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Dt125r bogging at 6k revs help please?


Dt rich
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You mean the snorkel under the seat no that is not on I do have it some were and air filter is a new air filter and all connecting rubbers are fine and yep both reed swicthes are out not cut wrapped in a bag with cable tie on I don't see the carb being the problem as I have tried 3 and I no the first one was working fine

And okay thank you I will play about tomoro and let you no the result

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one at a time

Just tried all settings on the carb all the way to top one did not make a difference really just no smoke from exhaust now so have put it back to the setting it was on as i dont want to sieze it from lack of oil ( no 2stroke pump premix)

Any more things I could try as I'm going to sit in the shed all day today taking things part and puting then back together as I have no idea what this is lol

Could it pos be cdi unit? It has some big square one on it not the normal little rectangle sort of one?

Also I changed the Reed blok and noticed there is a little bit of rust on my crank not loseing any coolant or anything and only replaced hea gasket 100 miles ago

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Today's things I have done spark plug carb cleaned another reed block another stator another mag another ignition changed needle settings played with air screw took head off and cylinder looks fine still see marks from a hone previouse owner was not lieing about rebuild was a few more bits but can not member them all

Also wen I changed spark plug an first tarted it to let it warm up it was ok once warmed up so took it up the road was ok for first gear soon as inwanted second it started doing it again so carrie on rideing at the point it struggles for a while pulled over whacked spark plug out was brown but fairly wet (and bloody hot:() so poppe the plug in and just went up to 3 nd half k revs for a while pulled over and black was soaked and jet black any ideas any one?

I have tried loads of deifferent jets and messed about with air screw nothing changes the blackness off the plug

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Well that tells me its rich,go down 1 size on the main jet,put the clip of the needle in the middle and set the A?F screw at 1.5 turn out from fully seated.New plug and go again .

What ratio are you mixing your fuel at?

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It i the flat side carb

And I have tried variouse different jets and messed about with air screw still does the same thing all at any given change

And I'm outing 125 ml to 5 litres witch is what previouse owner said he has allways done

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Did you put snorkle back on? and wen you adjust air screw, [ at idle] if screwed fully home = the engine should stumble. [ means the pilot jet is big enuff] if screwed fully out= revs should rise,,,if nothing happens it means the pilot jet has been tampered with, [ie too small] if your plug is black ,its over fueling, or air filtre choked, :yeah:

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Yep tried I with the snorkel on made no change just a bit more lumpy up to the revs an it's a new air filter

And previouse owner kindly chewed the fu** out I the air screw so does nt come out any more than 2nd half turns but does stumble when all the way in

I currently have a #240 main jet the standar is #210 I have tried very thing up to #240 and that is at its best as with smaller it struggles to get up in the revs I dot see it being the jetting as was running lovely broke down started up and it doe this problem ever since then

My compression feels low ( borrowing a friends tester in the week) but I can start it with my hand so that is telling me from my research low compression still starts first second kick tho this is my first 2smoker that I have actually cared for properly not just a little banger for the fields so not sure if it could be a compression problem

I'm so gratefull for all your help I'm sure ill get there soon good thing motorbikes keep me calm or it prob would have been smashed or burnt by now hehe

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Are you sure put the #210 back in as I've got a dep pipe carbon reeds I thought with exhaust change mayb needed to change jetting

And yer brand new coil lead and plug cap

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Its a long shot" but how is the choke assembly....remove and inspect,,,it may not be seating properly.. :eusa_think:

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Well I wouldnt go more that 1 size bigger for the DEP pipe and the reeds wont make a jot of difference, but this doent address how something suddeny happened and it ran crap ever since, thats why I suggested the HT lead connection. Have you explained this sudden breakdown? was everything hunky dory befor that event?

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I will read my haynes tonight to get familiar with the choke and have a look tomoro that is what it feels like the choke is cutting the engine but I can hear the difference wen choke is on and off

And okay I'll put a #220 in and see how I get on and yep I have explained it first post in this post I think ill check now if not ill explain again

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Was not on this post well I could not see it

Basically I was sitting at a red light for about 5mins in the rain bike was fine till this point I started rideing was fine then all of a sudden it just happened like I say it was raining and was the first time I have ha I out in the rain but all connectors and wires have been checked for water so I'm not to sure what else it woul do if it was because of the rain

They way it broke down was I 3rd behind a learned dropped down in to second to get in the power band for the overtake and then as power valve kicked in is when it started doing this problem bike then cut out as I stayed on throttle so pulled over took about a minute for it to fire again

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that is what it feels like the choke is cutting the engine but I can hear the difference wen choke is on and off

Is it cable operated" ? if so slacken it a bit,, , just read that other post,, you say as powervalve kicks in , thot it was pinned open,?

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Nope don't think it does come off I've had Petcock off and cleaned the little filter that go in the tank both of them reserv and normal one but that's the only bits I could see that needed cleaning an that could be cleaned :s

Do you think compression could do this as I can start it with my hand never use to be able to

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