DT125R ARCHIVE

Ralzy · Guru

Problem is leaving me scratching my head

Calum122 · Guru

Ok so heres how it goes. From my knowledge the standard exhaust has a catalytic converter in it.

To keep the engine cool the carberetta is over jetted to compensate for the catalytic converter. By taking the out this catalytic converter you may have now too much fuel to air mixture.

Ways to rectify this problem.

To test to see if this is your problem you could remove the snorkel in the airbox and see if your still having this problem.

Or

You could rejet it appropriately by putting the standard jets back in (Pre catalytic converter models).

Hope this helps and sorts the problem.

Ralzy · Guru

Already taken the snorkel off no joy on that one it has a a 240 jet in the carb I didn`t think the 02 model DTR had a catalytic converter

Calum122 · Guru

You didn't say what year your bike was.

A 210 jet sounds rather high anyway. I'm not an expert though. If your exhuast had that mesh in it then that could also too make your bike run hotter. That may also lead to a greater jet required for cooling.

You could try to down size the jet slightly. Other than that it could be faulty PV. Try pinning the PV open and disconnecting the PV server. Then take it for a test run.

xGINCATx · Guru

Calum122 wrote:
Ok so heres how it goes. From my knowledge the standard exhaust has a catalytic converter in it.

To keep the engine cool the carberetta is over jetted to compensate for the catalytic converter. By taking the out this catalytic converter you may have now too much fuel to air mixture.

Ways to rectify this problem.

To test to see if this is your problem you could remove the snorkel in the airbox and see if your still having this problem.

Or

You could rejet it appropriately by putting the standard jets back in (Pre catalytic converter models).

Hope this helps and sorts the problem.

The 'standard exhaust' on DTR's have never had a cat converter in them, they've only ever been in a DTRE or DTX

And I've never known a DTR carb be over jetted to compensate for having a cat converter in the exhaust.. Infact my 04 RE only had a 210 main jet in from stock, I tried a 240 main jet and if anything it made it worse/harder to reach top speed!

The 03 DTR I had seemed the have the same problem as the OP in the fact that it struggles over 65MPH, Fastest I had mine was 70MPH with my head tucked down and the wind behind me
I had removed the clock restritor thing (IMO did 0.fack all in terms of speed) and removed the snorkel too and all that did was increase the air intake sound and made it sound abit better lol
Exhaust at the time was a full standard system, so I think I did well for 70MPH lol

Long rant I know, but I don't have any suggestions either, I just think the 00-03 series are hard to get over 70MPH, I'll let someone who has one and has been over 70MPH chip in and try and get it sorted for you

Calum122 · Guru

Like I said I wasn't aware of the year!

They do do that sometimes! Over jet it to cool it down.

My only other suggestion is faulty PV.

xGINCATx · Guru

Calum122 wrote:
Like I said I wasn't aware of the year!

They do do that sometimes! Over jet it to cool it down.
My only other suggestion is faulty PV.

Picture of his bike clearly isn't 04 onwards, plus he mentioned the speedo restriction behind the clocks so my guess is it's a 00-03 model

I just think the DTR's released in that time frame are hard to get to full speed, I've also had a 97 which flew with a faulty PV that was pinned open

Another thing I've thought of is that somewhere on the forum someone mentioned about a powervalve being 180degrees out of alignment.. I'll try and find it and post it if possible..

Ralzy · Guru

Its just doing my head as when its not bogging out it really wants to go and do the bizz. when this happens it sounds so much different & muffled than it normally does especially having the snorkel off. Grrrrrr lol hope others may be able to share some light on this. Thanks for you input

xGINCATx · Guru

Found it
Linky
Worth checking for the effort it takes to remove to bolts holding the PV cover on..

Calum122 · Guru

O RYT! YEAH I FORGOT YOU CAN ONLY HAVE ONE BIKE AND ONE BIKE ONLY! TRUE! (thats sarcasm)

That could be anyone's bike or he may have been talking about another bike. As for the speedo restriction I wouldn't know about that.

My brother's DT was rapid.

http://www.youtube.com/watch?v=bOGAEzTaBgI&context=C3a3419fADOEgsToPDskIz4olIkl4ZAu1otVSdCnCy

That was a 2001 model.

Ralzy · Guru

I should of mentioned the year & model of the bike at the beginning of my post which I will now amend. I will look into the 180 degree turn & even pinning the valve open to see how it goes that way.

Ralzy · Guru

Tried 180 degree turn & even pinning the valve still no joy yesterday. But I`ve just come back from a spin tonight and it seemed to go much better sounded different too. Power was different revs went up to 9000 which it never usually does thought YESSSS Shweet. Then I came back all chuffed had a quick drink and thought right see what its like now I`ve stopped for a bit. Went back out and its feckin doing the same thing again WTF gutted to say the least so back to square one again Grrrrrr.