Dt Handling

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#1
Hey guys, I ride a 91 DT 200, I've only been riding for about 2 years and the bike is pretty much standard exept for a few little things ie muffler etc. Being my first bike i hav'nt really got much to compare it to, but it seems rather heavy and stiff to handle in tight situations (compared to my friend's bikes such as a KDX 200 and even an XR 250). Is this a general characteristic of DT's or is it just my bike in particular. I know the bike needs new head stem bearings, but that doesn't really seem like the problem.

p.s can anyone suggest some good "go fast" bits.
 
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#2
The DT line in general was porky, underpowered, and handled like a truck. They were by very nature a compromise, like most dual-purpose bikes of that era, and were barely capable offroad. I used to have a '79 DT 250, it ate rod bearings and crankseals like there was no tomorrow.
 
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#3
Being a 91 it will be a water cooled DT200R not a DT200LC I guess. The 200 LC shares a lot with the DT & RD125LC. The 200R more with the WR200 as it is case reed induction. These share nothing in common from the boiler Spanky is talking about. Did they get the wc ones in the states?

But yeah a KDX will mince it, your life will be a nicer place if you trade, even to an older KDX in good condition.
 
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#4
Don't get me wrong, i'm not unhappy with the power of the bike, a simple tweak of the power valve, along with some wiring alterations and a pipe, lets me lick most kdx's i've come across. It even makes wheat bix out of some heavily modified mx 125's. The only downfalls are its ridabilty and weight. Will rebuilding the front forks with heavier springs help with this problem or it will it only change the rebound over jumps etc.
 
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#5
Originally posted by David Trustrum
Being a 91 it will be a water cooled DT200R not a DT200LC I guess. The 200 LC shares a lot with the DT & RD125LC. The 200R more with the WR200 as it is case reed induction. These share nothing in common from the boiler Spanky is talking about. Did they get the wc ones in the states?
Nope, we didn't have the pleasure of this model here in the states. We never had a water-cooled DT, or one with a power-valve. And I don't remember us having a 200. I think the last small-bore DT here in the states was an air-cooled 175. And the DT line had little in common with the IT line. The DT 250 had a very ballsy engine once uncorked (a simple silencer change made a huge difference), but it handled like a Mack truck, and had attrocious suspension. The 175 handled a little better, but was rather weak. The DT line was a dual-sport line, so EPA laws killed it here before two-stroke tech advanced to the point of power-valves and water cooling.
 
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#6
]
The DT line was a dual-sport line, so EPA laws killed it here before two-stroke tech advanced to the point of power-valves and water cooling[/QUOTE
.

So I guess that means you never got the 220 with traction control?
hehe



]
It even makes wheat bix out of some heavily modified mx 125's[/QUOTE

Dude! You’re an Australian that can’t spell Weetbix?? (std Australasian breakfast)


Hard to know what to say, I mean an older bike, chances are the fork & shock oil need changing & the springs are probably too soft ‘specially the front which is a Yamaha signature. The suspension will always be a little budget but is it worth spending too much?

Knackered steering head bearings will make any bike crappy in the tight & I bet the rear suspension linkage bushes need attention, which will impede performance.

You could embark on a weight loss program of pulling off things until the bike stops & put the last thing back on.

The Powervalves were battery operated on the LCs but uncertain of the Rs. If so you can make a battery eliminator kit with a capacitor & a regulator.
Mind you they were bad at frying their electrics so it is risky.
 
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#7
The type R dt also had a battery operated powervalve, i found it just as easy to remove the battery and then simply disconnect the wire connecting it to the powervalve. Oh yeah, it was also necessary to adjust the small nut behind the powervalve cover plate, (power gains were amazing).

About those "Weetbix", i didn't think anyone was going to know what i was talking about anyway.
 
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#8
Yeah could be deceptive with the pv locked open it will hit harder, but if the controller was functional the pv will have been opening fully at high revs anyway. When I first got my DT the PV controller was missing so I tried to fit an RZ one I had lying around. Sadly they fire twice as often so I had to get an original one.

The bike seemed to loose it’s wheelie prone nature but it was really because the bottom & mid were so much stronger that it didn’t hit so hard. Helped on muddy hills etc. If you are using it on open tracks this may not be so noticeable. I wonder if yours was operating properly before?? Could you see it adjust to fully open?
 
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#9
David,
Your probably right about the power gains being masked by a change in power delivery, ie more punch in the top end and less down low. It sure does make for interesting riding, but like you said it doesn't really help you in the bush/bog.

