L-Plate Rider
2000 KX 80 engine rebuild
Hello there KBer's
As I have already posted, I am new to this forum and I thought some of you might be interested in a current rebuild we are in the process of.
We got this bike, not going, from a chap in Christchurch for a cheap price. Actually we probably paid too much for it but it is our first 2 stroke engine rebuild.
Here are some pics.
It's a fine line between attention to detail........ and obsession.
L-Plate Rider
We had an accident removing the clutch hub and broke off one of the fingers.
Engine removed from frame and ready for dis- assembly.
Engine mounted on the engine stand.
Engine dis-assembled and benched. I found these little foil pie dishes at the four square. 12 dishes for $ 2.99. They work great for parts seperation.
Engine mounted on an engine stand we built. Ready for the right side to be dis-assembled.
We opted for a sleeve as opposed to nikasil coating. There were a few reasons for this. The coating was expensive and the sleeve parts complete with Piston cost approx $ 150.00 landed in NZ. They were imported from Partzilla in the States.
It's a fine line between attention to detail
Fully qualified Sifter.
Hate to say this Geoff...but I think you'll regret that decision.Originally Posted by GEOF
L-Plate Rider
Yeah thanks crash.
We are yet to find out.
There are many reasons we went with a sleeve and price was not the main reason. We wanted the availability to bore out and use this engine to learn about porting and polishing. We really were looking at it more from an engineering project to get edcuated from.
We will be installing our own sleeves later on if we decide to continue on this way.
This has been a great conversation on TT with the americans. From a racing perspective I can see the benifit of Nikasil......... for the weekend warrior and a hobbie engine rebuilder like us......it really came down to an engineering decision.
I will say one thing. I learn't alot from porting this thing. I estimate there would be 80 hours in match porting and blending this cylinder.
Hey crash...........I am interested to know your thoughts on nikasil vs a sleeve.
It's a fine line between attention to detail
Fully qualified Sifter.
In my experience with KX's (mostly 500's admittedly), they never perform as well with sleeves in 'em as they do on the std electrofusion cyl. They seem far more prone to siezures (don't think they transfer the heat as well) and if not properly installed (which obviously ain't a prob with you guys) can cause all sorts of probs. But I was road racing 'em and that's pretty hard on them. On the main jet most of the time for far longer perids than I was ever able to on a 500 in the dirt! Mind you...80's work pretty blooody hard!
No8 Wire Extraordinaire
from a longevity point of view you can't beat plating. Sleeves are of course worse for heat transfer & are still worse than the old cast in sleeves of the early 80s. If done accurately & tight yo may end up with a merely adequate result. Be careful what rings you run. Gen Kawi rings for example eat iron bores. Wisecos etc are often fit with plated rings & should be okish. Unless they specify otherwise.
Polishing is a total waste of time. Porting, well you kind of have to know what you are doing. Bigger is better maxim will get you into trouble sooner than help you.
That clutch post may be repaired by countersinking a bolt from the back of the basket, but you have to consider a few things.
Use a rattlegun to undo that nut or build a clutch holder out of an old steel plate.
Not sure what your attachments are, don't seem to go anywhere.
Don't you look at my accountant.
He's the only one I've got.
L-Plate Rider
Good info..........Thanks Crash and F5. I am interested to know F5........Are you also racing with your 2 stroke experience?????
We are just weekend warriors.....father and son stuff in the workshop and a few trail rides and hill climbs in the weekend.
The sleeve we installed has bridge releif and the piston has two counter sunk holes in the front for lubrication. We drilled these out 2 thou and added the counter sink.
We have a 2 thou tolerance piston to cylinder clearance and 3 thou tolerance for bridge relief.
I am hoping I have eliminated any major risk of seizures but I am sure there is always the possibility.
F5.......I deleted those attachments.....not sure how it happened. I have reloaded them now.
It's a fine line between attention to detail
L-Plate Rider
Match porting the exhaust ports
Match porting the sleeve to the transfer tunnels.
New Wiseco crank. I did not want to use this as I have heard too many bad things about them but it was already in another donor engine we are using for parts.
It's a fine line between attention to detail
No8 Wire Extraordinaire
Been racing F4 & F5 (Buckets) forever, but my dirt bikes are purely for play riding. Your clearances sound generous enough to keep out of trouble.
Don't you look at my accountant.
He's the only one I've got.
