So Close!...
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iOS 12.5 isn’t supported anymore, we live in the age of built in redundancy
Oh well!
My front sprocket has been wearing unevenly on the inner side. I’m wondering if there are different front sprocket spacer sizes? If the lock/tab washer thickness could affect, or if I’m just missing a normal washer? I’ve never seen a sprocket wear away on one edge/side before. I can’t work out what is causing the discrepancy in the front to rear alignment to cause the wear. Any insights, anyone?…
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Am I right in thinking that there are only 3 wheel spacers for the entire Dtr range? Two rear and one front? I’m hoping that I don’t have the wrong width spacer on my bike that is causing the offset in my sprocket alignment?…
I’d rather fix the problem than treat the symptom by fitting a spacer-washer to the front sprocket… -
@SpookDog The front wheel spacer is very different to the rear wheel spacers so you'd know if you'd got that wrong, in fact it's a much smaller ID than the rears IIRC so that's ruled out.
The DT200R drive side rear wheel spacer is a lot shallower than the 125 (because the 3ET alloy swingarm is a lot fatter at the ends) but you'd notice if you had a DT200 spacer and a 125 steel swingarm, I mean you'd have to physically pinch the swingarm ends together to tighten the rear spindle. Which would probably result in bigger problems than slightly uneven sprocket wear.
Depending upon how your snailcam chain adjusters are oriented and which side your rear spindle nut is on, it's possible to inadvertently adjust one side wrongly when tightening the nut but if you've owned and ridden the bike for a year or two you're unlikely to get this wrong. I like to have the spindle nut on the brake side and the snailcams oriented so the brake side one has to rotate clockwise to tighten the chain; this minimises the possibility of the cam slipping. Also snugging them against the anchor pins on the swingarm by wedging a rag between the chain and rear sprocket whilst tightening the spindle nut helps.
Assuming your swingarm bearings have no play (worth checking) my money is on the swingarm side clearance adjustment having been done wrong by a previous owner. It's a lot less complicated than Haynes makes it look (how unusual lol); you're basically trying to get the swingarm to move freely with 0.4-0.7mm of side-to-side play with the swingarm pivot nut done up tight (the arm should fall under its own weight with the nut tightened and without the rear wheel/linkage attached). Crucially, if you need to add shims to take up excess play, Yamaha insist you only add them to the right-hand (i.e brake) side; the one 0.8mm shim on the drive side is what retains front/rear sprocket alignment. Here are some pics of the procedure in the Yamaha manual along with my calcs from the last time I reinstalled a DTR swingarm written in my childlike scrawl.
One other thing, if you get an All Balls 28-1212 or similar bearing kit (the WRP one is exactly the same) they come with 1mm shims; Yamaha shims are either 0.8mm or 0.3mm so you might need to order some if you get the arm out and find you don't have enough to get the side clearance right. And 90Nm is ridiculously, thread-rippingly tight for the swingarm spindle nut IMO; Yamaha do this a lot on the DTR, I guess so they don't get sued for major components falling off when young lads are out riding. I've always done up that nut up to 55Nm and it's never moved.
No-one ever does swingarm side clearance on the DTR; even with some of the "DTR specialist restorers" you can tell by their social media pics they don't bother with this step but potentially, if it's far enough out it could produce uneven front sprocket wear over time. Even if it's not the culprit, checking it will it give great peace of mind!
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@SpookDog Also just had a look on Fowlers Parts, the 3RM DT125R and 3ET DT200R output shafts, sprocket lock washer and spacer behind the front sprocket are all the same part number. Only the sprocket nut is different (I guess thinner to accomodate the 200's 520 front sprocket) so I can't see that affecting sprocket alignment (unless someone has tried to bodge it with a DT200R sprocket nut and extra washer between the front sprocket and spacer, but this would be very unlikely).
https://www.fowlersparts.co.uk/parts/4105071/dt125r-3rm5-1993-999-a/transmission
https://www.fowlersparts.co.uk/parts/4059369/dt200r-3et1-1988-010-b/transmission
Only other thing I can think of would be if the bearing behind the front sprocket is on the way out allowing the output shaft to move around. This does happen eventually when people adjust chains too tight on bikes with long-travel suspension but would be very noisy if it were that far gone and you'd be noticing oil leaks and gear selection problems and all kinds of stuff...
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@HOTSHOT-III Yeah I didn't even realise the swinging arm even had adjustment! That's pretty meticulous to say the least. I know that the Aprilia has a swingingarm tension bolt procedure, but again it's never something I have ever done.
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Cheers for the info bud! I did the swingarm shims check by the Haynes manual. It was a while ago though. Put 20,000 miles on it since then
I do have the rear spindle but on the chain side, with the snail cams having the flat edge down. Don’t know if that affects it at all?
