2T rebuild, failure, what went wrong??

[DeanMember]

Mate that bites hard although the cast sleeve will work I think it may be a false economy of sorts. The cast item will have to be rebored regularly during a race season depending on how much he rides.where as the nikasil bore is harder than most materials and should only require regular ring checks. The cast sleeve tends to hold the heat too much and you may get hot spots which has the potential for localised seizure. I think in Australia Electrosil in Victoria are the guns for doing the coating as they also do the Kwaka race teams bikes even when they are new they redo them as the standard coatings are not good enough (their words) probably looking at around $400 plus they will need a new piston kit to match it.

Also if connor is soon ready to step up to a 125 maybe go the resleeve option if it is cost effective then trade her in. so many things to ponder :laugh: The joys of Motorcycling :laugh:

best of luck Mick

Good on Moose for lending alex’s KX

Ollie

[Mick DMember]

Ollie, seeing as though I have to rebuild it, I think I will get it done properly and keep it, as it wont be long untill my daughter will need a 85cc bike,judging on the way she was ripping around on it on Wednesday.

[dennis da menaceMember]

i thought Bull was talking about the ‘ends’ of the ring.

as in if they are shiny they have been rubbing/touching therefore they are too big for the bore,

or if they are brown/black there is a gap therefore eliminating the not enough gap problem :huh:

[BillMember]

menace wrote:

Quote:

i thought Bull was talking about the ‘ends’ of the ring.

as in if they are shiny they have been rubbing/touching therefore they are too big for the bore,

or if they are brown/black there is a gap therefore eliminating the not enough gap problem :huh:

Spot on Menis but im no wordsmith

will do a ring end Gaping thread when it goes back together with Mick if he wants to

[DeanMember]

micknmeld wrote:

Quote:

Ollie, seeing as though I have to rebuild it, I think I will get it done properly and keep it, as it wont be long untill my daughter will need a 85cc bike,judging on the way she was ripping around on it on Wednesday.

after seeing the Eric Gorr website you would be silly not to go this option and I overlooked your Revhead daughter :laugh:

Ollie

[Mick DMember]

Well my options are…….

1 Bore it out and resleeve with cast iron sleeve, supplied with Wisco piston and a rebuild kit (2 week turn around)$608.90

2 Get the Nikosil redone, supplied with Wisco piston and rebuild kit (2 week turn around) $592.40

3 Send the barrel and head to America to be serviced by Eric Gore and recieve the following;

•Cleaning and disassembly
•Inspection and measurement
•Over-boring to 100cc
•Porting
•Replating
•Diamond honing
•Head mods
•Powervalve service
•Piston and gasket kits.
You’ll get your choice of powerbands; more low/mid, more mid/top, broader powerband, and choices of fuel; pump or race gas.

Price AU$410.25 plus around AU$100 freight plus insurance.

At least 1 month turn around.

4 I am awaiting a quote from Japan for a brand new barrel and OEM piston kit.
I am guessing it to be around $550

Decisions decisions :S :S :S

[GregMember]

Number 2 for me Mick

2 Get the Nikosil redone, supplied with Wisco piston and rebuild kit (2 week turn around) $592.40

Quickest turn around, he doesnt need it modified really, keeps it closest to as is (which was very reliable) and warranty and stuff is still local as in Australia. Price is more or less the same, no overseas freight to muck you around or exchange rates

Just what I would do though :blink:

The wisco needs be correctly warmed up though no half arsed she will be right waugh rd approach

TB

[Mick DMember]

Yeah that’s my thoughts too TB, I dunno if we need the extra CC’s as he is soon to get another bike and Taylah will have it then and I will also know what I am dealing with.

I can also get an OEM piston kit for it from Japan for $136.00 delivered.

[Mick DMember]

Mr Blue wrote:

Quote:

Your photos are pretty ordinary considering your profession Michael!!!

Sorry Bruce that is the difference between a $99 trail camera that lives in my Camelbak and my $2000 media camera I use at work. Here are some better pics.

Note the wear on the side below the port and a piece of ring embedded in the crown.

I think that is the end of the ring embedded into the side of the piston 180 degrees around from the pin.

And another pic for good measure

[GregMember]

[/quote]

Is that the pin is located?

TB

[Mick DMember]

Trailboss wrote:

Quote:

Is that the pin is located?

TB

No 180 degrees around from the pin

[GregMember]

So this has happened 180 degrees from the ring opening?

TB

[Mick DMember]

YEP……

[GregMember]

The break in the ring 180 degrees from the ring opening has been because when the ring was installed on the piston a weak point in the ring was created as the ring was stretched open to go over the piston. The weak point has given way after a short period the broken ends then get caught in the exhaust ports etc because there arent supposed to be ends there which is why the have locating pins.

Not anyone’s fault really, as you expand the ring to get it over the piston with your thumbs or circlip pilers you dont want the ends to scratch the pistons so maybe you over expand it. I see this in oil consumption complaints all the time broken rings 180 degrees from the opening and when failure analysis is completed it is always the cause because as you expand it, it expands in one point, get a ring old or new and do it and watch it. We have special ring expander’s at work now I will take a photo and show how they work the whole of the ring not just opposite the opening

Hope that helps Mick

TB

[DeanMember]

It must of had some piston slap :dry:

Ollie

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