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

denisgavriloff · Newbie

Randomly stopped starting

ttboof · Super Guru

I'm sure a few more suggestions will come in you have covered the basics so might be something odd an or simple

As it ran for a while before it died is there a good flow of petrol

A carbon track on the spark plug fairly rare but can happen basically it will spark OK out of the motor but back in the spark may track back up the insulator

If the have the airbox duct off open the throttle quickly and see if fuel squirts in from the accelerator pump if it is give it a few pumps and see if the engine fires a bit

May indicate there's still a fuel problem

The inlet stub between the car and head can fail but unusual to completly kill the motor

If the air filter is over oiled it can cause a no start as well

Just a few things to think about

TTRfan · Super Guru

Hi Denis and welcome to the forum!

It's easy to check that your fuel is getting through.

Switch off the fuel tap and, with the TTR in as near upright position as you can get it (probably on a bike stand or milk crate), put a large rag or receptacle under the carb to catch fuel and unscrew the carb float bowl drain screw. Then turn on the fuel tap and check if you have a good flow of fuel coming out.

If you don't then the chance are that the fuel filter on the tank tap is clogged (that's the easiest one to check first) or else the filter that sits above the flat needle.

There is a possibility that the float is sticking in the up position which shuts off the needle valve but a sharp tap on the float bowl with the plastic end of a biggish screwdriver will usually get the float moving.

Brian

denisgavriloff · Newbie

Thanks, I'll try those out and get back to you.

denisgavriloff · Newbie

To fix carbon tracking I should get a new plug right? If so, which one is fit for the TTR250's?

TTRfan · Super Guru

CR9E

But, I have found that TTR spark plugs are rarely the cause of non or poor running. Also, if you are gonna take yours out be very careful to make sure there is no dirt or grit around the plug when removing it as it will just drop on top the piston.

Brian

ttboof · Super Guru

A good clean might do it . But a new ones the proper fix

If your eyes are good you might see the black mark looks a bit like lightening before you clean it

I'd still go with Brian's check first to make sure the fuel is getting through

denisgavriloff · Newbie

How can I check if dirt got into the cylinder? I realized there wa dirt by the plug after I had taken it out. I wanna make sure I didn’t get any in there. Also what’s the best way to get it out?

ttboof · Super Guru

good question

there is probably no way to be sure if any dirt fell in , id put the plug back in loose very carefully so as not to disturb any more dirt , then use compressed air or similar to blow the rest out from around the plug .

if your lucky very little or no dirt has fallen in .

next take the plug out and crank it over with out the plug and hopefully blow any crud out

ive done the same before on bikes in the bush and can honestly say dirt's got in but haven't had any bad outcomes (usually turn it over with the pug out to clear the dirt , mud or water )

now you know what it looks like in around the plug next time a good wash with the garden hose is a good way to move any dirt (follow up with compressed air if available )

-- Edited by ttboof on Friday 19th of October 2018 04:30:33 AM

ttboof · Super Guru

dont forget to check the fuels getting through , sounds like you will be able to rule out the spark soon though .

not sure which part of the world your from but as Brian said the plugs dont often carbon foul , the fuel we have locally has been known to do it on cold starts . where as we dont get the build up of muck in the carb when sitting for a while like in England think its the different standards and it doesn't get cold here ( ive heard some places have additives to combat low temps )

looking forward to hearing your back on the road