Forum whore
racing or play, sleeves in 2 strokes are nothing but problems most of the time, would not recomend it but your down that road already,
make sure you warm up the bike properly, they cold seize very easily,
L-Plate Rider
Hey Scott..........Thanks for the info. What sort of problems have you experienced? Also good advice on the warming up. Makes sense.
It's a fine line between attention to detail
L-Plate Rider
Hey guys. Here is some info I came across a while back and posted on TT in the states. I am interested to hear your thoughts on this.
I came across this article from RPJ Performance. I sure hope they are right. Nikisal plating is really expensive here and we are not racing mainly riding fast paced fire breaks on hills so I really hope we are doing the right thing. At least for this first build. Anyone please chime in with their thoughts????
I am not saying plating is bad it is that it is not a financial option at this stage.
[
RPJ performance
Why Re-Sleeve?[/size]
Installing Sleeve in a cylinder is required when your stock cylinder has been bored to the last offered over size piston or when a chrome plated cylinder is damaged.
Advantages of sleeves over platting are:
* Heat Transfer: It is claimed the thin plating dissipates more quickly, but a steel liner becomes a heat sink once everything is up to operating temperature, eliminating hot spots in the cylinder wall. I often find plated cylinders with very little time on them up to .005 out of round
* I have seen as much as 5 hp gain on 2 strokes using a steel sleeve, rings seat better with steel liners
* Durability: No thin plating to peel or flake off. Manufactures use Plating to save on production time and money. You donít see plated cylinders in Heavy Duty applications such as Large diesel engines that run for a million miles! With proper Air filter maintenance and good engine oil a steel sleeve will last just as long as Nikasil plating.
* Weight Savings: Yes plating is lighter. But a steel liner for a Honda CR125R weighs 12oz. The first mud hole you ride through adds more weight to your bike than that, or just donít drink that can of soda before your ride!
* Honing: you can work with steel to get perfect piston to cylinder wall clearance. Plated cylinders begin with only a .004 thickness, if honed it may become too thin.
* you can bore steel to fit an oversized piston, rather than throw the cylinder away.
* Porting: Plated cylinders cannot be properly ported, as the plating has to be blended around the insides of ports, once this is ground the platting will begin to strip off causing serious engine damage.
* Rings seal: Ring seal is better to a steel sleeve, plating is much too hard for rings to properly seat.
*Lubrication: Pores in a steel cylinder lining hold oil for lubrication for longer lasting piston & ring life.
* Racing: Sleeves are recommended for all types of riding including racing.
* Tread Green: Sleeve installation is friendly for our Environment, It does not require Harsh chemicals or disposal of Hazardous Waste Materials onto our planet. The materials machined away in the sleeve installation process are recycled.
* Cost Savings: Cylinders can be re-plated but the cost is about $250 every time it is worn or damaged. Once a steel liner is installed it can be re-bored to fit oversized pistons at less that $50 generally over sizes in .010 020,040 060 & .080 are offered. By the time you used up all the bores you will have spent around $350 in machining costs. If you needed to re-plate each time you will have spent $1250!
It's a fine line between attention to detail
Fully qualified Sifter.
Who gives a shit. We're buring fuel aren't we!?
No8 Wire Extraordinaire
Hey you've got a sleeve in, clearly you will try it & hopefully it will work just fine for you, don't lose any sleep about it.
I will say that with any statement one has to ask what has this person go to offer or gain? I for example have suggested that I don't like sleeves & maybe I don't like to lose face so will stick with that line lest I look silly. I have btw had an engine sleeved to undersize it for a class & that part of the process wasn't a problem.
The blurb you have posted is clearly from someone selling sleeving process. He might have a bias.
Actually I'll piss on a few of his statements. Ones about throwing the cylinder away. - erm, you replate them. Also you can weld damage & replate with surprisingly invisible consequence.
Hmm, just noted Pete's post has some replies edited in main body so I'll not address those.
What I will say though is Works factory bikes over the years of 2 stroke development have had zillions of $ thrown at them. They could easily have sleeved these super low volume cylinders. They were plated. End of his argument I think.
Don't you look at my accountant.
He's the only one I've got.
Fully qualified Sifter.
Yeah I fucked that up. Meant to (as in tried to but too simple to) do it in a diff colour font. And yeah...what you say. My SR500 uses a plated cyl. Cost was of no concern on works bikes back then or now. Best poss performance was and still is however.
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