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DT125R Forum -> Tuning -> 2002 DTR DE-RESTRICTION HELP
Post Info TOPIC: 2002 DTR DE-RESTRICTION HELP
shanedtr


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2002 DTR DE-RESTRICTION HELP
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Ive got a 02 dtr 125.
I have read the info on this site about de-restricting them, ive got a full big one race pipe, removed the rev restriction, but can only get 65 at a push.
It has a induction type sound at the end of each gear...

Im pritty good with bikes, so got all the tools etc to mess with it but...

How can i get a bit more speed?

cheers

-- Edited by shanedtr at 13:16, 2009-02-15

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shanedtr


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and what spark plug should i be using?
as im not sure whats in it....
cheers

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AndyA


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The BR8ES is the best plug because it runs a bit hotter than the standard BR9ES but I have put an Iridium plug in my wifes which is the BR8EIX, I hope that helps. AndyA.

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shanedtr


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Yeah cheers mate, any ideas on the more speed side of things?

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Gixergav


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Get rid of the big one front pipe.They are crap mate.Use a dep or better the standard but derestricted front pipe.That mod alone will probably sort it.
No end of people have power and revving issues with big one pipes.They are the worst performing pipe for a dtr

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shanedtr


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Is there anything else i can do?
cheers

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Gixergav


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Is the snorkel fitted on top of the airbox? If not get it fitted.
Your bike will have a restricted cdi like all 97 on bikes.You have to derestrict that,change to a derestricted one or change the loom and cdi to a pre 97 one
But plenty of folk seem to hit 70+ on these restricted cdi boxes
Make sure the powervalve is operating correctly
I reckon the big one pipe is the cause of your trouble though

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medxb183


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got mine off the clock today,all i have done is ,pulled white oblong box from speedo,fitted big one end pipe but have gutted the front standard exhaust,everything taken out,cut inlet manifold as on dtr de restriction page and removed snorkel,running on iridium plug,was riding with my brother today and he has a african twin,he could not believe it that i was right on his tail when he was doing over 80mph,cant wait to give it a full test without any windbiggrin

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meds
SimsonS51E


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Hotter Plugs F*ck Engines ...
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shanedtr wrote:

and what spark plug should i be using?
as im not sure whats in it....
cheers


HOT PLUGS F*CK ENGINES ....


Running HOT plug, does F*ck all for performance, but can & will shag your engine !

The heat ratings for plugs has F*ck all to do with the heat of the spark, it is the length of the insulator, which is directly linked to the plugs ability to wick away heat ...

The plug needs to run at optimum temp in order to burn off oil & deposits so as to keep the electrode clean / clear.

Common two stroke tuning will usally need one or two numbers of cooler plug [one that wicks away more heat] to keep it at the correct temperature,as by de-restricting / tuning motor more heat will be created & higher rev's ... 

If you were to go on the safe side [Cooler] the very worst that can happen is the plug will not reach optimum temp & oil up [you shouldn't be out in the woods on a 2 Stroke
 without a spare plug anyhow !!] ...
The motor will cough & stop ... No Biggie !

If you tune motor & use Hotter' plug with the misguided idea that hotter is faster etc etc [Bull*hit !] ... the plug will get so fookin hot it will start to glow red hot, causing pre ignition ... !

Warm Day,  Thin Air,  Tuned Motor worked hard ... Wrong Plug !

Your piston top will look like the surface of the moon
& eventually Hole !
More likely engine will sieze first !  Both Bad Karma !

It's not as risky on a liquid cooled motor as an air cooled ...

But im speaking as someone who has F*cked more than one top end with above scenario !!!!

Has anyones got a reasonable idea why you should ever use a hotter rated plug ... Espec' on a tuned / high revving 2 T  ???????????

UNLESS YOU WERE RIDING IT ROUND LIKE A GRANNY, AND THE PLUG KEPT OILING UP ?






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Blue - DT 125 RE - '04 - First Of The Leccy Start Lanza'Like Bikes ! 
shanedtr


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RE: 2002 DTR DE-RESTRICTION HELP
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cheers for that, so what plug would you advise then?

ive removed the oblong white rev restriction, and it has a full big one race pipe.

Cheers

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SimsonS51E


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Run standard plug ... Don't Go Hotter !

Your restricions seem to be ....

http://dtr125.net/tuningf.htm

But general feeling is that Big One Xpanny chambers give real poor top end performance !

Standard Xpanny with restrictions to airflow removed or DEP front needed.

Reed Switch in speedo needs to be moved well away from unit & bagged up. I HAVE NEVER SEEN ONE OF THESE ! IM ASSUMING THEY ACTIVATE WHEN BIKES NEEDLE HITS 60 MPH ????
So it will need to be well away from anything ..

Post some snaps [somebody ... anybody !] of this reedswitch arr' .. and how it see's .. the needle ? Im assuming it acts like a proximity switch ?
Magnetic ??

If so, and it's normal state is N/O, there is no reason it can't be removed !
Just need to see how one works when needle is sub 60  &  After 60 .. !

Don't bother with the Reed Valve in the inlet manifold mod's .. they don't work too good ! and not needed !

Does your bike have a PV and a servo to control it ????

Does it work ? & zip either way on ignition switch ??


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SimsonS51E


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Older DT's ......

Old Manual on Site ....

