Torque Settings for Head

[Ryaz]

Does anyone know the torque settings and procedure to get the head off a 1991 Kawasaki KX80? Do they have chrome sleves? Cheers

[Racey Rider]

I have found (and a mechanic has said) for a small single cly 2/ motor, the Torque settings arn't too important if you can't find them. I have taken the head and barrel off my 150 lots of times, and just tighten it up to what feels snugg. Just don't tighten or lossen one bolt fully at a time, but put pressure on (or off), all the bolts in a way that keeps even pressure on the head. And do one bolt this side, one bolt that side, one bolt back over here, etc to stagger how the pressure comes on/off. Not just go right round the outside of the head from right to left. (Clear as Mud?)
Works for me anyway.
Racey.

[Ryaz]

Cool as, thanks for that. About to do it, will post back soon.

[Jackrat]

Yep,what he said.
I never used a touqe wrench on my two strokes,mainly coz' I never had one.
I think the bores on your bike are Nickasil lined.

[Ryaz]

Thanks for that. Whats Nickasil? Can I still rebore the sleve? Cheers :p

[John]

Thanks for that. Whats Nickasil? Can I still rebore the sleve? Cheers :p
Nikasil, Aluminum impregnated with Nickel

[Jackrat]

I'm not sure about that,I think they just give them a very light hone an replace the rings.
Nikasil is similar to chrome just a hell of a lot stronger and harder to damage.
I've heard about major piston damage that didn't cause any damage to the Nikasil bore.
But you'd be better off asking a shop I think.

[Pixie]

Don't know the torque settings,but never rotate more than about 180 deg from stop to stop,or till neck pain occurs.

[Ryaz]

Okay, do you know if it can be re-bored? Cheers

[Ryaz]

I took the gearbox side cover off, and everything look alright (keeping in mind I've never seen inside one before) but there was nothing broken etc. If there was something broken in it, would it be obvious? Cheers

[Ryaz]

Just got back from town, the Kawasaki guy said that the con rod rollers are gone...lol

I guess this is going to cost me approx $150 if I did the labour myself? Needs new bearings and rollers and con rod apparently, is this right?

[Oscar]

Okay, do you know if it can be re-bored? Cheers

No.
New barrel, or if yer lucky it's got a press-in sleeve.

[Ixion]

Just got back from town, the Kawasaki guy said that the con rod rollers are gone...lol

I guess this is going to cost me approx $150 if I did the labour myself? Needs new bearings and rollers and con rod apparently, is this right?

Uh, be aware that replacing a roller big end on a built up crankshaft (which it sounds like you're talking about) is not a job for the fainthearted. You have to split the crank, press out the crankpin(honking big press needed), then reassemble and align, which needs a set of trammels and a DTI and a LOT of patience (and that big press again)

You may also need to get the crank assembly rebalanced.

[Oscar]

Just got back from town, the Kawasaki guy said that the con rod rollers are gone...lol

I guess this is going to cost me approx $150 if I did the labour myself? Needs new bearings and rollers and con rod apparently, is this right?

Did anything let go?
Is the cylinder surface damaged at all?
If there's no obvious damge you'll prolly not need to replace more than rings.
Take the barrel, piston and rings into your dealer and get him to measure gaps.

[marty]

speaking of torque settings - helped a mate put the head back on his audi on the weekend - torque head bolts to 45ft/lbs, then tighten a further 180 degrees! fuck they were tight.

[marty]

the point of that post is, i would have thought about 50ft/lbs would be plenty for 80cc's

[Ryaz]

Did anything let go?
Is the cylinder surface damaged at all?
If there's no obvious damge you'll prolly not need to replace more than rings.
Take the barrel, piston and rings into your dealer and get him to measure gaps.
Nope, nothing let go as far as I know, and the barrel looks fine. I have to at least replace the rollers, do I need to replace anything else?

[Ryaz]

the point of that post is, i would have thought about 50ft/lbs would be plenty for 80cc's
Just been told it uses about 20ft/lbs :) Cheers Marty

[Oscar]

Nope, nothing let go as far as I know, and the barrel looks fine. I have to at least replace the rollers, do I need to replace anything else?

Strictly speaking no.
As it's in bits, I'd replace at least the rings and check the piston for wear.

Are you talking about replacing the big end bearing?
Or the gudgeon (piston) pin rollers?

[Ryaz]

Strictly speaking no.
As it's in bits, I'd replace at least the rings and check the piston for wear.

Are you talking about replacing the big end bearing?
Or the gudgeon (piston) pin rollers?
Well I'm not exactly sure what the right name for the rollers are, but its when the conrod joins the crankshaft, the bearings that keep it smooth. That explains why when I started it up it sounds really rattly.. How much is a new set of rings worth? And for a piston? Cheers

[Oscar]

Well I'm not exactly sure what the right name for the rollers are, but its when the conrod joins the crankshaft, the bearings that keep it smooth. That explains why when I started it up it sounds really rattly.. How much is a new set of rings worth? And for a piston? Cheers


Ahh, the big end bearing.
You're prolly going to need expert help.
If it was mine and I had it apart to that degree (and assuming it's done a bit of work), I'd be replacing piston, rings and the piston pin and small end bearing.

[Ixion]

Ahh, the big end bearing.
You're prolly going to need expert help.
If it was mine and I had it apart to that degree (and assuming it's done a bit of work), I'd be replacing piston, rings and the piston pin and small end bearing.


yep, tis no job for a beginner. You will usually need to replace at least the crankpin, the rollers, and the conrod. New little end bearing is a given. Might as well do the gudgeon pin.

But why did the big end fail? Are you sure your lubrication system is working ? Apart from the unlamented Ariel two stroke , it's not that common. Usually the mains go first, so you might want to check/replace those too.

[Ryaz]

Yep, the only problem is money ;) I can't really afford anything, so I need to put in as less as possible, just the bearings if thats possible..

[Oscar]

yep, tis no job for a beginner. You will usually need to replace at least the crankpin, the rollers, and the conrod. New little end bearing is a given. Might as well do the gudgeon pin.

But why did the big end fail? Are you sure your lubrication system is working ? Apart from the unlamented Ariel two stroke , it's not that common. Usually the mains go first, so you might want to check/replace those too.

12 year old bike.
Get one owner who don't know what an aircleaner is and you've got a rumbly big end...

[Ixion]

12 year old bike.
Get one owner who don't know what an aircleaner is and you've got a rumbly big end...

Ah, that's getting long in the tooth for tuned two smoker. So being, I'd pick the mains will also be toast, or well on the way.

Might be cheaper to source another engine ?

[Ixion]

Yep, the only problem is money ;) I can't really afford anything, so I need to put in as less as possible, just the bearings if thats possible..

Unfortunately, there's no cheap out on this one. Labour cost is the same regardless of what you replace beyond the roller and cage. And if the big end's gone usually (not always) the hardening on the crankpin and conrod eye will be shot.

Cheapest out might be to source a secondhand crank assembly. That would save all (or most all) the labour cost, and maybe be cheaper than just a new big end set.

[Oscar]

Ah, that's getting long in the tooth for tuned two smoker. So being, I'd pick the mains will also be toast, or well on the way.

Might be cheaper to source another engine ?

It's so long since I worked on a two stroke I dunno what parts cost.
The last one I worked on of my own was my 1989 RMX250, and that was in 1990....

[Ryaz]

I'm getting my KX80 repaired, is it absolutely essential to balance the crankshaft? I'm not racing, just trail riding. Cheers