Kawasaki Sportsbike Riders Club - Australia - Online Forum

Hi all, I have a damaged bore thats had the last oversize piston(KH100) in it,I would like to bore it out and put in a larger piston.

Does anyone know if this is possible and what type of piston would suit ?

Have had a look at the wiesco list and was thinking older air cooled KX 100, but without one to look at and measure up...Dunno very new to all this and could be way off track.

Any help appreciated

If your on your last oversize, I would re-sleeve it and stick with the standard sizes. The problem is if you go too far you will run into internal balance problems, to overcome this you will need to add weight to the crankshaft counterweights.

Something to think about, I learned the hard way.

Have a look at the nickosil process may save time and money
http://www.electrosil.com.au/news1.htm

Dean70 wrote:..... I have a damaged bore thats had the last oversize piston(KH100) in it,I would like to bore it out and put in a larger piston....

basically, those concepts are mutually exclusive....

The reason it is the 'last' oversized piston are many and varied, but basically, once you hit this point, you just can't * bore it out more and put in a larger piston* - it just doesn't work like that.

The simplest and probably cheapest option for you, is to find another KH100 barrel that is on its standard bore size, bore it out to first oversize and fit a piston to suit. Getting your hands on a stock-bore KH100 barrel will be the hard part. If you get one from a wreckers, make sure they measure the bore size accurately for you before you buy it, in at least 3 locations from the top of the barrel to the base, around the cylinder - to get an idea of what the bore size actually is.....

You can go with re-sleeving options if you can find a sleeve for this model - maybe Nobby at Hyside Racing could help here ??

Will have a check around for a barrel .
Don't think Wobbly has any but will ask him .

Go to your local go kart track and or go kart engine rebuilder and have them hone the barrel and fit a suitably sized Yamaha J engine piston. KH 100's run .5 and 1.0 oversize but the J engine yamaha run pistons in increments of .05 and over size up to 52mm dia giving you plenty of scope. The small end is same same and piston clearance also.
Alternately kick around a wreckers or Ebay and source a KV barrel - Alloy - they are lighter and dissipate the heat much better than the overweight cast iron barrel of the KH. Once again get hold of this barrel, get it honed or bored so that it is true and fit up the Yamaha piston.
Total cost at Silhoette Karts Thomastown for honing a barrel plus new piston and circlips $156.

which capacity J mate ?

Gosling1 wrote:which capacity J mate ?

That would be the Yamaha 100cc Kart engine "J"
Shares the same stroke and bore. Single ring, light weight, forged pistons. Either yamaha genuine or Strike pistons.

Thanks for all the replys, wobbly you know your stuff!!

Now I know my barrel is a KV and will be going to Melbourne (Thomastown)in January, its all going to happen


Good forum, good people, all good

Dean70 wrote:Thanks for all the replys, wobbly you know your stuff!!

Now I know my barrel is a KV and will be going to Melbourne (Thomastown)in January, its all going to happen


Good forum, good people, all good

Allow 3 days turn around unless previously arranged - Kart season is now on and they are flooded with kart engine building for sure.

Oh and for the record.
I'm not a good person. I'm a C#nt
Oh and stick that Kuda thing up your own arse. I f#cking hate it

[quote="Slow and wobbly
Oh and for the record.
I'm not a good person. I'm a C#nt
Oh and stick that Kuda thing up your own arse. I f#cking hate it[/quote]

Thats why we let you use spanners and nothing sharp Grumpy Prick
How are you getting to Mac Park NumbNuts ???

Driving the sponsors vehicle. Going empty if you need gear carted. Talk soon.

On with the KH100 show

[quote="Slow and wobbly
Oh and for the record.
I'm not a good person. I'm a C#nt
Oh and stick that Kuda thing up your own arse. I f#cking hate it

[/quote]

Err......Ok...now I know the rules

Thanks anyway

don't worry about S&W too much mate, he does hate the kuda with a passion......

but he knows his small-capacity stuff like no-one else down that way - thanks Ado, I was thinking 1982 mx-style 'J' motors ! not kart motors.....nice tip.

You guys doing Mac Park in the new year ?? lucky bastards....

Bring it ON Mac Park .
Practice day on the 1st of Jan . Which makes New Years Party at the track . Should be a lotta fun .
Ardy is camping at the track this year . Sir Al , Freddie , Nobby and Darryl from Hagon will be camping too .
Now we have Wobbly coming as our spanner man .
Swweeeet .