Stevie’s French '98, Mid-90's WR/YZ/DT (An idiotproof guide to building your own DTR)
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Hello guys how is everyone! I hope everyone’s been keeping well
I’d been meaning to update this for a while but I’m saving it, hopefully there might be a big load of progress made however for now I’ve just been enjoying the bike and the weather
So for a while when I came bike from uni I’d had what seems to be a common problem of my bike randomly deciding to stop being able to rev out past 8k for no reason what so ever
It’d stumped many people, caused me to think my engine was on the way out and all sorts of things.
I decided to get the exhaust off align the valve and pin it, problem solved it’s revs out freely. I really enjoy riding my bike pinned in the right scenario however the only issue I’ve found is that past the 8.5-9k you get the worst throttle chop I’ve ever experienced. The throttle is still very responsive but under load at high rpm’s it’s like it revs backs off automatically and then will come back on whilst maintaining throttle position, this is the case even when just slowly rolling on the throttle with the RPM’s. I have wondered if the fact I’ve got a YZ 250 1/4 throttle and I’m still using the stock throttle cable which doesn’t fit 100% with the throttle because I still want to run the oil pump. *** on that note what’s a really good 1/4 throttle that’d solve that *** I’ve also noticed whenever I’ve had smaller sprockets on and pulled harder in low gears that the throttle chop effects often worse. So whilst pinning the valve has solved a problem it’s just kinda created a couple more for me but I’ll touch more on that later.
Whilst it’s certainly very choppy at times it’s still very very fun for popping the clutch. Another thing yes she wheelies. I’ve checked my piston and rings and whilst they’re worn and the dome of the piston represents the texture of sandpaper it’s really nothing horrendous. She still makes power, starts first kick and idles just above 1.1-1.2k. All the boys with WR’s still try giving it the pub talk about two strokes which just adds to the satisfaction of owning a two stroke that’s already done 10’000 miles in a year and is still going strong
I could only imagine now what this would be like without this issue unless it’s just a drawback of pinning a DT wide open?
I wish there was a way the get all the benefits of the low down torque The DT is capable of producing and still feel that sudden sharp hit of power after 7k. It’s definitely enlightened me more about why you guys like your custom ignitions so much and why the YPVS is such a good system. Here’s why...
(Whilst on my off-road trail riding shenanigans I come across a rather sharp 45-50 degree incline, 10-15 feet high and quite long, your run up is a straight and a sharp left the bumpy path that’s the same width as your bike and that’s been cut out through a thick hedge of nettles Brambles and everything else you don’t want to fall into. 110% full send it. Now this is the moment I understood how much torque the DT is capable of. I’d took a couple “bitch runs” as they’re called if you bmx or skate and soon realised as my powervalve pinned I’ve not got enough room to rip through the straight and make a hard left as not only is there not a lot of space to turn you’re also automatically on the incline so there’s not enough room to carry moment through and hold it wide open in powerband and you can just clutch in and rip it because it’s to tight, you’d wash out. Being so steep you couldn’t just sit straight up launch up it either or you’d just bog. Still I like the challenge, I said fuck it flipped the valve so it was the opposite of pinned and if she went. Pulled straight up like it was easy without even hitting the 8k Rev limit it’d have with powervalve set like that. I don’t know many other two strokes capable of that. ) This brings me to another thing... having experienced and messed about with the YPVS system a lot recently are there any of you that think it doesn’t work to it’s fullest potential? I’m just curious if there’s someone who understand two strokes better then I do as there’s maybe a reason it doesn’t completely open and close.
.This now brings me to my final thing that could make all of the above irrelevant. As mentioned I’ve spent hours now fiddling with the YPVS, I even thought the valve magically flipped 180 degrees by itself. Here’s the thing though with my exhaust off and the powervalve aligned flush the black plastic cable carrier is as far left from the aligning hole it can go, practically touching the 5mm Allen bolt that holds the casing. This means that the cleaning cycle would go left right but when valve would be aligned with the aligning hole it’s mean it’s closed which in my opinion doesn’t make any sense? The only way I can get it to align like that is by tightening the right cable as far as I can without it whilst loosening of the left as much as possible If memory serves me right this is meant to be the other way way around where the hole being aligned means your valves indicates as being flush
I’d found photos of how it was originally set up and it was completely the opposite from how I’d have to set it up now for it to be textbook “correct” and that’s what gave me the issue of it not revving past 8k.I’m just really stumped as to what’s caused this to happen or is causing this
I’d really like to get YPVS running again as I’ve tucked the switch for it just behind my tank so whenever I want to disconnect it for some fun with it pinned at a moment’s notice I can but still enjoy everything about the ypvs that makes it so good and what makes the DT pull very quick in those lower rpms. It’s also helpful it’s much quieter
Once again thanks in advance and sorry for the massive essays hope you enjoy. I hope everyone has been in good health and been able to take their bikes out at least a couple times whilst the weathers been nice and if you haven’t then I hope you’ve made progress with any projects you’re working on. Hopefully they’ll be some exciting stuff here soon...
