DT125R ARCHIVE

MDK · DTR Legend

DT won't go past 40MPH. :-(

Boxing · Guru

MDK wrote:
you say the pv is open fully ? is it locked or servo operated ?

also you say the rev limiter is still in place that can do's what the name says limits your rev.s

althou you say your bike is a 97 is the negine still the original 97 ? over time loads have ahd newer engines fitted as in some cases can be chaeper than haveing full rebuirlds or for other reasons .

you checked all the other things like a
good/new spark plug
reed switch - pic image
air filter clean and good

any starange sounds knocks or rattles

ect ect

maybe tell us more about what mods if any have been done and some pics up of the bike and engine ..

-- Edited by MDK on Saturday 30th of March 2013 02:09:52 PM

-- Edited by MDK on Saturday 30th of March 2013 02:10:26 PM

No knocks or anything like that.

Just took the clocks apart, no leads going into the speedo side, only the rev side. It's a 1997. I guess it's the CDI? But it appears to have zero power in the 5-6,000 RPM range.

I guess it's the CDI? It'll need a new one?

Also, engine is the same one as on the logbook. Serials match, so that's not been changed.

And powevalve goes into the open range in the 5,000-6,000 RPMs.

EDIT:

Speedo has a black and blue lead, are these the restrictor ones?

-- Edited by Boxing on Saturday 30th of March 2013 05:57:58 PM

Boxing · Guru

Hi all. I have a 1997 DT, today is my 17th birthday so I've only just got it road legal. Took it out thinking it'd be quicker than my ped, and it won't go past 40. And it won't rev past 6-7K RPMs. I've looked at the powervalve, its open fully and working. It's got a full DEP exhaust, and still a rev limiter. But it should go past 40MPH, even with the rev limiter.

Any ideas? I'm getting an earlier CDI.

Reef · Guru

Ok im sure you did a similar post to this, are sute its just not clogged up, is it smoking really bad?? If so id say warm it up, then in neutral keep revving it hard for about 20 seconds and if it was clogged up it should be revving a lot better, take it out then it shoulf be sorted

Boxing · Guru

reef wrote:
Ok im sure you did a similar post to this, are sute its just not clogged up, is it smoking really bad?? If so id say warm it up, then in neutral keep revving it hard for about 20 seconds and if it was clogged up it should be revving a lot better, take it out then it shoulf be sorted

I've been riding it all day today. It won't go past 6-7K RPMs and won't go up to 40MPH. And up a hill, its even worst. About third-fourth gear to go up a hill. :/

My peds faster than this.

Seanyftw · Guru

Check the coolant mate, mine ran low and it wouldn't rev properly. if there's not enough coolant my bike will struggle to get to 30

Boxing · Guru

Seanyftw wrote:
Check the coolant mate, mine ran low and it wouldn't rev properly. if there's not enough coolant my bike will struggle to get to 30

Checked it. Coolant is nearly full, not far off full.

Anyone else had this problem? Anyone here got a 1997, with a 1997 engine?

MDK · DTR Legend

I do remember a post with what sounds like the same problem haveing a look throu my old posts now to find it as I am sure we got a result ..

this one is from a tdr topic..

he had the same low speed and revs this is how he fixed bear in mind it was a tdr but tbh same engines

Well a bit of an update!! biggrin
Myself and my Dad got around to having a look at the bike today.... first we took off the exhaust and found that the powervalve was actually the right way around! So we then grounded the black/ blue wire and took the snorkel off the airbox..... My god the difference is unbelievable!! only took it out for a quick blast there and had it up to 90km/h before i even shifted into 6th gear!! definitely an extra 20km/h added to the 110km max I was getting out of it! runs a lot smoother throughout the whole rev range now too! delighted! Looking forward to a proper spin on it now!! wink
Thanks for the help lads, and anyone with a TDR.... ground that fookin wire!!

another like sounding post about a 1997

not sure if he sorted it maybe pm him and ask

http://dt125r.activeboard.com/t50759888/dt125r3mb-guttless-till-5800rpm/

another .

http://dt125r.activeboard.com/t50651913/1999-dtr-coughs-and-spluters-at-6k-revsits-fine-untill-then-/

http://dt125r.activeboard.com/t50512913/running-problems/

Boxing · Guru

Scrims de-restricting guide

this one:
http://www.scrimsmustangsclassicyamaharestorations.com/derestricting-the-yamaha-dt125r-1988-through-to-2007.html

Says that it's the CDI. So perhaps I should just get a new CDI. I'm going to drop it off to a mechanic on Monday and ask him what he thinks. Might need a rebuild seeing as its done 10900 miles.

Boxing · Guru

Pictures as requested.

Bikes exactly the same, except for a full DEP system now.

