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DT125R Major help needed .....please


mark2010
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Hi

Ive bought a 10 year old DT125r and ive had nothing but problems and i was hoping to get some help on here?

The previous owner has had it derestricted it had dep exhaust and thats about all i know of the bikes history it has 15000 miles on the clock.

1. i have blach gunk and blue smoke coming from the power valve caps on both sides (ive ordered now seals and o rings for this)

2. Its using a lot of fuel

3.The spark plug indicates over rich fuel/air mixture but the haynes manual doesnt tell me how to fix it

4. the bike is running very poor at low revs and speed i have to change gears very quick as it sputters it feels and sounds like it misfires when im around town but as soon as i go on an open road and about 6k the powerbank kicks in and it nearly pulls my arms out of the sockets and only then does it run fine

If anyone could give me some advise and somethings to try it would really help me out

Kind regards

Mark

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well the best bet is ride it flat out all the time XD jokes

you could try and get some carb cleaner and cean the carb out but it sounds like it needs a new air filter to level out the rich running or you could get a standard air filter and buy some new standard size jets for the carb just to make sure it hasent been upjeted to much check all oil mixture settings or do you have to pre mix the oil with the fule

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well the best bet is ride it flat out all the time XD jokes

you could try and get some carb cleaner and cean the carb out but it sounds like it needs a new air filter to level out the rich running or you could get a standard air filter and buy some new standard size jets for the carb just to make sure it hasent been upjeted to much check all oil mixture settings or do you have to pre mix the oil with the fule

I agree - sounds like a carb problem - but I would do a full stripdown, check the jets, blow out all the airways etc.

Can't help you on settings but there are plenty of others here who can.

Good luck.

:D

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Hi

Ive bought a 10 year old DT125r and ive had nothing but problems and i was hoping to get some help on here?

The previous owner has had it derestricted it had dep exhaust and thats about all i know of the bikes history it has 15000 miles on the clock.

1. i have blach gunk and blue smoke coming from the power valve caps on both sides (ive ordered now seals and o rings for this)

Thats due to someone turning the powervalve round on a regular basis, they will creep back if they aren't pegged properly.

2. Its using a lot of fuel

Thats because the powervalve has been done and it probably has a huge main jet to stabalise the mixture (prob a 220 i have known 240 used)

3.The spark plug indicates over rich fuel/air mixture but the haynes manual doesnt tell me how to fix it

Its wrong cos the powervalve ( there is a thread here) is static, you can either have arm wrenching ooomph from 6k OR a wheelie machine TO 6K but without the servo nothing 'normal' you just move the 3-4000rpm of power around.

4. the bike is running very poor at low revs and speed i have to change gears very quick as it sputters it feels and sounds like it misfires when im around town but as soon as i go on an open road and about 6k the powerbank kicks in and it nearly pulls my arms out of the sockets and only then does it run fine

This may come as a shock, its cos the powervalve has been messed with. There is a thread on here where JimR outlines how to power up the valve he may be on later to give more info but if it were me i would go back to the start. Lock the powervalve in the std position and then strip clean and reset the carb. If she runs fine at that you know your on the right track and you can power the powervalve (er?) after picking jims brain or have a play with it manually but don't forget high revs will need some mixture correction or you will be melting pistons.

If anyone could give me some advise and somethings to try it would really help me out

Kind regards

Mark

Hope that helps........

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Hi

Ive bought a 10 year old DT125r and ive had nothing but problems and i was hoping to get some help on here?

The previous owner has had it derestricted it had dep exhaust and thats about all i know of the bikes history it has 15000 miles on the clock.

1. i have blach gunk and blue smoke coming from the power valve caps on both sides (ive ordered now seals and o rings for this)

2. Its using a lot of fuel

3.The spark plug indicates over rich fuel/air mixture but the haynes manual doesnt tell me how to fix it

4. the bike is running very poor at low revs and speed i have to change gears very quick as it sputters it feels and sounds like it misfires when im around town but as soon as i go on an open road and about 6k the powerbank kicks in and it nearly pulls my arms out of the sockets and only then does it run fine

If anyone could give me some advise and somethings to try it would really help me out

Kind regards

Mark

Hi Mark,

is the valve connected up or just pegged open ?

with exhaust gas & oil comming from the power valve cases it may be worth a check on the exhaust port for carbon build up

What MPG ru getting

Regards Jim

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Hi Mark,

is the valve connected up or just pegged open ?

with exhaust gas & oil comming from the power valve cases it may be worth a check on the exhaust port for carbon build up

What MPG ru getting

Regards Jim

Hi Jim

I believe the valve is connected i am going to replace the orings and seal tomorow and i will check the exhaust while im at it

The MPG is a very sad 35 ???

