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    Saw an ad posted yesterday for a 2008 TDR with a seized engine for £470! But the best part was, it was just a couple miles down the road from me!

    I thought regardless of the engine, the bike should sell for parts up to and beyond the amount I paid for it should worst come to worst.

    The chap delivered it to me today so I thought I better get to it and see the damage!

    (Just so you know, I was told a previous owner had let the bike run dry of oil.)

    First and foremost, I have had engines seized in the past and know that if there isn't too much damage, the back wheel obviously shouldn't move when the bike is in gear. Well already there is a bigger problem here as the back wheel on this lump moves without a hesitation when in gear... So already it seems to me that just a top end is out of the question. Never split cases before so this should be an experience!

    Here it is just after being delivered!


    It sounded as it does when there is a dead battery, but the battery was fine as all the lights were coming on no problem. (I later find out that the starter motor was broken.)

    Rusty lump!


    So far I have removed the head and cylinder. The gaskets were of course melted and pretty much every bolt and nut will need to be replaced as 90% of them are not safe to use again. They are either half made of rust now or have completely snapped in half. But anyway I managed to get the cylinder off and what did I find? IT LOOKS LIKE THE BEST CONDITION CYLINDER I HAVE EVER SEEN! No re-boring for me! 🙂

    Dead head gasket

    Nice black piston!

    Basically when I pulled the cylinder off, the piston moved freely and the crank was turning with only a slight scratching sound when I moved the back wheel. It then decided to stop turning and now the back wheel moves freely in gear again.

    Tomorrow I may pull out the engine/check the clutch because I suppose if the clutch was always engaged or disengaged, (I'm unsure of correct terminology here) then the back wheel would move without the crank spinning?

    Anyway I thought that was enough for one day as it started to get dark and the garage I work in is very badly lit atm 😞

    ---Originally posted on 23rd September 2014


    Managed to get the engine out today after fighting with more rusty bolts.

    DT and KX in the background.

    However there is some good news and some bad news.

    Good news is I managed to pull out the piston clip that my friend stupidly dropped down into the bottom end. I didn't realise until today that this was why the crank wasn't turning as he said he saw the clip hit the floor when he took it out...

    ---First update on 25th September 2014

    Here's a vid of me turning the crank. You can just about hear the sound it makes.

    ---Issue with crank being chipped (or so I thought...) posted on 25th September 2014

    I now need a new clutch basket... I did buy a clutch holding tool but I stupidly decided to try taking it apart before it arrived. Live and learn.

    Here is a the damage.

    This hole in the bottom of the engine is perfectly normal for anyone who is wondering

    ---Updated again on 25th September 2014

    Just about managed to get more or less everything apart with only a couple of minor issues and four quick trips to the garage to borrow their air impact drill! Firstly, this bolt will need replacing but seems to be the only one.

    I'm assuming I'll have to order a set of them now? And no I did not do that myself, it was pretty much rounded when I opened it up!

    Secondly, the thread for the above bolt is on the starter motor here, but as you can see it's slightly broken...


    Two very awkward-to-remove bearings!

    Gears ahoy!

    Gotta make sure to cable tie these nicely!


    The cable ties here are to ensure I put all the washers etc back in the right order. (This seriously helped me a year down the road when I ended up putting everything back together!)

    And lastly, everything put snuggly away ready for another day.

    ---Updated again on 27th September 2014

    I have all the bearings out that I could tap, the last 3 two of which are needle ones for the clutch can't be tapped out so I guess I'll just leave them in there. They seem fine to me.

    ---Small update on the 27th September 2014

    Started cleaning up the cases 🙂


    Not finished yet but got most of the crap off!

    ---Posted on 29th September 2014

    Nothing major just showing some bits that have come in the post 🙂

    Second hand working starter motor £45 from DeeTeemx. Turns out my one, (on the right) didn't spin up when connected to a 12v source so this was probably the only thing really wrong with the bike before I dismantled it all...

    Second hand clutch basket £15 from DeeTeemx.

    Gaskets, spark plug and gearbox bearings from eBay and 'SimplyBearings'. £78 total.

    A few stainless bolts from 'abolt-fromtheblue' on eBay. £14.

