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De Restricting my DT125R

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mine is also a 4BL### and JYA4BL###

so yours is an import too then and will be restricted in the same way as mine, mine is a French bike it has a km/h speedo and i will put money on it that i will have to replace the headlamp...even though it has just been mot'd. i'm just hoping they will mot it next year with a miles / kilometres converter fitted and a few stickers on the face.

I will be fitting the 250...assuming of course i find a 240 in there when i check. If its too big no worries i would rather that than too small. As for the reed switch i dont even know if it has one fitted yet with it being an import but i will check it out all in good time ;)

Dont get carried away with the headlight OG, check it first. A lot of bikes dip up and down, not down/left. The headlight my suzuki did up and down and that was a Frenchie, the TDR also dips up/down with no bias.

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Excellent post Paul, I would like to add a few points though.

Firstly the PV can sit in 4 different positions, either one of your picture examples can be set 180 degrees out. This has caused me no end of headaches in the past and is why I find its always best to do the PV with the exhaust off so you can get a visual on it.

Vez

Well there you go casting seeds of doubt in my pickled brain, so much so that i whipped the exhaust off again and can breathe a sigh of relief, you can see the cutout flush with the top of the port and arcing down around the curve at the sides...Phewwww

102_1442.jpg

102_1445.jpg

Edit:The only reason i could think to change to a 240 is because the post 97 UK model had the PV servo fitted. Would make sense i suppose  :lol: So it leaves me wondering is a 250 enough for the DEP OG has ordered.

Where is the carb number, i cant see it?

I have been told my bike as a 4BL import would have a 240 jet as standard. I have ordered a 250 on the strength of this, maybe a 260 will be considered too.

Dont get carried away with the headlight OG, check it first. A lot of bikes dip up and down, not down/left. The headlight my suzuki did up and down and that was a Frenchie, the TDR also dips up/down with no bias.

I just have a nagging feeling this will cost me a headlamp, what narks me is that he got it MOT'd, Still theres plenty of time i suppose until January, will surely pick up an ebay one by then. ;)

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Guest MaD.VeZ

 Just a thought, IF there is a bias it may be the headlight bracket that causes the bias, and not the headlight unit . My MOT is due in June, ill ask about the headlight then, if you can wait that long before buying one.

I'm with cynic though, don't think there is a bias on motorbikes.

*note to self, must read posts properly before replying about main jets.

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 Just a thought, IF there is a bias it may be the headlight bracket that causes the bias, and not the headlight unit . My MOT is due in June, ill ask about the headlight then, if you can wait that long before buying one.

I'm with cynic though, don't think there is a bias on motorbikes.

*note to self, must read posts properly before replying about main jets.

Hi, guys.

Just had a fantastic time reading that lot! Yeah i have a 2004 dt. Thats an RE right?

Anyway mine is also an import so heres a few points that ive found when MOTing my bike.

If the guy who does it is ok you should be able to just stick a peice of tape across the bottom left corner of the headlight to stop it from "dazzling other road users" which it does not do as you will know.

The only restriction i have done to my bike is removing the wire from the back of the speedo, which i was under the impression needed to be earthed to the frame in order to have effect. I did this by tightening one of the bolts that holds the headlight surround on. This allowed my bike to rev more freely. I havnt done anything with the echaust or PV though.

I also have a converter on the back of the speedo in conjuction with a sticker on the speedo that simply says "mph". The converter itself changes it so you dont need to have 10, 20 30 etc stickers on it.

The rubber tank protector just below the fuel cap has come off on mine a number of times. Just a heads up!

Hope that helps. All your info has helped alot! Might have a look at the PV saturday as im gonna have the pipe off to respray ready for some filming im doing on wednesday for a documentary im making about dt125s. Theres a thread in the general section that i would appreciate it if you had a look at =D. (Ive managed to convince the college to allow me to bring my bike into the photography studio for a day to light it nicely and film it :D )

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And by coincidence today i fitted a Motrax brand mechanical kilometer converter to mine

This is what you get

100_1380.jpg

This is fitted, a bit tricky to fit I needed to move the wiring around to accomodate it.

100_1377.jpg

Andy did you ever test its accuracy against anything?

While I was in this area I removed the reed switch as seems to be 'The thing to do'

anyone know what this thing is actually doing?

