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My TY250D recently developed the habit of firing on the second or third kick (usual), then running for about 2 to 3 minutes then stopping. It had been sitting unloved (not ridden) for about 8 weeks.

Kick to your hearts content, it would not restart. Did this 2 days in a row, time to sort it out.

I have checked the fuel is running freely from the tank, no blockages there.

I pulled the main jet from the carb and there was crap all over it, either old gummy fuel or silicone that should not be there!

Next step pull the carb down. I have pulled it apart, blwon everything out with carb cleaner, not much evidence of crap in the bottom of the bowl but a bit on the main nozzle (where the needle sits into).

My query is (and I do have one), is the float level for a D the same as a B or C? I have the Cycleserve manual and a parts book for a C. The carb looks the same but for a B/C it says (in the service manual) its a Mikuni model 493 / 61. The carb on my D is a 493/62?

The float level in the book says 24MM +/- 2.5mm.

Is this a safe bet on a D?

Any help appreciated.

Cheers

Shaun B






poooingbefore

Yep. Check it with the carb tilted about 45 degrees, not upside down. In fact, roll the carb until the floats just close the needle and measure at that.

Cheers,

Stork

B model carby is 493 61 24mm +/- 1.0 mm
C/D model carby is 493 62 23mm +/-1.0 mm

Just to confuse things
TY250D Owners service manual [the one that comes with the bike] -Float Height: 24 +/- 2.5mm
OR
http://images.cmsnl.com/img/partslists/service-data-pg1ty250d-1977_bigyau0951servic_d8a9.gif
Float Level : 23+/- 1.0 mm
The level shouldn't really change [if you use genuine needle and seat] over the carby life anyway
Is the only differance between B and C/D carbs, the jets and needle, I mean they look the same apart from the B is black.

Thanks heaps for the responses guys.

I think I will go with the 23mm +/- 1mm as per Davids reply plus the spec sheet that Brownie provided.

Once I have the beast running again shall post some pics as well.

Cheers and thanks again.

Shaun B

Float level is important but not critical, certainly follow the above advice but the major question has to be .......is there a spark...........??
The source coil on bikes 20-25 years old can be a problem, especially if its been subjected to water / dampness. next time it happens, remove plug and see if there's a spark....TY's should nearly always go 1st or 2nd kick!

all ignition parts(coil, points and condenser) are still available from Yamahs

Have put it all back together but no joy, still no boogie.

I have checked it does have spark (just rested the plug against top of the head and kicked it over) but how bright / fierce is the spark supposed to be? This one does not appear that strong (certainly not like a car).

Those ignition bits are still available, try $134 for a coil, $26 for points and $62 for the condensor!

The same bits from John Cane in the UK should cost about $70 landed so thats probably the way to go.

Before I go ordering bits from the UK does anyone around the Gold Coast have a coil and lead they could lend me to try?

Cheers

Shaun B

Shaun,
Pretty sure the coil & lead are NOT your problem, these either do or do not work, there is normally no 1/2 measure. Experience tends to point towards the source coil and the trigger coil with poor insulation(if its a mono) or just a poor source coil if its a twinshock. Its a traditional ignition not a CDI, so it tends to stop working after a few minutes when the volts begin to drop or the condenser begins to let go. Just make sure the mag is clean and not full of moisture, etc.

shaun, I went to the local Yamaha dealer and this was backed up by the dealer in Coffs harbour. Coil is $40 from MCS and you can get the other stuff as well.