DT200: In storage for years, gotta get 'em running...

[mugget]

Hi folks,

Well it seems like I may be a 2 stroke tragic... Haven't even got the KTM 380 back together yet and already another project on the go. Although hopefully this is nothing as involved as the 380... I'm not worried at all about making it look pretty, just going to get it running & ride it!

A mate & I have been itching to go and play in the dirt, so we figured we may as well scratch it with DT200's. He found the two bikes for $500, seemed like a good deal. They are '92 and '94 models, the older one has about 30,000km I think and the '94 around 13,000km. There's also a bunch of parts from a 3rd DT200 that was not running, and "in progress" project. The story is that they've just been sitting in a shed for a few years. They were running & were ridden before that. But since then no one has touched them. They kick over, but the fuel tanks are dry. Got the cap off one and it's a bit rusty inside, I guess the other is the same (cap will take a bit more effort to remove).

Picked them up yesterday arvo, haven't had a chance to look at them yet but I just wanted to make sure I'm heading in the right direction to get them running.

Fuel tank - will obviously need to be cleaned out, then rust converted/sealed?
Or just buy a 2nd hand clean tank? Found one for $75 which is the same cost as the Caswell epoxy kit, but looks like they're mostly around $90-130...

Then onto the engine, change the oil & coolant obviously... then,

Carb - Check the drain screw & if fuel comes through, leave it as-is?

Engine - Is it worth taking the cylinder off to have a look? Not sure if anything in there would have gone old & crusty... They do have compression (tho not sure how much, just put them in gear & pushed). Would you do a leak down test or just leave it as-is & see if it starts?

Also I don't know if it's likely that the gear oil would have gunked up? Any need to remove case covers & flush it out or a oil change should do it?

The previous owners used premix fuel in them... so I'm not sure if the autolube is stuffed, don't know why you'd use premix otherwise? But I guess I can just leave that for the moment and use premix?

Cheers for any advice & tips... I'm sure I could sort it out on my own, but that would take quite a while and I just wanna get up and running as quickly as I can.

Oh yeah - wouldn't be a proper thread without pics:

[JonW]

A few of us have had these over the years, they dont like starting without decent compression, but otherwise tend to run forever.

tank... they rot, do the clean and liner i say.

clean the carbs up fully, old fuel turns to gel then varnish

only take the top off if you think you need to, what lies therein will cost you money. With a $500 bike you need to start it and see what its like before you go spending more money i think. but to be reliable it may well need a piston/rebore and crank seals, if not a whole new crank...

oil, flush with ATF and you can run that and chnage it often if you like. will clean it up.

use premix, i bet they stuffed the pumps if they let then run dry anyway.

hth.

[mugget]

Sounds like a plan... was hoping to luck out and avoid a carb teardown but yeah, probably fat chance I can get away without it.

Cheers!

[hybrid]

Can I have one?

[mugget]

Haha, should have expected you to ask hybrid!
But I don't think my mate will be too keen to part with his, and I'm quite liking the idea of having a bike sitting in the garage that is ready to hit the dirt.

Ordered tank sealer, didn't realise that one kit should actually be able to do both tanks. Good thing because it's $95 with shipping.

Now just have to check with the local Yamaha dealer to see if they have carb rebuild kits... Not sure if that is definitely going to be required? Will just have to take it apart & check all the o-rings, seals, etc. I guess?

[hybrid]

Don't worry too much about the dealer having them.
They will be a mikuni or something like that, so kits will be readily available from plenty of places.

[JonW]

Some DTs had a funny carb, certainly the later ones did, its not got a mixture screw or something... anyway, i would just gently take em apart and clean everything and be sure not to use carb cleaner unless you know you have all the rubber parts out as it often swells them. if youre gentle you might be able to reuse everything.

[mugget]

A funny carb... you're not kidding! A couple of mates came over today and we had a bit of a play around getting the airbox & carb out and trying to strip & clean the carb. One of them started taking off all the hoses attached to the carb and then coolant started leaking out! Were like "WTF mate??!" From what it looks like I think it's just basically a 90º elbow built into the carb - is that actually need to cool the carb? Or is it just some unexplained weirdness?

Also the carb outlet/crankcase side were off before those hoses were removed (not the way I would have done it...) and I think a dribble of coolant went down to the reed cage. Haven't pulled the reed cage out yet, but just wondering how concerned about that I should be? Should I put a bit of premix down into the crankcase just to make sure the bearings & everything are lubricated?

Anyway we got the carb bowls off, yeah one of them was a fair bit gunked up, main jet blocked so bad I could see the gunk hanging out of it. Just need a security torx bit to take one last screw out, remove the inlet side piece. Then take off the choke and see what else is left. Will soak the metal parts in acetone overnight.

Good thing we had a spare expansion chamber as well, the pipe on the newer '94 bike had some holes rusted through the pipe just below the exhaust port. Had a peek through there at the piston and it looks really good, so things are looking positive so far!

