ESE's works engine tuner

[koba]

If too much top end retard was the cause, you should expect to see erosion on the exhaust side of the piston crown (caused by the over heating of the exhaust port).

From your other posts I would be surprised, based on your exhaust port width (limited by no bridge) and data you have posted regarding ignition timing.

My experience is that terminal problems caused by too much top end retard is only applicible with ultra wide bridged exhaust ports, narrow unbridged ports simply do not have the width to allow enough hot exhaust gasses through fast enough to heat the piston crown terminally.

Just like an RGV I Borrowed for a hillclimb once... *Sigh*

[TZ350]

.

My FZR/GP125 that nipped up after an hour or two on the dyno, Hampton Downs and 3 laps of practice for the 2-Hour.

When it nipped up at the 2-Hour I thought it might have been given too much "retard" and overheated.



Green line fixed ignition (that was used at Hamton Downs), blue line after playing with the programable ignition retard.

I could move the green line up to the blue line just by playing with the retard curve.

So much retard after peak power at 9k and how hot the motor got frightened me so I settled for the red line.



Ignition curve for the red line. With the retard thing this motor sure gets hot.



Top of the piston.



Piston ring locating pin is missing or worn away allowing the ring to turn.



The ring turned and the ends caught in the exhaust port.



Cylinder bore damage.

I think that the ring has been working against the locating pin and dislodged it or worn it away.

And with the exhaust port at 75% of the bore, obviously extra care and thought is needed in shaping the exhaust port so that it does not abruptly push the ring back and hammer one end of the ring against the locating pin.

Years at 70% without any problems, and now at 75% this has happened twice recently.........

[ac3_snow]

The ring turned and the ends caught in the exhaust port.

ouch!! glad your day still ended up alright.
will you be needing to start again with a new barrel now or are you able to bore that one out and clean up the damage? at least you had some luck, having the spare bike there

[TZ350]

ouch!! glad your day still ended up alright.
will you be needing to start again with a new barrel now or are you able to bore that one out and clean up the damage? at least you had some luck, having the spare bike there

Thanks for your interest.

I may be able to save the barrel, it interests me because it has an exhaust port opening 86 deg ATDC and large transfers. I will keep it untill after Taupo when I hope to make some straight pipes with slip joints for testing. There are some ideas that others have suggested, that I would like to try out.

I have another barrell with similar large transfers and an exhaust port opening 80 deg ATDC for more port-time-area that I will try with my old RM copy pipe. That would be the same setup as NedKellys 23rwhp engine but with more transfer area and wider ex port. Unfortunatly it is also a 75% ex-port-width barrel just like the one that I have just broken.

[Buckets4Me]

ouch!! glad your day still ended up alright.
will you be needing to start again with a new barrel now or are you able to bore that one out and clean up the damage? at least you had some luck, having the spare bike there

you taking the piss or what

luck he say, luck. It's not luck when your partner gets knocked of the race before and is carted off to hospital
and the other team get a bif in the first few laps into the 2 hour and hurt as well (I think there are some scared people that payed a few dollars to stop them this year)

[Yow Ling]

you taking the piss or what

luck he say, luck. It's not luck when your partner gets knocked of the race before and is carted off to hospital
and the other team get a bif in the first few laps into the 2 hour and hurt as well (I think there are some scared people that payed a few dollars to stop them this year)

Sounds like if you didnt have bad luck you wouldnt have any luck that day

[TZ350]

ouch!! glad your day still ended up alright.

I know the names, captn_soup, mooools and ac3_snow but can't place who was who that got to ride Henks spare bike. If that was you, you guys did pretty well, if not, did you ride the 2-hour too? and did you enjoy it?

[Henk]

Capn Soup and AC3_snow rode the spare bike and yes they did bloody well for a couple of guys that haven't been racing long and hadn't ridden the bike until Sunday morning. They beat us

[TZ350]

Sounds like if you didnt have bad luck you wouldnt have any luck that day

Hi Yow Ling, yep Chambers and I on a good day are to fast for B grade and too slow for A so have pretty much decided to ride F5 as there arn't that many F5 bikes at Mt Welly and run the F4's at long tracks like Hampton and Taupo where we get a bit more elbow room. And occasionaly lend the 125's to someone like Av or David M who can do them justice at Mt Welly......

The 2-Hour was won by a Team riding a 2-Stroker and it's very interesting to see some realy good riders like Rick and Kel who are keen as to build Strokers too, with any good luck, next year could see the return of 2-Strokes to the pointy end of "A" grade.

[TZ350]

Capn Soup and AC3_snow rode the spare bike and yes they did bloody well for a couple of guys that haven't been racing long and hadn't ridden the bike until Sunday morning. They beat us

They beat us too........ buy a country mile.....

[Henk]

They beat us too........ buy a country mile.....

Same here 6 laps x 400m = 2.4km, about a country mile.

[Buckets4Me]

Same here 6 laps x 400m = 2.4km, about a country mile.

so whats 200+ laps x 400m =

[speedpro]

If too much top end retard was the cause, you should expect to see erosion on the exhaust side of the piston crown (caused by the over heating of the exhaust port).

From your other posts I would be surprised, based on your exhaust port width (limited by no bridge) and data you have posted regarding ignition timing.

My experience is that terminal problems caused by too much top end retard is only applicible with ultra wide bridged exhaust ports, narrow unbridged ports simply do not have the width to allow enough hot exhaust gasses through fast enough to heat the piston crown terminally.

I would be very interested to see a picture of your piston!

I've had TS100 pistons fizzled right down to the ring across the exhaust port.

[CM2005]

so whats 200+ laps x 400m =

we did 168 laps, which was 67km lol epic considering the bike was in bits 2 hours before the race with oil everywhere, broken cases, no pipe or bodywork.. hah
4th to last in the race,and i binned it twice!! Crashtastic! Need more ground clearance!!

[Moooools]

Would have been a quick trip up there if it was me.