# Piston Hole - Can I repair it? **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [November 19, 2019, 4:35am UTC](https://community.cartalk.com/t/piston-hole-can-i-repair-it/153077 "2019-11-19T04:35:47Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![loic\_159340](https://avatars.discourse-cdn.com/v4/letter/l/5e9695/32.png) [@loic\_159340](https://community.cartalk.com/u/loic_159340)\ **Post date:** [November 19, 2019, 4:35am UTC](https://community.cartalk.com/t/piston-hole-can-i-repair-it/153077/1 "2019-11-19T04:35:47Z")
Hi guys, Valve bent, piston got hit, cylinder wall still in specs despite a visible (but not “feelable”) scar. Yes, I used a bore gauge. See picture: ![image](https://global.discourse-cdn.com/cartalk/original/3X/4/e/4e90125866b053c0c604066611bf685cb3392d6f.jpeg) Can I smooth it out and let it run for another year? Or am I guaranteed hot spots and should replace the piston? I’m trying to flip this vehicle without spending too much, yet I don’t want to sell a lemon or something unsafe. It’s 1-hr of sanding vs 2-days of tear down! Thanks! ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [November 19, 2019, 4:38am UTC](https://community.cartalk.com/t/piston-hole-can-i-repair-it/153077/2 "2019-11-19T04:38:55Z")
That doesn’t look repairable to me. But then again I’ve never tried such a thing. Common sense says to just replace the piston and be done w/it. ---
**Author:** ![oldtimer-11](https://avatars.discourse-cdn.com/v4/letter/o/e79b87/32.png) [@oldtimer-11](https://community.cartalk.com/u/oldtimer-11)\ **Post date:** [November 19, 2019, 5:36am UTC](https://community.cartalk.com/t/piston-hole-can-i-repair-it/153077/3 "2019-11-19T05:36:07Z")
How on earth could you sand that in place? And how can you have two more days of tear down when you already have the head off. ---
**Author:** ![Mustangman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mustangman/32/44130_2.png) [@Mustangman](https://community.cartalk.com/u/Mustangman)\ **Post date:** [November 19, 2019, 1:19pm UTC](https://community.cartalk.com/t/piston-hole-can-i-repair-it/153077/4 "2019-11-19T13:19:05Z")
The piston is damaged, clearly. It has to come out so you can see if a ring land is damaged. If there are no cracks, you might sand the top to smooth it out. It has to come out anyway because you need to run a hone down that bore or the rings will never seal. ---
**Author:** ![loic\_159340](https://avatars.discourse-cdn.com/v4/letter/l/5e9695/32.png) [@loic\_159340](https://community.cartalk.com/u/loic_159340)\ **Post date:** [November 19, 2019, 4:02pm UTC](https://community.cartalk.com/t/piston-hole-can-i-repair-it/153077/5 "2019-11-19T16:02:44Z")
Because this is a motorcycle, not a car, and the cylinders are not removable, to access the piston the crankcase must come apart and be split on this model. Which sucks! ---
**Author:** ![Cavell](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/cavell/32/43396_2.png) [@Cavell](https://community.cartalk.com/u/Cavell)\ **Post date:** [November 19, 2019, 4:25pm UTC](https://community.cartalk.com/t/piston-hole-can-i-repair-it/153077/6 "2019-11-19T16:25:31Z")
the area with the vertical scratches is about 1.5" wide. not just where the gouge in the piston is. i would want to remove the piston to inspect it for damage. what is causing the vertical scratches? ---
**Author:** ![ok4450](https://avatars.discourse-cdn.com/v4/letter/o/e9bcb4/32.png) [@ok4450](https://community.cartalk.com/u/ok4450)\ **Post date:** [November 19, 2019, 6:41pm UTC](https://community.cartalk.com/t/piston-hole-can-i-repair-it/153077/7 "2019-11-19T18:41:57Z")
Just curious, but what kind of bike? A Gold Wing, Interstate, or what? Rather than split the block I would try to use a Dremel tool and round the sharp edges of the damage off to prevent hot spots. That’s what I’ve always done with nicked pistons on cars and never had an issue with doing so.Luckily there was never any ring land issues but that Murphy’s law thing always lingers around. ---
