KX85 piston comparison

[clmintie]

Rebuilt the 85 today with Grace...

Below are the old and new pistons, 99.6 hours on the piston and 50 on the rings. Looks pretty good to me..... Note, everything was dripping with TTS/castor........

[barty5]

Rebuilt the 85 today with Grace...

Below are the old and new pistons, 99.6 hours on the piston and 50 on the rings. Looks pretty good to me..... Note, everything was dripping with TTS/castor........

looks all right to me couple shiny bit but youll allways get that

[SpikedPunch]

Oh snap, we're doing mine tomorrow :) Did the compression, it's only 100 psi so looks like it's time :bye:

[L Rider]

Oh snap, we're doing mine tomorrow :) Did the compression, it's only 100 psi so looks like it's time :bye:

So you've found your problem then...

[SpikedPunch]

So you've found your problem then...

Guess so! Bit stink but oh well, lucky I have a kit on hand from Bart's <s>farts</s> parts :sunny: Means no riding tomorrow though :crybaby:
So where's she gonna run it in Clmintie? Sandpit? I'm not really sure what to do for that bit.

[barty5]

you got all the right tools? make sure you put rag round under piston once barrel is off so you dont drop the clips down when pullin them out or back in. helps to do one side before you fit the piston.

[clmintie]

you got all the right tools? make sure you put rag round under piston once barrel is off so you dont drop the clips down when pullin them out or back in. helps to do one side before you fit the piston.

Yup, like this.............

[barty5]

Yup, like this.............

you got it had one fly out the other night on chia's bike dang thing bounce of something then came back landed on the crank. those clips do like to fly about if yoour not carefull.

[noobi]

what make of piston is that clmintie?
wiseco?
because the wiseco piston i got didnt have piston windows or blank holes like the B piston in your photo :blink:
iv got to run mine in tomorrow aswell

spikedpunch, was your bike particullarly hard to start when hot? more so that it had been?

[barty5]

what make of piston is that clmintie?
wiseco?
because the wiseco piston i got didnt have piston windows or blank holes like the B piston in your photo :blink:
iv got to run mine in tomorrow aswell

spikedpunch, was your bike particullarly hard to start when hot? more so that it had been?

looks genuine to me

[clmintie]

what make of piston is that clmintie?
wiseco?
because the wiseco piston i got didnt have piston windows or blank holes like the B piston in your photo :blink:
iv got to run mine in tomorrow aswell

spikedpunch, was your bike particullarly hard to start when hot? more so that it had been?

Kawasaki... Came in the spares kit............

[noobi]

Kawasaki... Came in the spares kit............

i kinda got that from the "B" stamped on the top that it was probably genuine. :sweatdrop
didnt think Kawasaki make pistons though.....? barty?

[Brian d marge]

If you haven't wiped the old piston , con you post a couple more pictures ?

why is one side lean and the other not? a ;leak ?

lots of blow by .

and can i see graining on the inlet side ? air cleaner dirty ?


I am only guessing from the pictures ..

Stephen

[barty5]

i kinda got that from the "B" stamped on the top that it was probably genuine. :sweatdrop
didnt think Kawasaki make pistons though.....? barty?

They dont its like have the stuff on youor bike what ever you ride its made by some one else and then assembled by the manufacture. A lot of that jap bike have Prox pistons in them from original just like most things when done like this they come of the line before they get thier making put on hence that one has a B marked on it in ink most are ingraved.

[SpikedPunch]

you got all the right tools? make sure you put rag round under piston once barrel is off so you dont drop the clips down when pullin them out or back in. helps to do one side before you fit the piston.

Yup, we're sorted, recently converted half the kitchen into a garage...:wacko:

spikedpunch, was your bike particularly hard to start when hot? more so that it had been?
Yup, it started getting a bit tricky back around the jolly roosta. Wasn't great to start cold either. Hopefully it'll be back to like when I first got it, barley needed a tap.

[L Rider]

Guess so! Bit stink but oh well, lucky I have a kit on hand from Bart's <s>farts</s> parts :sunny: Means no riding tomorrow though :crybaby:
So where's she gonna run it in Clmintie? Sandpit? I'm not really sure what to do for that bit.

