Stevie’s French '98, Mid-90's WR/YZ/DT (An idiotproof guide to building your own DTR)
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@SpookDog nah it deffo wasn’t the jets, I’d checked them and cleaned the carb (ive also had this issue in the past so I know what it feels like), I’d done a compression test and it had about 95psi cold + holds compression really well too.
I couldn’t find any air leaks at all either. The only thing I’d done different since that problem occurred was fiddled with my idle screw whilst riding one time, having eliminated everything else it had to be carb related ?Photos to come too
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I have nothing against against the Portugal replicas but I can’t tell you how annoying it is that the battery cover isn't black, it’s good to have the originals on. I’m just glad I took them off ASAP as that could’ve been them smashed to pieces.
Not long after she was loaded up and taken on an adventure. You’d be surprised what you can carry on that luggage rack with just some bungees, a cargo net and a lot of faith.
I don’t remember taking this photo but as you can see the rally is in full swing
Being at bike rally surrounded by street fighters, HD’s and customs I thought it’s be funny to enter my bike into the Backstreet Heroes Show and well, I didn’t win any prizes (not that I expected too, I hadn’t even cleaned it since I’d last been in some fields and crashed) and in all honesty no one even really looked it at it.
However I did catch these guys smiling having a little moment reminiscing of their days being yoof’s and owning a DT themselves. never gets old does it?
I honestly love this bike so much. She just looks right.
Happy with how she sits, and the skimmer profile now I’ve pulled that headlight down.
I have plans for a custom graphic for the headlight to match the rest of the graphics and to spray the headlight white. What do you think would look better?
You’d also be surprised how tall this bike is, knobblies, 19” rear wheel + wr450 front end have made her impossible to ride if you’re vertically challenged
Sorry about the video I asked some random older dude to take a photo, apparently he doesn’t know how to use an iPhoneLoading up second time around was a piece of piss and I managed to get everything packed up a lot more efficiently leaving more room for extra gear on other adventures.
Even sat on the motorway she didn’t miss a beat either, never ceases to amaze me how good these bikes are.
Overall great rally, first one after 10+ years. I got loads of photos of the bike show so I’ll upload them at some point -
Update she’s currently out of service.
I left the petrol station one evening got half way up the road then lots of spluttering, engine coughing, limping and dying followed by plumes of a very toxic smelling smoke pouring out my exhaust so much so it was hard to see the car behind me.Aka all the signs your right side crank seal just gave up on you. Now as this means it’s a split the cases Jobby I’m going to rebuild the whole engine, get her fresh, get the trail tech dash wired up and see just how many miles I’m putting on her.
Not knowing your miles your doing isn’t bad until it’s time to maintain the bike or do routine check ups.
Plus I still don’t have a speedo so it’d be nice to get that sorted.I also have another bike on the road meaning I don’t have to rely on the DT so unlike before I can take my time and enjoy building the bike.
First thing is sorting the engine out.
I have 3 frame of minds with this
- give the engine to someone one to fix. It’s convenient and you know it’ll be done right first time, albeit costly.
- I leave the engine as it is and very very slowly acquire the parts needed to build a wr200 3XP / DT hybrid.
- get all the tools etc needed and have a proper go at rebuilding the engine myself whilst changing as little to the engine as possible.
First options convenient but being honest here I can’t afford to pay someone, I’m too tied into other things.
I also feel like I’m cheating myself doing that and I really need to learn and get comfortable rebuilding two strokes, so if not now then when.Second option with the WR200 setup is my ultimate goal for the bike eventually so it makes sense just to leave everything alone and work towards that. However that means losing many hours of seat time and tearing around in dirt.
Third option. The one I’m most in favour off and will most likely do. I really want to make a thing of restoring bikes and working with two strokes in the future so it feels like the right time to have a crack at it.
