Does my bore look okay?

**flyingcr250** · 13th November 2009, 17:21

it sorta looks to me that it has worn through the coating in a couple of places, is this possible?

thoughts........

**little.whittle** · 13th November 2009, 17:25

Hows the piston?

**IIIRII** · 13th November 2009, 17:27

Looks like varnishing to me, is it smooth if you run your fingernail across it ?

**flyingcr250** · 13th November 2009, 17:32

Originally Posted by little.whittle

Hows the piston?

doesnt look bad at all

**little.whittle** · 13th November 2009, 17:34

How many hours did u do on that?

**flyingcr250** · 13th November 2009, 17:35

Originally Posted by IIIRII

Looks like varnishing to me, is it smooth if you run your fingernail across it ?

yea its smooth.... is varnishing bad?

**flyingcr250** · 13th November 2009, 17:36

Originally Posted by little.whittle

How many hours did u do on that?

85hours...........

**little.whittle** · 13th November 2009, 17:45

poor thing haha

**flyingcr250** · 13th November 2009, 17:48

Originally Posted by little.whittle

poor thing haha

100 hours is supposed to be nothing for the 2T EXC's

**little.whittle** · 13th November 2009, 17:50

wow!

my one is recemended every 30-35

**IIIRII** · 13th November 2009, 19:18

Shit no, no worries, as long as theres no obvious grooves you can feel with your fingernail or anything else it should be fine, nikasil is really really hard so the bore should be sweet

**camchain** · 13th November 2009, 19:18

Hey, nice clear sharp photos. I'm not an expert by any stretch but everything looks OK to me. You can't beat a good accurate measure up with a bore guage, take it to engine recon then you'll know. Common hot spot/seize spot apparently is the bridge on the exhaust ports, yours looks nice. You can see more wear down at port level (to be expected) but you can still see hone marks here and there, hopefully they are original. Search for my thread and photos of my grubby bore for comparision (about 9mths ago?).

Piston looks real good (but wot - no pic of front of skirt?) Danger has gotten super long hours out of his 200 pistons and your 300 much lower revver so longer lasting. I'd be tempted to run that for another 80hrs if it measures up OK.

I don't know how close the power valve is to piston on the 300s but on mine, piston/rings had been picking up carbon build up from power valve. I used CRC and a green kitchen pad to deglaze my bore. Don't mention the 'H' word. KTM wear limit on nicasil coating is only .025mm - very little to play with. Extremely unlikely to be any wear through the coating, it's super hard and tough.

After you give everything a real good clean you'll see the Nicasil coat runs into ports a few mil. The Nicasil is darker - looks a bit like a varnish.

**flyingcr250** · 13th November 2009, 19:27

Originally Posted by camchain

Hey, nice clear sharp photos. I'm not an expert by any stretch but everything looks OK to me. You can't beat a good accurate measure up with a bore guage, take it to engine recon then you'll know. Common hot spot/seize spot apparently is the bridge on the exhaust ports, yours looks nice. You can see more wear down at port level (to be expected) but you can still see hone marks here and there, hopefully they are original. Search for my thread and photos of my grubby bore for comparision (about 9mths ago?).

Piston looks real good (but wot - no pic of front of skirt?) Danger has gotten super long hours out of his 200 pistons and your 300 much lower revver so longer lasting. I'd be tempted to run that for another 80hrs if it measures up OK.

I don't know how close the power valve is to piston on the 300s but on mine, piston/rings had been picking up carbon build up from power valve. I used CRC and a green kitchen pad to deglaze my bore. Don't mention the 'H' word. KTM wear limit on nicasil coating is only .025mm - very little to play with. Extremely unlikely to be any wear through the coating, it's super hard and tough.

After you give everything a real good clean you'll see the Nicasil coat runs into ports a few mil. The Nicasil is darker - looks a bit like a varnish.

im gunna take it in to the bike shop tomorrow when i order my new piston kit, for the amount of hassel it is to get the head off, think id rather just put a new piston in. if you sw the rest of the bike youd see ive got a lot of work ahead of me lol