I ran mine in at Sandpit - was back when i could only ride the learners so did it on that. Could do it on some of the easy tracks out their though. SIL's we ran in at Thunder back in summer

[clmintie]

If you haven't wiped the old piston , con you post a couple more pictures ?

why is one side lean and the other not? a ;leak ?

lots of blow by .

and can i see graining on the inlet side ? air cleaner dirty ?


I am only guessing from the pictures ..

Stephen

Here's some more pix for you..... Note that the pix make the carbon look thicker that it is, as I run my finger over the line between 'shinny' and carbon, it's hard to feel any difference in height...Maybe better described as 'soot' no doubt due to using a blend of TTS and R30. We use 3 air cleaners and chuck a clean one in every ride, often between races in summer. Airbox gets duct taped when very wet.... I realise by leaving it in for 100 hours, I've pushed this piston way beyond what would normally be called it's 'use by date' it's just that the first 30 40 hours were pretty 'gentle'.....

[clmintie]

Guess so! Bit stink but oh well, lucky I have a kit on hand from Bart's <s>farts</s> parts :sunny: Means no riding tomorrow though :crybaby:
So where's she gonna run it in Clmintie? Sandpit? I'm not really sure what to do for that bit.


Sand pit on Wednesday............. Day off to ride with the 'Sandpit Fanny Pack'

[Midget200]

Sand pit on Wednesday............. Day off to ride with the 'Sandpit Fanny Pack'

Oh you lucky man riding with the Fanny Pack!!! I haven't got a bike. Put mine back to full-sized. Hard to find a good 85 on Trade Me. Might have to buy new! Need it by Wednesday.

[buffstar]

Oh you lucky man riding with the Fanny Pack!!! I haven't got a bike. Put mine back to full-sized. Hard to find a good 85 on Trade Me. Might have to buy new! Need it by Wednesday.

well! it wouldnt be the fanny pack without ya luv :bye:

[buffstar]

oh whoops :Offtopic: better watch out for the thread police

sorry all

[clmintie]

Guess so! Bit stink but oh well, lucky I have a kit on hand from Bart's <s>farts</s> parts :sunny: Means no riding tomorrow though :crybaby:
So where's she gonna run it in Clmintie? Sandpit? I'm not really sure what to do for that bit.

I've shown you mine, you gunna show me yours???

Can you post a pic of your old piston please?

[clmintie]

Oh you lucky man riding with the Fanny Pack!!! I haven't got a bike. Put mine back to full-sized. Hard to find a good 85 on Trade Me. Might have to buy new! Need it by Wednesday.

Oh I do hope you can ride Wednesday, the girls are really looking forward to it.... Just don't buy the one I might need the bolt off at Spectrum....... :sweatdrop

[green machine]

Oh you lucky man riding with the Fanny Pack!!! I haven't got a bike. Put mine back to full-sized. Hard to find a good 85 on Trade Me. Might have to buy new! Need it by Wednesday.
Go on get a new one.....nuthin like throwing ya leg over a bike that no one's ridden before!!!

[barty5]

I've shown you mine, you gunna show me yours???

Can you post a pic of your old piston please?

Hmm not lookin good they bought it out to albany for me to have a look at couple a bad scrapes on the piston looks like it was bout to have a sezie up. recommended getting workshop to take closer look at the bore for them and clean it up if pos.

[Midget200]

Go on get a new one.....nuthin like throwing ya leg over a bike that no one's ridden before!!!

I know, I know, so tempting! I'm gonna go down to Spectrum tomorrow and have a sit on one! The trouble is they won't give me much on a trade in! I'm prepared to drop, but not too much!!! I've had my bike on Trade Me for nearly 2 weeks, 160 views, but no one buying! Buggar!!!

[noobi]

i think that the map on that piston means that the ports arnt flowing as well as they could, like the air isnt meeting in the middle and combusting more on one side, you can tell because its not a symmetrical shape

we're probably going out on wednesday too. weather dependant at this point. was pretty good today though

[SpikedPunch]

I've shown you mine, you gunna show me yours???