Says ....    BR 9 ES

Haynes Maunual  ....  BR 9 ES ...



Newer DT's 04 to 07 .......

Manual for DT 'RE' & 'X'   BR 8 HS ....

http://www.spark-plugs.co.uk/pages/technical/ngk_symbol_code.htm

2 = Hot   /   11 = Cold ...

0.7mm to 0.8mm Gap on plug across range
 [get some feeler Gauges, tight ass ! wink !]

Suggest using correct plug, for reasons stated before !!!  furious

Newer motor runs hotter plug, but if you were to go one cooler, worse that can happen, plug oils up ! {carry spare with you !}


But if your de-restricting & planning on fast road stuff [most DT's on the road are full chat / flat out for 80% of their lifes !]
Would stick with the cooler plug
The ... 9



-- Edited by SimsonS51E at 18:00, 2009-02-16

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Gixergav


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Br9es plug for a dtr.Always use NGK plugs too.
In all the time i have been tuning strokers i've never had to use a plug other than what should be used
NGK plugs are tough too.Believe it or not but some Top Fuel drag engines 4000+BHP run standard off the shelf NGK plugs so they can take the abuse

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medxb183


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Gixergav wrote:

Is the snorkel fitted on top of the airbox? If not get it fitted.






have re-fitted the snorkel back on mine yesterday,so going to see whats it like now as i too have my doubts about removing it. will let you know later today.

 



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medxb183


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having replaced the snorkel on my dtr for the first time since derestricting the bike i find it does not improve performance whatsoever,there is also no drop in performace either....so in my view go as you please,sounds better with it offbiggrin

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meds
Seiki


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the snorkels purpose is to stop mud and debris getting into the air box its not a restriction

i think what gav is saying is that a stock bike is set up with the correct airflow for the jet size to give the best performance all through the range

by removing the snorkel your increasing the airflow ever so slightly and without adjusting the jet it can only do more harm then good

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medxb183


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with mine being de-restricted what would you advise ? on or off ?
thanks for advise.

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meds
Seiki


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even though its de restricted the stock airbox should still provide more than enough air for a stock jet size i would re fit it m8 it

if you want to get into messing with jet sizes then i would say take it off and maybe even drill your airbox but its a bit of a black art m8 if your unsure what your doing it can be real bad for your bike



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medxb183


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up to now i have just followed the de-restrictions as on the dt site...but i do a hell of a lot of miles,1,000 in 2 months,so need reliability,it hits 75mph most of the time and the 80+mph mark ,on a calm day i would expect 85mph,but living in north wales you want get many wind free days untill the hight of the summer...i dont think thats bad for a 125 in general...would you advise some reeds ? acceleration i do enjoybiggrin, if i put some other reeds in would i need to alter the jet size...
whats your view on the reeds ?

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meds
Seiki


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hmmm reeds well first things first you woulden't need to re-jet but weather it improves performance is one of them topics of debate

they can improve throttle response but there not gonna make a dramatic noticeable difference we've talked about this before and id say unless youv'e done everything else that can be done its not at the top of the mod list

all bikes are different things like rider weight,if the bikes been ragged in the past and gearing can make the difference between a 75mph dt and a 85mph dt if you really want to spend money on something worthwhile whip the top end off your bike and take it to an engine shop for head skimming,porting and polishing this is how you take your dtr 1 step beyond and by far the best value to performance upgrade

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medxb183


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thanks for the info,i will stick with your advise

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Gixergav


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You need reliability so stick with the stock internals of the motor.If your hitting 75-80mph then thats as fast as a derestricted dt will go.To get it going quicker will compromise reliabilty.
How often do you get flat out? If not often then going up a tooth or two on the rear sprocket will make it accelerate quicker but lose some top end speed.
Running without the snorkel will only pass more air through the box but the engine can only breathe so much.No real point in removing it
The dtr has fibre reeds as stock so changing to racing reeds will again make very little difference.On a more highly tuned motor i would advise changing them but the stock reeds work very well.Some tzr 125 race bikes i have seen have used standard reedblock and reeds despite running ported and flowed top end which shows just how efficient they are

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medxb183


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Gixergav wrote:

You need reliability so stick with the stock internals of the motor.If your hitting 75-80mph then thats as fast as a derestricted dt will go.To get it going quicker will compromise reliabilty.
How often do you get flat out? If not often then going up a tooth or two on the rear sprocket will make it accelerate quicker but lose some top end speed.
Running without the snorkel will only pass more air through the box but the engine can only breathe so much.No real point in removing it
The dtr has fibre reeds as stock so changing to racing reeds will again make very little difference.On a more highly tuned motor i would advise changing them but the stock reeds work very well.Some tzr 125 race bikes i have seen have used standard reedblock and reeds despite running ported and flowed top end which shows just how efficient they are


thanks for the help and advise,its not very i get flat out only now and again and its only in short bursts.

 



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martyna


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Hey guys, I'm new here, so I want to ask about fuel consumption. Does the bike use much more fuel? I'm interested in de-restricting it, but I want to know if I will be able to afford it if fuel consumption is twice as it was.

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Dickhead


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back2future.jpg


make a new thred mate ur get a better responce



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craigbulmer


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Robin, I like your use of pictures, funny lol

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Dickhead


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hopefully its just a phase

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