k-dubya Posted May 28 Report Share Posted May 28 The short story - the threads for two cylinder head bolts are stripped in the cylinder barrel. The bitter story - DO NOT buy torque wrenches from Amazon. My question to this esteemed body - should I replace the cylinder or try helicoil or some such repair? If it is to replace, OEM or third-party? Quote Link to comment Share on other sites More sharing options...
faussy Posted May 28 Report Share Posted May 28 (edited) 1 hour ago, k-dubya said: The short story - the threads for two cylinder head bolts are stripped in the cylinder barrel. The bitter story - DO NOT buy torque wrenches from Amazon. My question to this esteemed body - should I replace the cylinder or try helicoil or some such repair? If it is to replace, OEM or third-party? Id go for the repair, youve nothing to lose considering buying a replacement is effectively scrapping it. Time serts are better than helicoils. Try it yourself if youre feeling up to it, or give it to a small machine shop Edited May 28 by faussy 3 Quote Link to comment Share on other sites More sharing options...
k-dubya Posted May 28 Author Report Share Posted May 28 Thanks for the pointer to the TIme Sert. These are new to me and, dang, they're expensive (but cheaper than a new cylinder). As for the OEM vs third, I found a couple options out of Europe ... but learned they're for the years up to 2022 ... and no longer available. Do you have any insights into how much room there is for an insert? It looks like the space between the thread well and the cooling tunnels is quite thin. Quote Link to comment Share on other sites More sharing options...
lemur Posted May 28 Report Share Posted May 28 Biggest difference other then cost: HeliCoil is a coil spring and will not provide a watertight repair at the threads. TimeSert sells a threaded insert and threads can be made to seal water pressure if you end up drilling into the water jacket. Using a drill press to start the tap straight into the clearance hole is a good practice. The manufacturers catalogue will detail the size of the clearance hole required. 2 Quote Link to comment Share on other sites More sharing options...
lemur Posted May 28 Report Share Posted May 28 If all else fails; see if the casting will take aluminum weld, fill the holes with weld, drill new holes and tap them to the standard size. 1 Quote Link to comment Share on other sites More sharing options...
lemur Posted May 28 Report Share Posted May 28 Hints for all on reassembly; torque charts are based on wet threads not dry. Service manuals or the net sometimes give inappropriate torque values, triple check them because many confuse inch pounds with foot pounds during conversion, or they are just printed wrong. If you are not using a 1/4" drive torque wrench on M6 or M8 bolts it might be the wrong tool for the job, I've also seen people not use the handle correctly, the handle pivots at the correct distance to the tool, it doesn't flop back and forth like that without reason. If unfamiliar with operation practice on something that does not matter first. 👍 Quote Link to comment Share on other sites More sharing options...
k-dubya Posted May 28 Author Report Share Posted May 28 Thanks for the pointers. I've got lots of years with a torque wrench, but what I had prior to this mess were too big for the job. I ordered a 'highly rated' 1/4" drive wrench off of Amazon ... and it didn't work. Shame on me for not testing it first on something less critical. Quote Link to comment Share on other sites More sharing options...
k-dubya Posted May 28 Author Report Share Posted May 28 An interesting side note in all of this - several online sources state the torque specs for the 300 head bolt is 18 ft/lbs. I just bought the Gas Gas service manual - it states the spec to be 11.1 ft/lbs. Second lesson in all of this - even multiple sources on the web do not ensure accuracy. Dang, this is a maddening lesson. 😡 Quote Link to comment Share on other sites More sharing options...
lemur Posted May 28 Report Share Posted May 28 You have to buy a GasGas service manual? that sucks, it should come with a new bike. Quote Link to comment Share on other sites More sharing options...
k-dubya Posted May 28 Author Report Share Posted May 28 Got a free online owner's manual with the bike but had to pay for an online repair/service manual which, frankly, has very little useful info in it. But, GasGas is KTM now ... Quote Link to comment Share on other sites More sharing options...
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