I think if i can successfully rebuild the DT then I’ll venture out more but until then I’d just be beyond chuffed to have rebuilt her myself. -
Assuming that I am going to rebuild the engine myself could anyone give me a checklist of tools I’d need, parts to order as well as any tips or ticks you’ve picked up yourself.
Also any books or anything like that that teach you proper engine building procedure and etiquette. it matters a lot to me that I pick up the right habits, understand the function of each part properly and that I do the job as professional and proper as can be.
I’m honestly like a sponge and have been obsessed with stuff like this recently but I don’t think I’ve found the right stuff to feed that obsession. -
@Stevie-Wonder Here's my post from the other day with a link to the crankcase splitter/crank puller set and the drawings for the puller adapter I had made to avoid damaging the main bearing on assembly. The circular part with the internal thread in pics 1 and 2 was made up at the same time and fits inside the collet (marked "nut" in pic 5):
https://dt125r.co.uk/post/28916
Even the mighty Rocky Mountain ATVMC transmit a side load through the main bearing when using crank pullers (check out the comments) but get this adapter made up and you won't have to!
https://www.youtube.com/watch?v=p0LK30KVWJg&t=298s
Here's a link to the 6mm glass shelf I bought to lap in the crankcase sealing/gasket surfaces. I just gaffa taped #400 wet and dry to it:
https://www.shopfittingwarehouse.co.uk/shelving-racking/shelves/glass-shelves
Lidl were selling cordless impact wrenches for about £60 a few weeks ago (cheaper than Screwfix etc.) so they might still have some; invaluable for undoing clutch/primary drive/sprocket nuts and you can make a flywheel holding tool pretty cheaply from 1" x 1/4" steel strips.
The Yambits clutch holding tool is pretty good as well as their autolube pump rebuild kit; might as well do this if the clutch cover is coming off. In fact I did my clutch cover build first (i.e that and the waterpump seal) then put it to one side out of harm's way. Also for the cross head screws get a set of pound through JIS screwdrivers from Yambits and cut the tip off the size 3 to make a large JIS impact driver bit (it has an 8mm hex all the way down the shank which fits the common 1/2" drive Argos etc. impact drivers):
https://yambits.co.uk/screwdriver-set-pound-thru-japanese-industrial-standard-jis-p-108432.html
Also get some valve grinding paste as this really helps the bit bite into the screw head. You don't want any chance of grinding paste getting anywhere near your new engine internals so chuck the screws away afterwards (especially the internal ones which were loctited during manufacture) and just order new ones by part number as they're only pence. And obviously get a brand new 50ml blue Loctite.
1/4" drive torque wrenches are pretty cheap these days due to so many fasteners on bicycles needing to be torqued (carbon handlebars etc.) so get yourself one of these for the cross head screws holding on the crank seal baffle plate, gearbox bearing retaining plate etc. Good for motorcycles generally as the 1/2" drive ones used by car mechanics are a bit insensitive for our purposes:
Initially I opted for genuine Yamaha bearings everywhere which was a huge mistake; because they're more expensive than just buying engine bearings from a bike shop, Yamaha dealers have a slower turnover of bearings which meant mine had been sat on the shelf for a (very) long time and some of them felt a little rough when I unboxed them. So I put it down to experience and bought a full Koyo set from PJME (they sell Koyo exactly the same size/grade as OEM) and they felt much better (i.e like a new bearing should). Also Koyo don't make the one behind the clutch with a single metal shield any more so my genuine Yamaha one was a 2RS (i.e rubber sealed on both sides) bearing which I wasn't really happy with inside an engine. PJME get the ones with two metal shields and remove one of them before sending them out to DTR owners which is good attention to detail IMO.