MDK · DTR Legend

Boxing wrote:
Scrims de-restricting guide

this one:
http://www.scrimsmustangsclassicyamaharestorations.com/derestricting-the-yamaha-dt125r-1988-through-to-2007.html

Says that it's the CDI. So perhaps I should just get a new CDI. I'm going to drop it off to a mechanic on Monday and ask him what he thinks. Might need a rebuild seeing as its done 10900 miles.

yeah worth a try and the older cdi is a good idea but your bike is a 1997 so not one of the worst years for a cdi the best cdi in my mind you could get is maybe the 1989 .

I would also be 100% sure ur pv is set right . not sure if you said is it pinned or servo ? maybe if possible get a pic of each side of the engine . are your boost bottles ect in place is your pv seals ok air leaks can cause no end of troubles poor running or not running at all .

eG x LoGiKzZ · Guru

even with your cdi it should still be a fast bike, id say its the powervalve aswell

Boxing · Guru

So I'll take the PV cover off tomorrow, and take a picture of the PV.
I'll get a picture of the other side of the engine too.

Also I'm buying a 1996 CDI and loom off of Ralzy soon. And furthermore, a mechanic will give it a once over on Monday.

If it helps any further, the bike struggles on hills, if I'm going up a hill the top speed is about 25-30MPH, or even less depending on how steep the hill is.

And I've just found the owner that's scared to go over 40MPH on a DT has a 450CC quad!

I found his YT account:
http://www.youtube.com/watch?v=3UgmTwVbGsk

I won't go accusing him of being a scammer yet though, we'll see what happens when I go to the mechanic.

MDK · DTR Legend

what gear are you attacking a hill with ?

the power valve can have a big impact on speed and running you still have not said is it pinned wide open or still on servo .

I have seen so many ppl say yeah I have locked the valve wide open and once I look they have it totaly wrong and tbh haveing the servo and cables fitted is a must for a dtr to run as it should .

where was it you tested your top speed ?
looking at those pics there is wet mud on the wheels did you get top speed on a field ?

also how long have you been rideing a geard bike ?

Ralzy · Guru

I agree the same I think the issue does remain with p.v or something is not set up correctly I have offered to go and have look and help the lad out. As hes not miles & miles from me. I would rather him not buy a cdi & loom of us unless his bike really needed it and the loom and cdi is from a Red G reg bike so 89/90 it is not a 96 from Somerset as ive checked got a hoard off him a few weeks ago as he only lived 3 miles from where I used to live its same bloke that Reefy bought the DTX rear carrier on ebay the other day from.

Boxing · Guru

I think the PV is operated by a servo, I don't know. It opens up around 5,000 RPMs.

And I used to ride geared bikes off road, so it's not anything to do with that.

And I'm tackling hills in between second and fourth gear. It's just got no poke, my ped used to get up hills at 40MPH. :|

I'll post some pictures of the PV in a minute and get the exhaust off.

And the reed switch... Is that behind the clocks? I've gone through Scrims de-restrictions and it just says the exhaust and CDI restricts it. It has a full DEP system.

I'll see if I can disconnect the PV and go for a test run.

EDIT:

The exhaust has had some O-ring things to hold it in place, my dad reckons if I take it off, I'd need new seals. :/

And I haven't got a clue how to close the PV, it's not something I've touched before. Is there a guide or anything? I'm a n00b with these sort of things.

-- Edited by Boxing on Sunday 31st of March 2013 02:39:29 PM

MDK · DTR Legend

-- Edited by MDK on Sunday 31st of March 2013 02:46:36 PM

Boxing · Guru

My PV is nothing like that one in the top video.

Picture of the right side of the engine:

PV after turning the ignition on and doing it's cleaning cycle. Engine is not running:

PV with engine running it won't go open until about 5,000 RPMs.
P010308_17.21_[01].jpg

-- Edited by Boxing on Sunday 31st of March 2013 03:03:14 PM

Boxing · Guru

Calum122 wrote:
Take the exhaust off. Have a look at the powervalve from there. Move it sonit is flush with th engine. Find the YPVS servo and disconnect it. Turn the ignition on. The valve should not operate. Put the exhaust back on and go for a blip.

Make sure you've done all the derestrictions.

Reed switch and rev limiter.

You wont be able to interchnge between all the cdi's so make sure its not somethig else.

The 1989 cdi's run a different stator so you wont be able to use that CDI.

The reed switch is on the 1997 DT? I only had a blue and red cable IIRC. I forgot the colours, but I have two leads going into the Speed-o side of the clocks. Should I pull these two leads out and test it? Or will that mess my bike up?

On second thought, them wires are to light the clocks up when the headlights are on and its dark. Derp.
-- Edited by Boxing on Sunday 31st of March 2013 03:08:08 PM

-- Edited by Boxing on Sunday 31st of March 2013 03:08:57 PM

-- Edited by Boxing on Sunday 31st of March 2013 03:17:25 PM

Calum122 · Guru

Take the exhaust off. Have a look at the powervalve from there. Move it sonit is flush with th engine. Find the YPVS servo and disconnect it. Turn the ignition on. The valve should not operate. Put the exhaust back on and go for a blip.