Can you post a pic of your old piston please?

As Bart said, it's not looking fantastic. Krad's got some pix on his phone he can show ya later.
Trying not to get too panicked until we've had it looked at proper, but 'gutted' would be an understatement. Fix bike or get wisdom tooth out..hrrmmm :no:

[barty5]

As Bart said, it's not looking fantastic. Krad's got some pix on his phone he can show ya later.
Trying not to get too panicked until we've had it looked at proper, but 'gutted' would be an understatement. Fix bike or get wisdom tooth out..hrrmmm :no:

both sound just as sorta painfull bike should be ok sure its not as bad as it look just pay for second opinion

[camchain]

i think that the map on that piston means that the ports arnt flowing as well as they could, like the air isnt meeting in the middle and combusting more on one side, you can tell because its not a symmetrical shape

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

[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).

[camchain]

Hey spikedpunch. My rough guess would be that it may have gotten hot. There's less material & so less dimensional stability around ports & on piston skirt so these bits expand more with heat (on piston pic, scuff marks don't run all they way up to top of piston by the looks of it). Normally would expect probs on ex side (hotter) rather than inlet side though, so may have sucked some dirt in and not overheated. Some of those scrapes look fairly deep and considering nicasil coating is only about 0.1mm it could be an issue.

It's voodoo science how they get a superhard material like nicasil to stick to aluminium, given different materials = different expansion rates etc. I don't know if the coating can stay stable if it's worn through in small parts.

Taylor Automotive off Khyber pass might be worth trying if you're in the city. They have a lot of experience building Porche race engines (which have nicasil bores). I've taken bike parts there before, had bores checked by them.

BTW, I've found I get good results for macro shots with camera set to single point focus. Like me, my camera gets confused looking at shiny surfaces.

Noobi, nice 'burn' with your mappa tassie reply :)

[krad_nz]

Took those pics with my phone mate. Not too many options unfortunately :P

[camchain]

Took those pics with my phone mate. Not too many options unfortunately :P

Sorry krad - didn't mean to criticise, just passing on to anyone reading thread something I found out after a bit of frustration with my own pics. Good pics for phone cam!

[krad_nz]

Hahah, no worries mate. I wasn't having a go at you. ;)

[SpikedPunch]

I just found out my bike is really an '03, not an '05....Aaaahhh can this week get any more awesome? :bash: Better not ask, would rather not know....
FFS, I feel so ripped off :crybaby:

[barty5]

I just found out my bike is really an '03, not an '05....Aaaahhh can this week get any more awesome? :bash: Better not ask, would rather not know....
FFS, I feel so ripped off :crybaby:

how did yah work that out???

[clmintie]

home a lot this week with school holidays. .

Sandpit with the kids on Wednesday?

[Midget200]

I just found out my bike is really an '03, not an '05....Aaaahhh can this week get any more awesome? :bash: Better not ask, would rather not know....
FFS, I feel so ripped off :crybaby:

Geez Spiked Punch, feck the bastards not telling you! Bad week for you, can't believe it. I definitely want to go new now! The KX at Spectrum is looking better and better!

[SpikedPunch]

how did yah work that out???
Used one of those VIN decoders. 'Just for fun' :pinch:

[L Rider]

Sandpit with the kids on Wednesday?

He was planning on just taking Brooklyn up with his JR - try to get him riding it. Atlanta isn't at school yet so she's at daycare while i work.

[L Rider]

Used one of those VIN decoders. 'Just for fun' :pinch:

I've used one of those before when buying Atlanta's quad & it came out with the wrong years - i emailed Suzuki & got correct year.

I must say though before we've brought 2nd hand we've always checked out the year as you can never trust anyone.

[camchain]

I just found out my bike is really an '03, not an '05...

Not having a good run at the moment spiked punch. Try not to be too bugged by year thing, need to keep in mind that new model year bikes are always available months in advance - in previous year.

Not only that, it's entirely possible your bike was a leftover sold in 05 (not a bad thing at all), I'd say it's even likely, given what you were told & that RM100s aren't that common. Without sale docs, bit of an issue when selling though. Best to just be honest about it, and that you were told it was bought in 05. When buying used you're often going off feel for the seller as much as bike, and people appreciate honesty.