    Still yet to arrive is the engine paint, (£20) and bits from PJME:
    main bearings,
    and clutch springs totalling £130.

    Still yet to order is the piston! (+ Any non engine parts that will need replacing.)

    ---Updated again on 4th October 2014

    Good news, Skellerns in Cheltenham have allowed me to send them my crank, conrod, cylinder and head! I was uncertain about what size / shape piston to get because, due to my bore being nikasil, the piston variations are measured in increments of 0.0x Which is a bit too accurate for my liking! Also according to them, some 4FU cylinders use flat top pistons whilst others use dome. So they have said they will supply me with the correct piston and let me know if any work needs to be carried out on the cylinder / head. Although apart from a good clean, I don't think any work will be needed.

    I have finally got around to starting the painting!

    Before cleaning with all parts removed. Water pump seal was a bitch to get out.

    After cleaning / sanding with masking tissue at the ready!

    Couple layers of primer.

    But unfortunately no pictures of the finished product at the moment. I ordered graphite instead of silver so couldn't use that!!! (Added another £10 to total cost)

    I will of course be replacing the screws and needed something to secure the water pump / oil pump bits on so just screwed them back in for the duration!

    ---Updated again on 10th October 2014

    Finished version of the clutch cover 🙂

    ---Updated again on 13th October 2014

    Small update:

    Skellerns checked out the parts I sent them today and have said the cylinder was in very good condition so I can use a standard piston supplied by them. They are also going to hopefully be supplying me with all the cylinder to crank case and head to cylinder bolts, nuts and washers. I gave them my frame number and they have said according to Yamaha it is a 2001 German import. Looking at around £80 for piston + rings.

    ---Updated on 22nd October 2014

    Just a mock up of the bottom end together.

    ---Posted on 13th November 2014

    ---This is the point at which I nearly gave up... But a year and a half later and an update will be coming shortly as the bike is finally running! Here's a picture of the engine all ready to go back into the frame.

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    So a year and a half later and I am SO happy to say that the bike is running! Just running it in at the moment but the torque is unreal compared to the DT 125 X I had last year. (Although that DT was running a piston that probably had quite a few thousand miles on it but still.) I genuinely think the flat top piston makes a hell of a difference.

    I only managed to get around to putting it all back together because it was taking up so much room! But now after taking it for a quick spin up the driveway, I am really having a tough time deciding whether or not to just keep it. It's bad I know, but I really rushed getting it all running... As such, the bike still looks like a right shit heap.



    Unfortunately the years of sitting meant that the rust eat right through the silencer so I had to perform the ultimate redneck bodge which included duct taping an exhaust I had lying round onto it so it wasn't stupid loud when I started it up.



    Surprised the expansion chamber stayed intact looking at it.


    But hearing the engine run was the motivation I really needed to continue the build.

    Just about started here with jump leads.

    Then a few hours later it was running a lot better!

    Those videos were taken before I put my silencer on.

    So now I either have to try and source a stock silencer for very cheap, OR just go all out and purchase a full system for it. I'm thinking of choosing the latter at the moment because a full Giannelli system for it is only £135 brand new posted! Not choosing Giannelli out of preference, It's just the cheapest reasonable-performance one I can find.


    Now some of the ins and outs behind getting it running.

    I had to make a few purchases along the way, firstly being a new 4FU head which are very hard to come by, but thankfully DeeTeemx came through again last year and I snagged his last one.


    This is what happened to mine.

    Then I ended up needing another temp gauge...


    And then another neutral switch...

    Also stupidly purchased new push rods and the ball bearing that sits inbetween them.

    And somewhere in-between all this I ended up realising why the TDRs with the newer frame never had kick starts...


    From rebuilding this bike, I still don't really know why it was left to sit for so long as the engine wasn't seized, the only things wrong with it when I got it were the clutch adjustment was way out, and the start motor wasn't working. I have also found a couple of what I feel are useless bits, carb warmer hoses?! A coolant overflow tank?! A couple of YEIS bottles which I'm not convinced do much...

    Any reason to not run the carb warmer hoses?

    And this coolant bottle just seems pointless. The overflow pipe from the top of the radiator goes to it, and then it appears to just fill up and spurt out from the overflow on the bottle itself?!



