Author Topic: 200L powervalve - does it really need a battery and plastic 'cog' arrangement?  (Read 628 times)

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Offline DTDave200

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Hi everyone,

new to the forums and impressed with all the good info on here- a great site and resource.

I've recently bought a DT200L 1985 model which is pretty rough but a runner. I'm in the process of getting it back to reasonable shape, and have noticed the power valve is not working at any time. I've heard heaps of conflicting info, but was wondering if anyone knows if the power valve can work without a battery (as the bike currently has not battery)?

Also, would anyone have any idea of the order of the plastic 'cogs' in the servo motor assembly? It looks like it's been opened, and I'm not convinced the order is quite right and the cogs don't seem to turn or mesh well. An exploded diagram or photo would be fantastic (none in the service manual).

Thanks very much for any info you can provide.

David


Offline 4V5

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welcome to the forum!

I've not got one pulled apart but the DT200L shares the servo assembly with the European DT125LC.

34x-85820

http://www.ebay.co.uk/itm/Yamaha-RD125-86-87-SERVO-MOTOR-ASSY-34X-85820-00-NOS-genuine/173740044093?epid=28017835856&hash=item2873b6af3d:g:PMMAAOSw5yFazIFw:rk:1:pf:1&frcectupt=true

that 200 model also ran until to around 2000 in the brazil market so relatively rare here and Canada but very common there. I've not worked out how to buy and freight stuff from there to here yet though
IT465x4 IT400C IT175F YZ465G YZ250C YZ250WR XJ650G RD350LC RD250LCx5 DT175Nx3 TW200x2 DT200L DT200R RT3 RX100G GT80F YZ80L PW50J KH250B1 KZ250D1 PE175C TS250ER TS185ER AG175B AG100

Offline mikeyvet

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On the DT200R the power valve will function without a battery with the engine running so long as the regulator/rectifier is OK, it just won't go through the rotation when the bike is first turned on.

The regulator rectifier will die if you run the bike long enough without the battery.

Offline Glenngt750

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@Mikeyvet- When you say "it dies" about the reg/rec., do you mean that there is permanent damage. Or do you mean it just quits working, without a battery?
From:Edmonton, AB. Canada. Bike(s): 1990 Yamaha DT200R, 2006 Honda GL1800A, 1977 Suzuki GT750, 1985 Honda VF750FF, 1987 Honda VFR700F2.

Offline 4V5

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it will fry it. and.. everything else.

these DT200L's I have noticed have a good chance of having major electrical issues when they come up for sale.
IT465x4 IT400C IT175F YZ465G YZ250C YZ250WR XJ650G RD350LC RD250LCx5 DT175Nx3 TW200x2 DT200L DT200R RT3 RX100G GT80F YZ80L PW50J KH250B1 KZ250D1 PE175C TS250ER TS185ER AG175B AG100

Offline mikeyvet

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The DT 200R I bought that was run without the battery had a reg/rectifier that no longer passed DC current out so the powervalve and indicators no longer worked, but still regulated the AC current to the headlight circuit.

Thats a DT200R, Australian model, I suspect the wiring in the DT200L is similar but can't guarantee it.

Offline DTDave200

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Thanks for the welcome and all the replies.

Yes I think it's certainly probably fried the regulator / rectifier as it's in pretty sad shape and looks like it hasn't had a battery for a long time. I think worry about the thousands of other issues it has and leave the power valve for now. Should I set it in the midway position (half open) so as not to compromise either the top end or bottom end performance too much?

Thanks again guys for all the good advice.

Offline twinrock

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As far as I know on all yamaha ypvs do not work with out battery.. They need one even if it's flat I actually testing this on a dt200 a couple of days ago.. As for the 200L the power valve controller box with is separate on those like an rz350,was a common issue with the  dt200L . Here in aust they are not comon however you can run the dt200r electricals, which has an integrated powervalve control box in the actual servo motor,  but u  need to swap everything over including flywheel..thats what I did as they are far more comon.. At least here anyway

Offline Nottsbiker

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You can run any bike without a battery as long as you fit a condenser in its place which is commonly referred to as a battery eliminator.

I'd imagine but am not 100% certain that the YPVS will function correctly with a running engine and obviously do nothing at idle - my 200WR works like this and has a small condenser mounted behind the headlight which probably weighs 10% of what a traditional battery would do.