200h on the clock, and guess what....

[Tom250]

today i pulled off the topend of my ?13 300e, the bikes having around 200hours now and i thought it may be good to have a look to rings and piston.
piston looks good, little shiny parts, three minor scratches. last year the bike sucked some water because of the poorly and brainless constructed airbox so i guess this is what the scratches caused. measured the rings, upper 0,4, lower 0,3. guess its pretty in the range for its hours. the piston i will meaure next week, dont have a micrometer in my workshop, but i guess he will be in tolerance. cylinder also looks good in generally, two little scratch points from suckin water, a ride with the hone tool through it will fix that and will give back its crosscut.
im pretty impressed about that little wear in that engine, rod also dont have any play. ok i ride the bike smooth and take care of it, where i ride the bikes not getting much revs, no mx, but hey, anyway, after this much hours?
interesting how the cyliner is created, there is plenty of guiding surface for the piston, if you compare it with an pumpkin cylinder, there are more holes in than guiding survace. if the piston is in shape and the right measure, i bring em back on and i guess hes still good for another 100 hours....
by the way, spuish is 2,2mm.
well done gasser.....

 

[thejackrabbit]

what premix oil do you use?

 

[swazi_matt]

Just recently someone posted a link to slavens video where he says not to use a honing tool. News to me but made sense thought I should pass it on

 

[pscook]

Don't use a hone tool on Nikasil lined cylinders.

1. The stones are not the right grinding surface to interface with the nikasil
2. The stones will grab the ports and damage the cylinder

Use a diamond hone in the right size, or use red scotch brite to clean up the cylinder. You can also use a diluted muriatic acid (stone and grout cleaner) to wash the plating, just don't let it sit too long and clean it thoroughly when finished.

 

[Jakobi]

Show us some pics Pics make these threads and are great for others to comment on and for the newer tinkerers to get an idea of whats what

 

[Tom250]

pics i will post later.
well with the honetool. i saw this video from slavens, what confuses me, a hontool isnt good, but a sandpaper is??? his argument, a honetool leaves dust in the pores isnt really an argument, you clean the cylinder afterwords anyway with break cleaner wich washes the oil away including the peelingdust. and with a sandpaper i guess you havent any feel to get a right surface. from the experience of a friend wich runs a workshop in germany, he repairs any kind of bikes and bikeengines since 20 years, would say about a hundred engines a year, he always goes through a nicasil plated cylinder when putting a new piston in and never had any issues. i had a bike in 08, a husky wr250, wich i dived in dirty water and tryed to start up immediatly, in that cylinder was not just minor scratches, would say he was on the edge for a recoating, he went through with his honetool, put a new piston in and i rode that bike would say for at least another 100hours before i sold it then.
i understand that risk to break out the coating on the ports, but from my friends and my experience also, it never happend. its hard for me to imagine to brake out an edge from an port, then hone stones are a 100mm long and bring the pressure on a big and straight surface, and also that nicasil material is as hard as a stone. im up to learn more and change my opinion if its logic, currently this is my understanding of it.
in my bike i ran different oils, last year i used motul, mostly the 710, also sometimes the 800, both always in a 1:50 mix. this year i get a castol power1, bought a 60liter barrel.
sure my riding style is good for the engines life too, i mostly grunt around on trails and in the montains, there is no need and also no possibility to rev the bike.

 

[sweeper]

Cmon people!

No honing,boring,cutting,machining of any kind on a nikasil bore.

Not even a good old fashioned hillbilly drill operated cylinder cleaning device of any type.

If there is something in the cylinder you can't live with then use a white scotch brite.
Don't get crazy.Scratches don't mean jack on nikasil.As long as the bore is clean and true and free anything that can hang a ring.

That piston looks great.The rings after 200 hours have done a fine job of knocking down any high spots in there.

They don't make slightly over sized pistons for nikasil bores.

 

[Jakobi]

This topic has been done to death all over..

A cylinder needs to be honed to allow the rings to bed in properly. Thats why they are honed from the factory and a new cylinder will show heavy cross hatching.