Thanks Mark

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Hi Jim

I believe the valve is connected i am going to replace the orings and seal tomorow and i will check the exhaust while im at it

The MPG is a very sad 35 ???

Thanks Mark

Hi Mark,

35mpg is not too bad for a PV engine running at the max (without the servo motor connected). To ensure it is working you will need to hear the cleaning cycle at startup/igniton on and just back off the right wrist. I would guess you dont have a full valve motor as if the bike was leaking it would only leak from the right as the servo/cables etc are situate to the left & it would be a bike in a sorry state if the valve was was leaking here.

Regards Jim

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I thought i used red, must have been invisible.

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Hi Mark,

35mpg is not too bad for a PV engine running at the max (without the servo motor connected). To ensure it is working you will need to hear the cleaning cycle at startup/igniton on and just back off the right wrist. I would guess you dont have a full valve motor as if the bike was leaking it would only leak from the right as the servo/cables etc are situate to the left & it would be a bike in a sorry state if the valve was was leaking here.

Regards Jim

Hi Jim

Im afraid it is leaking from both sides but only a small amount from the side with the servo and yes i can hear it turning both ways when i turn on the ignition

I am going to remove the cylinder head tommorow and have a good look at the power valve and check the piston rings at the same time

Ps whats a PV engine

Regards

Mark

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I thought i used red, must have been invisible.

Hi

please accept my apologies for not replying to your comments

I did appreciate your help and i was going to let you know about the power valve moving once i had taken it out and checked it

Once again forgive me if you think i was been rude but that wasn't my intention

Regards

Mark

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Hi Jim

Im afraid it is leaking from both sides but only a small amount from the side with the servo and yes i can hear it turning both ways when i turn on the ignition

I am going to remove the cylinder head tommorow and have a good look at the power valve and check the piston rings at the same time

Ps whats a PV engine

Regards

Mark

Hi Mark,

Power Valve engine so you did answer that its got the kit on now (that is not standard for a UK bike) and if the bike is a UK it is possible that someone fitted the servo kit badly (simply crimped the sealing rings). But by now I would guess you have the cylinder off the bike and the problem solved.

Regards Jim

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Hi Jim

Im afraid it is leaking from both sides but only a small amount from the side with the servo and yes i can hear it turning both ways when i turn on the ignition

I am going to remove the cylinder head tommorow and have a good look at the power valve and check the piston rings at the same time

Ps whats a PV engine

Regards

Mark

Hi Mark,

Power Valve engine so you did answer that its got the kit on now (that is not standard for a UK bike) and if the bike is a UK it is possible that someone fitted the servo kit badly (simply crimped the sealing rings). But by now I would guess you have the cylinder off the bike and the problem solved.

Regards Jim

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Hi Mark,

Power Valve engine so you did answer that its got the kit on now (that is not standard for a UK bike) and if the bike is a UK it is possible that someone fitted the servo kit badly (simply crimped the sealing rings). But by now I would guess you have the cylinder off the bike and the problem solved.

Regards Jim

Hi Jim

Well i have changed the o rings and seal and there is no leaking oil up to now so fingers crossed

Now another problem i guess i must have put the power valve back in wrong

I no longer have the arm pulling acceleration i had before and it now struggles to hit 70 ...........what have i done wrong ??

Also the previous owner had lifted the air filter covers to alow more air in ........is that normal

Thanks for all your help

Regards Mark

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Hi Jim

Well i have changed the o rings and seal and there is no leaking oil up to now so fingers crossed

Now another problem i guess i must have put the power valve back in wrong

I no longer have the arm pulling acceleration i had before and it now struggles to hit 70 ...........what have i done wrong ??

Also the previous owner had lifted the air filter covers to alow more air in ........is that normal

Thanks for all your help

Regards Mark

Hi Mark,

it sounds like you have hitched up the valve incorrectly ... did you leave the l/h cover off & cycle the valve in order to work out that the valve is in the correct place ? There is a chance you have the valve 180 degrees out which will shut down the bikes performance and it will be a simple point of turning the valve around the correct way before the electrics are connected.