This is the YouTube vid I watched before taking on replacing my engine bearings:
https://www.youtube.com/watch?v=EuXe8mQcdqk&t=555s
Good he goes through two different methods but I decided to just put the cases in the oven at gas mark 7/170C; most of the bearings just dropped out on their own after about 30 mins (very satisfying to listen to this) but one or two did require a tap and I had to buy a blind bearing puller set for the needle rollers (including the one underneath the clutch actuator arm) and the balance shaft bearings. He also has a good tip about removing locator dowels @4.40; I'd definitely replace these and the cylinder studs as corrosion gets to them even in the south of France (two of mine came out rusted to the cylinder base nut on my '93 French import).
To install the new bearings I heated the cases again and put the bearings in the freezer overnight. I was concerned about condensation rusting them as they returned to room temperature so I tested three bearings I didn't want to use by freezing all three; one with assembly lube, one with two-stroke oil and one as it comes lightly lubed out of the box. The out of the box one rusted after 30 mins on the kitchen worktop, assembly lube went like wax when frozen which I didn't like the look of (it would have caused problems during the stressful situation of trying to drop in the new bearings before the crankcase cools) and the two-stroke oil remained fluid and provided enough corrosion protection during this period so was the best for me. The balance shaft bearings were a bit stubborn; they're a lot smaller than the mains and there's a lot of meat around where they fit in the cases so I guess there's not as much potential for expansion there for a given level of heat.
Will add to this if I can think of anything else!
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@HOTSHOT-III wow that’s a lot haha, I feel like I need to sit and read the Haynes manual back to back for w good few nights
Thanks by the way, also I had planned of going with koyo, I’ve only ever heard good things about them
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@Stevie-Wonder It really isn't that complicated. Ultimately, you'll be pulling the bike apart long before those bearings give way anyway.
The thing is, if you're going down the 3XP route on the stock DTR bottom end, you'll going to be adding a lot of undue stress to the bottom end that it wasn't designed for, so it'll need regular maintenance/rebuild anyhow.
I'd definitely recommend the Haynes idea. Watching that video is good too. And keep the haynes handy.
Get lots of food bags (or zip lock bags) handy along with cable ties to keep nuts washers etc together and in the order they came out. A nice box to put all the engine bits in. It's well worth getting the cases cleaned properly before removing the bearings. This removes the risk of scoring any journals if there is any debris left there before removing the bearings. I've never had a problem using the oven technique and it's my preferred method.
That's a really good book for understanding engine rebuilds etc, there is a PDF floating about, but I had the book.
Ultimately, nothing should be tight and everything should turn freely by hand. If at any point it isn't, then taka sit back and examine the situation as chances are you've missed something.
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@Stevie-Wonder No worries, also I've just remembered a 30mm open end spanner fits on the end of the Yambits clutch holding tool perfectly, giving more leverage so I didn't need the ugga dugga gun to undo the clutch nut.
And try and undo as many fasteners as possible with the engine still in the frame to avoid chasing it round the bench. Using an impact driver, reducers down to 1/4" drive, extension bars and an 8mm socket with my improvised JIS bit I think I was even able to crack off all the crankcase screws with the engine still in the frame
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@Calum probably sounds complicated because there’s a lot I don’t know and words and things that I don’t know what they belong too and a lot to remember
What extra stress do you mean as I thought the 125 and 200 shared crank bearings so I figured in that sense you shouldn’t have to worry so much
Either way I’m prepared for the extra upkeep, the way I see it is the it’ll get me very comfortable with the engine and once I’ve done one time every other time should just easier
I’m actually a big fan of the zip lock/sandwich bag method, i also Chuck some two stroke oil or acf50 in the bags with the bolts sometimes it helps revive/preserve them
What I was planning on doing was getting a few bits of carb board and tracing the cases and numbering the bolt holes then poking the bolts in the appropriate places, keeps them safe and knowing where they went is self explanatory.
@HOTSHOT-III cheers for that, I don’t have any access to any mains power or power tools so any more primitive methods are preferred
I’ve also been watching this video a lot
https://youtu.be/7hHF5FC5ko4
Not a fan that they didn’t use decent gaskets but the video is good quality and it’s made me want an engine cradle -
Removing the bearing from the crank is the worst part. It’s so easy to ruin the crank by trying to lever of the bearing. It is how I removed mine tho, just have to be careful not to dent the crank edges with the levers. I used wood to protect the crank edges...