In the above photo you can see the reed switch taped up out of the way. I have learned that this 'speed limiter' is fitted to german bikes to limit to 80km/h, and also fitted to French bikes (mine) but not functional.

Thinking about it though...even if it was functional then with the converter fitted it would only be functional at 80 MPH not 80 km/h, well fast enough for me so may as well have left it in :rolleyes:

SpeedoReedSwitch.jpg

Went for a ride around and didnt notice anything, but still running in so keeping to around 6000 rpm. Seems willing enough though.

DEP pipe bigger jet and Boyesen reeds are wainting to be picked up. :D

Also bought another reed cage, inlet manifold and cylinder head from ebay. (watch this space) ;)

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While I was in this area I removed the reed switch as seems to be 'The thing to do'

anyone know what this thing is actually doing?

I have learned that this 'speed limiter' is fitted to german bikes to limit to 80km/h, and also fitted to French bikes (mine) but not functional.

Thinking about it though...even if it was functional then with the converter fitted it would only be functional at 80 MPH not 80 km/h, well fast enough for me so may as well have left it in rolleyes.gif

Went for a ride around and didnt notice anything, but still running in so keeping to around 6000 rpm. Seems willing enough though.

DEP pipe bigger jet and Boyesen reeds are wainting to be picked up. biggrin.gif

Also bought another reed cage, inlet manifold and cylinder head from ebay. (watch this space) wink.gif

Well then, if we have the same bike Oldgit, you did do the right thing by removeing this reed switch.

My bike will not go over 7300 - 7500rpm. My speedo is in km/h and once you hit 85 km/h then thats it, you can go no faster !

With this reed switch out ( I know you cant try it yet ) you should be able to red-line the rev counter.

Seems willing enough though -------- sounds good to me !

How do you know your bike is French ? is mine French ?

Regarding your headlight ; on mine I have a screw at the top left for up and down adjustment and a screw at the bottom right for left and right adjustment.

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Well then, if we have the same bike Oldgit, you did do the right thing by removeing this reed switch.

My bike will not go over 7300 - 7500rpm. My speedo is in km/h and once you hit 85 km/h then thats it, you can go no faster !

We do they are both 4BL models, i know (Think) mine is French because of this sticker on the rear mudguard.(see pic)

I dont see the connection you are making with referance to the speed limiter and the maximum revs. With this limiter being part of the speedo then you should be able to rev much higher if you are under 85 km/h...so you have a restriction to sort out. as you quite rightly say I cannot yet confirm if mine will rev over that figure. Are your roads in kms or miles?

100_1370.jpg

Regarding your headlight ; on mine I have a screw at the top left for up and down adjustment and a screw at the bottom right for left and right adjustment.

Havent got a clue as to the headlight, the only thing I do know is it is crap.

I can tape up a bit of it as has been said but to be honest my MOT is not until January so I will tape it up and by January will have a new one fitted anyhow.

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Yea our roads have changed to kms.

Now you have me thinking about this limiter.

Even under 85km/h it still will not pass 7500rpm.

Even in neutral it still wont go past this.

Edit: What I was hopeing is that with this reed switch gone then it might tell the CDI something else and that in turn would give us full revs. But since it is only on the speedo then I see what you are saying.

So our bikes must/might have a rev counter limiter fitted also or maby this is the way these bikes are restricted and not in the speedo. This will need further investigation so I might have a poke arround at this over the weekend.

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Yea our roads have changed to kms.

Now you have me thinking about this limiter.

Even under 85km/h it still will not pass 7500rpm.

Even in neutral it still wont go past this.

Edit: What I was hopeing is that with this reed switch gone then it might tell the CDI something else and that in turn would give us full revs. But since it is only on the speedo then I see what you are saying.

So our bikes must/might have a rev counter limiter fitted also or maby this is the way these bikes are restricted and not in the speedo. This will need further investigation so I might have a poke arround at this over the weekend.

Pull your exhaust off

Check the restrictor tube is not present

Remove cover over PV pulley

Switch ignition on then off, check the slot aligns over the hole behind it (use a 4mm drill shaft to check)

While the pulley is aligned as above, look in the exhaust port and check the PV and exhaust port are aligned and smooth...like in my photos earlier.

If it isnt your PV is in the wrong position like mine was...see earlier to rectify.