As pscook has stated though, your standard old hone won't 'cut' Nikasil and is more likely to damage the cylinder or flake the coating from the port edges. Avoid it. In short, when you rebuild you want to deglaze the cylinder and remove any deposits from the surface. For me, a scotchbright pad and some carb cleaner works a treat and brings them up looking great. Phils other suggestions work well too, and scotchbright actually makes hones out of thir material to help speed up the process. http://www.enginehones.com/abrasivehones.html

If the crosshatching isn't visible still it means the cylinder is showing some wear, and the only way to know exactly how much is to spec it up with a bore gauge (which any engine builder would do anyway).

Oversized pistons are available A,B,C,D but the idea of honing out to the next size isn't feasable. In general the thickness of the nikasil plating is only around 0.1mm (0.004") so when its worn out, its time for a recoat.

 

[sweeper]

If dealing with a stock nikasil cylinder or a cylinder which has been replated back to its stock bore.
Hone-no
Scotchbrite-yes
Slightly oversized pistons-no

If you have a resleeved cylinder-see above post.

 

[Weird Rooster]

In short, when you rebuild you want to deglaze the cylinder and remove any deposits from the surface. For me, a scotchbright pad and some carb cleaner works a treat and brings them up looking great. Phils other suggestions work well too, and scotchbright actually makes hones out of thir material to help speed up the process. http://www.enginehones.com/abrasivehones.html
.

Hey Jake. For us less experienced tinkerers, can you explain or provide a link to how you go about prepping the cylinder with a scotchbright pad? Do you use just a single pad by hand and which colour/grade do you use? Thanks

 

[Jakobi]

Red/Green pad. Bit of carb cleaner. Work in a 45 degree action. Make sure you wash it really well when its done with some soapy water and then I give it a final wipe out with carb cleaner again.

 

[GasGasDreamer]

A cylinder needs to be honed to allow the rings to bed in properly.

Dont tell my engine that.

After about 150 hrs the jug was fine.
New rings and gaskets only.
It made a big difference, especially in the low rpm.
The days of rings seating like your saying ended probably at least 10 years ago, IMHO.

 

[Jakobi]

Dont tell my engine that.

After about 150 hrs the jug was fine.
New rings and gaskets only.
It made a big difference, especially in the low rpm.
The days of rings seating like your saying ended probably at least 10 years ago, IMHO.

The cylinder was honed before it ever went on your bike. At 150hrs on a jug that is fine it will still show some of the cross hatching.

I'm not saying the cylinder has to be rehoned every top end, but if its glazed up and polished its not going to achieve the best results.

 

[GasGasDreamer]

The cylinder was honed before it ever went on your bike. At 150hrs on a jug that is fine it will still show some of the cross hatching.

I'm not saying the cylinder has to be rehoned every top end, but if its glazed up and polished its not going to achieve the best results.

ok.
i did scrub it with mild scotchbrite type pad and dawn soap.
i made sure to install the same height gaskets to keep the piston away from the tiny ridge at the top of the jug, where the piston doesnt travel.
thanks

 

[sweeper]

The cylinder was honed before it ever went on your bike. At 150hrs on a jug that is fine it will still show some of the cross hatching.

I'm not saying the cylinder has to be rehoned every top end, but if its glazed up and polished its not going to achieve the best results.

All back and forth aside,for those many of you that do not have alot of practicle experience ,and practicle is the key word when it comes to this topic;who come to this forum looking for some advice on how to freshen up your nikasil coated cylinder a couple of things to keep in mind.Is the cylinder in tolerence,short version,is the hole pretty much the size its supposed to be for your piston and rings to fit in properly.Is there any taper or wierd wearing happening either to one side of the jug or more wear at the bottom then the top.Dont get crazy here be reasonable some wear is normal,nikasil is a beautiful thing,looks dont matter all that much.The idea is to clean the cylinder,short version to get rid of that which is not nikasil while leaving all the nikasil there.This is why you do not hone,in the true sense.What nikasil coating you take away,you will not gain back.Youll just have a bigger hole which you do not want.Even a prettier bigger hole,you do not want.