If the crank bearings are good, and the big end bearing, you don’t need to build the bottom end. If it’s not broke, ect...
I would definitely do your main seals though. You have had similar symptoms to my ‘weak mixture at low throttle ‘ problems that were causing my head gasket to blow...
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Okay thank you guys, I’ll be pulling the top end off and checking the bottom end.
For the price of a set of rings, an OEM gasket and having the head and cylinder skimmed itd be stupid not too.
I do have a really good pick set in my repertoire which has made life beyond easy for grabbing out seals in wheel bearings etc so I’m pretty sure I should be able get them out, I’ve got a pretty good feel for those things.
However I would’ve been pretty hap-hazzard about the crank mating surfaces, which of course being ally would be easy to score or burr -
The seals came out real easy in my case bud. Just replace them with good reputable ones if you can’t afford genuine parts. I made the mistake of buying fleabay China the first time round
️What do you mean about the ‘crank mating surfaces’ though? You mean crank cases? If so, that little hole/slot in the front bottom of the bottom end makes a good leverage starting spot. Be gentle and put in plenty of rubber mallet tapping all around and it will separate without having to use brute force. Shit man! If I can do it!! 🤪
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@SpookDog sorry I meant the outer surface which the seal presses against
And consider myself told! I think I haven’t spent much time with the engine apart either so I’m a little blurry and unfamiliar except from what I’ve read so it’ll be a good exercise to pull her apart.
Give me a couple weeks to get paid and I’ll be ordering the bit needed.
So far I need, gasket, new head studs + screws + copper washers, @HOTSHOT-III crankcase splitter tool thing, clutch holding tool (i think I have one already), cordless impact wrench, JIS screwdrivers (I already have a pack of 5 which are very good and I’m if I remember right I’ve got JIS ratchet attachments too), 1/4” torque wrench / a nice handheld torque wrench (i actually already have one except it’s for cars and is huge not very ideal for doing cylinder studs etc), lots of sandwich bags + sharpie and zip ties, sheet of cardboard for making a template to stick bolts that require being placed in a specific order into.
Anything I missed?
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@Stevie-Wonder do you need new head studs? What's the matter with the existing ones?
You're definitely dotting the i's and crossing the t's.
If you are just doing the top end then you won't need much in the way of sandwich bags and zip ties. It only takes an hour, including time to take the tank off so there won't be any time to misplace stuff.
I didn't use an impact gun, instead stick a screwdriver inbetween the primary and secondary gearbox output cogs. That'll lock the crankshaft to get the clutch basket off. If you do it in situe then the engine mounts will hold the engine steady. Again no more than an hours job to replace the crankshaft seals.
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@Stevie-Wonder
You lever on the seals centre, not it’s outer edge
You will need a tool to hold the clutch centre while you undo/do up the clutch centre nut. Sticking a screwdriver in will allow you to undo the crank nut though
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Cheers for your help boys, I’m convinced it’s a piece of cake now and I honestly look forward to taking everything apart to see if we can get her running again.
I see why you love two strokes so much, very little to go wrong and very easy/cheap to replace.
With the head studs I thought may as well as everything else would be new, plus don’t you need to replace the washers anyway?
Also yeah thinking about it as long as I’m organised and methodical I should be good, most of the bolts that come off can be left or put back in the put it in to avoid them getting lost anyway
@SpookDog Ohhh like use a hook pic or a spikey to stab into the middle to pull/lever it out. If that’s the case I always thought it’d be much harder then that
Also can anyone reccomend a tool for that job.
