1985 i.t 200

6 replies to this topic
  • prplhzei.t200

Posted February 04, 2013 - 05:08 PM


I read somewhere that it seems these 200's have problems with base gasket leaking. Mine did a few weeks ago, so I made a new gasket out of some cellulose something or other gasket material. I also replaced the nuts with new flanged nuts. Saturday a friend of rode the 200 about 30 or so miles and he didn't have any issues ( like revving real high) or anything. But when I unloaded yesterday I noticed some what looks like seepage around the base of thy cylinder. Between the nuts on both sides. It's not really leaking, but I wonder if the gasket is soaked with oil and just seeping thru. I grabbed a wrench and gave the nuts a little turn,just barely tho. Anyone shed any light on this subject?

Thanks in advance

  • USED YZ426F

Posted February 05, 2013 - 01:35 PM


Really, without knowing exactly what you used to make your gasket, there is little that anyone can tell you about whether you have oil seepage, or some other issue.

You shouldn't have any oil seepage (or any other for that matter) around the base gasket. I suppose it is possible that the gasket material you used got stained by some mud or water during the ride.

I would use an actual gasket for the base and ensure that your cases are completely clean and flat where the jug mates up. You shouldn't need any gasket sealer or anything else to get everything sealed up properly.

Clean, flat mating surfaces, and properly torqued fasteners have all I have ever needed to get a proper seal.

  • ickfinger

Posted February 05, 2013 - 04:11 PM


I was told by a guy that the aluminum head mount should be removed because it tended to tug and twist the cylinder to bad extents. The guy who told me this raced IT's a lot and knew a bunch of good stuff. Do a search in the vintage section and youll see all helpful stuff!

Edited by ickfinger, February 05, 2013 - 04:18 PM.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • prplhzei.t200

Posted February 05, 2013 - 05:21 PM


ya i removed the headstay. I guess thats what its called. I read that the 200's were notorious for cracking the head cuz of it.The gasket was real gasket material of the automotive type. It had seepage on both sides of the cylinder. I think I will see if I can find the actual gasket for it.

  • scalejockey

Posted February 05, 2013 - 05:54 PM


The base warps over time on these cylinders..mainly from over tightening. Chuck the cylinder in a lathe and machine it flat again just down to the lowest points near the side ports,so not to raise compression.
The cylinder studs will have to be removed first...

Edited by scalejockey, February 05, 2013 - 05:55 PM.

  • prplhzei.t200

Posted February 06, 2013 - 12:19 PM


You mean chucking the cylinder itself? The studs stay in the lower cases. I've been getting in tight with the guy that owns the local Honda/Yamaha shop.He might be able to do such a job. Thanks

  • scalejockey

Posted February 06, 2013 - 08:03 PM


You mean chucking the cylinder itself? The studs stay in the lower cases. I've been getting in tight with the guy that owns the local Honda/Yamaha shop.He might be able to do such a job. Thanks

Yes,chuck up the cylinder with internal clamps on the head end.Spin it and cut down the base.
Have done this numerious times...
You can have some fun and cut it down the thickness on one head gasket,then run two head gaskets,that will get ya some more low end power (along with the boysen port mod) But that's a whole different subject...

Related Content


Yamaha YZ85 2016 by Chris.GVS

Yamaha YZ85 2016
  • - - - - -
  • 0 reviews

3 points of Spooge by CaptainKnobby

Dirt Bike   Make / Model Specific   Yamaha   Yamaha 2-Stroke
  • Hot  48 replies

Yamaha YZ125 2017 by Chris.GVS

Yamaha YZ125 2017
  • - - - - -
  • 0 reviews

125 or 250 2 stroke? by Syrex

Dirt Bike   General Dirt Bike Forums   What bike should I buy?
  • Hot  46 replies

Yamaha YZ125 2016 by Chris.GVS

Yamaha YZ125 2016
  • - - - - -
  • 0 reviews

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.