet dot com
>
> > See this above? It's a sig. Try to snip it.
>
> >> Who is "You man"?
>
> > Sorry? I don't understand this.
>
> >> I see you still think your the knowledge base of all things motorcycles.
>
> > That'll be 'you're'. And, no, I don't, but I do have quite a lot of
> > experience. And as has been pointed out, a two-stroke single is the
> > simplest engine there is, so if it stops running, there are only so many
> > things to check.
>
> >> If the person posting really wants to get his bike running right and
> >> learn
> >> how to do it with the least amount of mistakes, he should ask those who
> >> work
> >> on these bikes every day.
>
> > Not every day, but certainly every week.
>
> >> Also please keep the name calling to a minimum, there are children
> >> visiting
> >> here.
>
> > What names are you referring to? I don't see any name-calling in what
> > you've quoted above.
>
> > My advice to you is to come off the high horse, and stop acting like a
> > prat. In the nicest possibly way.
>
> > --
> > BMW K1100LT  Ducati 750SS  Honda CB400F, SL125 & SH50
> > chateau dot murray at idnet dot com
> > "What you're proposing to do will involve a lot of time
> > and hassle for no tangible benefit."
>
> How low will you go? Calling the spell check gods to back your position
> means you have no valid point to make. As for keeping the name calling down,
> it appears you just could not resist one last swipe.
>
> BTW, read your first reply because I still would like to know who "You man"
> is referring to (these are your own words).
>
Ah. Mea maxima culpa. 'You mean'.

I still don't understand what the name calling is, though. Who have I
called what, exactly? Take your time.

Re: Tuning a DT 250 2 cycle Mikuni carburetor

On Tue, 25 Mar 2008 07:58:16 -0700 (PDT), "TOG@Toil"
<totallydeadmailbox@yahoo.co.uk> wrote:

<snip>
>> >> > You man, like this old guy who recommended checking the spark plug
>> >> > first
>> >> > and the coil/HT lead second, and who scored a bullseye?

I suppose if you consider hitting the broad side of a barn from 10'
away with a shotgun "scoring a bullseye", then that you did. Not quite
rocket science when a 2S has no spark.

You need to raise your standards...

<snip>

DJ

Re: Tuning a DT 250 2 cycle Mikuni carburetor

On 25 Mar, 16:11, IdaSpode <not@home watching.tv> wrote:
> On Tue, 25 Mar 2008 07:58:16 -0700 (PDT), "TOG@Toil"
>
> <totallydeadmail...@yahoo.co.uk> wrote:
>
> <snip>
>
> >> >> > You man, like this old guy who recommended checking the spark plug
> >> >> > first
> >> >> > and the coil/HT lead second, and who scored a bullseye?
>
> I suppose if you consider hitting the broad side of a barn from 10'
> away with a shotgun "scoring a bullseye", then that you did. Not quite
> rocket science when a 2S has no spark.
>
> You need to raise your standards...
>
I quite agree. Nobody said it was difficult. Like Mark Olson, I'm
constantly amazed at the way people will suggest the most abstruse and
difficult solutions to problems, when the simplest is usually correct.

I mean, there we had people discussing the points and the magneto.
Check the plug, plug cap, HT lead, coil and wiring connections, in
that order. And after those, then you can start looking deeper into
the engine.

As for this one, could be a few things. Bunged up carb is most likely.
Could conceivably be leaking crank seals, and oil deposits on the plug
are being mistaken for soot. But I'd bet on the carb first.

And I still think my original suggestion is valid. Get a bloody manual
and check the settings. I've lost count of the number of posters who
come to this ng asking for the most basic service data or, worse,
asking where they can d/l a freebie manual. JUST BUY THE FUCKING THING!

Re: Tuning a DT 250 2 cycle Mikuni carburetor

On Mar 24, 2:29 pm, "SC Tom" <tkimbe...@socal.rr,com > wrote:
> "graybeard via MotorcycleKB,com " <u42342@uwe> wrote in messagenews:819c3f8b96031@uwe...
>
>
> You are not really going to get the expert help you need here. These guys
> mean well however most don't have a clue on how these old Yamaha Enduros
> work.
>
> For the best help, join us over atwww .yamahaenduro,com
>
> Tom

Right. These things only look vaguely like a motorcycle, but they are
something totally different.

