Hi, stripped my top end as head was leaking, found the problem, 2 of the studs are loose, so put 2 inserts in the holes and skimmed the head and top of barrel, thats that sorted. The barrel has a slight scratch init, would problys be ok but iv decided to get it bored. Only thing is its already been bored to the maxium for dt's 57.9, so getting it bored to 58.4 and using the tzr piston and taken abit off the powervalve so it clears the piston. Also polished the exhaust port for the hell of iy, dout that will do anything, Just wondering if anyone has done this with theres, im sure there have, and just wanting to know if you feel much of a difference in performance from a standerd dt? Thanks.
Aye mines bored out to 58mm + with a TZR piston, but cant really tell you if it differs from standard bore as it was already bored out to the max when I first bought the bike,so I got another barrel, and started again. plus the power valve was originally pinned open, and I've since put a servo motor on it, polishing the exhaust port always helps, and deffo take off a smidgin from the powervalve, as it will hit against the piston. remember to have some reamed from the gasket too, and the cylinder head as you'll be changing the cylinder volume.
Boring out will no doubt give the bike more power as the engine size will increase. The difference in power won't be huge if noticable if you ask me. As far as polishing goes. The idea is to make the air flow smoother over the areas. Race bikes have it done but they are rebuilt after every race. I'd do it as you have nothing to lose but the time it takes but for a long term thing i doubt it makes a huge amount of difference.
I polished the top of the piston and my powervalve before I put it together and it ran from a rebore to lands end, then to john o groats, then back to worthing and performed extremely well! My bore was +1.25.
Yeah im not expecting the polishing to to make any noticeable change like, not quite sure why i done it, probables boredom lol mines going to be bored by 2.40 so should feel a difference with that. Looking forward to getting it back on the road now.
the polishing (top of piston,powervalve and exhaust port) helps the gases escape quicker,but best of all helps reduce power loss through carbon build up
Yes my bike is bored to 58.40mm.Done the pv job aswell.
But ive been told by alot of motorcyle shops round my way, that once the dt is bored of over 1-2mm.That you mite find, that it will start blowing head gaskets alot faster than usual.
Which is true from my experience.
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merry crimbo
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DT125R Forum -> PISTONS -> Anyone got there dt bored to 58.4 and using the tzr piston?