  • Coolant expansion bottle is a must. If you are finding that the bottle is filling up and overflowing then sorry to be the one to tell you this but that's the symptoms of a head gasket failure. And if you used that one supplied to you in that cheap gasket set then that will be why. Athena or Genuine are the only gaskets that cna be usrd on these cylinder heads.

    Engine was lookong good apart from that. I always skim the head and barrels on a rebuild.

    Those 4FU heads have a combustion ring that adversely affects performance. A 3MB would see noticeable gains on that.

    Hey you have done a good job breathing life into it. Its a good project don't be ashamed to move on.

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    So it's a coolant expansion bottle... I can't quite work out it's purpose... On mx bikes the coolant will only drip out of the overflow if you put too much in. I'm sure it doesn't expand? Don't worry Callum I remember you mentioning it to me more than once. I used the Athena one and haven't had any coolant overflow so can't see how the bottle is used. Yeah I would like to find a new project but ill need to do a little bit more to this at least so it can pass an MOT.

  • @MIGHTYMAN Yes the water expands as it warms up. It moves from the radiator to the overflow. It should not spill out. Not even drip. Shouldn't lose a drop.

    I have had this happen to me on my motors, both car and bikes. It's either the thermostat not opening. Causing the water to just overheat. Or the head gasket is blowing, causing undue pressure inside the engine.

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    I'm not losing a drop and never have in the past. I'm just saying I thought it was just an overflow. So, if the coolant expands and falls into the coolant expansion bottle, how does it end up back in the radiator loop as there is only one pipe going to it?!

  • Oh sorry. As it cools and contracts it creates a vacuum which pulls the water back out the bottle and back into the radiator.

    Sorry I didn't understand your question at first.

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    Okay now that makes sense. But why don't mx bikes have them? I just filled my TDR radiator loop up with the same Putoline stuff I used to chuck into my KTM and it doesn't seem to have expanded so far. I'm sorry if it seems like I'm being a bit thick but I like to know all the info before I can fully understand something.

  • I took the the coolant tank off, I just run a short pipe off the overflow into a Redbull can now,

    Makes no difference, never lose much fluid even after it get's very warm.

  • @Darty Yes that theory Mightmany. To put it into practice I am not convinced either. It is what it is. Darty has the right idea.

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    Got a pretty good video of it nearly fully back together and running nicely earlier.


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    I was going to post in the wanted section but I highly doubt anyone will have what I'm after. So I'de like to know if anyone has any info on whether or not there is any other front brake callipers that are the same as the one on this bike? My one is totally seized so had to remove it ages ago. I think it'll be costly to rebuild it so might as well buy a second hand one.

  • looking at the pic it looks the same as a fzr600 if its 100mm centres if its 90mm could be the same as a fzr400 ,, would a tzr 125 not be the same ?

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    I might dismantle it tomorrow so I'll jot down some measurements. Found out I'm going to have to do something about my rear brake on my WR so I might as well rebuild them both I'm thinking. Took the WR one apart today and it wasn't too difficult really. £15 for the rebuild kit so I'll see how it goes.

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    Small update,

    A used stock TDR 125 exhaust popped up on eBay the other day so I grabbed it for £60 delivered. I quite like the original look of the bike, even if the performance won't quite be all there. I think it's a good selling point. If I do decide to keep the bike I might pay out for an aftermarket one though. Not bad condition I thought, should clean up nicely.



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    @mad73 Yeah I have seen that but I was hoping to pay a bit less as all.

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    Plastics definitely need some work, but overall they are in a lot better condition than I remember. Left to do is fit new indicators, fit new exhaust and rebuild front calliper. Then I'm pretty sure it'll be okay to get through an MOT!

    Totted up all the receipts I have for the bike and it came to just over £1200 including original cost of the bike... Wasn't surprised, but if I had of known it was going to need that much spending on it, I would have considered just selling it for parts tbh!


    Another video of it running with the full stock exhaust system on it now.


  • Looks sweet man, good for that money.

  • It's looking grand pal. Well worth the time and money. 1200 is cheap for what it is. You should get your money back for sure. And the experience is priceless