I recently picked up a 1997 Suzuki RM80 that I’ve been having some fun restoring and rebuilding I could make a thread on if anyone’s interested -
@Stevie-Wonder definitely blog about the rm would ne interesting to read.
Pretty sure I would have said YPVS to be your problem and pinning it is usually a way to figure that out.
It shouldn't be too hard to fix the YPVS setup.
That idle is a little low. Should idle around the 2k mark. Having such a low idle will affect low speed performance as the idle controls up to 1/8 of throttle. So you will want to make sure it's correct.
Always Originate, Never Pirate!
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@Calum said in Stevie’s French '98, Mid-90's WR/YZ/DT (An idiotproof guide to building your own DTR):
@Stevie-Wonder definitely blog about the rm would ne interesting to read.
Pretty sure I would have said YPVS to be your problem and pinning it is usually a way to figure that out.
It shouldn't be too hard to fix the YPVS setup.
That idle is a little low. Should idle around the 2k mark. Having such a low idle will affect low speed performance as the idle controls up to 1/8 of throttle. So you will want to make sure it's correct.
I’m pretty sure you told me that a while ago and I’d just end up trying / checking every single thing besides that.
Had a bit of a ta-dah moment last night and think I’ve solved my own problem, I was messing around with my P top end looking at valve positioning and I think either me or the mechanic I was with made the mistake of putting the plastic onto diamond at the wrong angle which would explain why my adjustments on the tensioners and everything else is so off.it shouldn’t be/isn’t complicated at all especially after looking at suzuki and Kawasaki’s powervalve systems.
I’ve had a few people tell me that it idles really low however it’s been like that for as long as I’ve owned the bike / it came from unit 23 anytime I’ve bumped the idle up a little bit she doesn’t like it, I just thought all older DT’s where like it. Never hurt the bike or felt a negative effect from it so I’d just left it
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Like reading a wall of text is hard enough, let alone trying to diagnose the problem.
Split your question up using
Headings
Titles
- Bullet Points
and short paragraphs with spacing & photos and I'm sure we can have it sorted.
Check the exploding diagrams & consult the Haynes manual for more information. Haynes is worth its weight in Diamonds! So get one if you haven't already.
Always Originate, Never Pirate!
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Poor Sentence Structure
@Calum it’ll do for now, I will improve for future reference
Here’s a couple points to consider though
•Having ASD my concentration is wank and struggling with the pen to paper process is one of the defects of it.
•Due to the above, it takes me a much longer amount of of time to write my posts so apologies for those who find themselves.
•I’m actually really good at English it’s just when it’s late at night and I’ve spent way to long writing a blog post (which is usually huge because I suck at updating it regularly) I don’t think about reviewing, I’m usually scrambling because my phones about to die
•You are right though the structure of that is horrible to read. If you had dyslexia you’d probably just say nope. With that being said I have so many photos it’s unreal that’d solve this I just haven’t got around to cracking how to upload from my phone and not have to worry about hidden trackers in the photos from where some of the photos etc would’ve been taken on iPhone.Actual Problem that’s now no longer a problem
Either way problems fixed, turns out the problem was just the plastic was sat on the wrong angle of the diamond the entire time. Amazing how something that simple stumped so many people.
A bit of a bastard but at least I’ve had an education on YPVS, powervalves and the importance of them to two strokes. It’s also taught my why Yamahas cylindrical rotating valve system is such a good, simple and robust design. Interesting stuff. I’d like to learn how the guillotine valve works like on my RM80I had consulted Haynes manual quite a few times and no luck. It’s not the first time Haynes hasn’t give me the answers, I had the same problem when replacing my fork seals.
I’m just being picky though. With YouTube and a Haynes manual it’s really not that difficult to do and do good job of it.YPVS STUFF
With the YPVS now working properly again, I am well and truly loving life and in love with my bike again. Torque. Lots and lots of torque. Long gone are the days of abysmal nothingness before 6-7k. I forgot how nice it was to comfortably cruise somewhere without having to hammer it and I forgot just how essential that little bit of low down power is to a DT to be able to pull through the gears. Especially with knobbly’s and a 19” rear.
Pinning the valve was fun. I’ve enjoyed that snap of power like on a 85cc MX bike and really helped me getting comfortable with getting the front wheel above the ground.However as many of you have said before me and will learn after me, in no way does it improve the bike or make it faster. Instead it’s just filled me with appreciation for it being there in the first place. For that reason alone I recommend you if you’re reading this just once disconnect your YPVS and feel the difference it makes. Even if you don’t like it you’ll still find there’s something really fun about riding a two stroke with that cliche two stroke feel, even if it does hinder performance. -
@Stevie-Wonder I mean? It takes me hours to write blog posts? How quick are you expecting it to take.