Make sure you've done all the derestrictions.

Reed switch and rev limiter.

You wont be able to interchnge between all the cdi's so make sure its not somethig else.

The 1989 cdi's run a different stator so you wont be able to use that CDI.

Ralzy · Guru

I already said to Boxing when he spoke to me there is a likelyhood the stator would need changing if he was to use that cdi loom as certain models are not compatable with certain looms and cdi`s

MDK · DTR Legend

if you had a working servo you would know it you would hear a motor sound as you turn on the key .

also there would be two cables going in to the power valve comeing from a black rubber coverd motor

if you have no servo or it is there but not working then your pv is not working also if its not there at all and your pv is pinned /locked at one position that could be your problem .

with out the servo motor your power valve will not move at all so will not kick in at 5k rpm's

Boxing · Guru

MDK wrote:
if you had a working servo you would know it you would hear a motor sound as you turn on the key .

also there would be two cables going in to the power valve comeing from a black rubber coverd motor

if you have no servo or it is there but not working then your pv is not working also if its not there at all and your pv is pinned /locked at one position that could be your problem .

with out the servo motor your power valve will not move at all so will not kick in at 5k rpm's

Yeah, it runs on a servo.

Someone on here has a 1997, surely? And they know how to fix this problem? I don't really want to have to strip down the whole bike and put in a new loom and CDI, just to get rid of this rev limiter.

MDK · DTR Legend

kinda feel like your brushing of anything we say cus we dont have a 1997 dtr's whats being a 97 got to do with the problem it will apply to just about all the models .

and there could be loads of diffrent problems that could lead to this so there is not gona be that just one fix for that one problem on that one year of dt125r .

all the suggestions above are a way of fault finding you have to go throu the entire bike eliminating every part as being good that will then lead you to the one thing that is bad = finding the fix

( I don't really want to have to strip down the whole bike and put in a new loom and CDI, just to get rid of this rev limiter. )

you dont have to strip down the whole bike to do these jobs they could be done by just removeing the seat and tank .

Boxing · Guru

The bikes had all new parts, its had a full service, the air filter has been changed, new chain and sprockets. The previous owner was very suspicious. He said he didn't dare go over 40MPH, he now has a 450CC quad.

I'm taking it to a mechanic tomorrow. And I ain't dismissing your advice based on a year, I've stripped down the clocks and done most of the stuff you all said. Except the PV and taking the exhaust off. :|

I'm taking it to a mechanic tomorrow, and will have the compression tested etc.

MDK · DTR Legend

so did the last owner say it has had all this work done ? its a common sales talk with bikes like this 75% of sellers will say its had new piston rings bla bla bla .

I never take anyones word for it as some here found out the hard way when bike blow with in weeks cus the last owners lie about work been done .

do you know this mechanic well who is taking a look as the run of the mill mechanic will tell you it needs a full rebuild even when it dont

Boxing · Guru

Yeah, really trusted mechanic, fixed my ped up for its MOT, and done a shit load of wiring.

Dad's been going to him for over 20 years. His a family friend as well. Top bloke. So in other words, yeah, his a good mechanic.

Hopefully it'll be something simple. And I've checked the sprockets and chain, and the air filter. All new.

ShaunyBoy · Guru

sounds dodgy as fuuk, the previous owner is feeding ya bull with a shovel. how old was the previous owner? and if he owns a quad of any engine size he is prob a bit chavvy.

the previous owner knows whats wrong, i would put money on it.

Calum122 · Guru

Yeah +1 what MDK said. If you're not going to listen to what we say then you're better off taking it to a mechanic.

It's so annoying that I'm spending time giving you advice on a two minute job and you just ignore it.

The exhaust is literally four bolts and this would tell you A LOT!

If you took the exhaust off and looked up the exhaust port you could see the condition of the piston, bore and powervalve. All these things can affect the performance of the machine. Decent photos could give us an idea as to what the problem might be.

But like said. If you're arent going to nother then take it to a mechanic.

Boxing · Guru

The rev limiter is 6,000 RPMs, not 10,000.

And I've stripped half of it out. The bikes a complete shed. The bolts are all odd, someone's been messing around with it. The petrol tank is leaking and all sorts.

I'll be looking through the threads in a minute.

And insurance was done three weeks ago now.

It doesn't matter, I'll see what will happen in the future.

I can't do the bedding in process, I'm a speed demon. So I think selling it would be the best solution once its fixed up, I don't know.

I'll see if my opinion is any different when its sorted out.

/thread

-- Edited by Boxing on Monday 1st of April 2013 05:43:26 PM