I have had my exhaust off twice now and its easy, all done in 1/2 - 3/4 hour

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Guest MaD.VeZ

Pull your exhaust off

Check the restrictor tube is not present

Remove cover over PV pulley

Switch ignition on then off, check the slot aligns over the hole behind it (use a 4mm drill shaft to check)

While the pulley is aligned as above, look in the exhaust port and check the PV and exhaust port are aligned and smooth...like in my photos earlier.

If it isnt your PV is in the wrong position like mine was...see earlier to rectify.

I have had my exhaust off twice now and its easy, all done in 1/2 - 3/4 hour

3/4 hour..  :lol:  15-20 mins on a cold day while smoking and drinking a coffee   :P . You take the full exhaust off or just the expansion chamber?

I though the reed switch was 60 mph restriction not 80??

And 2-wheels have you removed the exhaust restriction?

Vez.

PS the 97 DTR is going soon, so i may be an illegal member here for a while  :unsure:

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3/4 hour..  :lol:  15-20 mins on a cold day while smoking and drinking a coffee   :P . You take the full exhaust off or just the expansion chamber?

I though the reed switch was 60 mph restriction not 80??

And 2-wheels have you removed the exhaust restriction?

Vez.

PS the 97 DTR is going soon, so i may be an illegal member here for a while  :unsure:

The reed switch may well be 60mph...but on mine its 80km/h, so if i then use a converter as i have done it would mean reed switch at 80mph for as long as I am using that arrangement.

Yeah 4/4 hours is time to do all that ...and...set the PV if it needs setting ;)

so thats you and blackhat both illegals now :o , I will call a meeting to see if we can bar you both :rolleyes:

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And by coincidence today i fitted a Motrax brand mechanical kilometer converter to mine

This is what you get

100_1380.jpg

This is fitted, a bit tricky to fit I needed to move the wiring around to accomodate it.

100_1377.jpg

Andy did you ever test its accuracy against anything?

While I was in this area I removed the reed switch as seems to be 'The thing to do'

anyone know what this thing is actually doing?

In the above photo you can see the reed switch taped up out of the way. I have learned that this 'speed limiter' is fitted to german bikes to limit to 80km/h, and also fitted to French bikes (mine) but not functional.

Thinking about it though...even if it was functional then with the converter fitted it would only be functional at 80 MPH not 80 km/h, well fast enough for me so may as well have left it in :rolleyes:

SpeedoReedSwitch.jpg

Went for a ride around and didnt notice anything, but still running in so keeping to around 6000 rpm. Seems willing enough though.

DEP pipe bigger jet and Boyesen reeds are wainting to be picked up. :D

Also bought another reed cage, inlet manifold and cylinder head from ebay. (watch this space) ;)

I beleive thats the same converter i have on mine. Mine is a 2004 model and and i bought it from a dealer in kent for 2095. At the time it had 183 km on the clock and the tyres still had as much rubber stubble as a french womans armpits!

I have tested the bike against my Dads Suzuki Gt750 briefly and it seemed correct, however the test itself wasnt too accurate as, at the time it was too fast to take my eyes off the road ( id only just moved on from a suzuki ts50x which barely touched 30mph).

From what i have read about the reed switch, it "retards" the revs at around 7000rpm. I may be wrong but i believe taping it out of the way is only 1/2 doing the job as i think it needs to be earthed to the frame. I noticed a great difference after earthing mine, but then i never tried just taping it out of the way. might be worth an experiment.

Got my 2002 offroad Dt out today because i have issues with too much pressure and some dirt/oil in the coolant expansion tank. You really can notice the difference between a bike without the YPVS motor kit on it. Also repsrayed the exhaust on my 04 dt yesterday ready for some filming on wednesday =D.

Anyone take a look at my thread in general and have anything that would be of any use? Any emails/contact would be fantastic, even if it were stuff i already know, just to put in my workbook and show that ive contacted people.

*EDIT* Also thought id ad, i dont know what my revs are so i cant comment on that as there is no counter, just a speedo that lights up in blue in the dark. OOh la la ( just cos it looks nice IMHO, not cos its french, cos its not..... Its a dutch import!)

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Ok lastnite i had a look at my bike.

It was in the fully restricted state, so today i got to work on it.

