AndyDtr08

A week or so back on the seafront by me a young lad of 18 was blown off his scooter by the 82mph winds we had. He was wearing a helmet and died from head injuries. Extremely unlucky but I'm sure the helmet would have had some effect. Riding a motorcycle you'll never be 100% safe. A helmet merely reduces the risk as does the rest of the gear. Anthing that reduces your risk of death has to be worth it. I would always wear one.

A standard DT will do 65. De restricted, should do 80. Tuned, who knows...people claim crazy things like 110 which is could be possible for a very short period after a very large amount of money but who would want to one a 125 trail bike that shakes at 70? Once mine is finished I'll be happy with 80-85 and thats will a high compression head and full sports exhaust system.

Sorry but I can't condone "shatting" on other bike riders. Especially when riding yourself. It would be extremely dangerous and messy!

An update. The barrel was rebored. I got a Mitaka piston kit with RIK rings with it. That has been re fitted with my 3MB head. The barrel is a 3MB y-1 also. It appears there are varying barrels too, 3bn y-2 etc. I'm guessing they will also be restricted in some way. Glad i got the 3MB one re bored now! When fitting the piston I made a big boo boo. I removed the wadding from the crank and dropped a piston circlip down the crank. An hour or so later after what looked like 3 men operating with torches and mirrors and hooked wire we managed to get it out. Lesson learnt! The engine is now back together and appears to have a lot of compression. I tracked down a 30mm piston and seals for the rear caliper to Wemoto and ordered the front (35mm) online from ebay as it was cheaper and wemoto still havnt got them in stock. http://www.wemoto.com/bikes/yamaha/dt_125_r/98-00/picture/stainless_steel_piston_and_seals_rear_caliper/ http://www.ebay.co.uk/itm/YAMAHA-DT125R-DT125RE-DT-125-BRAKE-CALIPER-PISTON-KIT-/230739697058?pt=UK_Motorcycle_Parts&hash=item35b9285da2 I started dismantling a set of forks ready for a rebuild. Managed to bid and win a set of seal on ebay that someone never got round to fitting to a bike before they sold. Paid 7.50 including delivery so saved about 12.50 there. http://www.ebay.co.uk/itm/120925653682?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649 I can't get the large allen headed bolts undone on the underside of the fork legs. The manual seems to say that they will turn the inners of the forks but I cant even get them to budge yet! On the exhaust front. The 2 spare standard ones I have, one ha a big hole and appears to be scrap. The other looks like its been chopped and welded and has been welded wrong so the mountings dont line up. I'm going to try and repair the DEP for now until I can get hold of a decent condition standard to chop myself. There are a few holes in the DEP so will either get it welded or try some GUN GUM. Have cained my funds at the mo so a new exhaust will have to wait until I've sold some of the spares or servo's I've accumalated. Got a load of my stuff returned from the DVLA too because I didnt fill out the check correctly. The problem with being young. I've never used a check before. cheques 1 and 2 in my book are both 25 quid to the DVLA for replacement log books! I don't understand, do they sell the cheque for money to someone else becuase it has my autograph on? Next step is to fit a battery and the powervalve kit back up. Then hopefully we'll be ready to fire up the engine. Rebuild brakes and it'll nearly be there. Only thing holding me back now is time constraints. Watch this space!

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When you turn your key in the ignition to on, the valve should run its self clean cycle and you will hear it make 2 noises as it turns one way and then returns to its rest position. Does it do this? There are photos and explanations in the pinned thread in the dual sport section. Start by taking the cover off and checking if it's pinned into place at the top. If it isnt, chances are it is all operating correctly. Then again it could be turned 180 degrees in the port. The best way to check it all is with the exhaust off as said before. If you are not good with mechanics you may be better asking a garage to look. When replacing the exhaust you'll need to make sure you re seal it well as you'll lose power if not and make the whole process pointless. The Haynes manual has a guide on how to set the cables correctly. Be careful if your adjusters havnt been moved and are corroded. The threaded section can easily snap if not lubricated properly.

Yes Haynes covered the "TZR" but it doesnt cover these models at all. There were 2 different types of 4DL. One has a banana swing arm and the other is straight. Yeah they had 125cc engines put in 250 frames. Pm me your email and I can send you through the parts manual I have.

A friend has the same bike. I will ask him what manuals he has as he may have downloaded some. I have a parts catalogue for the 4HW which is very similar I beleive? There isnt a haynes manual for the bike unfortunately but you may be able to get a service manual online. Let me know if you want a parts manual. The reed block will be the same as the D125R so you could take the clearances from that i expect.

I've had an Idea. When I'm up at boretech tomorrow I'll ask if I can measure up the sizes of one of the DT125's tank stickers he has in. He has a 1999 with 100 miles on the clocks thats been left there by a customer for 5 years. I'll measure them up and take photos. Get a friend to design them well and take it to a sticker printing shop and get some made up.

Unfortuantely he only sells the stickers for the plastics as apposed to the decals that are needed for the tank. I bought my stickers from him. I did enquire when I ordered but he can't get hold of them. If I do find I can get them made up. I'll get a load done i expect as it will be cheaper. Boretech rang today to say my barrel is done. I was exploring the world of Harry Potter at the time though at the studio tour and so didnt answer. Going to pick up a bike for my dad tomorrow. He's bought a Triumph TR6 C and we need to go to collect. Hopefully I'll be back in time to pick up the barrel before they close.

I'd like to know that too. Our postie's arnt even allowed push bikes any more. They all have to walk with trolleys.