I like to know what month bike was sold if I can - there being almost a years diff between Jan and Dec! My current ride is an 07 model but manufactured July 06 (but no sale date docs). Previous one was manufactured Nov 04 but sold Aug 05 (had docs). With bikes that hardly (if at all) change between model years it's when it was bought that really counts.

[L Rider]

Not having a good run at the moment spiked punch. Try not to be too bugged by year thing, need to keep in mind that new model year bikes are always available months in advance - in previous year.

Not only that, it's entirely possible your bike was a leftover sold in 05 (not a bad thing at all), I'd say it's even likely, given what you were told & that RM100s aren't that common. Without sale docs, bit of an issue when selling though. Best to just be honest about it, and that you were told it was bought in 05. When buying used you're often going off feel for the seller as much as bike, and people appreciate honesty.

I like to know what month bike was sold if I can - there being almost a years diff between Jan and Dec! My current ride is an 07 model but manufactured July 06 (but no sale date docs). Previous one was manufactured Nov 04 but sold Aug 05 (had docs). With bikes that hardly (if at all) change between model years it's when it was bought that really counts.

Very true re leftover in shop etc.
We brought a JR50 beginning of this year as they no longer make them. Although it was brought beg 2009 it had just come into the country it was manufactured in 2006 i think as this was last year of manufacture.
However even some shops get the years mixed up - they had said the JR was a 2009 JR50 which is actually isn't.

[Reckless]

Here's some more pix for you..... Note that the pix make the carbon look thicker that it is, as I run my finger over the line between 'shinny' and carbon, it's hard to feel any difference in height...Maybe better described as 'soot' no doubt due to using a blend of TTS and R30. We use 3 air cleaners and chuck a clean one in every ride, often between races in summer. Airbox gets duct taped when very wet.... I realise by leaving it in for 100 hours, I've pushed this piston way beyond what would normally be called it's 'use by date' it's just that the first 30 40 hours were pretty 'gentle'.....

The castor based castrol R will leave more deposits. That piston looks like a typical karting piston on Castrol R. Not too bad. Bit of blow by though, I'd probably run it in a bit harder to get a bit better ring seal. Mind you some of it could be at the end of the 100 hours when things weren't so tight. I do rings 50 hours (measure the piston as well) new piston and rings at 100 for trail riding. This gives two bites at the ring seal and a good look at it, at the 50 or so hour mark. Only $30 bucks or so for rings so a good thing to do.
Why you blending your premix Climintie any particular reason?



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.


Looks to me like its not been well maintained in a fair while. The top pin looks like its been very baggy causing the piston to bash about in the bore. Rings lost there tension heaps of blow by. Something may have been in there as well causing that scratch! But its low down and not torn its self through the rings etc. Never trust the last guy many just change rings or pistons and leave the old top bearings in. For the price of a piston I'd always do a 2 smoker as soon as you can afford it after buying it unless the info you have on it is 100% reliable
Wouldn't worry about the shortage of water mate you probably didn't drain it all out the engine anyway!
What to do next!!
YES take the barrel to someone that will give you a good judgement upon if its gone though its Nikasil or not.
Then get them to measure it up and see what size piston you need. You could quite well need a B instead of and A, or visa versa, (which ever is bigger) if your barrels a bit worn. You don't want a piston thats to small rattling round in there.
Get them to feel the bottom bearing in the crank as well! If that's shagged it cold be 1/2 the problem. Hopefully not though.

I've seen worse barrels than that (hard to tell from pics though). As long as the barrels is OK and the crank pin is good, that will patch up and go for ages. Its not a new bike so you can't expect it to be 1000% but it looks like it'll go back together OK!
There was a thread on here recently where we discussed Honing etc and in that there was a good recommendation for a shop that had the proper diamond Hone, maybe camchain knows the book mark to the thread. I personally wouldn't hone it, especially an older barrell with thinner Nikasil, but each to their own! Do your check ups and measure ups, clean it up a bit, fit the new stuff properly, run it in hardish to get it the new rings to seal well and that'll be ok for ages!

