TDR 125 restrictions?

[machete101]

Hello

I have a TDR 125, that struggles to get to 60mph and then maxs out around 60mph. It has no trouble getting to 50 but struggle to get to 60, its seems to limit the revs to 8-8.5k when it gets to 55. I was just wondering are there any restrictions on the tdr 125 or anything that i can check that could be causing this problem.

The bike is fitted with the powervalve which i believe is set up correctly. Also can anyone recommend what tooth sprockets to have on this bike?

thanks

[stevo as b4]

I think TDR125's are generally too old to have any electronic speedo switch/CDI restrictions.

But the most likely place to find a restriction or several as well as a Catalyst in the case of the TDR is in the exhaust system.

Older DT125R's with the same engine used to have a funnel shape restrictor welded into the front of the expansion chamber. And I believe that later model DTR's had half moon shape restrictor plates fitted into the fattest part of the expansion chamber.

[Kickstart]

Hi

Which model of TDR125 is it? Most I have seen are Italian market bikes and probably never restricted. If one of those then probably either in need of maintenance (eg, new piston, exhaust cleaned out, etc) or has been restricted some random way by whoever imported it

All the best

K
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[machete101]

[Kickstart]

Hi

4FU is I think the model that was imported (or at least that shape was officially imported). So could be a real restriction. But I would expect that to be 9kW or 11kW restriction.

All the best

K
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[machete101]

[charliemopic]

For your reading pleasure

https://www.scrimsmustangsclassicyamaharestorations.com/derestricting-the-yamaha-dt125r-1988-through-to-2007.html
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Current Bikes: Yamaha TDR125 & Kawasaki Versys 650

[Vincent]

Is there an extra red light on the clocks that says something like "speed"?
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[Vincent]

If you havn't seen it already, and it's correct, this may help:-

https://www.biker.ie/forum/showthread.php?t=43444

"its restricted twice in the expansion chamber and the powervalve restricted in its use.
the exhaust is easy to get the restriction near the header out but theres another washer further inside and would involve cutting open the pipe in half, removing then welding back together so not really worth the hassle.

to derestrict the powervalve remove the cover from the speedo and at the back of the clock there should be a long white colour thin fuse like object this is the reed switch that cuts the power after 60mph i think.

if you take this out of its slot wrap in a ballon and place as far from the slot as you can will do the job.
my DT has only 2 of the apparent 3 restrictions gone but i never had much of a problem getting to top speed so i dunno"

The year of manufacturer should be on the log book or import slip.
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[Vincent]

Is there a number on your CDI?
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[Kickstart]