You don't need to do it in one hit. It's supposed to be enjoyable. So take your time to craft something that is both enjoyable to yourself and others.
Personally, no doing any type of blogging on a mobile device is a no. This site is great to peruse and comment on a mobile. But for blogging, give me a keyboard all day long.
Again, I wouldn't really call it stumped, if you had uploaded a photo, or if I were there in person, I would have spotted that as soon as we came to adjust the valve. But reading lots of text is very difficult. If I were to be tested, I'm sure I'd fall within the Dyslexia/Dyspraxia category for sure.
If you've never seen the bike before, I'm not sure how you'd figure out the plastic thing was on the wrong way. I guess by examining it with the exhaust off is how I usually tackle YPVS issues. I don't even bother with the valve cover, it's must easier to simply take the exhaust off and do it that way.
Glad that's sorted anyway, so it's now on to the next item on the list...
Always Originate, Never Pirate!
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@Calum said in Stevie’s French '98, Mid-90's WR/YZ/DT (An idiotproof guide to building your own DTR):
@Stevie-Wonder I mean? It takes me hours to write blog posts? How quick are you expecting it to take.
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I appreciate the advice, it helped a lot I do believe I’ve cracked it. The return button is now my friend, for the sake of both my eyes and yours.
My only shortfall with blogging is keeping in the routine however I enjoy writing a lot so there’s a trade off I suppose. -
I completely agree but I honestly think if it wasn’t for having a smartphone I’d blog at all. Even being 22 and doing film and editing stuff I just don’t ever get my laptop out to use it for anything then things that you have too.
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True, true, I’m not saying it stumped you but it certainly had me and a lot of much wiser mechanics. Something like that could’ve been recognised easily but unfortunately I hadn’t cracked image uploads.
It just highlights how much experience matters
as all the help in the world couldn’t fix a problem when they have as much experience dealing with it as I do.
“If you've never seen the bike before, I'm not sure how you'd figure out the plastic thing was on the wrong way.” Just a reminder to me and all, in a journey of learning we often don’t know any better. We’re all learning.
Also what you said about the YPVS etc n all that me too. I’d spent so much time fiddling with the YPVS, getting it aligned countless times before working out where it was wrong ripping the exhaust off that now It doesn’t even seem like a task to do. I also leave the pulley cover off to keep an eye on it (every now and again if I’m out I’ll kill power to the YPVS and ride it pinned for a bit of fun) I’m gonna get a custom clear acrylic cover for it though.
Anyway next item on the list....
So I must admit I’ve been a bit bad at keeping this updated but then again I really don’t think I have much to update.
No big stories this time.
Updates are really as follows, had a hilarious eureka moment that ended two days of anxiety about if I majorly hugely fucked up buying that swingarm a while back. I didn’t. My gamble paid off massively. I’m a proud owner of a DT200WR Deltabox unit and well, what a beautiful piece of shit it is. Honestly. Not only was it simultaneously the most confusing and biggest pain in the ass to dig up info on but the welds look like they where done my Ray Charles left hand whilst he wiped his ass with the other.Not that many people will get the opportunity to see one, plus photos and info are rare so I’ll do why I can to upload some.
But basically the DT200WR variation swingarm is literally a fully built 4BF that Yamaha’s took a 45-30 degree cut to the rear section to weld in the different style chain adjuster.
You can literally see how the cut runs straight through, including the slide for the calliper mount
facepalm
Is it nice? Yes. Is it rare? Very. Do I love not having tortoise shell chain adjusters? Fuck me do I. Was literally everything about it a pain in the ass? You have no idea. Even locating axle blocks for it took over a week and wasn’t until a couple weeks ago I finally knew 100% for certain it was what I had.
Nonetheless as you can probably tell I’m glad to finally have that all over and sorted. Only thing to do to it is get it polished up proppaOne other thing, I’m now on the hunt again for a shock to with the swinger. Unfortunately I passed up the opportunity of buying another rare part a DT230 Lanza Shock. Seller didn’t know what it was and neither did I until I found out it sold. The geezer only wanted about £60 for it but I didn’t have the funds. Lanza shocks I’m pretty sure are completely adjustable and also don’t have a fixed piggyback design, perfect for our DT’s.
Seen a couple 86-87 YZ 250 shocks in the states that after a few beers don’t look too terrible...I’ve also had the 19” rear on her a while now and I’ve got to say what a lot of fun. Highly unstable above 70 mph though to a point of being scary. Had to play around with the gearing a little bit too and come to the conclusion that stock gearing and dropping a tooth at the front with a 19” rear actually has some surprisingly good and useable results depending on what you’re doing.
