DT125R FORUM

I think your CDI will be restricted if its stamped 3RM-10 but should be ok if its 3RM-20 or 3RM-30. If its the latter, check the powervalve isn't rotated to a restricted position which is what mine was.

Just been out for an evening ride before the forecast says it’s cold and wet again.

It’s like a totally different bike, and everything I’d hoped from it when I got it

Yeah friends have had import cars and you definitely need to have a lot of love for them to deal with the cost/rarity of parts!

My last car was an M3 and there was horrendous M tax on parts for that!

Nice read, shame about the ending

Having come from cars, bikes are refreshingly cheap for parts from what I’ve seen!

Well at least I wasn’t talking complete nonsense

Mines a ‘2002’, registered January 2002 and on a 51 plate now so guess it was pre-change.

@NINJA that’s a fresh approach vs multiple other places that don’t want external links cheers dude.

@NINJA said in Another New Guy:

@d3cme Share a link to the post you found dude, as someone else may benefit from it in the future!!!

I wasn’t sure if it was against the rules but well worth a read to future people who may have similar.. im really hoping it’s all sorted anyway, looking forward to getting out on if when the oil cap turns up.

https://yamahaclub.com/forums/topic/20583-de-restricting-my-dt125r/

@Calum said in Another New Guy:

@d3cme I haven't seen a powervalve that wasn't a diamond. I always recommend taking the exhaust off and matching it against the exhaust port.

I saw some pictures where it was rectangle and totally filled the slot, not sure on year etc though that the pic was from.

Bikes are new to me, cars I’m fine with but I was apprehensive about taking the exhaust off. I ordered a new gasket but it didn’t seem to have one in to replace? Absolutely the best way and only took a couple of mins.

So I may have sorted my problem... I say may, because it makes sense but am yet to test.

On another forum I found some posts from about 8 years ago outlining someone else’s derestriction journey. Looks like he had a 2003 french import DTR, so very close to mine.

He found that the Powervalve under the pully was a diamond shape and needed turning to a derestricted state as it wasn’t flush with the exhaust port. Now I’d seen mention of a diamond shape thing somewhere and also mention of turning the powervalve but didn’t really understand what it meant. There was also a restriction in his 3MB-14160 expansion chamber just like the older models straight out of the cylinder.

I was working last night so had some time this afternoon to take a look, and found my powervalve had this diamond shape on the end, and after getting the exhaust off I could feel that it wasn’t flush in the port.

Now that I’ve aligned it all, and run it up the servo is back to normal (it was a bit sticky straight after turning so I guess things were gunked up where they shouldn’t be).

Annoyingly I can’t ride it currently as the gearbox oil cap is all chewed up and I had already dropped the oil and taken it out by the time I realised. Hopefully a replacement will be here tomorrow.

Initially though it seems much smoother and revs more freely after warming it up a bit, but won’t know for sure until I ride it. I guess with the powervalve being out of line entirely it would have been restricted right through the rev range and ‘wide open’ still restricted as much as fully closed?

Not sure if this means I’ll need to rejet... biggest worry currently so will keep an eye on the plug. Couldn’t see anything in the exhaust so hopefully be much better now.

Sorry for the long post, will get a few pics up later to hopefully make sense of it all..

Thanks All,

I think a certain amount of this is managing my expectations. I used it for work today and it was great, I think its just not got the 'kick' I was expecting from the YPVS. I'll have a look at the PV tonight and take the exhaust off to see whats what!

I was actually eyeing that exhaust up earlier @NINJA, looks very nice!

@NINJA said in Another New Guy:

@d3cme There are restrictions in the exhaust front pipe too, which can only be removed by cutting it open and welding it back up. A straight swap to an aftermarket exhaust is easier and may be cheaper too.

Is there a way of checking? I think I saw that the 2002's have it in the larger part of the exhaust as opposed to immediately in the neck? Will I need a new gasket? I'll borrow a borescope in and see if I can make anything out.

Seen some bits about flipping the PV 180 degrees? Any truth in that?

Sadly no change still having moved the Reed Switch well out of the way.

Think I'll whip the exhaust off later and check there is a powervalve in there lol

@Calum good point, thank you!

@Calum said in Another New Guy:

@d3cme That's fine, older DTR's don't have that bottle. I removed it from my DTRE and used an older style boot. Eventually deleted it entirely by using a pod filter.

When you say older though, mines a 2002 so later DTR, but early if compared to DTX/DTRE I think? Looks like it’s how it should be as opposed to obviously missing something though.

@d3cme said in Another New Guy:

@NINJA said in Another New Guy:

@d3cme You can't miss it dude, it sits against the frame next to the air filter cover, aka that black bottle between the fuel tap and the sprocket;

Take and post a pic of your bike the same as the pic I posted above please dude.

I deffo don’t have that! I’ve got the bracket now I know where it sits... can’t see where it would connect on that elbow though?

The elbow on mine looks like the alternate ‘19’ in the diagram. Not sure what it means though? No YPVS? different YPVS?

@NINJA said in Another New Guy:

@d3cme You can't miss it dude, it sits against the frame next to the air filter cover, aka that black bottle between the fuel tap and the sprocket;

Take and post a pic of your bike the same as the pic I posted above please dude.

I deffo don’t have that! I’ve got the bracket now I know where it sits... can’t see where it would connect on that elbow though?

Sorry half effort answering both of you there.

It will rev freely up to the indicated 10,500rpm redline in neutral or with the clutch in.

Power valve seems to be ok (unless there’s nothing in there if that’s possible?) but was the first thing I checked and did need to align it but didn’t really change anything as I can’t get into the range where it would be wide open cycles as you’d expect when turning the ignition on and settles lined up now. Battery was knackered when I got the bike so I’ve replaced it, does anything else need resetting/setting up after?

Temp sender I’ll get ordered as won’t do much good broken if nothing else (yikes how much!)

@NINJA said in Another New Guy:

@d3cme Your water temp sensor may be knackered? Which is a possible cause to your problems, but it sounds like you have another problem causing the restriction. Is the power valve set up correctly? Has the YPVS (?) air bottle been removed? It's number 35 in this pic, it comes off the intake between the carb and air filter box;

https://www.fowlersparts.co.uk/parts/4171936/dt125r-3rmm-2002-050-b/intake

I can’t see anything missing but not sure I can see that part exactly.. will need to strip it back a bit more to see for sure I think.

While I was looking I’ve got 2 ports on the carb without anything on, I got some pics and will look on that site to see if I can see the same view for the carb and work out what they are.

@theportingmaster said in Another New Guy:

@d3cme I have a 2002 dtr imported from the isle of man, has the 3rm-20 cdi. Moved the reed switch about 6 inches just cut the insulation so could pull the 2 wires really out of the way. Mine didn't rev past 7-8000 max till moved the reed switch now revs past 11000 and goes off the clock. If you rev it stood still in neutral does it got to 11000.

This sounds promising then, I’d literally moved it to where the cables were glued into the insulation. I’ve just moved it to under the headlight so will give it a try and report back...

That was after about a 30 min ride (also annoying condensation in there too).