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Post Info TOPIC: dt125r sudden very weird issue


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dt125r sudden very weird issue
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hi everybody i need a few pointers on my dt ,yesterday i rode the bike all day with no issues at all when this morning came at aroun2 2.00 i started her got down the road and she died  instantly like if you were flipping the killswitch ,anyway i got recovered back home at 4 this morning and just went out to see whats up with it she started straight away no issue at all , so i then opened her up and it sounds like shes choking and she wont go up in speed when it does this so what are we looking at here? i seem to have a good spark but something is telling me that the kill switch has somehow got water in it.

any thoughts?

thanks



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Unplug kill switch and test again would be my advice

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Check the plug.

Are your fuel settings correct?

Have you got too much or too little fuel or air.

Is the side stand switch working correctly. Has water frozen near it? Just lube that up with wd40

What temperature is it running at?

Check coolant.
Check up the exhaust port for excessive wear to the piston/ barrel.

Decoke the exhaust.

Check carb/ clean carb.

Check the basics.

If you're still stuck ask again.

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quick update

i have got her idling at 2k rpm but there seems to be a tapping top end which has just developed as i dont remember hearing it earlier
cheers


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Sounds like piston slap.

Best take the exhaust off and have a look up the port.

If you're lucky and want to do it on the cheap you can get away with new rings.

If you want to do it properly you'll need a rebore new piston and rings and small end bearing.

My bike got nicked. Ramped for 355 miles and eneded up with piston slap.

I skimmed the head new piston and rings lots of 2 t oil and still runs as sweet as a nut on the original sleeve. Personally I'd stay away from boring out when I can.

I'm going to bore it out and have it replated.

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thanks for your replies ,but i rebuilt this engine not that long ago i had the crank split new big end bearing,new conrod,new small end bearing ,new piston,rebore the only thing i didnt touch was the carb also i have now another new development she is now backfiring hard and it is immensely loud im talking about people hitting the deck when i go past!.im getting very worried now also she is sitting on the line of white and red on the temperature im going to cry.

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what can cause slap?


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Alright,

There's a reason why I would stay away from the rebore mate!

It is possible that if the barrel has been rebored before and this is it's 3rd or even 2nd or 1st rebore that the Powervalve can hit the piston rings once hot enough.

I hope this isn't the case as this WILL ruin the cylinder and bottom end of your bike.

When you rebore after a certain time (I'm not sure use the search feature or look on the forum) people here bore the YPVS to avoid this. Personally I would just have the barrel replated.

Also was the ports chamfed?

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Simply worn piston rings or barrel.

It is possible, however unlikely, that you're not using the correct piston.

If the bikes been rebored and you're using an incorrect piston then you'll be well down on compression which would lead to misfire, bogging out and lots of piston slap and no power!

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when i sent the barrel to be rebored they provided the piston to so i dont know on that one i have really kicked the dts ass th last couple of days jumping ,donuts etc it is a strange fault as it is intermittent and my powervalve is locked fully open .


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and no the ports wern't chamfered as the ****ers said that it is a pointless practice


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Hmmm.

Ever heard of the break in period lol?

There are many explainations that I can think of.

Did they chamfer the ports off is my first.

You ramping the bike aint helping

What grade oil are you using.

I assume then that they're using the correct size piston.

Did you bleed the oil system.

What spark plug are you using?

Is it iridium?

Does it need replacing?

Is the air filter dirty?



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i appreiciate this alot.i think we are getting there i just looked on the youtube and listened to piston slap and the sound is a little worse than mine but it rings the same tune


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i took the air filter out about a month ago due to it bogging which was a bad idea anyway but she ran better,and no they didnt chamfer ,its not iridium its a ngk br9es,and i didnt bleed the oil but she is using a fair amount,

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To be honest it varies.

Mine was very subtle but definitely noticeable.

Slight ring when reved.

I didn't notice it to tell you the truth it was my brother than said it.

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What grade oil.

During the break in period you want to use a low grade mineral oil.

This wears out any imperfections that were made during the rebore.

I.e. Unchamfered ports.

After a certain mileage I ALWAYS recommend fully synthetic oils.

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in the gearbox i use 10w40 and for 2t i use halfords own brand .i pretty much ignored the running in period and dont know if this affected it as ive been using it for 4 months this has been the 1st issue aside from the bogging

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whats my next course of action i literally have £160 here to play with but dont really want to spend that if i can avoid it .


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Gearbox oil is fine although I use 5W 30.

I would NEVER use halfords own brand ALWAYS a good known brand. Personally I use Silkolene but castrol is better than most!

Yeah well you aint doing yourself any favours by ignoring running in periods.

For short term use the break in period doesn't matter.

For long term longevity it is ESSENTIAL!

Allowing for the mechaincal parts to bed in nicely.

You wouldn't notice the benefits of breaking in for 4 months. You wouldn't notice it for longer. I know people who out the box brand new ramped the tits off their bikes and never had any problems. It's further down the line that problems occur prematurely.

That's the first thing I'd check anyway,

Take the exhaust off. Use an inspection light to have a look at the barrel and piston. Check for signs of wear i.e. scoring.

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how long are you online ? im going to do this now


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Lol. Literally just gone off line.

I'm on my iPod now so I may be a bit sparse.

Lol. I don't get paid to help other lmao!

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hahah ive got some pics ready
#

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Yeah. Upload them to photobucket then post them on here so we can have a look

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IMG_0185.JPGIMG_0184.JPGIMG_0181.JPG



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LOL.

Yeah that looks ragged.

Let's see what others think but that isn't good!

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I'm no Expert but it looks like you've scored the piston. That looks like its done some serious mileage.

Can you take the plug out and take some photos of the plug.

It doesn't look like you're using the correct mixture of oil.

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proper mooshed lol norfe will know what caused that. looks like the piston tried to jump out the exhaust port biggrin



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Thank you mate. I do require a second opinion some times.

Can't see too well on my iPod

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IMG_0192.JPGIMG_0190.JPGIMG_0191.JPG



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them pictures are fooked sorry


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