Regards Jim

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Hi Mark,

it sounds like you have hitched up the valve incorrectly ... did you leave the l/h cover off & cycle the valve in order to work out that the valve is in the correct place ? There is a chance you have the valve 180 degrees out which will shut down the bikes performance and it will be a simple point of turning the valve around the correct way before the electrics are connected.

Regards Jim

Hi Jim

Im going to have a look tomorow i should have taken a note of how it was before i removed it

How do i know when i have it in the right place how would it look inside if i looked through the exhaust port when its in the right place? would it be fully open .....im getting confused

What do you think about the air filter cover ?

Regards

Mark

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Hi Jim

Im going to have a look tomorow i should have taken a note of how it was before i removed it

How do i know when i have it in the right place how would it look inside if i looked through the exhaust port when its in the right place? would it be fully open .....im getting confused

What do you think about the air filter cover ?

Regards

Mark

Well ive turned it 180 and it seems to be how it was now

One last thing i now have a coolant leak from the underneath frame next to foot peg on the last hand side i did drain and refil the system .........would this be just an overflow pipe>

Thanks again

Mark

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Well ive turned it 180 and it seems to be how it was now

One last thing i now have a coolant leak from the underneath frame next to foot peg on the last hand side i did drain and refil the system .........would this be just an overflow pipe>

Thanks again

Mark

if you can see where its comming from under the fram if its an over flow then it will be ablack ruber pipe thats just dangaling down with anthoter black pipe(fule over flow)

if not then you have a leak in the system posibly a hole in the rez or rad

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Well ive turned it 180 and it seems to be how it was now

One last thing i now have a coolant leak from the underneath frame next to foot peg on the last hand side i did drain and refil the system .........would this be just an overflow pipe>

Thanks again

Mark

Hi Mark,

just so I get this correct .... you connected the valve up when it was fully open and you lost performance from doing that ? A simple way oh checking that the valve is in the correct position is to remove the exhaust pipe so you can look up the exhaust port and switch the ignition on and after the servo cycles the valve should end up closed if you are ending up with the valve open you have the thing connected up incorrectly in one of 2 ways

1) The cable pully was connected to the valve in the wrong position

2) The cables are fitted the wrong way round

With a bit of experimentation you will end up with the valve in the correct place.

Your coolant leak :- Has the engine/cylinder have and white streaks on it ? If so these will give you a clue where the leak is but if not I does stand a chance that you do have some coolant being expled from the overflow. I guess you filled the rad and squeezed the rubber pipes in order to expel the air ... if not you may have an air lock which in turn will cause coolant to dribble from the overflow

Regards Jim.

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Hi Mark,

just so I get this correct .... you connected the valve up when it was fully open and you lost performance from doing that ? A simple way oh checking that the valve is in the correct position is to remove the exhaust pipe so you can look up the exhaust port and switch the ignition on and after the servo cycles the valve should end up closed if you are ending up with the valve open you have the thing connected up incorrectly in one of 2 ways

1) The cable pully was connected to the valve in the wrong position

2) The cables are fitted the wrong way round

With a bit of experimentation you will end up with the valve in the correct place.

Your coolant leak :- Has the engine/cylinder have and white streaks on it ? If so these will give you a clue where the leak is but if not I does stand a chance that you do have some coolant being expled from the overflow. I guess you filled the rad and squeezed the rubber pipes in order to expel the air ... if not you may have an air lock which in turn will cause coolant to dribble from the overflow

Regards Jim.

Hi Jim

I must have put the valve in the wrong way round as the pully was conected in the right position and the cables were fitted right ...........i didnt look when i put it in i know my bad ! but i turned it 180 this morning and its now fine

ooooooooooooooh i didnt squeeze the rubber pipes shall i just drain it again and refil it properly or will it just sort its self out?

Regards

Mark

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Hi Jim

I must have put the valve in the wrong way round as the pully was conected in the right position and the cables were fitted right ...........i didnt look when i put it in i know my bad ! but i turned it 180 this morning and its now fine

ooooooooooooooh i didnt squeeze the rubber pipes shall i just drain it again and refil it properly or will it just sort its self out?

Regards

Mark

Hi Mark,

coool you got the valve set correct now and the bike is back to normal !

Coolant Leak :-

No need to drain the system just get the bike warm(ish) and remove the cap (becareful as there is a chance of getting scoulded) this should expel any air within the cooling system then just refil ...

Regards Jim

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