Paging sweller

You wouldn't have one of those nice oversize pilot jets for an MZ
TS250, would you? You know: the ones that achieve a decent tickover?
I'm certain mine's running the original, so you can have a tickover
and hunting on the over-run, or a nice smooth overrun and not much of
a tickover. You know the scene.

Ta.

 

Never heard of that.

Set the ignition so it's less advanced 2mm BTDC rather than 3mm.

....and do it with a dial gauge.

My Supa 5 or Trophy don't hunt and both idle ok.

 

Hokay.

It was a common mod - I've just called Burwin and they have the jets for
under a fiver.

 

2mm BTDC is *more* advanced than 3mm BTDC.

 

I was an MZRC member when it was only 2 stroke and never came across it.
The hunting never seemed an issue but I may have a certain "MZ Tolerance".

Let me know what size it is they send you - I may have some in my boxes
of carbs.

 

Are you sure?

 

Not sure how you can measure timing in mm anyway.

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..'_/_|_\_'. Ace (b.rogers at ifrance.com)
\`\ | /`/
`\\ | //' BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2, IBB#10
`\|/`
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Two strokes are set in mm and you use a dial gauge. A quick Google turns
this up:
http://www.geocities.com/spoomym/timing/timing.html

It also explains advanced. To put it in four stroke terms the Guzzi
(from memory) fires at 8 degrees BTDC and full advance is 34 deg BTDC

 

Pretty sure, if you retard it you're firing at further before TDC where
compression is lower, you move it closer to TDC to advance where
compression is higher and make more power. Retarding ignition will make
starting easier, advancing will make it more difficult.

A common trick with points model RDs was to advance the timing from
2.3mm BTDC to 1.8mm BTDC to push the power further up the rev range, so
it will pull higher gearing.

 

Other way round and it's less to do with compression and more to do with
engine speed and load. Basically, the further the point of firing is
before TDC the more advanced it is (the spark occurs in advance of TDC).

Saves me typing:
http://en.wikipedia.org/wiki/Ignition_timing

 

The **** that taught me all this 30 years ago got it wrong, or I
listened wrong. Doesn't matter, I never really did much points stuff
anyway.

Thanks for pointing it out

 

May explain why you've had to rebuild so many blown up two stroke
engines...

The same principle applies to electronic ignition too.

 

I never really did, mine were generally reliable once built and left
alone. I just checked an RD forum and moving timing from 2.3mm to 1.8mm
BTDC is a common enough thing to do.

I just set 'em up like the maker says in the destructions and leave
them well alone from then on.

 

Yeah yeah, I got it wrong for 30 years....go on, poke fun at the
foreign bloke.

Like I said, it never really mattered to me, I just adjusted them as I
was taught and left them alone. Whether it was retarded or advanced
never really mattered to me

 

They said 4.5-5.0

 

How is it?

 

I think you're right.

My mate Ratty has an almost new Ohlins shock for sale, I'll ask how
much.

I still think the front on your bike is set up way too hard. It's like
the springs are suited to a 35 stone bloater, but the standard shock
was set up for someone my weight.

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