[barty5]

Very true re leftover in shop etc.
We brought a JR50 beginning of this year as they no longer make them. Although it was brought beg 2009 it had just come into the country it was manufactured in 2006 i think as this was last year of manufacture.
However even some shops get the years mixed up - they had said the JR was a 2009 JR50 which is actually isn't.

Was told a trick some shops use if the bike has excel rims there is a number on the rim the last number is the year the rim was made, ie 7 = 2007 8=2008 if its a 7 then the bike is an 2008 if its a 8 then the bike is 2009. you get the idea as the rims are made the year before the bike is as they come outa stock. Its not fool proof as rims can be swapped etc but if your told its an 07 and there was a 3 stamped on it youd be asking questions.

[clmintie]

I put 20ml of caster to 10l petrol. I like to have a little "different length molecule' in the synthetic oil. While the modern oils do a fantastic job, they don't take kindly to sudden shock and a little vege oil can save a nip... Make sense?. Certainly doesn't do any harm and makes me feel warm and fuzzy... (Smells like a racing bike should too... :innocent: )

[B0000M]

somehting hondas used to have on them was a sticker up on the steering head, telling you what year and modlel the bike is. unfortunately for some reason they stopped doing this, my old 99 had it, and all the previous bikes, but im not sure when they stopped.

[Reckless]

I put 20ml of caster to 10l petrol. I like to have a little "different length molecule' in the synthetic oil. While the modern oils do a fantastic job, they don't take kindly to sudden shock and a little vege oil can save a nip... Make sense?. Certainly doesn't do any harm and makes me feel warm and fuzzy... (Smells like a racing bike should too... :innocent: )

As you say can't do any harm. Nothing wrong with the old Castor as long as it mixes ok with the TTS etc and doesn't seperate. Smells bueaty as you say!! LOL!!

[krad_nz]

You could quite well need a B instead of and A, or visa versa, (which ever is bigger) if your barrels a bit worn. You don't want a piston thats to small rattling round in there.
Get them to feel the bottom bearing in the crank as well! If that's shagged it cold be 1/2 the problem. Hopefully not though.


I think there is only one piston size for a nikisal barrel.
What should I be feeling for with regards to the bottom bearing? I checked for vertical play in bottom end bearing by applying upward force to the little end of the conrod. I couldn't feel any play.

[Reckless]

What should I be feeling for with regards to the bottom bearing? I checked for vertical play in bottom end bearing by applying upward force to the little end of the conrod. I couldn't feel any play.

Thats good all ok then!


I think there is only one piston size for a nikisal barrel.

No there is generally two sizes but I'm not familiar with your model so I could be wrong. The manual will give you a piston size and a bore size then a max measurment the difference is allowed to be. Just make sure your within specs and all is OK!!

[krad_nz]

Thanks mate, good advice. :)

[camchain]

You'd think there'd only be one piston size for nicasil bore but you can get oversize jobs alright. As Reckless says, check specific model. KTM officially supplies A & B size Vertex pistons, but Vertex actually makes A,B,C,D sizes (As do Pro-X). They only go up in miniscule 0.01mm increments but I figure correct clearances for Nicasil bore must matter otherwise they wouldn't bother with such tiny oversizes.

[barty5]

there are 2 sizes for this bike

[SpikedPunch]

Hmm well that would be a bummer hummer, I've got a perfectly good shiny piston sitting here just waiting to go in. Ah well, I'm talking a half day off work tomorrow to sort some stuff, will try and get into spectrum and engine specialties too if there's time.
Also, upon further research (boy is my face red!) it looks like the kx100 was only rebadged by suzuki for 03 and 04 (they're the only years I can find info/pics for-if anyone knows otherwise please correct me!), would explain why I've had so much trouble finding parts, it's kind of a relief haha. Would add cred to the theory that it was maybe an 03 sold in 05.

