January 17, 20188 yr Any body know if a gasser 300 head spacer will fit my 2016 jotagas 300 it has the gold S3 head insert fitted but still pinking when hot ?? Cheers for any help ?
January 17, 20188 yr A GasGas head insert won't fit the Jotagas. If you can obtain a disc type head spacer it should be easy enough to lay it on top of the head to see if the bolt holes line up, but if you use a spacer and low compression head insert won't it be flat as the proverbial ................ I presume you're using 98 octane fuel. Have you tried richening the mixture/changing the jets, etc? What make of carb' are you using?
January 17, 20188 yr Author Thanks lowbrow , I was thinking the alloy spacer not the insert , so may give it a go it's running a kehin carb , unleaded plus fuel 62 ml putoline 2 stroke oil per 5ltr . Not checked jets yet but tried the mixture screw in a bit further , doesn't seem to make a difference what map it's on . Plug looks fine doesn't do it all the time . Read on here that some S3 gold inserts are not the correct volume so am going to check that out . I built a Villiers engine bantam a while back and had a similar problem when it was hot it banged away like a whore on speed, had the head milled out to a larger volume and it transformed the bike .
January 18, 20188 yr I remembered that I have a head spacer from a 300 GasGas so tried to do what I suggested and it's not that easy with the motor all built up in the frame. The PCD and spacing of the stud holes does appear to be the same as the Jotagas. The head spacer idea predates the later two part head design and I agree with you that it's better to machine the insert especially if you can find data on the correct shape and volume.
January 18, 20188 yr Probably better to get the desired s3 head insert to lower the compression,more expensive though
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