Yamaha 250 ty.it soots plugs then packs up .clean the plug and it starts again.any suggestions?

Question

Yamaha 250 ty.it soots plugs then packs up .clean the plug and it starts again.any suggestions?

Answer 1

Dirty air cleaner causing it to run rich.

Cheap quality oil in the pre-mix.

Over rich pre-mix ratio - should be 32:1

Needs a top end rebuild - cylinder, piston & rings - do you remember when the last time it was rebuilt?

If not, I would say it's time for another.

Answer 2

Sounds like the fuel/air mix is too rich.  Look in the manufacturers manual and it may tell you which s***w to adjust on the carburettor.

Answer 3

This happened to me once, What i didnt consider was that the fact the bike was left idling then cutting out, thus finding plugs sooty (perfectly normal on a bike left idling) I naturally blamed the plugs, as after i had cleaned it fired back up.

BUT, what was really happening was.. The bike had started, left to idle and cut out (plugs sooty -normal) then the time it took to clean the plugs and put them back, the ignition coil had been allowed to cool down, allowing them to provide a nice spark but soon after it would heat up and fail.

This had me baffled for weeks, its now one of the first things i check!

Ant

Answer 4

have the carbs adjusted seems its running rich a misfire will also cause this  as will blocked air jets

Answer 5

sounds like your carb mixture is too rich or you need a hotter plug!.

Answer 6

are u getting ur plugs from a car shop or motorbike shop as i had the same problem kept buying plugs from a car shop and burnt it all out. paid a little bit extra from a bike shop and it sorted it out

Answer 7

the old ty250...air/fuel mixtur is out..runing to rich...turn airscrew all the way in and then 1 and 3/4 out...thats std setting,....check air filter and clean if nessasery.

Answer 8

THis is a question that BEGINNER RIDERS ALWAYS ASK. Therefore My answer is for a beginner Rider.

If your not a beginner, you probably have mechanical issues.

On plug Selection ALWAYS USE NGK for a bike. I don;t know why but I can never get other brands to last in a bike. NGK ONLY. You will haveta get  these at a Bike shop, most OEM shops will have the right plug.

Your Bike comes stock with a NGK BR9(....something

(extra letters)

CHECK ME AND YOUR BIKE AND MAKE SURE YOU START WITH THE STOCK PLUG.

Your Riding around Putting around part throttle alot, therefore the bike Doesn't GET ON THE POWER BAND and you never GET THE PLUG TIP  HOT .

The excess gas keeps your bike cool, and for the PLUG TIP that means the oil and gas makes deposits that 'FOUL ' the tip making it unalbe to FIRE.

YOu bike IS PROBABLY JETTING correctly for mostly WOT RIding, Experts and Intermediates.

As a Beginner you CAN rejet for your riding style but I don't recommend it. Since as you get faster, or Go ride some where that is wide open, like the sand dunes, you'll forget you jacked your jetting and then you CAN burn up your piston.

Also you may loan your bike to a friend and if he gets on the pipe more he could also hurt your piston.

Simply go down and get a BR8EG, iridium if you can, if not get any BR8 that has the SAME LENGTH THREADS as your stock one.

YOur bike has stock a BR9, a BR8 is OnE STEP HOTTER, which means the TIP HOLDS HEAT IN IT more than the BR9, and this extra heat will keep the tip burned off.

NOw you can simply change your plug back to a stock BR9 when you go to ANY PLACE that is WIDE OPEN riding. (and you will want to do this)

Also, keep your muffler packing fresh as it will affect how your bike runs.

Also make sure your not leaking exhuast our the headpipe by the springs.

PROPERLY Clean air filter.

And you should be set.

If this doesn't do it, you'll haveta LOWER THE NEEDLE, and or readjust the AIR s***w.

If you need help with these email me.

Technical answer:

The spark plug's firing end will be affected by the internal environment of the combustion chamber.

As the spark plug can be removed for inspection, the effects of combustion on the plug can be examined.

An examination, or "reading" of the characteristic markings on the firing end of the spark plug can indicate conditions within the running engine.

The spark plug tip will bear the marks as evidence of what is happening inside the engine. (NGK's spark plug reading chart)

A light brownish discoloration of the tip of the block indicates proper operation; other conditions may indicate malfunction.

For example, if the plug is TOO COLD, there will be deposits on the nose of the plug, likely very oily  with a two-stroke.