[clmintie]

Hmm well that would be a bummer hummer, I've got a perfectly good shiny piston sitting here just waiting to go in. Ah well, I'm talking a half day off work tomorrow to sort some stuff, will try and get into spectrum and engine specialties too if there's time.
Also, upon further research (boy is my face red!) it looks like the kx100 was only rebadged by suzuki for 03 and 04 (they're the only years I can find info/pics for-if anyone knows otherwise please correct me!), would explain why I've had so much trouble finding parts, it's kind of a relief haha. Would add cred to the theory that it was maybe an 03 sold in 05.

FWIW
Grace ran in her new piston today at Sandpit (3.2hrs) and reports no difference in top end, but much crisper off the bottom and mid range... At least you have this to look forward to SpikedPunch. Tracks were fantastic......... :woohoo:

[SpikedPunch]

FWIW
Grace ran in her new piston today at Sandpit (3.2hrs) and reports no difference in top end, but much crisper off the bottom and mid range... At least you have this to look forward to SpikedPunch. Tracks were fantastic......... :woohoo:

Lucky girl ;)!! Jealous! Hopefully sort this shizzle in time for a sunday ride. If it's dry me and krad might go to harrisville on saturday, I'll just be watching this time... :crybaby:

[clmintie]

See you at Harrisville, haven't been for a while and we might be lucky with the weather (Sunday looking VERY WET)

[L Rider]

Hmm well that would be a bummer hummer, I've got a perfectly good shiny piston sitting here just waiting to go in. Ah well, I'm talking a half day off work tomorrow to sort some stuff, will try and get into spectrum and engine specialties too if there's time.
Also, upon further research (boy is my face red!) it looks like the kx100 was only rebadged by suzuki for 03 and 04 (they're the only years I can find info/pics for-if anyone knows otherwise please correct me!), would explain why I've had so much trouble finding parts, it's kind of a relief haha. Would add cred to the theory that it was maybe an 03 sold in 05.

Lol at being red faced!! does sound more like an 03 sold in 05 doesn't it.
Well least now things are starting to fall into place re parts:2thumbsup

[SpikedPunch]

Right, twenty eight bucks, same day service, bore all nice and honed. Thanks spectrum and engine specs! :2thumbsup
And of course thanks everyone on here for all your info and suggestions, it's been much helpful, don't know where I'd be without KB :)!

[krad_nz]

Spectrum said that it looked like this piston has been too hot which caused it to nip up. Basically said it was running lean. So time to put the needle back up to the factory position.

An alternative explanation is that it 'cold seized'. Ie: Bike was revved aggressively from cold. The piston heats up faster than the barrel. This causes the piston to start nipping up. Punch did have a tendency to give it death on starting, partly because it was difficult to start when cold. This of course was due to the low compression caused by poor ring seal etc. I like this explanation myself.

The 'cold seizure' is what a mechanic once used to explain what happened to one of the guys son's on his cr80. He seized his bike by giving it death from cold. Some time later with the engine all sorted and nothing else modified the bike is still going strong. His son now lets the bike warm up a bit before giving it full noise.

Apparently the pattern of the scrapes on the barrel can be used to help identify if it 'cold seized'. Take from this what you will, I like the theory.

[LittleJohn]

Right, twenty eight bucks, same day service, bore all nice and honed. Thanks spectrum and engine specs! :2thumbsup
And of course thanks everyone on here for all your info and suggestions, it's been much helpful, don't know where I'd be without KB :)!

Good team of tradespeople you used. Bet you feel a lot better now. So have you rebuilt it yet???

[camchain]

Spectrum said that it looked like this piston has been too hot which caused it to nip up. Basically said it was running lean. So time to put the needle back up to the factory position.

An alternative explanation is that it 'cold seized'. Ie: Bike was revved aggressively from cold. The piston heats up faster than the barrel. This causes the piston to start nipping up. Punch did have a tendency to give it death on starting, partly because it was difficult to start when cold. This of course was due to the low compression caused by poor ring seal etc. I like this explanation myself.

The 'cold seizure' is what a mechanic once used to explain what happened to one of the guys son's on his cr80. He seized his bike by giving it death from cold. Some time later with the engine all sorted and nothing else modified the bike is still going strong. His son now lets the bike warm up a bit before giving it full noise.

