KX85 piston comparison

[barty5]

Hers is the pic krad sent me dosnt show up the best but the left hand side where you can see its worn has a very fine amount of aluminium left from the piston right side no where near as bad. No pics of piston but so bad scrapes on it.

[noobi]

KTM mech told me burn pattern on my piston should look like a 'map of Australia.' I thought this sounded weird until I saw my piston. Turned out to be a very good description. Maybe gassers have 'map of Tassie?' lol

lol, thats what Steve at triplex described it like too. my bike had a map of the dark on it, it was covered, no clean spots. not sure it thats a good or bad thing ?
if gassers have a map of tassie, there getting more concentrated burn than if it looked like austrailia

[krad_nz]

Thanks for your help earlier on today Aaron.
Here are a couple more pics showing the bore and piston. You can see some nastiness on the inlet side of things, either side of the inlet port. Aaron suggested that this could be just starting to seize up? Punch mentioned that the bike was feeling low on power and didn't have the topend hit she was used to.

I'm not really sure what to do next. The damage itself can be sorted out but I don't really understand why its happened to begin with. Air filter is cleaned regularly. Clutching at straws below.

Points of interest:

- coolant is meant to be about 0.67 litres total. When we drained it there was only about 0.4-0.5 litres. Maybe caused engine to over heat? There is no overflow bottle on these bikes so it probably should have been monitored frequently but wasn't. I've never seen it steaming or anything however.
- we've dropped the needle one notch from standard to address a serious spooge issue.
- shes running about 32-35:1 oil ratio, Castrol TTS.

Thinking of taking to an engine specialists to get an expert opionion on what to do next.

[Rupe]

Thanks for your help earlier on today Aaron.
Here are a couple more pics showing the bore and piston. You can see some nastiness on the inlet side of things, either side of the inlet port. Aaron suggested that this could be just starting to seize up? Punch mentioned that the bike was feeling low on power and didn't have the topend hit she was used to.

I'm not really sure what to do next. The damage itself can be sorted out but I don't really understand why its happened to begin with. Air filter is cleaned regularly. Clutching at straws below.

Points of interest:

- coolant is meant to be about 0.67 litres total. When we drained it there was only about 0.4-0.5 litres. Maybe caused engine to over heat? There is no overflow bottle on these bikes so it probably should have been monitored frequently but wasn't. I've never seen it steaming or anything however.
- we've dropped the needle one notch from standard to address a serious spooge issue.
- shes running about 32-35:1 oil ratio, Castrol TTS.

Thinking of taking to an engine specialists to get an expert opionion on what to do next.

When was it last done?

[krad_nz]

Thats a good question.
Supposedly the previous owner sold it to us with about 20-30hours on a new piston and rings. It doesn't have an hour meter so who actually knows. Its probably done another 40-50hours on top of that at a guess.

Plan after putting new piston in was to install an hour meter too.

[SpikedPunch]

Not totally sure being second hand, rings were done about 30 hrs ago I think at time of purchase, was just trail ridden by previous owner, no racing. Don't know about the owner before that. Got it in March I think, riding at least once a week, no hourmeter so I don't know how much time I've put on since.

[Rupe]

Thats a good question.
Supposedly the previous owner sold it to us with about 20-30hours on a new piston and rings. It doesn't have an hour meter so who actually knows. Its probably done another 40-50hours on top of that at a guess.

Plan after putting new piston in was to install an hour meter too.

Most bikes on trademe have had recent top ends, but not all of them have receipts etc when you go to look at them, you've got to wonder???

Maybe the top end was well over due, you prob need to get that barrel looked at tho before you put it back together.

[barty5]

Thanks for your help earlier on today Aaron.
Here are a couple more pics showing the bore and piston. You can see some nastiness on the inlet side of things, either side of the inlet port. Aaron suggested that this could be just starting to seize up? Punch mentioned that the bike was feeling low on power and didn't have the topend hit she was used to.

I'm not really sure what to do next. The damage itself can be sorted out but I don't really understand why its happened to begin with. Air filter is cleaned regularly. Clutching at straws below.

Points of interest:

- coolant is meant to be about 0.67 litres total. When we drained it there was only about 0.4-0.5 litres. Maybe caused engine to over heat? There is no overflow bottle on these bikes so it probably should have been monitored frequently but wasn't. I've never seen it steaming or anything however.
- we've dropped the needle one notch from standard to address a serious spooge issue.
- shes running about 32-35:1 oil ratio, Castrol TTS.

Thinking of taking to an engine specialists to get an expert opionion on what to do next.

wouldnt stress to much bout the amount of coolant you got out there will still be some in the motor you dont get out till you fully strip normally. I ran mine the other week for two hrs before i could top up missing at least 200mls

[telliman]

wouldnt stress to much bout the amount of coolant you got out there will still be some in the motor you dont get out till you fully strip normally. I ran mine the other week for two hrs before i could top up missing at least 200mls

noticed my radiator was empty tonight after changing oil and stuff, would that be the water pump?

[barty5]

noticed my radiator was empty tonight after changing oil and stuff, would that be the water pump?

if it was me i would check the oil make sure there is no water in it then pressure check cooling system. And check rad cap they wear every time you remove it (the seal) and weakin with age this can allow coolat to excape. When did you last check it??

[SpikedPunch]

Shoutout to LJ and L rider, I remember LJ posting about an engine shop on the shore a while back that was meant to be pretty good for this sort of thing, what's the address/name/info again?

[L Rider]

Shoutout to LJ and L rider, I remember LJ posting about an engine shop on the shore a while back that was meant to be pretty good for this sort of thing, what's the address/name/info again?

ummmm, lol i'll ask john as i can't remember.

[L Rider]

Ok, its Engine Specialists. 4894806. 96 Hillside Road Glenfield.
John reckons you'd be better taking into spectrum & getting them to have a look as to what can or cant be done on it.
But up to you...

[SpikedPunch]

Ok, its Engine Specialists. 4894806. 96 Hillside Road Glenfield.
John reckons you'd be better taking into spectrum & getting them to have a look as to what can or cant be done on it.
But up to you...

Ta for that Yeah, will try that out.

[LittleJohn]

Ta for that Yeah, will try that out.

Looking at your pics I would say you may get away with a VERY light honing, Engine Specialists can do that easy. My question would be what did the exhaust and inlet ports look like. If these have start to wear down then you have more serious problems. Looking at the piston itself I would say it is either way over due for a change or someone as been running to lean a mixture and to hotter spark plug (not you as your mixture should be sweet).

Feel free to drop it around for me to have a look at it, home a lot this week with school holidays. Also check the top of your crankshaft connecting rod to make sure there is no heat stress (cannot see the underneath of old piston to determine what it looks like).