Arctic Cat TT M1000 A/F Ratio Gauges

[kkhaos]

I checked the compression before I replaced the pistons for maintenance. The compression was with in 3 lbs of each other and about the same as it was new. But 1300 miles I thought why not replace them.
This is what I found. The other one was fine. (like New) 9Replaced both) This in the Mag side. Can see by the wash its a little lean. The chunk is missing in front of the exhaust port.
Twisted Turbo
10lbs boost
110 & 91 no oxy 50/50. Going to 60/40
A/F 11.5-12 wfo

But which gauge do you go by? There both new with 1 ride on them.
Makes me wounder... I could see a couple 10s but seems way to far off for new.

What do you think caused the chunk to break out between the rings?

 

[RobertTrivanovic]

From what I understand the chunk your missing is caused by detonation.

 

[HIDY]

That piston doesn't look lean to me it is washed clean. is there any sign of the ring catching the exhaust hole.

 

[kkhaos]

Piston

No,
It looks perfect to me.

 

[Boyko]

Detonation busts up ring lands. Running lean melts the top of you piston usually the crown by the exhaust port, lean and deto can burn a hole through your piston sometime right in the middle.

As far as tuning with afr goes, The quick and dirty method I sometimes use is to ad fuel at the wide open area until you get a bog happening, than tune for .4 or .5 leaner.

Bogs at 11.7 tune for 12.2 not to say this is a good way to do it but it works for me. Make sure you have fresh spark plugs in and you sled is running well when you do this.

 

[rusty rider]

Kkhoas, what's your turbine wheel look like?

 

[Uncle Bob]

you had better have a look at your turbo I bet your looking for a new center section. it is washed clean but 50/50 for 10 pounds on this machine is stretching it for sure . I ran 8lbs at 50/50. I'm now a converted av gasser and love the consistancy

 

[kkhaos]

Turbin

I was thinking it was fine because it ran perfect all weekend. I was doing pistons as maintenance because of all the miles.
But Here a picture. Looks good to me.

 

[Uncle Bob]

you may have got really lucky but look inside, the damage will be on the other side of the turbine