Apparently the pattern of the scrapes on the barrel can be used to help identify if it 'cold seized'. Take from this what you will, I like the theory.
Cold seize seems very possible cause alright krad. Excellent to read these threads and see what others are experiencing.

I put my cylinder and piston in the oven for a rough idea of what was happening as things heat up. Piston skirt exanded very quickly, much quicker than everything else (At one point piston wouldn't even slide into bore).

I'm even more careful to warm up bike fully before riding it hard now. Likely even more important with long piston skirts on 2 tangers. My guess is modern water-cooled engines slower to warm than old air-cooled as well. I check progress with hand on radiator. When thermostat pops open (at 55 deg) and lets hot water flow into rads I feel OK to start riding but still taking it fairly easy at first.

[cheese]

I've always heated my bike up till I can feel it in the radiator through my gloves. Also my bike will just not run right until its warm.

[SpikedPunch]

Piston is in!!! Go team!
We got it going out on the back deck about 9:00 this evening (was busy during the day) sounded really good. Dad even came out to watch, seemed pretty proud haha. :niceone:
So the real test will be taking her for a ride tomorrow. Yuss, been suffering withdrawals after a whole week off the bike :bleh:

[barty5]

Piston is in!!! Go team!
We got it going out on the back deck about 9:00 this evening (was busy during the day) sounded really good. Dad even came out to watch, seemed pretty proud haha. :niceone:
So the real test will be taking her for a ride tomorrow. Yuss, been suffering withdrawals after a whole week off the bike :bleh:

good to hear im itching to get out next weekend berm buster yeha

[L Rider]

Piston is in!!! Go team!
We got it going out on the back deck about 9:00 this evening (was busy during the day) sounded really good. Dad even came out to watch, seemed pretty proud haha. :niceone:
So the real test will be taking her for a ride tomorrow. Yuss, been suffering withdrawals after a whole week off the bike :bleh:

Good stuff:niceone:

[clmintie]

Piston is in!!! Go team!
We got it going out on the back deck about 9:00 this evening (was busy during the day) sounded really good. Dad even came out to watch, seemed pretty proud haha. :niceone:
So the real test will be taking her for a ride tomorrow. Yuss, been suffering withdrawals after a whole week off the bike :bleh:

So how was today at the sandpit? Bike behave itself?

Must have been chilly..................:cold::cold:

[krad_nz]

Was mint at the sand pit today. Surprisingly it didn't rain. Excellent conditions. Bike behaved itself and survived the day. Was easier to start, had more bottom and mid range according to SpikedPunch. It sounded nice and crisp too. Also with the needle raised up to stock I was expecting it to splooge again, but it didn't. She must be riding harder, or its something to do with poor compression.

Motocross track has been reversed so watch out. Especially if you exit the farm loop. Sure the arrows point the other way but I figured someone was taking the piss. Should have a sign saying its been reversed. Was 'exciting' having two motocross bikes coming at you full noise.

[clmintie]

That sounds like good news.... well done the pair of you.. :clap::clap::clap:

[LittleJohn]

Was mint at the sand pit today. Surprisingly it didn't rain. Excellent conditions. Bike behaved itself and survived the day. Was easier to start, had more bottom and mid range according to SpikedPunch. It sounded nice and crisp too. Also with the needle raised up to stock I was expecting it to splooge again, but it didn't. She must be riding harder, or its something to do with poor compression.

Motocross track has been reversed so watch out. Especially if you exit the farm loop. Sure the arrows point the other way but I figured someone was taking the piss. Should have a sign saying its been reversed. Was 'exciting' having two motocross bikes coming at you full noise.

I though that the motocross track was closed, until after doing the farm loop. Thats when after going the reverse way I saw the sign near the start of the track. Bummer it was the end of the day otherwise would have given it a go. Next time maybe.

Was such an awesome day out there today, great weather.

[xen]

Good to hear you guys got it sorted sweet. Some good info in this thread, thinking about doing rings or at least looking at mine now haha.




Motocross track has been reversed so watch out. Especially if you exit the farm loop. Sure the arrows point the other way but I figured someone was taking the piss. Should have a sign saying its been reversed. Was 'exciting' having two motocross bikes coming at you full noise.

Yea I'll bet !