Going to need help setting up 780 srx

drew, opinions are great on the internet on what to use. in the end, you have to try the best setup for your sled. and thats real world. like what i posted with the 8bu-10s. 3:16x (yammie tony)
 

YAMMIEGOD3:16 said:
drew, opinions are great on the internet on what to use. in the end, you have to try the best setup for your sled. and thats real world. like what i posted with the 8bu-10s. 3:16x (yammie tony)
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I agree. I like to learn so getting opinions and trying different things is the best way for that. I like to learn the hard way usually.lol
 
Another question. Should I leave the carbon on the top of the pistons. I am guessing I should but not sure. I read that used plugs are easier to read but haven't seen anything on the piston tops. I would guess that with the rpms these run it shouldn't take long for it to show.
 
It seems like these pistons might have a coating on top but I am not sure. How can I tell and if they do how hard can I scrub them? I soaked the tops in berrymans chem dip a couple times for a day each time and it doesn't seem to be doing too much anymore. That stuff works great on my powervalves. I have never had to clean the tops before so any suggestions on a better way? IMG_20161206_092459229[1].jpg
 
You got that kit from me didn't you? That thing had less than pinky nail size wash marks on it with 157.5s. I sent you 160s with it to start for a bit more safety factor. I didnt want anyone coming back to me because they blew up a $1000 top end first time out. You can still barely see the wash marks a little in your pic although you've washed most of it off. Those 47.5s are fine. I can't remember did I give you the whole carb rack or just the Jets?
Like said those bu00s will work but backshift won't be the best.
I never got a chance to run that sled except once across a field when I bought it, but that was a strong runner.
 
Drew, this is a random picture I pulled off the Web for an example of the piston wash you're going to be looking for. See the 2 shiny spots on the right. That is your wash. That will be on the intake side of your pistons. There will be other wash marks around the rest of your ports as well. But these two I like to have about the size of a pinky nail. That's safe for most all conditions. The smaller those cleaned off marks the leaner you are.....the bigger they are you are richer. Before you cleaned the pistons you had small wash marks in these areas. With the coated piston tops they don't stand out as much because you don't have that shiny background.
Hope it helps.
 
staggs65 said:
You got that kit from me didn't you? That thing had less than pinky nail size wash marks on it with 157.5s. I sent you 160s with it to start for a bit more safety factor. I didnt want anyone coming back to me because they blew up a $1000 top end first time out. You can still barely see the wash marks a little in your pic although you've washed most of it off. Those 47.5s are fine. I can't remember did I give you the whole carb rack or just the Jets?
Like said those bu00s will work but backshift won't be the best.
I never got a chance to run that sled except once across a field when I bought it, but that was a strong runner.
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Yes, this is the kit from you. I was hoping you would jump in on this. Don't worry if I burn this thing up it is totally on me. I didn't get the carb rack from you. I wish I would have bought it. You gave me 47.5 and 45 pilots and 160 mains. You don't happen to remember if the air box was stock or gutted?
 
staggs65 said:
Drew, this is a random picture I pulled off the Web for an example of the piston wash you're going to be looking for. See the 2 shiny spots on the right. That is your wash. That will be on the intake side of your pistons. There will be other wash marks around the rest of your ports as well. But these two I like to have about the size of a pinky nail. That's safe for most all conditions. The smaller those cleaned off marks the leaner you are.....the bigger they are you are richer. Before you cleaned the pistons you had small wash marks in these areas. With the coated piston tops they don't stand out as much because you don't have that shiny background.
Hope it helps.
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That does help and makes sense. Now that I know the tops are coated I did see the wash marks. It just didn't look like my other pistons.
 
Also, that explains what this carb rack on my work bench came out of. Lol. I've been working in Singapore for the last 6 months and was wondering what it came off. I can check the needles for you too.
 
staggs65 said:
I can check on the airbox tomorrow. I don't recall off the top of my head
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Ok. I raised the needles to 3.5 already and I have the 47.5 pilots in. Its not going to hurt to throw the 160's in and see where its at. The next size down I have is 156.3 so I suppose I should just get the 158.8 and 157.5 ordered just so I have them. If nothing else I should learn a bunch about jetting. Hopefully without burning anything down. My biggest worry is not getting the conditions to test in before its time to go north and then I will have to switch it all back to a 700. Hoping for snow once it is all back together. Thanks for the help.
 
staggs65 said:
Also, that explains what this carb rack on my work bench came out of. Lol. I've been working in Singapore for the last 6 months and was wondering what it came off. I can check the needles for you too.
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Lol. Singapore doesn't sound fun. That would be cool to know what the needles were at.
 
Needles, 3rd groove both shims under.
Air box, can't say 100% because I have a stack of them, but 1 of the ones at the top of the pile is all cut up with extra holes. More than likely from that sled. It also had Boyesen reeds. Pm me your address again and I can send you a set of 155s, and if I can lay my eyes on them 157.5s and you can tune your way down
 
staggs65 said:
Needles, 3rd groove both shims under.
Air box, can't say 100% because I have a stack of them, but 1 of the ones at the top of the pile is all cut up with extra holes. More than likely from that sled. It also had Boyesen reeds. Pm me your address again and I can send you a set of 155s, and if I can lay my eyes on them 157.5s and you can tune your way down
Click to expand...
Thanks for the info. I have the 155s already and ordered 158.8 and 157.5. When I get those I will have every size from 153.8 up to 160. In our pms from before you mentioned it had the 160 mains and 42.5 pilots. Could someone have put those mains in trying to compensate for the airbox being modded. In theory the 157.5s should be more than enough to start with and if that looks pretty rich move down to 156.3 and I should end up around the 155s and possibly down to the 153.8s.
 
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