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DT125R Forum -> TDR125 -> Poorly TDR 125 - 2007 Model
Post Info TOPIC: Poorly TDR 125 - 2007 Model
muttsnut5


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Poorly TDR 125 - 2007 Model
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Hi, thanks for the response and pointers, all very helpful. I've had the silencer off and cut it open, I found the problem, it seems when the CAT came adrift in the expansion chamber it must have been bouncng around for a good while as most of it was stuck fast in the outlets of the silencer, so I've cut the tubes short now so that all 3 can flow straight out of the exhaust pipe end, it certainly sounds alot better and rev's much quicker.

I will have a look at the CDI wire as that sounds like a must do mod to get better performance, I think a 240 is in it, but I am only going on measurements from a 240 jet I have for my LC, which looks the same jet but as I say the one in it is a tad ropey so I may change it anyway.

Going to give it a run tomorrow, suspect it will be much faster, at least 60MPH I would hope biggrin !!!

Presumably the DEP silencer will make it free flowing and sound fruiter than the one that's on, even after my butchery on it, although its all welded up again now and in paint, so won't look too bad when back on the bike, its a nice comfy bike and big for a 125, so I am hoping to get around 75 to 80 out of it, if I can then that would do me for winter trashes

I'll do the test run tomorrow and update the thread so people can track the progress as I am sure others must have had this issue with the CAT breaking up and blocking the exhaust?



-- Edited by muttsnut5 on Tuesday 27th of November 2012 09:50:18 PM

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muttsnut5


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Hi Guys, new to your forum as I have a poorly TDR 125, to cut a long story short, the bike wasn't running when I got it, anyway, I've got it running now after a significant amount of work which included cutting the expansion chamber open and removing the cat that had come loose and was stuck in the exhaust outlet, hence why it wouldn't start/go - it couldn't breath !

So I took it for a spin since it was working thinking that was the issue solved, but it won't go past 40MPH no matter what I do, except down hill and I got 55MPH out of it, it really doesn't like revving at all !

Since then I think the silencer could be blocked - its done 10k miles, so possible, plus when its running there is hardly any pressure coming out of the end of the pipe, certainly a lot more comes out when the silencer isn't fitted, so I am going to cut open the silencer tonight to have a closer look etc.

Anyway, it seems the previous owner wasn't exactly truthful with me as I've had the carb apart and the main jet appears wrong, its in bad shape and I can't decipher what size it should be, does anybody know?, also since the bike is in bits I am thinking I may as well go full hog and de-restrict it, I past my test 30+yrs ago so license isn't an issue

I intend using the bike as a winter hack but need better performance than this and I am sure it is more than capable of it, but before I start ripping loads of parts off it and putting different parts on I'd prefer to just de-restrict it and keep it looking bog standard as best I can.

From what I have read, the following mod's seem to work for the TDR, but is it the same for a 2007 model?

1. Ground the black/blue wire coming from the CDI unit

2. Gut the cat out of the exhaust (done) and open up the rear silencer and gut that, or fit a DEP etc? - prefer to keep expense down - so will gut it since I have a welder etc

3. Change/update the reed block - is that just trimming the snorkel part of the large rubber inlet block off, or change the reeds as well?

4. Fit a bigger jet, since I don't know what size is fitted, can someone advise on the stock size (240, 270?) and what up size I should do if I mod the bike completely as detailed above?

Is there anything else that can done, or should be done to make the bike more performant?, my aprillia 50 is faster than this at the moment !!

Thanks in advance guys, don't normally work on such small stuff, my main diet of 2 strokes is LC's and AC RD's, of which I have many and  have restored loads, so happy to help anybody out there who might need it 

 

 



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FunkeyMunkeyDavid


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hello and welcome! the tdr is the same engine/carb as the dt so i'd start with a 240 main,they run well on that. dont cut/chamfer the reed block because it does nothing,all motocross bikes have the same thing. hytech reeds are a good little upgrade for response/fuel flow. gut the front pipe and dep back box,the standard rear strangles them. earthing the wire was the main restriction on tzrs,good chance its the same on tdr's. then its check and adjust the powervalve and see how she goes. been on 2 tdrs that topped 85-90 biggrin



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FunkeyMunkeyDavid


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the cats are prone to coming loose and breaking up,convieniently blocking the whole system. the dep tail seems to let it breathe better with the right amount of back pressure,sounds like you've sorted the problem though! someone else was going to do the wire mod and get back to us,not heard yet though?



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FunkeyMunkeyDavid


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my bad,he did reply and i'd not read it no from what he says its defo a go on grounding the blue/black wire and taking the snorkel off the top of the airbox...



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muttsnut5


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ok, I'll test ride it with the exhaust mod today and then do the CDI mod and snorkel and then report back on the difference between the 2, that way we will know for sure. A DEP would be nice, but to be honest if the standard works fine I'll leave it for now as if I want very fast I will ride one of my others and it won;t cost me anything !



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muttsnut5


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well I took it down the road after fixing the exhaust and it topped out in 6th gear - approx 75mph and it was at 10k revs, so I am not sure it needs a wiring mod, or if I did it what more I would get as it certainly shouldn't be revving any higher without risking blowing the thing to bits

Presumably the wiring mod is to free rev's up to redline , or is it to bring the power valve in at a lower rev range, it certainly doesn't have a kick as such, but it does go reasonably well, just wondering whether or not to do the mod now, thoughts anyone?



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Skintt125


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Hey,

It was me who grounded the black/blue wire the other week and took out the snorkel from the airbox! If your bike is hitting 10k revs then you don't need to ground the wire! My bike topped out at 7k revs b4 I grounded it! Now it screams right up to 10k biggrin

I have a micron end can on mine and I have also hacked out the welded in restrictor in the header pipe... I havn't gone near the CAT in the expansion chamber as that is a little too much for me to handle! Haha! I hear that the normal main jet size for the TDR is 270, so I think I'm going to upgrade to a 290 next! Also on my list of things to do is the boysen reed petels, hi flow air filter, 17t front sprocket and (when I can afford it) a full gianelli or arrow system! that should give her a nice bit of power to hold me over until I upgrade to a 690 supermoto biggrin

Keep me updated on how you get on with yours anyway... would be interested to hear how certain mods affect the bike! smile I'll keep you posted as I add parts to mine!

Cheers,

Kev.



-- Edited by Skintt125 on Saturday 1st of December 2012 05:30:01 PM

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