I think it’ll be a couple weeks before I can order the bits too
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Like I said, small flat head screwdriver
Only replace the head studs if you have to, then only with genuine ones. Never buy fleabay ones! They may as well be made of glass 🥴
Breaking a stud of in the barrel is a pain in the ass. My local reputable bike shop put in the helicoil pissed, like the tower of piza
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Engines out, ready to be stripped.
I’m going to leave the engine standard and focus on performance upgrades last.
In the mean time I’m just going to take things slowly and get her ready for next year.Whilst stripping the engine I noticed the swing arm bushings etc looking like they could use replacing.
Rather then rebuild the stock swingarm I’ll buy a bearing kit for the DT200wr swinger I’ve got, get it painted and finally chuck it on the bike. Im really really excited about seeing this on the bike and feeling the weight difference between the two swingarms.
Another thing is 19” rear wheel jacks the ass up a lot, the bigger wheel doesn’t look right and tire options are limited. Plus with USD’s on the front and knobbly tires it makes the DT a very tall bike. Even for someone 6ft.
For those reasons that’ll be going shortly.I have to wire in a trail tech vapor speedo too, I have been without working clocks for sometime now. Not good.
Im shit with electrics so I’ll probably pay someone to do that and save all the agg.
I wish they where just the standard DT clocks but that’s just not on option anymore with the front end I’ve got now.This is everything I reckon I’ve got to do
Everything the DT needs to make 100%
Front brake hose holder clip €22.50
5DH2587500Brake pad retaining pin £
5DH2593300Front wheel inner Axle threads needs heli-coil/tap and dye as does brake hose guard cover bolt
Cover, Hose €23 (UFO/Polisport disc cover will also do the same job and give 90’s aesthetics)
5DH2314E00Oem Fork guard bolts (Anodised ones are usually ally and the threads give way after a couple twists, it’s amazing it’s took until now for most of them to go missing/work their way free)
Rear panels + graphics (bikerpartshop + hazard)
Helmet lock 5H0-21308-01
Possibly oil + coolant for once engine’s drained
Seat cover - either custom or bikerpartshop dark blue replica
- Battery strap
22F-82131-00
https://sumorubber.com/straps ( a very handle little sight that specialises in battery straps for vintage bikes, the steel on my battery strap that clips to the frame had completely deteriorated)
DT125R headlight frame / bracket holder. (I love the 3et light for its slimmer profile but the smaller size with the bigger forks means there’s not a lot of space to put your dash, the original would be more practical, look better and fit better.)
Working fucking clocks!!!
Speedo cable wire for Vapor
&
Magnet pick up sensorDT200WR swinger needs difference in pivot mounts measuring + chain alignment checking
18x2.15 excel rim
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@Stevie-Wonder With the engine removed from the frame, now would be an opportune moment to test the fitting of your DT200WR swingarm. Sounds counter-intuitive I know, but assuming the swingarm pivot bosses are the same width/distance apart as the stock steel arm (meaning it will fit into the chassis), it's the engine boss which dictates it's (and in turn the rear sprocket/wheel) position in the bike. Sprocket alignment is the biggest enemy here; you won't notice front/rear wheel alignment being a few mm out as once you factor in tyres, rims etc. (MOT allows 4mm lateral rim runout) most bikes on the road aren't perfect anyway.
Here's an explanation how to do the swingarm side clearance with pics from the Yamaha manual. Don't forget you'll need to do this again after splitting and reassembling the crankcases as this process might alter the engine boss width:
https://dt125r.co.uk/post/29135
It's actually possible to do this without going near the chassis if you have the engine out; I went through the process using a 3ET swingarm and a spare set of crankcases to do a workbench mock-up to assess sprocket alignment. 3ET swingarm, spindle, drive side spacer and rear caliper mount (it's thinner due to the fatter ends of the alloy arm) and stock DT125R hub produced almost perfect sprocket alignment according to my 600mm straight edge. I might need to play around with this slightly to get it perfect; there was a 3mm thick M20 washer between the caliper mount and arm when this pic was taken and the sprockets look about 1mm out.