Was also very pleasantly surprised with the performance both on-road and off-road of the Michelin AC10 I have on the rear. (I paid £110 for the wheel and got a free set of new AC10’s with them). Now I’m really picky when it comes to tires and I’m also a huge fan of the Maxxis Maxxcross IT’s and thought they’d be hard to beat but honestly the results have been really really good. I’d never gravitated toward them before due to their huge spacing however on the bike they provide a very nice continuous contact patch along every angle of tire, they’re surprisingly nice on road too just a little less forgiving if you lean to far on a corner due to the nature of their tread design.
Last but not least:
The only other update I have is that I’m thinking about selling up my 4FU and 4DL topends. It’s just been a recurring thought recently of being uncertain if I’ll ever actually get around to using them / if using them will give me the things I want.
I’ve been preaching to a lot of people recently how for the amount of money you’ll probably get into modifying a DT the biggest gain HP for your buck would be to buy a 170 kit and have it ported and I feel I might fall victim to my own advice.
I want to play with the 125 top ends so bad and see the difference but I also think for the amount of £££ I’ll spend I’ll be disappointed. Especially if I get into tuning that 4FU. -
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@Calum said in Stevie’s French '98, Mid-90's WR/YZ/DT (An idiotproof guide to building your own DTR):
@Darty A picture says a thousand words
@calum that would explain the volume of written content..
I will eventually learn how tag images in I promise.
Once you see a photo though you’ll see what I mean. Although calling it a bit of shit probably wasn’t choice words.In other news I’ve made a nice discovery.
I think I’ve cracked how to run my modern Yz front end and keep the old standard clocks or potentially run some DT200 ones if I need to slim the cockpit space down a little.
Now I spend a bit of time on the webs n that and I’ve never come across anyone who’s done that to their DT before so it’d be cool if it works.
I know I’d be really happy because I never really had any plans for having an LCD display. The old clocks just give me too much nostalgia, they remind me I’m sat on an old bike. Something I don’t want to take away from.
Whilst it’d be super clean and convenient it just ruins what the bikes about. Motorcycling is a very visceral mechanical experience. It’s very much you and the machine and computers spoil that. I want to see those revs rocket at 7k not because a sensor tells a computer, that tells a screen, that that’s what it’s meant to be doing but because the engine is actually making it ‘ya know what I mean? I remember @Darty having a thing against this too just glad I wasn’t going to have to resort to a gps bicycle speedo or something ridiculous -
I made my own brackets out of old Aluminium cuts, with a Bandsaw and some hand files.
I even eventually spray painted them Halfords Special Black (Show Bike m8)
Didn't even use any maths, just cardboard templates and some callipers.
Even the YZ Yoke for 1997-2002 has threads you could use.
Keep it real
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I haven’t crossed that bridge yet but that was kinda the idea i was going for. I’d seen it done before and figured it’s simple as couple little bits of metal and if you’re lazy you can get brackets premade on eBay, easy peasy
I might have to use a gps bicycle speedo for a little bit though if I can’t get hold of the parts I need or my plan don’t work. I guess one way to keep miles low is to remove the device that counts them should circumstance force it for a little while
...Although that’s all very much at the future because without a certain someone moving his ass and helping me with something I’m stuck. Or am I??? I dunno, this is a blog after all isn't it? I suppose I ought to write about it.
So as luck would have it I managed to find someone who for swapped their DT with a set of YZ426 forks (Facebook groups and their size do have their advantages)and I’m pretty sure they’re 100% identical to my YZ ones. Even better though the guy used the bearing cup method.
You want to know the shocker though? He was a down to earth, nice bloke and was very helpful. I was humbled. How wholesome. None of that weird toxic one-up-manship you’d usually see from Facebook/the internet.
Anyway said bloke was even nice enough to share with me his plan and measurements which as you can guess is very very helpful for me.
Why is this so useful? Surely I could do it myself?Well this is the thing I’ve been relying on help from a family member to give me some help and explain some stuff because there’s parts to it I don’t understand. I get the concept and basic idea behind it. I think I’ve got the stuff I need for it it plans and measurements wise. I’m just stuck because I don’t know how to translate that information or understand the other basics behind it. In my mind I still compare bike forks to bmx forks. However if I understood all of that I wouldn’t have to relying on and stuck because my family member. I could go to the engineering shop and get them to make me the bearing cup I need this week.
I guess that just about describes exactly why I’m at a standstill currently because even financially I can find a way to make it happen. -
Precisely that @SpookDog! The issue isn’t bodging the clocks in, it’s making them useable in the first place