Will do! I'm looking exploring the avenue of tank decals now. It'll be the 3 "squares" as on the 1999 model. http://www.yamahamotorcyclespares.co.uk/spares/epc2.asp?modelID=9132&PageiD=26&m=YAMAHA+DT125R+++1999+FUEL+TANK&uID=0 From that it looks like they'll be 80 quid for the 2. About 40 each side. Bloody expensive and I'm not sure I want to spend that much on them. I'm going to see what other options I have. I could buy some from Yamaha dealer, take them someone and get some made up then get a refund!

Yeah you can't get a torque on all of them. I've found that too. Have to just test the torque wrench on another on the bike and then try and match that feeling with a similar length spanner.

I would agree. Get home and check the compression. If you didnt re tighten the head nuts after you'd ridden it in a bit it could easily be a cylinder head gasket leak. I, personally, would have the head off and put a fresh gasket in and start again. 12-13 quid from yamaha for the peace of mind. Just remember to re tighten this time.

Incase anyone looks up this thread and needs help, I've answered my own question. The front appears to have an oil seal and a dust seal. The dust seal is held in place by a circlip. The rear doesnt have a circlip but has an oil and dust seal. Rear piston is 30mm and front is 35mm. Be careful, all of them on ebay are 35 and wont fit the rear caliper. Only place I've found other than Yamaha for rear is Wemoto. New 30mm piston and seals is 30.44, from yamaha its about 50 i think. Just the seals are 30 from yamaha. Their front set with piston and seals is about 26 quid. I'm waiting for it to come into stock.

Oh one other quick on. Brake lines. Anyone bothered upgrading to braided and if so how much and where from? The front on this looks pretty bad and will be being replace with something.

Ok guys cheers for the advice, I'll definitly upgrade to a heavier oil when I do the forks. I've got 2 sets off and one set on this bike. These are leaking and i suspect the spare ones I have will be too so I'll be rebuilding one set. Never re built forks before so will be a good learning curve. Any advice on that front would be useful. I had to tidy the garage up today so my Dad can get his car back in whilst it's stopped raining for a day. Had a quick go at the rims with some peek and a toothbrush just to see if they would come up nicely. I'd planned to put the ones on I bought but might leave these on, will have to see. They came up nice though. Then I was moving spares into my brothers old room which I'm using at storage for bike parts now and spotted the headlight surround so had a go with the stickers. I found the best technique was to line it up with the back on. Get someone to hold it still and then peel back some of the backing and cut away a bit of the back. Lay it back in place and it will be exaclty right. Then you can peel back the rest of the backing from the cut you made and begin to lay it down. As i layed it down I use my finger and went back and forth along the bit that was being stuck, pushing out the air all the way to the end. Worked pretty well. Ended with a few bubbles. All of which were from the start where I hadnt figured out that techniuque yet. Used a pin like NEV suggested to get rid of the bubbles.

Gonna go to WeMoto. It's just down the road from me in southwick so will get piston and seals for both front and back. 60 quid total. Dropped the cylinder up at Boretech Engineering today for a rebore, new piston kit. Should be about 110-115 all up he says. Picked up fresh gaskets from keys this morning too. Am not sure whether to re build forks or not. Have a couple of sets in the shed i could look re build whilst they are off the bike. I want to put fresh gators on anyway.

Worthing is South Coast, 12 miles west of Brighton. The plastics are all after market from Portugal. The front mudguard is a "UFO" which is similar to the one on the RE. I quite like the styling of it compared with the original anyway and cant get hold of the original front. Could spray one up but like I say, I like this one. hmmm... these are the options. http://www.ebay.co.uk/itm/FRONT-CALIPER-SEAL-FIT-YAMAHA-DT-125-R-/270970715085?pt=UK_Motorcycle_Parts&hash=item3f171cfbcd http://www.ebay.co.uk/itm/Yamaha-DT-125-R-3RMB-98-Front-Caliper-Piston-Seal-Kit-/150733948416?pt=UK_Motorcycle_Parts&hash=item2318718600 Think i'll go for full sets tbh. Andy

Hey 2Wheels. Yeah this one is a 1998 4BL version DT125R. It's the one in the first post. Black and White then. It's running the connections for a 3 wire servo which is useful as i have about 6 at present! The manual talks about circlips but like I say the parts Manual/Diagram shows it without. I think I will purchase new pistons with the oil seal, dust seal and circlips as the front was in far better condition and that was running a dust seal with circlip. Both pistons have signs of pitting and brakes are not something I want to take a risk on. Its 50 quid for the front and rear pistons and seals. Got to be worth it. Yeah a mate has a 2001 DTR and his runs the bigger YEIS bottle. The one I have there could well be from an earlier LC model but I'm not 100% sure. Are you running a 3MB head? I can't wait to get her running, MOT'd and on the road. I plan to ride it around the coast of the UK in september. Don't worry about taking your brakes apart for me if you dont need to. I've got a few spare calipers in the shed so i might take them apart and have a look. Think i'll go with the full set anyway. I'm taking the barrel up tomorrow i think for a re bore, turned out they were closed today so tidied the garage and then went to work to find the hospital flooded. Was on national news all day im told. worthing hospital being flooded. caused havoc!

You may want to post an introduction to the forum if you want help and advice. Even then, you don't reply to someone elses project thread. Start your own and you'll get more responses and better help.

So I'm re building the calipers on my DTR project. They were in a bit of a state. I'm a tad confused about which seal kits to get. The front had a piston seal and a dust seal which was held in place by a circlip. The rear caliperhad a piston seal but the dust seal appeared to have no circlip and was damaged badly. According to a Yamaha Parts diagram, neither have a circlip holding in the dust seal an just have 2 similar looking seals. Ebay says otherwise with kits being sold for both which have an piston seal, dust seal and circlip. Anyone got any advice on what to go for? Andy

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