Good shout going back to an 18" rim. If you can, go back to your stock 18" DTR rear wheel as well because stock rear wheel with good sprocket alignment = wheel alignment (or at least it places your stock rear wheel where it should be) which will keep things simple for now. Also 19" rear wheels on MX bikes were largely an attempt to reduce the rear wheel's weight which reduces unsprung weight/inertia to improve acceleration and suspension responsiveness on the track; most Enduro bikes run 18" because the flabbier tyre sidewall is more forgiving and offers better puncture resistance against rocks, roots, Ferguson tractor parts in the corner of farmers' fields etc.
https://www.thumpertalk.com/forums/topic/213621-18-vs-19-wheels/
I can't comment on the DT200WR arm as the chassis is different from the DT125R as well meaning you might need the entire rear suspension assembly to make it work (the DT200WR shared a much beefier relay arm and linkage with the WR200 IIRC). And compared to the 125 steel arm I'd be looking at overall length as well as the distance between the pivot and where the linkage attaches to try and get an idea whether the leverage ratio will change noticeably.
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@HOTSHOT-III said in Stevie’s French '98, Mid-90's WR/YZ/DT (An idiotproof guide to building your own DTR):
@Stevie-Wonder With the engine removed from the frame, now would be an opportune moment to test the fitting of your DT200WR swingarm. Sounds counter-intuitive I know, but assuming the swingarm pivot bosses are the same width/distance apart as the stock steel arm (meaning it will fit into the chassis), it's the engine boss which dictates it's (and in turn the rear sprocket/wheel) position in the bike. Sprocket alignment is the biggest enemy here; you won't notice front/rear wheel alignment being a few mm out as once you factor in tyres, rims etc. (MOT allows 4mm lateral rim runout) most bikes on the road aren't perfect anyway.
Here's an explanation how to do the swingarm side clearance with pics from the Yamaha manual. Don't forget you'll need to do this again after splitting and reassembling the crankcases as this process might alter the engine boss width:
https://dt125r.co.uk/post/29135
It's actually possible to do this without going near the chassis if you have the engine out; I went through the process using a 3ET swingarm and a spare set of crankcases to do a workbench mock-up to assess sprocket alignment. 3ET swingarm, spindle, drive side spacer and rear caliper mount (it's thinner due to the fatter ends of the alloy arm) and stock DT125R hub produced almost perfect sprocket alignment according to my 600mm straight edge. I might need to play around with this slightly to get it perfect; there was a 3mm thick M20 washer between the caliper mount and arm when this pic was taken and the sprockets look about 1mm out.
Good shout going back to an 18" rim. If you can, go back to your stock 18" DTR rear wheel as well because stock rear wheel with good sprocket alignment = wheel alignment (or at least it places your stock rear wheel where it should be) which will keep things simple for now. Also 19" rear wheels on MX bikes were largely an attempt to reduce the rear wheel's weight which reduces unsprung weight/inertia to improve acceleration and suspension responsiveness on the track; most Enduro bikes run 18" because the flabbier tyre sidewall is more forgiving and offers better puncture resistance against rocks, roots, Ferguson tractor parts in the corner of farmers' fields etc.
https://www.thumpertalk.com/forums/topic/213621-18-vs-19-wheels/
I can't comment on the DT200WR arm as the chassis is different from the DT125R as well meaning you might need the entire rear suspension assembly to make it work (the DT200WR shared a much beefier relay arm and linkage with the WR200 IIRC). And compared to the 125 steel arm I'd be looking at overall length as well as the distance between the pivot and where the linkage attaches to try and get an idea whether the leverage ratio will change noticeably.
Thank you for that @HOTSHOT-III thats really helpful. The swinger still needs painting, which I’ll get round to eventually none the less I’ll be doing what you said.
My 19” rear is just a YZ rim laces to DTR hub so in theory the alignment should be the same.