About the powervalve function, the friend/mechanic who directed the adjustments said that if i add a battery the bike will run even better, which suggests that the pv was retarded or not operating properly in the first place. To be honest, i didn't really understand the concept of adjustments. How will adding a battery change (if any) the power delivery? Will i get more low down power?
If i want more power down low, it it simply a case of re-adjusting the before mentioned nut, or is there more to it?
 
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#10
Adding a battery assuming the control box is intact should give you the best of both worlds. You’d tell the bike had been eating its . . . No I won’t go there.:silly:

All the powervalve is doing is raising the roof of the exhaust port at high RPM & lowering it at low RPM. This does several things but the effect is to extend the range the engine is efficiently producing power.

Yes you can lower the valve to improve midrange/bottom end as required, & on a std bike this should cause no problem at top end.

If however the compression had been raised you may find that this may cause detonation problems at high RPM.
 
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#11
After putting a new battery back in the bike, the power curve has smoothed out due to the correct operation of the powervalve. It still flogs the 125's but is easier to ride, because of the power is now being spread throughout the rev range.
The bike still has handling/suspension trouble, the front fork seals are shot and the front dives deep at any opportunity. Will replacing the fork seals and replacing the fork oil give me a greater level of stability or do i require a fork rebuild (what do they actually do in a fork rebuild anyway?).
 
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#12
Hey well everything you do will be an improvement starting at minor dollars.

First off you need to replace those seals. Then you should get some stiffer springs & set the preload (several articles about preload about the place) up by adjusting the length of the spacers above the springs. You can make longer ones out of sturdy PVC plumbing pipe. Do a search on ‘stiffening springs’ using the search key & there is a thread I wrote which is a cheap option for stiffening springs.

Check the forks are straight while they are apart & clean the old oil out thoroughly. Usual starting point is about 10w for something of this age I guess. They weren’t USD or cartridge I don’t think.

Treat the rear shock to a re-oil & regas (have to take shock to a specialist) & make sure the linkages are in good order.

Beyond that is specialist suspension work which is probably just a waste of money on an oldish bike compared to buying a new one.

You will probably find getting the forks & shock sorted will bring the sort of improvement you hope for -within reason.

Glad the PV worked out for you.

Oh yeah & let me get out of the plane next month when I’m over for the 500GP. I am not a Air NZ shareholder. :silly: :silly:
 
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#13
I bet some of you were wondering when I was going to find this post.

First I have my bike lightened up to less than 200lb. I also never felt the suspension bottom. I have taken this bike over 30' table tops and over shot and cased a few time and never felt it bottom.

Currently I have a 1980 MX motor and exhaust in it and for those who don't know a MX was a more tuned out bike, it was lighter and quicker than the DT but it didn't really have the top speed of the it. I also get about 1 and a half hours to 2 hours for every gallon of gas, plenty impressive for the old girl.

I'll also tell you this bike is industuctible and I have played plenty of tree ping pong and the bike just keeps running. I even have the same piston I've been running for the last 3 years, I never did a top end rebuild because I never had to (compression is still normal)

I've beaten plenty of bikes any wheres from MX125s to 250s to KDXs and XRs, I've been also beaten by them (especially those darn KTM200 EXCs those things are a hand full to beat even with a amature riding one). I'm not sure about the newer DTs but mine rocks and I'm proud to own one, ask anyone that owns or has owned a late 70s to mid 80s DT these bikes were the best in off road bikes for there time and still are.
 
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#14
Originally posted by Psyco Diver 69
ask anyone that owns or has owned a late 70s to mid 80s DT these bikes were the best in off road bikes for there time and still are.
I did own one, and I think you have been sniffing to much pre-mix:p . My '79 PE 250 was a far more capable bike off road than my DT could ever have dreamed of being, and the PE certainly was not the best offroad bike of its day.
 
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#15
Originally posted by spanky250
I did own one, and I think you have been sniffing to much pre-mix:p . My '79 PE 250 was a far more capable bike off road than my DT could ever have dreamed of being, and the PE certainly was not the best offroad bike of its day.
I'm not saying it was the fastest or the sharpest turning, I'm saying they were the most reliable and toughest bike and it was a great all around bike. It gets just as good as milageas any 4 stroke. Also I never experenced a DT engine I have a MX175 engine exhaust in my bike which is probably a faster and better engine.