blutaco Posted September 20, 2015 Report Share Posted September 20, 2015 The 199a I'm restoring has evidence of a cold seizure so a full top end overhaul is in order. I'm looking for any information or advice on conducting a rebore. Not sure if it's a plated bore or if a straightforward rebore will suffice. Any help welcome! Quote Link to comment Share on other sites More sharing options...
pschrauber Posted September 20, 2015 Report Share Posted September 20, 2015 A straightforward bore depending the oversize you need is from +0.25 - 1.25 in 0.25 steps. Luckily the barrel inside the cylinder is not plated. 1 Quote Link to comment Share on other sites More sharing options...
blutaco Posted September 20, 2015 Author Report Share Posted September 20, 2015 That's great. I'll let the engineer have a look first before ordering a new kit. The piston is marked T2+ on the crown and 83K5 inside. Quote Link to comment Share on other sites More sharing options...
stevem75 Posted September 20, 2015 Report Share Posted September 20, 2015 The T2+ indicates final cylinder diameter after boring. If using a Mahle piston (oem) , then these markings are critical as they need to be used to get the proper final bore size. If using a wiseco piston then follow their specs...... And then add another 3 thou to prevent cold seizure. Steve Quote Link to comment Share on other sites More sharing options...
blutaco Posted September 20, 2015 Author Report Share Posted September 20, 2015 Hi Steve ve Thanks for replying. It is the original Mahle piston. I bought the bike when it was 1 year old from a chap in Oban. I'll buy the new kit from Inmotion. Is there anything in particular I need to advise the folk doing the rebore? John Quote Link to comment Share on other sites More sharing options...
smelling123 Posted September 20, 2015 Report Share Posted September 20, 2015 Original bore clearance is 1.7 thou I'm told (by the gents at inmotion) that's all the rebore shop should need to know. Sounds quite tight to me, I'm having mine done to that spec but need to warm up gently.... Quote Link to comment Share on other sites More sharing options...
stevem75 Posted September 20, 2015 Report Share Posted September 20, 2015 I'd have to look at my manual to determine the final size but 1.7 is in the ball park. The mahle pistons work just fine at that clearance and so long as they are properly warmed up there won't be an issue. Wiseco pistons have to be run quite loose to prevent cold seizures and even at that they'll still seize at some point. In 25 years of being a professional mechanic I've never seen a wiseco piston not seize. Stick with mahle always if you can Quote Link to comment Share on other sites More sharing options...
smelling123 Posted September 20, 2015 Report Share Posted September 20, 2015 The difference being Mahle are cast, wiseco forged. The italkit pistons are cast and seem good.. 1 Quote Link to comment Share on other sites More sharing options...
bondy Posted September 20, 2015 Report Share Posted September 20, 2015 Hi i have 2 barrels in the shop now being rebored 1 piston is a italkit the other a new Mahhle i was told 2 thou i bought another brand new Mahle by mistake. Quote Link to comment Share on other sites More sharing options...
sherpa325 Posted September 21, 2015 Report Share Posted September 21, 2015 I always bore mine to 1.5 thou and have never had a problem, always very careful during run in. A friend had his bored and thought it was nice and quiet until we went riding together and then realized his brand new rebuild was quite noisy. To cut a long story short, he pulled it down and got the piston ceramic coated [cost about $40] The ceramic coating people can alter the thickness of their coating to suit, and after reassembly the motor was a lot quieter and ran great, fairly cheap solution. Cheers Greg 2 Quote Link to comment Share on other sites More sharing options...
guys Posted September 21, 2015 Report Share Posted September 21, 2015 Very useful information here, as my 159 might need a rebore. Quote Link to comment Share on other sites More sharing options...
lbhbul Posted September 21, 2015 Report Share Posted September 21, 2015 Nothing new for me to add only my own opinions, Mahle whenever I can get them, nice that 350 pattern pistons work wherever, we have at present 85mm piston well worn in M199. Mahle pistons @ .0015 thousandths clearance, (finding a good bore man very important). When forced to run a forged piston .003 thousandths and let her rattle until warm , then OK but not as nice as a Mahle. Sadly getting near impossible to source a Mahle here anymore. Larry 1 Quote Link to comment Share on other sites More sharing options...
bondy Posted September 22, 2015 Report Share Posted September 22, 2015 (edited) I bought 3 Mahle pistons not long ago from spain. I still have 1 84.45 brand new in box. Edited September 22, 2015 by bondy 1 Quote Link to comment Share on other sites More sharing options...
blutaco Posted September 22, 2015 Author Report Share Posted September 22, 2015 I'm hoping just to go to the first oversize for now but thanks for that Bondy. I take it Mahles are like hen's teeth now? Anyone know what Inmotion supplies? Quote Link to comment Share on other sites More sharing options...
bondy Posted September 22, 2015 Report Share Posted September 22, 2015 Inmotion ones are very good iv'e just put 1 in a 199b Quote Link to comment Share on other sites More sharing options...
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