pto side with 33 mm with 155s at -5 wot cant win 
preamium fuel with a water funnel was spot on week b4 at 20 f to close i guess other plugs are rite on some times u cant control all the varibles!!! i guess mr viper need ur adress again pmed u let me know thanks
preamium fuel with a water funnel was spot on week b4 at 20 f to close i guess other plugs are rite on some times u cant control all the varibles!!! i guess mr viper need ur adress again pmed u let me know thanks
yamadogg said:pto side with 33 mm with 155s at -5 wot cant win
oh boy...
93 octane premium or 91 premium? should be plenty good with 155 mains with needles raised at 3.5? what about airbox mods? I will check pm and if you left number give ya a call.
yamadogg said:pto side with 33 mm with 155s at -5 wot cant win
make sure not to run to mutch compression..stock compression is almost the maximum you can go with premium fuel
jamie
Member
Compression ratio ?? 155 plenty rich for a pump gas 780. 152.5 in every 780 I ever put toghether and still kinda rich.
staggs65
Moderator
that sucks Ron. hope you find the cause.
jamie
Member
Sounds like you have some tight heads on there.
nope, not the heads.......didnt burn the edge off the piston from being lean, it broke the ringland between the top and bottom ring. Other 2 pistons look perfect.
mopar1rules
Active member
My 780 jetting:
Mains anywhere from 156.3-158.8
Needles clip 4 with both shims on top
pilots 42.5
fuel screws around 1-1/2
never fouled one plug and safe for all crap pump fuel
Mains anywhere from 156.3-158.8
Needles clip 4 with both shims on top
pilots 42.5
fuel screws around 1-1/2
never fouled one plug and safe for all crap pump fuel
mrviper700 said:
sounds deton if he brole the ring land
Mad Max Performance
New member
Yep, that sounds like detonation for sure. Usually though, it will break the land off the top of the piston to the top ring... Sort of how Mr. Viper hinted. Burn it off, or break it. Did it break it off right at the exhaust port? Didnt snag a ring, or have the ring locator pin wear out and allow the ring to turn did it?
Holy Cow!!!!! A Mad Max sighting
You getting back into the game again Bob? I see you've been on showing up on SW and now here. I was actually just watching that vid of the kid on the the mod you put up online. Sounded just like the one I have sitting outside. Been riding the old mtn max (your porting, benders, etc...) this year as I've been fighting an electrical issue on my apex. Good to see you around.
Sorry for getting off topic. Back to the original topic Them 780 motors need good fuel to stay happy.
You getting back into the game again Bob? I see you've been on showing up on SW and now here. I was actually just watching that vid of the kid on the the mod you put up online. Sounded just like the one I have sitting outside. Been riding the old mtn max (your porting, benders, etc...) this year as I've been fighting an electrical issue on my apex. Good to see you around.Sorry for getting off topic. Back to the original topic
Them 780 motors need good fuel to stay happy.Mad Max Performance
New member
Hey! How are ya! I am just getting back into sledding a bit. Ported my sons old MM 700 you saw in the video, and I have an 835 viper ( that has a bad stator as of last night... lol) and my wifeys little 600 MM with PI end dumps. I dont plan on doing too many engines. Maybe one or two here or there. When my son started playing AAA hockey, and I was farming, the engine building had to go away. I sure miss it though. I hope this fella gets his 780 figured out. That sucks when they grenade.
I hope this fella gets his 780 figured out. That sucks when they grenade.