DT125R ARCHIVE

Calum122 · Guru

RE: now a non runner

madrevs · DTR Senior Member

Decided to clean the powervalve today dont think it had been done in years as was caked in carbon.1st pic is of clean valve and second pic is the damage where it had caught the ring.also cleaned tge piston crown and it had 1.00 stamped on so presume that means its 1mm os.another thingbi noticed is my powervalve has 3bn stamped on it and so does my head but the barrell is a 3mb are the powervalves and heads all the same or different depending on year

Thanks

Calum122 · Guru

Bin the 3BN head mate. They are a pile of wank.

The dtr 3MB00 barrel uses a 3BN powervalve. But the 3BN cylinder does not take the 3BN powervalve.

madrevs · DTR Senior Member

Are they really that bad whats the best one to go for

AndyYam · Guru

3mb is the unrestricted version.

madrevs · DTR Senior Member

Might have too see if I can get hold of one cheaply theres a couple on ebay but there like 40 quid which is a bit more than I can afford at the moment.

Calum122 · Guru

But you're looking at much more power gains from £40.

madrevs · DTR Senior Member

Oh really so theres alot of difference then might try having a ring round a few breakers see how much they are.are the 3bn heads worth selling on ebay.

AndyYam · Guru

I'd say 30 is about avergage price to pay for one. 40 is a little over the odds but its about what people are willing to pay. As more and more people with Dt's realise these are better, they will be more in demand and hence the price will rise.

madrevs · DTR Senior Member

Dont spose uve got one u want to sell

MDK · DTR Legend

dt125r.activeboard.com/t56435474/barrels-for-spares-will-need-re-bores-sold-as-seen/

madrevs · DTR Senior Member

Thanks mdk looks like hes only got one barrell left though with a head which is a 3bn so would assume the head on it is 3bn aswell.

AndyYam · Guru

ive not got any 3mb heads no sorry.

madrevs · DTR Senior Member

Ok thanks anyway have asked all the breakers on ebay so hopefully one of them will come back to me.one place has already replied but they want 50 plus post lol

madrevs · DTR Senior Member

$_2.jpeg Have managed to find a head with no markings on top a bit cheaper think its a aftermarket one are these the same as the 3mb ones has also got some pitting to the combustion area heres a pic

Calum122 · Guru

Hhhmm no markings?

I'm not aware of any after market ones. Only Italian Belgardas that don't have anything but a P stamped in the side. Although I have owned a no marking one before. Don't know what it was from.

MDK · DTR Legend

may be worth message some of thes on gumtree and ask for picks of the heads and markings

http://www.gumtree.com/search?q=dt&category=motorbike-parts-accessories&search_location=&current_distance=0.0&min_price=&max_price=

madrevs · DTR Senior Member

Thanks have just done that what about the pittings on the combustion area though is that ok to use like that

madrevs · DTR Senior Member

Also the combustion area looks completley different to my 3bn which is a good sign

Calum122 · Guru

Absolutely not. Pitting of the head is caused by detonation. Avoid like the plague. Far better off holding out for a decent condition one.

If you took it to a specialist it could be recovered for a fee. Maybe £30 or so.

madrevs · DTR Senior Member

Thanks for your advice

-- Edited by madrevs on Monday 17th of February 2014 06:19:35 PM

madrevs · DTR Senior Member

Dont suppose if anyone knows if the studs have to be removed for a rebore got a quote from a engineering place today and stupidly left it there to be done but have now had a change of mind.am going to pick it up in morning before they get a chance to start it.they quoted me

rebore including modifying powervalve removing head studs and sorting the damaged exhaust port:£80
Mitaka piston kit £55
Gasket set 15
Little end bearing 15
Apparently rebore was double what tgey normally charge cos of having to remove head studs

-- Edited by madrevs on Tuesday 18th of February 2014 11:32:14 PM

NEV · Guru

Gasket set seems cheap, I think its nearer £20 quid, make sure they use genuine Yamaha or Athena, and not some Taiwanese cheap ****e

madrevs · DTR Senior Member

I know what you mean am going to go down there first thing and cancel it as it seems like everything is way too expensive they want £80 just for the rebore and sanding the powervalve. Shouldnt have left it with them in the first place

Calum122 · Guru

Fcking hell. Head studs take two minutes. I usually remove them whilst on the bike to hold it.

£35 for rebore. I paid £85 for wossner piston kit. £40 for genuine gaskets. (Ripped lol).

madrevs · DTR Senior Member

Am definetly going to go get it in the morning before he starts doing any work to it

Victor · Guru

Did 2 barrels yesterday removed all head/exhaust studs in about 45 mins

Bent a few though >.< and engineers near me sell mitika pistons just over £40 last time i checked

And little end bearings for under £10 they do charge £35 a rebore though :(

madrevs · DTR Senior Member

Definitely seems like hes ripping me off cant understand it though cos hes got a good reputation around where I live.have spoke to pjme and theyre gonna charge me 115 all in which is alot more reasonable and that includes modifying power valve and removing studs etc also includes all the gaskets mitaka piston little end etc

Calum122 · Guru

Remove the studs yourself mate.

What you do is put two nuts onto the stud. Tighten them up against each other. So tighten one clockwise and the other anti. Tighten them up nicely. Then go anti clockwise on the bottom nut and provided you tighten the two nuts up correctly it'll take the studs out.

Obviously remember to locktite them back in after using the same method.

madrevs · DTR Senior Member

Sounds easy enough will give it a go