I heard there is a thing they call 'spark' inside these miracle
things. But I haven't got a clue what that would be.

As for T.O.G. he only scored a lucky hit with his advise
to check the coil.

Rob.

Re: Tuning a DT 250 2 cycle Mikuni carburetor

oldgeezer <schreuderrob@yahoo,com > wrote:

> As for T.O.G. he only scored a lucky hit with his advise
> to check the coil.

He didn't, actually. He gave good advice for the problem. Start with the
simplest things, and check them. Spark plug first, coil and HT lead
second, wiring connections third.

Experience born of decades of fiddling with old bikes.

Of course, if it makes you feel better to believe it was a lucky guess,
don't let me shatter your illusions.


--
BMW K1100LT Ducati 750SS Honda CB400F, SL125 & SH50
chateau dot murray at idnet dot com
"What you're proposing to do will involve a lot of time
and hassle for no tangible benefit."

Re: Tuning a DT 250 2 cycle Mikuni carburetor

On Mar 24, 5:39 pm, totallydeadmail...@yahoo.co.uk (The Older
Gentleman) wrote:
> oldgeezer <schreuder...@yahoo,com > wrote:
> > As for T.O.G. he only scored a lucky hit with his advise
> > to check the coil.
>
> He didn't, actually. He gave good advice for the problem. Start with the
> simplest things, and check them. Spark plug first, coil and HT lead
> second, wiring connections third.
>
> Experience born of decades of fiddling with old bikes.
>
> Of course, if it makes you feel better to believe it was a lucky guess,
> don't let me shatter your illusions.

Read between the lines T.O.G.
Someone writes that you and I and others have no idea
about the mysteries that combine to get a 2-stroke bike going.

And you gave the obvious things to check first.

To give it straight; A 2-stroke single cylinder air-cooled, is about
the simplest machine there is.
Anybody writing that you need to be a guru to understand
how they work, hasn't got a clue himself on how they work.

I mean: How dumb must you be to figure that a missing spark might
be caused by points, condenser, cabling, coil, or spark plug?

Of course you were right. And Yes: it was not a lucky shot.

Rob.

Re: Tuning a DT 250 2 cycle Mikuni carburetor

oldgeezer <schreuderrob@yahoo,com > wrote:

> Read between the lines T.O.G.

Ah. Sarcasm. I missed it. My bad.



--
BMW K1100LT Ducati 750SS Honda CB400F, SL125 & SH50
chateau dot murray at idnet dot com
"What you're proposing to do will involve a lot of time
and hassle for no tangible benefit."

Re: Tuning a DT 250 2 cycle Mikuni carburetor

"oldgeezer" <schreuderrob@yahoo,com > wrote in message
news:84ef95c2-c0cd-40bd-ac87-9e8199fbf2aa@s13g2000prd.googlegroups,com ...
> On Mar 24, 5:39 pm, totallydeadmail...@yahoo.co.uk (The Older
> Gentleman) wrote:
>> oldgeezer <schreuder...@yahoo,com > wrote:
>> > As for T.O.G. he only scored a lucky hit with his advise
>> > to check the coil.
>>
>> He didn't, actually. He gave good advice for the problem. Start with the
>> simplest things, and check them. Spark plug first, coil and HT lead
>> second, wiring connections third.
>>
>> Experience born of decades of fiddling with old bikes.
>>
>> Of course, if it makes you feel better to believe it was a lucky guess,
>> don't let me shatter your illusions.
>
> Read between the lines T.O.G.
> Someone writes that you and I and others have no idea
> about the mysteries that combine to get a 2-stroke bike going.
>
> And you gave the obvious things to check first.
>
> To give it straight; A 2-stroke single cylinder air-cooled, is about
> the simplest machine there is.
> Anybody writing that you need to be a guru to understand
> how they work, hasn't got a clue himself on how they work.
>
> I mean: How dumb must you be to figure that a missing spark might
> be caused by points, condenser, cabling, coil, or spark plug?
>
> Of course you were right. And Yes: it was not a lucky shot.
>
> Rob.
>


Name calling is sure sign of low intelligence.

This part of the thread is about carb settings or had you not noticed?

That being the case, have you considered after the lack of spark problem and
the start up of a carb problem the poster might need to check and replace
the main seals?

Tom