Trials Australia Forums

Did you send your piston in with the cylinder when you got it plated?

I ask because the EG 225 kits dont have the problem you have on the intake side of the piston. I cant see how a 69mm piston would cause problems but a 70mm piston doesnt.

I asked a guy I sometimes ride with who has an EG 225 on his KDX if his piston looks normal. He reports no problems in 3 years of riding.

I wonder if the platers didnt size the bore correctly?

Yes good question.

There are couple of things hear.

Where I sent the barrel also sell 220 Pistons so I said one of those and use it to size. After a few weeks I get a call saying it's been plated but to a 200 piston. (What they used to size the 200 with I don't know). As the rear port was already recessed for a 220 piston I said send it back (not my problem)

I thought is was going to an Australian platters but it turns out they send them over seas so it took another month or so. I presume they sent the piston this time.

If the barrel had one of those T exhaust bridge ports the bridge would have to be recessed as there is no way of stoping it expanding. On the inlet side I just presumed its to cold to heat that area up. The fuel air mix does a lot of cooling.

My 200' barrel was showing a lot of ware on the bridges with the honing in the plating well and truly gone. This was to be expected as its a high ware area as the skirt is shorter on that side with the cut away and hole in the piston so all the rock is concentrated on a relative small area. Having said that I did not expect the high ware the 220 piston was showing.

Now this could mean a few things like maybe the inlet bridges also need a little recessing (wouldn't be much). The rear bridges on a 200 barrel are about half a wide as a 220 barrel. Remember a 220 barrel is made for bottom end and for that reason just don't need to have such a large hole (one of the reasons I reduced the depth of the rear port when I fashioned it for boarding out to 220). To keep the upper mid and top end a large inlet track is good but a smaller rear boost port will promote bottom end. There is no shortage of top end so doing that will round the motor off.

I also suspect the sharp edge on the 45 degree angle as it comes in which is why I made the scavenging cutaways on the piston. Now that I have learned a new trick the slots are a superior method of dealing with the problem and both are not nessesory ( to late now).

You mentioned sanding a bit off the piston. This was a option which I thought about but decided not to because it was early days and there was still some coating on the skirt. It's a high ware area and would probably sort it self out soon enough with a little extra lube.

For all I know EG is recessing the bridges a tad or just that smidge larger boar. Who knows which is part of the fun when you DYI mods.

When I get my next piston I'm going to have a think about what size. In theory it should be one size up from the first piston it was made for. In this case the piston is a A so next time a B but A may be the better choice. I am also going to write to wossner and ask for a piston with out a rear cutaway or hole and make my own. If both were a little differently shaped it would support the piston more. What's the point of tinkering unles you tinker.

Tioli wrote:Where I sent the barrel also sell 220 Pistons so I said one of those and use it to size. After a few weeks I get a call saying it's been plated but to a 200 piston. (What they used to size the 200 with I don't know). As the rear port was already recessed for a 220 piston I said send it back (not my problem)

I thought is was going to an Australian platters but it turns out they send them over seas so it took another month or so. I presume they sent the piston this time.

I would be leaning towards this as the source of your high wear. I always send my piston when getting a cylinder replated. I can always find one cheaper than what the plater is selling them for and that way I know my bore is sized correctly for the piston I will be using.

Unfortunately I think you are right.

Tioli's quote of the week.

"I don't want to plan for something I don't want to do"

Nearly 20 years ago I wanted to change my motorcycling experience.

I sold every thing but this.


This and its friends had beat me up pretty bad.
The last time the surgeon said "you have done yourself a pretty bad injury. Barr I have done worse by now.


So I bought this.

Beautiful bike just needed a few mods like Ohlins and some Tioli magic.


Problem was how do you keep a new bike new?
I was over it. I know I can be anal but I'm not a slave to it. There had to be a better way. Cleaning with bits of rag on icy pole stickers between the fins and all the rest was unstable

My solution was to talk to some Harley riders.

There were two Harley's at my local shop so I pulled up on the r1200c and asked them a simple question " Hi, how do you keep your bikes so clean, how do you wash them". I have to thank them for two things.
1, they did not say what they were thinking.
2, they definitely had clean bikes.

So with out luck there the next time I passed a Harley shop I pulled in. "How do you keep these bikes so clean, how do you wash them" "truck wash" "truck wash!?" "Yep".


So this is my routine
1, every new bike or part gets smothered in silicon spray. Every thing but the brakes and tyre surface. It will turn your brakes to ice and your tyers to riding on water.
The cruiser nearly spat me of learning that. First time after a silicon spray and just down the road I committed to a fun corner you have to accelerate to get out off and the brake leaver just pulled in and stopped but did nothing. At a critical point in negotiating the corner and with out having washed off some speed the rear tyre went out. Couple of sliding laps to clean itself and luckily court. I knew what was coming and rode it out.

It puts a poar filling silicon layer on your surfaces. Nothing is getting in if you can keep it there.

My favouret one is the Yamaha one but this is good.


2, fill with water and add about a cap full of ct18


I believe this is the same as truck wash? It works like it should. By leaving a film that washes off and makes a new one.


Spray once with silicon (maybe a freshen up once a year)

Then for the rest of the time:
When I get back from a ride first thing is put the bike where I'm going to wash it. Plug the exhaust and pump up the sprayer and spray every thing. Drench it, about 2/3 of a bottle. Then leave it there for at least 10 minutes while you put the gear away.

Put a cap full in the bucket with water.

Hose the bike over to wash the dirt off.
I like to do this to the engine bays of the cars once a year. A mechanic told me never wash a hot motor or when it cools it will suck water into the electrics.

Give it a complementary sponge over and hose off.
Dirt does not seem to settle. If you rub some dirt in a light sponge over will fix that.
Start from the top by slapping a full sponge on and the suds running down do most of the cleaning. Just keep slapping it on and give it a quick once over and hoses off.
Works for me and my friends.

Any plans for other modifications to the KDX?

a few minor things then it just use, maintain and refine.

Starting to look around for the next project any ideas? I know I'm dreaming but a nice RZ or RG500 motor into a small more modern frame would be nice. I would like to hear one of those clanking away again. Wouldn't happen to have one would you?

Have you ever rebuilt a rear shock? I'm thinking of buying a spare so I can learn on it. The bleeding of it is the step I'm most unsure of.

No but my friend did and lowered it at the same time, came away very proud of himself. From what I can gather it's a bit like rebuilding a brake calliper. Seems like a big deal till you have done it once. You will have to factor in taking it to your bike shop to put the right gas in.
Good luck and enjoy.

I wanted to try some fork seal savers as they seem like a all round good idea.


Problem is for a KX125 I have to remove these guides. Exactly what they are there for I'm not to sure. Yes they will help keep the fork guards where they are supposed to be but is it really necessary


For the right side I just took the guide off and put the saver on and took it for a ride. I used the grove to locate the cable tie. After one ride I can see its frayed up the material a little


The saver comes with cable ties that I located with the guide grove.


This time I plan to relocate it so the top of the saver sits just up to the top of the guide grove and cable tie it there.