Consmos

Well hasn't this been a reply long time coming Thanks for the help everybody, it was a success in the end! I bought a pile of tools, sanded, primed and painted a number of parts (e.g. see photo of previously rusted, newly sprayed radiator mount), made friends with mechanics across the water who helped me out with the jets and paint samples (cheers to Wemoto, allens mikuni, and Bike Colours of Lancaster!), and generally made a nuisance of myself by hammering at all hours of the night. In the end, she looked pretty good ... That includes help from the mystery guy at Hurst Yamaha Belfast who supplied me with the plastics and stickers for prices that made me wonder if I should have gone into the sticker business. She lives and rides on, many thanks to everyone on the forum for helping a complete newbie through a top end rebuild. And here she is on top of a mountain in County Donegal, with my latest ride... a nice little XT660R So apologies for the late update but I was a bit carried away with the new bike. My dad is currently sporting a nice little Suzuki DRZ 400 E, I'm, thinking of trading the DT125 in for a 2010 RM450Z now that I've gathered a bit more experience offroading at at Paddy Dakar and Dave Thorpe's joint in Wales. So thanks again for the help, anyone interested in some light Enduro in Northern Ireland, drop a line!

Cheers again Nev. Having a nightmare trying to get my hands on the right paint for the tank. Have the frame painted, and know the Yamaha ref code for the paint, but every paint shop I go to has no listing for it - even companies with chromatic scanners that automatically match the colour. Nowhere has it! Anyone know a generic paint code match?

She lives! wooo turns out i hadn't tightened the cylinder head bolts enough haha. Now I can get to sorting the power jets cheers Nev I managed to get spray for the frame - and for anyone from Northern Ireland looking to spruce up a bike, Givran autoparts on the boucher road in Belfast are brilliant people - after months of unsuccessfully searching for paint I dropped into them and five min later had a can of exactly what I needed! Turns out the tank is a different colour though so back to Givran tomorrow seat is wrecked though so be aftet xmas before I can get a new one...

I should have been more specific there - I was looking at your dt125 pages when I posted that!

Where did you get the fork covers Nev? I'm in the midst of a total amateur job on my dt and trying to spruce it up a little while i'm at it, might as well while it's in pieces! I can't believe what a pro job you've done on that wee ride, pure awesome

So here's the score: I've flushed out the crankcase (and you should have seen the crap that came out, never mind the pile of aluminium that came out of the expansion pipe!) and have the bike together again but I cannot get it to start! I've tried the bigger power jets but it can't be that anyway, he engine isn't even starting. I've checked the spark and it's fine, sparking away merrily. The float bowl is filling with petrol so it's not a feed problem, I'm thinking maybe low compression or a problem with the primary stage jets? Any ideas how to check? I don't have any equipment to check the compression, will have to take it to a mech for that, but before I go there can you guys think of anything I could try regards the carb?

I tried halfords, they're not the most educated bunch so far and could only promise a 'close enough' job, I'd prefer exact match if I can find one... Colorrite don't seem to ship to the UK, and B&Q don't mix up aresols, just buckets. Found a couple of local folk who mix paint but again, not in spray cans. I spent ages searching for the correct colour code for the deep purplish blue then tried to buy some from Yamaha... Not only did they not sell it but they were able to tell me instantly that the colour code I had was wrong and that I shoulf have just asked them in the first place haha

Well quick update so far - I'm having a hard time getting hold of a couple of things, mainly paint and a new seat cover. I checked with Yamaha and the closest match to original I can find is from bikecolours.com in England. They have stock of what they believed was the official match to the deep purplish blue but arent selling at the minute due to a disputw with a customer who argued that it wasn't a good match. Bikecolours are sending me a sample free of charge to test out and report back to them! Ordered a seat cover from portugal and sadly the quality is that of a poor rip-off Anyone know where to get one? One industries and factory effex do some pure awesome covers but not for dt125's, seems that nobody sells them for this bike, not even Yamaha! Haven't managed to flush out the crankcase yet as the bottom engine bolt is totally seized. On the upside, new jets have arrived and when I get a chance I'll stick up photos of what a bit of halfords radiator paint, clear laquer and elbow grease can do for severely rusted radiator mountings

I'll buy a handful, they cost almost nothing compared to another rebuild so i don't mind wasting a handful of coins if it means treating the engine well! My intention is to have it fully derestricted although noone seems 100% about how many restrictions there are, I read a lot of apeculation. No intention of carving up the manifold as the benefit seems negligable, I'd just buy a new carb if it came to that. My power valve appears to be fully open and functioning, i can't see where it's supposed to be pinned? And it's definitely orientated correctly. The CDI has been grounded and the new exhaust system was going to be the final effort to get some pep out of it... Hell maybe it did work, I didn't have time to find out!