My swingarm ‘knobbles’ are a bit fubar tho, one of them (the sprocket side one) is flattened off where the cam touches it. Even allowing for this I don’t think it would affect the front sprocket like has happened?!
It’s like the front cog wants to be out 1mm more, or the rear 1mm in further… -
Thanks again for putting my mind to rest on the rear spacers!…
The other thing I forgot to ask was if anyone knew if Tzr sprocket spacers were different than Dtr ones? My bike is a pure mongrel and may well have a tzr lump in it for all I know …At some point I’m going to have to check that I definitely fitted the 0.8mm shim on the sprocket side of the swing arm as well, would explain a lot if I didn’t
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@SpookDog Depending on what TZR you're referring to...the TZRs ran a completely different engine. It was only the Belgarda models that ran the DTR lumps and you'd know if you were running one of those. They have
Motori Minarellistamps on them all over. -
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Second hand forks, yokes and spindle arrived today! Really good condition for the price (£50 + 20 post). Swingarm arrived last week, things are looking good…
5090 miles and my head gasket let go today as well
I’m actually surprised it lasted as long as it did! It was over the previous 700 mile threshold for failure before I found and fixed the weak idle jet mixture fault, so it must have taken a lot of misfire/knocking abuse before it was fixed!…
I just need to work out my plan of action next. I’ll probably just throw on a new gasket and rings with a re-hone to see me through the winter. I’ve got another bottom end & crank I’d really like to build with new Koyo bearings and seals to mate to a fresh rebore & piston… -
Does every dtr frame have a kinda U-shaped tubular piece that bolts onto the back of the frame, under the mudguard? I saw a picture of a frame with said bit fitted, but mine just ends in 2 flattened tubes with holes in them…
I’ve never seen this bit before the 1 picture, so I could do with some guidance from people that have original, righteous frames… -
@SpookDog
I take it your frame doesn’t have the rear sub frame attached ? Earlier 80’s models the frame goes round in a continuous bend. Later models had a bolt on rear subframe which have a kink above the exhaust to allow you to hold on to the rear of the bike. The 2002 DT125R I bought for my son didn’t have the rear subframe or shopping rack, common practice is to junk them and jack the rear mudguard up to give the bike the Crosser look, mind you both replacements were purchased on eBay for about £100 each from memory. And hens teeth to get hold of. Neither of them were straight and took a bit of manhandling to get right. Look up on fowlers parts for the year/model of frame and if you need a sub frame it will be displayed on that page. Sometimes it’s pictured with the rear mudguard. -
Cheers bud! It’s good to know these things. I’d love to have a proper good gurn at a righteous standard 88 bike just so I can see & list all the bits I’m missing. One of the many previous boners deleted the rear foot peg mounting holes, as well as I don’t know what else!
There are loads of bits n bobs I’d like to get, rear reservoir ‘lock’ cap, same for rad cap, oil bottle. Original reusable cable/frame ties, CDI rubber mount, & on & on&on… -
@SpookDog
Try WWW.ALEADO.COM
it’s a Japanese broker a bit like eBay, but you give them the money open an account bid on the item and the seller sends it to them and they forward it on to you in the UK. Usually see older better parts for sale. There not always cheap but you find they are better condition. Also change your country setting on eBay if you use that… always find parts are better from France and Germany ! -
203675742903 On eBay is that what your looking for ?
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Head is still leaking but very slowly/slightly, it doesn’t overflow the expansion tank unless I ride middle-hard (not flat out) I’ve ordered a 27mm hex drive (1/2 drive) for the forks. I have another new head gasket but I’m going to try and limp through the salt season, until spring before fitting any new parts. I’ll do the head if it gets worse but I really want to get my old barrel rebored by PJME (best finish I’ve seen on a bore!) Also I’ve a crank I want to get rebuilt and balanced. My bike doesn’t want to rev above 7-8k in gear, which doesn’t seem right?…
Need to get new bottom end bearings and seals all through, clutch buffer rubbers and a new rear shock, as well as dreaded swingarm & linkage bearings, bushes and seals
I wish that Satan Claus didn’t see me as naughty, it’s all so expensive a labour of love!
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Whoa! Just went for a 35~40mile jaunt, I don’t like flashing blue lights road blocking in front of me in the pitch black! It is well disorienting! It is nice to not be pulled over just because you’re out and about at 1 in the morning though. 20 years ago I would of been tugged on principal!…
Times are so different…
you do serious mileage on your bike. I haven't ridden any of my motorbikes since July. Fired up the DT yesterday, took a few kicks but akk seemed well.