Cut out the restriction tube in the downpipe. Then corrected the power valve. I didnt remove the reed switch yet just to see what happens. Then went for a spin. Much better !

The revs no longer restrict at-all and it will now go all the way to the red-line.

The bike was restricting at 85km/h and now I have managed to do 65 mph. (110km/h)

The roads wher i live are quite twisty and full of tight courners so this is the most i could push the speed without being dangerous.

The bike will quite happily sit at 60 mph and doesnt seem to be under to much pressure. I'd say on a straight road it would do alot more.

So Oldgit, on this model it does appear that the reed switch is not functional. Although i cant be sure cause i didnt have road to push it further.

Anyway thats what i've done so far and that is the performance so far.

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Wahey...nice one mate.

Tis a lot better, i'm amazed how you put up with it for so long, i couldnt stand it for more than a day or two. i bet is sounds a lot better when it comes onto the pipe now eh :D

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Wahey...nice one mate.

Tis a lot better, i'm amazed how you put up with it for so long, i couldnt stand it for more than a day or two. i bet is sounds a lot better when it comes onto the pipe now eh biggrin.gif

Yea, wasnt using it much so pacience for so long.

Yep sounds good. I did pull off the snorkal to for a we try but then i put it back on again, bit to noisey for me but i might cut it in half (ie. the lenght) to give half the efect.

Will be good now to see what the rest of the mods do for it.smile.gif

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Yea, wasnt using it much so pacience for so long.

Yep sounds good. I did pull off the snorkal to for a we try but then i put it back on again, bit to noisey for me but i might cut it in half (ie. the lenght) to give half the efect.

Will be good now to see what the rest of the mods do for it.smile.gif

As far as 'Bolt on' mod's go the next things for me are Boyesen 2 stage reeds, a DEP silencer and a slight upjet to suit...

but the carb looks a bit of a faff to get out and I have other plans to do with modifying the reed cage and the inlet manifold, so I might wait until my bits are delivered rather than have to work in this area twice.

Also maybe replacing the cylinder head in time, although I will wait until the first barrel off inspection and rings change for this one ;)

Last time (2 weeks ago)I inspected my barrel was through the exhaust port and I could see the herring bone pattern of the honing marks still there :D

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As far as 'Bolt on' mod's go the next things for me are Boyesen 2 stage reeds, a DEP silencer and a slight upjet to suit but the carb looks a bit of a faff to get out and I have other plans to do with modifying the reed cage and the inlet manifold.

Also maybe replacing the cylinder head in time, although I will wait until the first barrel off inspection and rings change for this one wink.gif

Yes to taking the carb out, you have so much messing and moveing to do with the air box its not funny.

Again i will follow your lead to the up jetting but dont know bout the reeds just yet.

Did you know there is still no MOT for bikes in this country yet. So becaue of this I am going to keep my origional silencer but just gut it out to the bare min without leaving it screaming.

Why about the cylinder head change, Am i missing something on this one ?

Ps. Before anyone says anything about MOT here, YES i do keep my bikes in tip top shape all the time and dont ride them if i suspect anything wrong!!!!

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Why about the cylinder head change. Am is missing something on this one ?

No not missing something, i dont suppose its often talked about but in the case of our 4BL bike's they are fitted with a cyl head of number 3BN.

Now 3BN has a strange squish band the likes of which I have never seen before and so I will possibly switch to a 3MB version at the first opportunity. This may make it clearer.

DT125RHeads.jpg

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No not missing something, i dont suppose its often talked about but in the case of our 4BL bike's they are fitted with a cyl head of number 3BN.

Now 3BN has a strange squish band the likes of which I have never seen before and so I will possibly switch to a 3MB version at the first opportunity. This may make it clearer.

DT125RHeads.jpg

Now this is getting a bit technical for me !

The only thing I know about the squish band is that if it is not set at the right gap then you use a lot more fuel.

Changing the head gasket to a thinner one can change the band gap and produce different performance. (race bikers do this) but I think there is more to it than this.

That 3BN head does look strange now that you have showen the two pic's. Wonder why has it got that hollow squish ? wouldnt it be better with the sloped one ?

You will definatly have to tell us about any change in performance when the time comes that you change the head. please! thumb.gif

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Like I said though its going to be a long time off, i'm not pulling the head off just to do that so will do it when theres another reason to do so. ;)

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