Got the jet out! Turns out its a 4/042 hexagonal size 210. So if 210 incinerated he piston, is 250 a big enough gap or you reckon I should go higher?

Right guys here's where we're at so far: I've managed to rip the carb out after having a hell of a time trying and failing in getting the airbox off - it simply didnt leave room to manouvre the carb out, had to use more force than i was happy with. There's simply no way it's going backnjn unless I get the airbox assembly out of the frame - does anyone know how?? I removed five bolts attaching it to the frame and two bolts holding the rear mudguard on, which also join the airbox to the battery housing,but i cannot for the life of me get the damn thing out! It went in at some stage so I know it comes out, and the haynes manual says it comes away from the frame but doesn't elaborate. I also cannot seem to get the float bowl screws out without chewing them off and wrecking them, they're pretty soft and they're in there tight!! But on he upside this is the most technical i've ever been so far with a bike, thanks to the forum and the Haynes!

That looks great andy. Where did you get the spray paints for the frame and the engine casings? And what do you recommend using to strip rust and old paint off first? In the midst of restoring mine and I am completely new to it all!

Cool. How do i know what's already in there? Having a hard time googling it. Does the number on the jet indicate the size? And do you think I need to change the air jet / pilot jet etc as well or should they be kept as they are?

In trying to derestrict my 04 i earthed the CDI cable (which did very little??). Then i tried turning the power valve round 180 degrees - my bike went fron 74mph top speed to 55mph flat out. So turns out mine wasn't restricted at the power valve, but if you're getting 55 out of it tops then i'd recommend turning your valve - worst that can happen is nothing happens, and it's not a hard job, even a novice like me can do and undo it.

Thanks, I'll have a proper nosey at the crank tomorrow and try to clean it out properly. As for the jet size.... This is where I fall down, I have absolutely no idea. I know that the two most complex systems are the carb and the gearbox, so I haven't touched either! The jets should be completely standard for an '04 dt 125, whatever that is! How will I know what size they are, are there markings? What is required to change the jet? Is there anything in particular to beware of or can I just amateur it apart and back together like the rest of the bike (with great care of course)? The engineer honing my cylinder almost slapped me when I suggested a plug chop, and he justified himself well - he claimed it was best to buy a pile of different jets and start with the very biggest I could find, graduating down slowly until the bike was just running, as a plug chop could mean that by the time I inspected the plug for damage I could have already destroyed my newly-repaired cylinder and another piston. Any thoughts? I need a proper education regards changing jets, I'm sure I could figure it out mechanically but I realise that misjudging it could send me back to square one!

Thanks for the help so far, took the cylinder to a mechanic today, he's going to try to hone it and worst case, bore it by tomorrow. He's of the impression that bigger jets were absolutely required for the exhaust and he believed that was the entire of the problem. That's kind of what i had thought, has anyone any ideas what kind of jet sizes might be best? The crank looks fine but there's a bit of aluminium dust on it :/

Allow me to correct myself - the pipe from the top end of the stock expansion pipe (and is no longer attached to an exhaust) is NOT the YEIS, it's the AIS - air induction system, which apparently "uses exhaust gases to pulse fresh air into the exhaust port, where it mixes with hot combustion gases. The additional oxygen provided allows combustion to continue for a longer time, reducing unburned hydrocarbons jn the exhaust gas content". So that additional pipe was part of the emissions reduction system. Again, out of ideas as to the cause of the problem!

Yep you're right there, the pipe from the original exhaust leads to a solid plastic joint which then feeds to a second hose leading to the airbix under the seat. The black boost bottle also connects only to the manifold via the rubber connector, no other inputs or outputs. What does the boost bottle do and how does it function? Could the hose from the airbox be relevant to the damage done to the cylinder? I don't see how it could if the aftermarket exhausts dont have any connector for it but i'm running out of ideas! Is it possible that something was wrong in the first place and the new exhaust just accelerated the damage?

Yeah there is a connector on the stock expansion pipe that was attached to what the Haynes manual said was the YEIS, although i have nonidea what that did or why. When i revved the engine with my finger over the now loose YEIS pipe I couldnt feel any positive or negative pressure, so no clues there either

Yep it's a little bit cheaper than the Dep equivalent, i just didn't want chrome as I read some reviews and heard that chrome exhausts rust quite easily after they take a few knocks. I reckoned a black one could be easily resprayed!

Hello all, 29 yrs and loving my wee dt125 re at the minute, they say you never thrash a four stroke like you thrash a two stroke really into offroading but it's hard to find places and people in northen ireland! Glad to be a member now, hoping I can be as helpful as everyone else always is here

Yep sorry meant expansion pipe! No didnt go for the big bore kit, just the exhaust can and pipe. How the hell could it suddenly run so lean?? The top of the piston was reduced to sand and there are tiny flecks of the remanents of molten spark plug on it!

