OzVMX Forum
Marque Remarks => Yamaha => Topic started by: lms6201 on March 20, 2008, 06:55:08 am
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what is the process for fitting a new sleive ? is the barrell heated or can the liner be pressed out / in cold , all recomendations pls
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The liners I've changed in the past were done with heat. To remove a liner I put it in the oven upside down with the barrel supported but not the liner. Raise the temperature till the liner drops. Last time I got to about 140 C
To refit them. Heat the barrell and put the liner in the freezer. I leave them for a couple of hours at least. I heat the barrel to a bit lower than what it took to get the liner out. The frozen liner makes up for the lower temp and still give a bit to play with. Have the barrel upright and drop (lower) the liner in. put some weight on the liner to hold it as the barrel cools
Temperatures will increase dramatically if you get caught doing this with out permission!!!!!!!!!!!!!!!
Brent
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Along with Brent's good advice(especially keeping the weight on, otherwise it will pop up when cooled), you will have to learn to see which liners actually press out as many oldtime barrels have cast in liners.Can you post a pic?
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no pic,s but it,s a late 490 , am thinking of the wiesco liner , cheap. also do they have to be bored ? or are they sized to std out of the factory , thanks muchly for the advise already ,
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Steve
Yamaha and other Jap brands cast the aluminium bit around the steel/cast iron bit so the steel/cast iron bit has to be machined away. It's Bultacos and OSSAs that you can take the sleeve out with heat.
Fitting the new sleeve to the 490 is as described above.
David
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I have done 70% of a 490 resleeve, unfortunately you will need access to a good size lathe, a pipe centre and a face plate.There is a fair bit of machining involved and a fair bit of work with the porting tool when the liner is fitted.Remember when time comes to fit the liner there won't be much time to work with as the liner starts to heat up rapidly.Then there is the rebore after all that to as the ID of the new liner is about 1mm under size :'(
Suzuki's and Kawasaki's press out fine. :D
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thanks people , seeing as my lathe is a baby , i,ll get it done , is serco still around ?
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If your in the Hunter Valley area we have a bloke at West Wallsend that does them for most of the bikes around here.
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Sending the barrel to Dave Hall would be a good idea as Dave does great work for very competitve prices.