Hello, what is the difference between the two bikes, and also would a servo unit from a TZR work on a DTR. Eg would this http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=110159830457&sspagename=ADME:X:RTQ:UK:11 go on a 1990 DTR
I'm pritty sure you will need more than what's on the picture there, the valve itself is not there. you have the cable pully and the YPVS cover, and the cdi box. i'm not sure whether your bike has the valve itself in it and just needs the pully for it to work mechanicly, buut it sounds wierd.
take a picture of your engine both sides then we might be able to work it out. you may have to disassemble some parts, but nothing hard!