Tanks definitely needed the tank sealer, took one off and tipped it upside down - rust fell out.

Draining coolant
Just wondering if anyone knows how this process goes? Just take off the coolant hose on the lower left side of the engine? Or at the water pump (right hand side?) or both? The coolant looked pretty clean so I was just going to flush it with demineralised water, then replace it with coolant? And is there an air bleed valve on the engine/water pump?

I found a DT125 workshop manual for reference, I think they're supposed to be basically the same? The carb diagrams look the same - just wanted to check that any jets that have no obvious way to remove should stay in the carb? The manual says the starter jet and all air jets are fixed type, so I'm guessing so. Just want to make sure I remove all the o-rings/seals before soaking in acetone.

Also if they run fine I'll look at getting a bolt kit to replace all the dodgy mixed bolts. But I can't find any directly for the DT200, only IT200, WR200 etc. Does anyone know if those would suit?

Cheers!

[JonW]

no its to warm it... stops carb icing!

coolant, like you said IIRC. drain what you can, then remove the lowest pipe and put a container under. bleed should be to the filler i think, but check manual.

pull the cylinder if you think coolant went down the bore... sorry but its crazy to run that unseen. :/

DT manual is a the sam, its just a dt with a bigger pot.

DT125 bolt kit should be the same for engine cases etc.

[JonW]

PS. I think I may have some top end gasket sets i can let you have for cheap if you need them, left over from one of my old ones...

[mugget]

To warm the carb - Hah! Well there ya go! Good to know.

I've disassembled everything as much as I can but I think there's still part below the main jet - the needle jet still has to come out? The manual just says "remove valve seat, main jet, jet needle holder" and then further down it just gets to "inspect needle jet". But I'm not sure how to remove it - all obvious screws have been removed. The "jet needle holder" isn't actually labelled in the manual so I'm probably missing something...

From the intake side of the carb I can't see how to remove this brass piece?


From the underside of the carb there's just that little notch in the base of the needle jet? Please how do I remove this?


And also just wanted to check that the needle jet is the last thing to come out? Since the starter jet and all air jets are fixed... but I don't know which ones they are.

EDIT >>
After a small bit of cleaning and closer inspection I found what looks like a little pin that slots into the carb body at the base of the needle jet... tried prying it out with a small screwdriver but no luck there.





Does this need a special tool? Maybe I'll have another look at it later otherwise I'll take it with me to the Yamaha shop & let them do it. Thinking I will get a rebuild kit anyway - not too sure about reusing the paper gasket?

EDIT AGAIN, SOLVED >>
Put the main jet back in and tightened it up, thought I could get the needle jet to spin & see if it was threaded. It's not, but just needed a bit of a loosen up then I discovered it pushes out into the carb body. Haha.
I think that's the last part to remove, going to soak in acetone tonight/tomorrow.
Maybe I just can't do this stuff on an empty stomach, or posting on forums has mysterious problem solving properties.

[mugget]

Todays update, no more varnish in the carbs.

But you've gotta be careful what containers you use your acetone in. I thought this one might be a bit iffy after I poured the acetone in and the plastic went white.



In hindsight I should have taken the parts out and saved a little bit of mess.



Wound up with half that container melted sitting on the bottom of the bucket. Not too much mess on the carb bodies tho.

Found out the bowl o-ring and the top gasket are like $20-25 a piece. I'll be reusing the o-ring, can't see anything wrong with it. But I'm going to find some gasket paper for the other card/fibre type gaskets. Something doesn't feel right about reusing them after they compress & expand in their particular ways.

[JonW]

looks like good progress mate.

[BRG1200]

Good job.
Just want to say, "Two Stroke" and "Tragic" don't belong in the same sentence.

[mugget]

Just want to say, "Two Stroke" and "Tragic" don't belong in the same sentence.

Hahaha, words to live by!

Well everyting cleaned up nicely, reassembled the carb yesterday:



At first I was a bit worried that I wouldn't know how to put everything back (first time I've taken a carb apart) but it was surprisingly simple in the end, they're not as complicated as I thought!

Put the carb back on the bike and attached a long length of fuel hose with an inline filter just to see if it would start up. First of all the carb bowl drain was just leaking fuel... thought I had the drain screw loose or missing an o-ring or something? But it was done up good & tight, still the drain was leaking. Well we tried to get it started and nothing...

Called it a night and went to the internets. Learnt that the carb drain just leaking fuel is due to an incorrectly set float valve. So that's the next order of business. And if it's leaking out the drain like that it means the carb is flooded? So there's no way it would start if it's leaking like that?

We were trying to start it with just the carb, no airbox, filter etc. (Weren't going to ride it around or anything so figured it's okay to start for a bit if it's just sitting in the shed, won't be getting any dust in the intake.) But it will still start like that, right? Or is it so finicky that it needs the airbox & filter for correct air flow etc.?

Anyway a mechanic mate is coming around this arvo to have a look & help sort us out, getting a bit keen to ride it on the w'end!