Hello Everybody First time posting anything so bear with me, but I can't think of a better place to start - I need to crowd-source some wisdom, and hopefully lots of help Long story short - I have no experience whatsoever in fixing bikes. Or maintaining them. I've never even changed the oil in my car. But after I finally got round to getting my bike license (after a number of unfortunate setbacks) I decided to whip the dust sheet off my pristene DT 125 RE. It may be eight years old, but it only had 4000 miles on the clock and was in brilliant nick. So I thought. Turned out a friend of the family had 'borrowed' the bike as part of some half-hearted crisis and wanted to learn to ride. This, he did not. He took it for a couple of spins and left it to rot in the sun and the rain outside his house for months. I hadn't even known it was gone. So imagine my horror when I saw this: *********** **************** The photos don't do it justice, but in brief: A mirror missing, the other so badly corroded that it was hanging off. Indicator torn off. A large hole in the left side of the seat. All the pastics were had faded and warped from exposure. The wheels were orange with rust. Rust eaten through the paint and into the frame, joints, radiator, tank. Gearbox oil seal rotted and oil was leaking out. Crankcase badly scored. And so on... I don't even know how he managed to be so careless with such little use, and he didn't offer to fix it. Determined to bring it back to life, I decided to throw myself in the deep end and learn by doing! One Haynes manual, a load of new plastics, nuts, bolts, mirrors, indicators, clutch levers, elbow grease, chrome polish, wire pads and partridges in pear trees later the bike was as you see below: ************** Not a bad job for a complete novice there was still the matter of the rusted patches on the frame and tank to take care of, I know they will be the end of the bike if I don't sort them, but after pricing a new tank and failing to find a second hand one, I've decided on stripping the paint back, priming it, painting it again and lacquering it. Does anyone know how best to take the rust and paint off in the first place? Any ideas would be great! Now here comes the really serious problem!!!! I decided that I'd now derestrict the DT and see what it was really made to do. Spent a very long time digging about on the net until I had figured out some tricks - power valve is the correct way round and it lets the bike reach 74mph, although wheelies were just never going to happen - I've wheelied on a 75cc kawasaki when I was a kid so I knew a 125 could do it! I grounded the CDI and got a little bit of extra pep off the starting line and it was more responsive at low speeds, but I didn't get the major power gains that so many people hd harked about online :/ I knew the major restriction lay in the exhaust and the expansion tank, so I eventually bought the bullet and ordered an Athena expansion tank and exhaust can. My Dad and I had some father-son bonding time putting it on when I should really have been studying for an exam All seemed well, the wee bike sounded a it louder, but when I took it out there didn't seem to be much difference. I kept her at tame speeds about a tiny minor road, then after about six minutes got out on to a major straight and pinned the throttle to see how fast she could go. The needle hit 74 and just kept climbing, and i was about to break into a smile at 80mph when there was a series of bangs and rattles and the bike rolled to a stop. Non-starter, trailer pickup required. The starter motor turned over but engine didn't start, putting the choke on would give the occasional backfire. The gearbox seemed fine. I later stripped the bike down and saw the damage: WTF! I had completely cooked the piston. The spark plug element was completely missing, looked like it had been totally burned off. And now the interior of the cylinder seems slightly scored, although I know that even slightly scored can be a big problem. Can anybody shed any light on this?! Can anyone help? I'm going to take the cylinder to a mechanic to see if he can hone the cylinder out and fix it for me, he was recommended by my local Yamaha dealer parts dept so hopefully he'll be able to sort it for me as the cost of a new cylinder (£435!) would just mean the end of this bike and a deposit for a new one I poked about with the remains in an attempt to find out what had happened, clearly the engine had been running too hot, but I couldn't figure out why. I hadn't altered the air intake at all. The website selling the Athena kit recommended standard carb jet settings for the exhaust so standard is what I kept, particularly since I don't have a bloody clue how to change that! I also asked the Yamaha dealer who said that they used to sell aftermarket exhausts and never recommended any change in jetting, and that he didn't think a new exhaust alone could have been the cause of the damage. When we removed the stock expansion tank, there was a hose coming from the top of the tank and leading up behind the radiator to a plastic block and another hose. Apparently this is the YEIS (yamaha energy induction system), which Yamaha explained was mostly for power regulation and cold starts, and wasn't strictly required. The reason I had asked them is that the Athena expansion tank had nowhere to attach this hose, so we just tucked it away. Could this be relevant? The Athena system definitely was the right one, and I can't see how they would leave that out of the design if doing so would wreck the bike. I'm looking forward to hearing some opinions, really want to get this machine back on the road!! Thanks!