DT125R ARCHIVE

Hey there folks.  Glad to be here, really useful forum.  I only came across it by typing queries related to the DT125 into google and usually found some useful info on here, so I thought I'd join and share my experiences so far and also get some second opinions and advice from some of you more experienced DT owners.

So me....I'm 30, and this DT is the first I've had, in fact the first bike I've had on the road.  I only did my CBT this summer.  I had a couple of crossers in the past though as field bikes.  An old air-colled twin shocker 1980 RM250 that I got when I was about 14, then a few years later (about 2001) I got a 1992 CR250 - lots of fun but there's hardly anywhere you can use them these days without dog walkers or farmers etc getting the hump!  So I flogged the CR after a year or so and haven't really been on a bike since.  Then a few of my mates jumped back into the crossers this year with YZ's, CR's KX's etc - me slightly green with envy!

So I decided I'd get myself on road but with the ability to go off-road, what else would you go for but a DT125?  So I start trawling Ebay, Bike Trader and gumtree.  I decided I wanted a RE, as late as possible - most were between £1500 and £2k but I saw one on gumtree for £1200, a 2007 RE on a 56 plate with 13000 miles that needed a few things doing, new ignition and side panels (where some little ****s had tried to nick it) and it was out of MOT and Tax where it had been laid up in the lads back garden for 6 months.  I went and had a look, got it started and had a test ride.  It sounded a bit rough, slightly rattly and it was a bit spluttery and smokey, but hey I'd be a bit rough if I'd been laid up for 6 months too.  Having never even ridden a DT before I didn't really know how it should feel, run or rev through.  It all seemed there though, it had a full DEP system, original handbook, lights worked and went through all the gears etc.  So I offered a grand, we shook hands, did the paperwork and I loaded my new DT into the van and set off home.  When I get it home and have a good look over it, I see just how neglected it has been, it is thick with gunk and grime and a lot of the screw/bolt heads are chewed up - it seems to have been maintained with a swiss army knife!

A couple of days later after charging the battery and getting some new fuel in it, I warmed it up properly and took it for a proper ride.  The slight rattle seemed to get louder after it was fully warmed up and at tick over/low revs it sounded like a loose nut was bouncing round in the cylinder.  Investigation required.  I stripped the top end down and examined the barrel and piston, verdict.... f**ked!  Deep scores on the piston and barrel and severely worn rings.  Top end rebuild kit ordered from PJME, about £75 for the bits and I also ordered some LED micro arrow indicators, a enduro numberplate holder with LED tail/brake light, a little LED numberplate light, new front disc and pads from EBC and a full set of second hand plastics in black from Ebay.  Took my barrell down to my local bike shop for rebore (+1mm) or hone.  Gave the whole top end a good clean and ge-gunk, especially the powervalve.

Fitted my new top end, spent days messing about with several different flasher relays trying to get my indicators to flash (I could possibly start a thread on this topic alone), changed my pads and disc (snapping one of the studs on the bottom of the right fork leg on the wheel spindle pinch cover thing in the process), changed my plastics over and spent ages modifying and rewiring my brake lights, number plate light and tail-tidy arrangement.  Oh, I also found a set of blue anodised Renthals in the back of mates workshop that had been on some crosser at some stage, so they went on too to replace the slightly bent standard item that were on there.  And I drained and refilled the gearbox oil.

I'd been reading on here and DTR125.net about the de-restricting methods, so I cut the green/black wire behind the headlight and extended it right down the battery negative terminal.  It already had full DEP system and on the induction side, something strange...where the little air-bottle that bolts to the frame in the airbox to carb rubber should be, mine just had a little inch long plastic tube with mesh across it inserted into the hole in the rubber.  So most of the air it was sucking was coming through here intead of the airbox??  Anybody seen this before?

Anyway when it came time to fire it up, I was cacking myself because I'd never done a top end rebuild on a bike before and a bike mechanic mate of mine had told me I should do the bottom end as well because I couldn't be sure that the rattle was all top end and also putting a new top end onto a bottom end with even the slightest bit of wear would quickly nacker the bottom end.  But being tight on cash, I decided to ignore this advice and just do the top (i wouldn't even have attampted the bottom end myself so as well as an extra £100 in parts for main bearings, con rod kit,seals gaskets etc I would have to give said mate the bike to do at a cost of another £100  to £125).  Anyway, I fired the bike up and to my relief it sounded like a dream compared to what it sounded like before and it didn't spit out any rings or anything.  Success!!  I put it through the MOT a couple of days later and it sailed through, got my insurance and tax and I was off, trying very hard to stick to the running in advice I got off this very forum.  I also stuck a good glug of 2 stroke in with the first tank of fuel to ensure extra lubrication for my new piston/bore.

The first 100 miles i took fairly easy but it was really hard to not open her up after that and not having a rev counter I really don't know how easy I was taking it.... probably not that easy!  She seemed to be going well. Anway in these first couple of hunred miles, the bike seems to have drank loads of fuel (about 4 tanks) and nearly a whole tank full of 2 stroke.  I thought this seemed a bit thirsty and I also noticed that there was quite a bit a black oil coming out the end of my silencer, the joint where the silencer meets the front pipe and around the the the front pipe to cylinder joint??  Is this a sign of the mixture being too rich, jet size being too big, the extra 2 stroke i stuck in with the first tank of fuel or some thing else.  Thirsty on fuel, thirsty on 2 stroke, oily exhaust emissions?? It also doesn't start on the button the way my mates 55 plate RE does, he just has to flick his starter button, no throttle and his fires up.  Mine needs a couple of seconds on the starter and a twist of throttle.

I had a look at my carb and tried to adjust the pilot air/mixture screw but this had been chewed up by someone in the past and could not be turned, so I've taken off the carb and the reed block to inspect these.  I've just won an Ebay auction for a 2007 carb )apparently in good working order).  The reeds in mine may not be standard, they are made out of a semi-transparent plastic/fibre and seem to a be a different thickness and stiffness on either side. 

So that's where I am at now, bike in peices on my patio, carb on the way hopefully and lots of questions - there is enough there for a few threads or to add to any existing threads on similar subjects if anyone can point me to where they are at.  Bike now owes me nearer £1500 so it hasn't tuned out to be the super bargain I thought it was but they rarely do, do they?