Yamaha dt125re rebuild



  • @bradt Mean rear tyre. I hope you plan on taking this offroad!



  • @calum (insert generic Australian accent) that’s not a tyre, THIS is a tyre!

    https://imgur.com/a/rSZ5X47



  • Light off-roading yeah as I’m using for work need it really can do without it breaking down!

    Just that leak to sort out now and struggling to locate one for today as need the bike tomorrow 😑 any local to Sheffield and wanna source a spare bowl gasket ?



  • @bradt Literally go and make one.

    Go to Halfrauds or a MotorWorld and just buy gasket paper.



  • So will try gasket paper as silicone has stopped the leak but still seems like I’m not getting fuel to the spark ? Anything else I need to check ? All carb was cleaned out new filter in there etc getting abit stressed now



  • This is a lot harder without electric start working so having to bump the bike every time I try and start it



  • Does anyone know where the black wire (I’m guess an earth) on the coil is meant to go

    Iv just fitted a new startermotor to the build makes it easier to start and found I have no coil

    Noticed the black wire with hook was connected to the coil itself should this be earthed to frame or is this right ?



  • The starter motor has a red wire only which connects to the starter solenoid (this is the square thing with two fuses in it by the battery). There is a black wire with a hook which connects to the neutral switch which is located near to the starter motor at the bottom of the engine casing on the flywheel side. this in turn plugs into the part of the loom which goes into the stator/generator coil via a bullet connector. Hope this helps.



  • @2Stroke4Smoke very helpful went through all wire and found a broken wire replaced and fixed nice bright sparks and fired up

    Thank you



  • @bradt Glad you got it sorted 🙂



  • So last night after during the match I decided to take the bike for a ride out see how everything was , bike felt great really responsive but loud but exhaust needs sorting

    Come out for work this morning bike fired up felt great work is only 5mile away iv got just round the corner and my red light came on and the bike was steaming pretty bad I coasted it to work and iv lost all my coolant I’m aware this could be down to the head gasket but I’m hoping it may be something else.

    There was pressure in the radiator when I took the cap off and the expansion bottle cap has stayed on any one know what else to check before I order a head gasket ?

    Thanks



  • Her she is looking pretty 🤔



  • @bradt have you bled the system of air?



  • I did but maybe not long enough cannot see where the coolant is coming from it’s just dried all white over the barrel and head



  • @bradt coolant doesent dry I’ve had my fair share of leaks on hot engines and never seen it dry



  • @declan surely any liquid would dry and leave some kind of substance after touching a hot engine. Iv reckon iv found the culprit there a little house what connect to carbs what isn’t fully on and can see it coming from there but the amount iv lost surely hasn’t come from there I’m unsure tired and frustrated and still gotta rude home on it tonight after work!



  • @bradt Be alright, just take a bottle of water with you. Don't open that radiator cap until it's cooled mind you!



  • So iv got back and did a little test on the way,

    So when I’m cruising (not full throttle) the bike fine doesn’t smoke out the exhaust and no steam off the engine, so on a little open bit of road iv throttled the bike started slowing down and there u go smoke and steam

    So seams to me when the pv kicks in I’m loosing coolant any ideas ??



  • @bradt Head gasket failure, happened to me two weeks ago. The water pump is driven off the crank so the higher the engine speed the more water is pumped round the engine and thus the more pressure in the cooling system so the higher the engine speed the more coolant will be lost to the crankcase. Just order a new one as it isn't a problem that will fix itself but rather will leave you stranded when you most need to get home! - I used an Athena head gasket and so far no issues, I think it was around £15.00 off ebay. It's pretty straightforward job, you'll need to check that the head isn't warped before reassembly by putting it on a known flat surface i.e a glass table or a granite work top and if you can rock it side to side, then it is warped. If it's warped you'll need to have it skimmed before reassembly - you can do this yourself or have someone do it for you.



  • Wasn’t that long ago I head the skimmed and new gasket carnt see any visible leakage from bottom of the head top of barrel, I can see the odd drip coming from the hose where it connect to the head from the radiator.

    But will be replacing the head gasket anyways done it plenty of times so it’s an easy enough job

    But thanks for reply mate