**Author:** ![loic\_159340](https://avatars.discourse-cdn.com/v4/letter/l/5e9695/32.png) [@loic\_159340](https://community.cartalk.com/u/loic_159340)\ **Post date:** [November 19, 2019, 7:38pm UTC](https://community.cartalk.com/t/piston-hole-can-i-repair-it/153077/8 "2019-11-19T19:38:07Z")
The hole is on the edge of the piston which probably caused the scratch, looking at it closer it could be grind to semi-flat or at least smoothed out. Also, upon removing the head I found the missing piece of the piston, a small ball ! Fortunately the previous owner didn’t run the bike too long for it to scratch everything! ---
**Author:** ![loic\_159340](https://avatars.discourse-cdn.com/v4/letter/l/5e9695/32.png) [@loic\_159340](https://community.cartalk.com/u/loic_159340)\ **Post date:** [November 19, 2019, 7:40pm UTC](https://community.cartalk.com/t/piston-hole-can-i-repair-it/153077/9 "2019-11-19T19:40:51Z")
You’re almost right! It’s from a Honda CBR600RR. Rings are not damaged as the leak down test came perfect with close to 0% leakage (after replacing the bent valve of course!). I’m just dreading, it’s a 130lbs engine with so many steps to “simply” replace a piston. No buddies to help me. ---
**Author:** ![oldtimer-11](https://avatars.discourse-cdn.com/v4/letter/o/e79b87/32.png) [@oldtimer-11](https://community.cartalk.com/u/oldtimer-11)\ **Post date:** [November 20, 2019, 5:14am UTC](https://community.cartalk.com/t/piston-hole-can-i-repair-it/153077/10 "2019-11-20T05:14:53Z")
I see nothing in your original post to indicate that this was a motorcycle. Some times the information you leave out makes replies useless. ---
**Author:** ![loic\_159340](https://avatars.discourse-cdn.com/v4/letter/l/5e9695/32.png) [@loic\_159340](https://community.cartalk.com/u/loic_159340)\ **Post date:** [November 20, 2019, 5:28am UTC](https://community.cartalk.com/t/piston-hole-can-i-repair-it/153077/11 "2019-11-20T05:28:13Z")
I’m sorry it wasn’t my intention. But in all fairness, isn’t a piston a piston? And a cylinder a cylinder? Whatever vehicle, it seems like the same repair process. ---
**Author:** ![oldtimer-11](https://avatars.discourse-cdn.com/v4/letter/o/e79b87/32.png) [@oldtimer-11](https://community.cartalk.com/u/oldtimer-11)\ **Post date:** [November 20, 2019, 5:40am UTC](https://community.cartalk.com/t/piston-hole-can-i-repair-it/153077/12 "2019-11-20T05:40:47Z")
Yes, but I was wondering why you had 2 more days of work to pull the piston when the head was off. You also didn’t mention having to split a case. Many things are harder to bo on a motorcycle because of space is so cramped. ---
**Author:** ![ok4450](https://avatars.discourse-cdn.com/v4/letter/o/e9bcb4/32.png) [@ok4450](https://community.cartalk.com/u/ok4450)\ **Post date:** [November 20, 2019, 6:37pm UTC](https://community.cartalk.com/t/piston-hole-can-i-repair-it/153077/13 "2019-11-20T18:37:47Z")
I sympathize with you on wrestling engines in and out of a bike. I’ve done it many times with Harleys and it never gets easier nor does the back get better. Last time I rode to Sturgis I ran my HD dresser onto the co-op grain scales where I live and it added up to just a shade under 1100 pounds with me on it. Trying to stop a 1/2 ton+ bike on a downgrade was a bear. When the rear brake caliper bleeder blew out heart went to my throat and the runaway truck ramp started looking like an option. ☹