A forum for owners of Yamaha TTR250 trail and enduro bikes!

Robin · Member

Starting issue

TTRfan · Super Guru

Hi Robin. Frustrating problem!

When you say you cleaned the jets, did you actually ream the pilot jet with a bit of copper wire? Normal cleaning doesn't always get the old fuel deposits out.

Regarding fuel flow, if you open the drain valve on the float bowl does it come out quickly?

Have you checked the float level? See how to do this toward the end of this web page https://ttr250.com/Carb/TTR250_carburettor_strip_and_rebuild_guide.htm

Although unlikely to be a problem, could the fuel cap breather be blocked?

If you can answer the above then we can move on to other possibilities wink

Brian

Robin · Member

Hi Brian,

I have cleaned the pilot jet with solvent and a strand of wire.

Fuel from drain valve is good.

I haven't checked the float level, but would that stop the bike running on idle?

Tank cap is ok.

Robin · Member

Hi Brian,

Regarding the float height - is there a measurement for adjusting the float height with the float cover off the carb. Rather than as per the manual with a tube on the drain outlet?

Robin · Member

Good afternoon

Carb is off the bike again.

Regarding the pilot jet is the longitudinal hole the same diameter the whole length?

I can put a 0.32 wire in both ends but it comes up against a restriction around the middle.

I can put a single copper wire strand through the complete length.

TTRfan · Super Guru

Robin wrote:
Hi Brian,
Regarding the float height - is there a measurement for adjusting the float height with the float cover off the carb. Rather than as per the manual with a tube on the drain outlet?

Not that I am aware of Robin. Anyone else know?

TTRfan · Super Guru

Robin wrote:
Good afternoon
Carb is off the bike again.
Regarding the pilot jet is the longitudinal hole the same diameter the whole length?
I can put a 0.32 wire in both ends but it comes up against a restriction around the middle.
I can put a single copper wire strand through the complete length.

I no longer have any TTR parts here so can't check a pilot jet but my recollection is that there shouldn't be any restriction.
As I worked on a lot of carbs, I justified buying a set of jet cleaners - see an example here.
Or maybe persevere with the copper wire?
Brian

Ttboof · Senior Member

TTRfan wrote:
Robin wrote:
Hi Brian,
Regarding the float height - is there a measurement for adjusting the float height with the float cover off the carb. Rather than as per the manual with a tube on the drain outlet?
Not that I am aware of Robin. Anyone else know?
With the carb upside down the metal brackets on the float should be parallel to the carb flange is a good starting point(dont know where i learnt it but have used it on all the carbs I've worked on ) Then its as per the manual with a hose and measure. Im not aware of any easier ways.

Only short cut I've found is connecting and checking the height holding the carb next to the bike without fitting it