The appearance of a honed cross hatched nikasil cylinder when new,is the aftermath of the machining process,that is required to bore and finish to specification a new cylinder that has been plated.You will find this same appearence in many items that have been through the maching process.

Keeping fresh pistons and rings in the nikasil bore will give it a longer life,of course it will end up costing you more then just replacing or replating the cylinder in the long run.Honda CR 250 service manual recommends 20 hours on rings 40 hours on pistons.Nuts of course but their is a concept their.

 

[Jakobi]

Well said sweeper. Hit the nail on the head.

A bore gauge and taking multiple readings in the cylinder is the way to go and I think I will be adding one to the ever growing range of tools I have.

IMO if you can't see the cross hatching any more, and you can hook a nail on a lip (top or bottom of cylinder) then its very likely it has worn out of spec.

Changing pistons more frequently keeps the tolerances tighter and reduces the amount the piston can rock in the barrel which again reduces wear on the nikasil. I generally just do a complete piston and rings at 85hrs.

 

[sweeper]

A bore gauge is great but spendy.You can also use a quality set of calipers and a small mirror for comparison purposes.But for most mortals a new set of rings and some quality feeler gauges will do the trick,checking the end gap as you slowly work a ring through the bore using the piston in an upside down position to run the rings down the bore.If you have a suspect area in the cylinder you can stack the rings so the ring gaps are covered,blocking the bore with a small rubber ball or something of the sort and shining a light up from the bottom of the bore,and then flipping the cylinder over as you reach the bottom..Any light that passes by the rings will give you some indication of the problem areas and how bad they are.Make sure you have stacked the gaps so they will not get hung up in any ports while you work the rings through the bore.Little problems here and there are acceptable in most cases.I usually lean to the it will run side of things.Once the cylinder is done you will know it,we pretty much run them until they quit holding compression or the bore is out of spec; the spec is conservative so we go a little more liberal there,or until the piston begins to make some noise.

You will increase the life of the bore considerably by rounding the sharp edges of the piston skirts with a fine emory cloth.We also use cast pistons over forged when available.This is a personal choice and will open a whole new can of worms,but over the many years the cast pistons have worked out the best for us.We have never had a cast piston come apart in a properly jetted bike with a nikasil bore,since 1986.We have had issues with the forged pistons.Again, I am not saying one is better then the other,or out performs the other.

 

[nknudsen]

A bore gauge is great but spendy.You can also use a quality set of calipers and a small mirror for comparison purposes.But for most mortals a new set of rings and some quality feeler gauges will do the trick,checking the end gap as you slowly work a ring through the bore using the piston in an upside down position to run the rings down the bore.If you have a suspect area in the cylinder you can stack the rings so the ring gaps are covered,blocking the bore with a small rubber ball or something of the sort and shining a light up from the bottom of the bore,and then flipping the cylinder over as you reach the bottom..Any light that passes by the rings will give you some indication of the problem areas and how bad they are.Make sure you have stacked the gaps so they will not get hung up in any ports while you work the rings through the bore.Little problems here and there are acceptable in most cases.I usually lean to the it will run side of things.Once the cylinder is done you will know it,we pretty much run them until they quit holding compression or the bore is out of spec; the spec is conservative so we go a little more liberal there,or until the piston begins to make some noise.

You will increase the life of the bore considerably by rounding the sharp edges of the piston skirts with a fine emory cloth.We also use cast pistons over forged when available.This is a personal choice and will open a whole new can of worms,but over the many years the cast pistons have worked out the best for us.We have never had a cast piston come apart in a properly jetted bike with a nikasil bore,since 1986.We have had issues with the forged pistons.Again, I am not saying one is better then the other,or out performs the other.

I agree with cast pistons in 2 strokes due to less time to cool between power strokes. Less expansion, can run tighter clearances w/o scuffing. Example All OE 2 stroke Ski-Doo pistons are cast Elko brand. Forged pistons are good for four strokes.