Lightened piston

[spanky]

Think they'll catch on?



Whoops.

[CMSMJ1]

is that yours?

I'll be stripping my no136 race engine this week..I have already got a mangled spark plug out of it...

[spanky]

Afraid so - it's my RLR engine with the lovely knife-edged inlet ports. It made a very brief metallic noise as I entered hangar straight at Silverstone on Friday, then half a lap later another one and that was it.

Not entirely sure what caused it but I did stupidly knock it down a gear instead of up earlier in the day. Maybe I threw a shim or something. Either that or one of the valves just gave up.

Pondering what to do now. I either pick up a standard engine or break the bike and start again. If you see an Ohlins shock on the FS section you'll know which I did.

What happened to yours?

[CMSMJ1]

That is a shame.

I did the same kind of deal. I snapped my own rearset gear lever and borrowed a spare set from Jim on here. These were flexy and did not not like race shift. the lever caught on the rod in the up position and so when I tried to change up (by pushing down) it stuck and when I kicked it to get it free...the bike changed from 3rd to 2nd at 13k revs... instant grinding and crunching...and a dead motorbike

I have not had the motivation to take it to bits yet. It pains me as I put a lot into that bike and engine!

Oh well....should be good for the bookcase to sit with my trophies, the HRC piston and my smashed sparkplug.

[Indiana Jones]

I feel your pain,looks and sounds so similar to the death of my RLR engine.
It's soul destroying.

Should have my new front head back from RLR next week,then a transplant onto my stock engine with my undamaged rear head.
See out the last two meetings of the season with a few extra ponies.

[spanky]

400GB group therapy... I like it.

Nice pic Dr Jones, a bit more useful for a post mortem than mine. Looking at yours, it seems to have lost the head from a single valve which has punched a hole in the piston - that pretty much confirms what happened to mine, i.e. the initial tinking metalic noise was a single valve head dropping.

Did you also accidentally massivley over-rev it or did it just go? I wonder if it's user error (like I think mine was) or a combination of HRC CDI redline and the engine tune and the valves just can't quite cope.

Out of interest how much is it to get a replacement head ported? ( feel free to pm if you don't want the wife to know).

Cheers,
J.

[Indiana Jones]

Most def user error.
Was under pressure holding my position and held a gear for longer,just past the shift light but not against the raised limiter,rather than shifting up and losing drive.
Next corner....dropped two gears like I had been doing except I hadn't gone up two.
Major over rev ,piston valve contact,loss of power and lots of smoke.
Game over.
That was Easter weekend in Bishopscourt,I drove 200 miles home and put in my old stock engine and back up to Kirkistown on the Monday and won some money.
Next meeting in Mondello I did a personal best in qualifying,put it in P3,lost the front twice in the races,wrecked my bike,season over 'till now.
Sometimes I ask myself "Why?"

[spanky]

I don't have a shift light and change up as I hit the HRC limiter, or fractionally before (I know, I know).

Kind of happier knowing what caused it since all three of us did the same thing but feeling more gutted as the quality of engine I've blown up sinks in.

[lukemillar]

Sometimes I ask myself "Why?"

Because it's frickin' addictive! And riding bikes on the road/trackdays just doesn't cut it the same way.

[lukemillar]

Out of interest (as I'm about to go down a similar path)

Are you guys all running raised rev limits? And could you chalk all these piston/valve interfaces down to over-reving on bad downshifts?

Cheers
Luke