slednutz tech lounge
 

Go Back   SledNutZ > On the Snow... > Polaris > Tuning
Ibreakstuff Says: Time to start the snow dance!
Register FAQSled Chat Members List Casino Media Garage Search Today's Posts Mark Forums Read Statistics

SledNutZ Quick Info
Friends of SledNutZ: JohnDee
GreenHulk.net PWC forums
Great Lakes Jeep Thing
Team Belly Pan Sled Forums
PEPPERMILL RENTALS IN THE YOOP! There's no where better to stay in the Rockland/Mass area!
Web hosting by Floogy

Carb jetting question. Indy 650 BB ported and piped.

Tuning

 
 
Thread Tools Display Modes
  #1  
Old 11-18-2009
VanDamage007's Avatar
VanDamage007
340 Fanner
VanDamage007's Info
 
Join Date: Nov 2009
Location: Michigan
Posts: 52
Default Carb jetting question. Indy 650 BB ported and piped.

Hello. I bought a 86 Indy 600 decent shape, blown center piston. I bought a new jug, new piston and had the top rebuilt by Irondog's in Clio. The Engine has the 650 big bore kit, The heads have been ported to the max, it has SLP pipes, comet clutch, The carbs have been bored out and the jets are as follows: L 320 C 320 R(mag) 370.

Heres the question, what determines the jetting? Why is it straggered? Are these numbers sounding good? I ride in Lower Michigan incase you are wondering for altitude.
Thanks for the help!
Also I just picked up a 1" paddle track with 1 1/4 woodys carbide studs. I think this should be a great track on the sled.

Last edited by VanDamage007 : 11-18-2009 at 07:15 PM. Reason: Add track info
Reply With Quote
  #2  
Old 11-18-2009
Ibreakstuff's Avatar
Ibreakstuff
Asswipe Admin
Ibreakstuff's Info
 
Join Date: Aug 2007
Location: Burbs
Posts: 8,466
Send a message via MSN to Ibreakstuff
Default

When we speak of engines, we use P for PTO, C for Center, and M for Mag. Nothing wrong with how you did it, we just have a standardized approach.

Jetting is staggered for different reasons. Sometimes the cooling routing causes a cylinder to run a little hotter or colder than the rest, and they jet it accordingly. Other times, the tuned pipes are slightly different volumes (to make the bends under the hood) and it warrants different (staggered) jetting. There are other reasons, ones that aren't as good, that could cause the jetting to be staggered: The PTO crank seal could be leaking and they richened that cylinder up to account for it - OR - someone messed up on the porting.

Jetting is determined by the engine; you want a perfect 14.7:1 (14.7 parts oxygen to 1 part gasoline) ratio. A larger CC cylinder has more oxygen in it and therefore requires more fuel, and that's where jetting comes in. Jetting is both complicated and simple. The whole point of jetting and adjusting carbs is to achieve a 14.7:1 ratio over the entire operating RPM of the engine. The problem is that not a single portion of your carb can cover the entire throttle range, and the different jets/needles/mixture screws cover different parts and they overlap.

Here is a ton of information on a basic venturi style carb, probably the kind that's on your sled ;)

http://www.slednutz.com/showthread.php?t=47
__________________
You don't have to flinch for me to know that you're scared.
Reply With Quote
  #3  
Old 11-18-2009
Ibreakstuff's Avatar
Ibreakstuff
Asswipe Admin
Ibreakstuff's Info
 
Join Date: Aug 2007
Location: Burbs
Posts: 8,466
Send a message via MSN to Ibreakstuff
Default

Here's some more:

http://www.snowmobileforum.com/engin...or-clinic.html
__________________
You don't have to flinch for me to know that you're scared.
Reply With Quote
  #4  
Old 11-18-2009
VanDamage007's Avatar
VanDamage007
340 Fanner
VanDamage007's Info
 
Join Date: Nov 2009
Location: Michigan
Posts: 52
Default

Kick butt. Ill read up. I really want to learn more about jetting. I guess you must tell if you have the 14.7:1 by exhaust tempatures? I have SLP pipes but a Aaen EGT gauge, but no probes. I guess I better get the probes. Thanks for all the info. Do the numbers seem high to you? Should I start there. I forgot to mention I bought new carbs that are not bored. I intend to switch the jets into the new carbs, and use them. The bored ones are three different carbs! I dunno if the original engine builder used them on purpouse but it seems odd. Id rather have the matching carbs unbored but jetted. Will that make a difference in jetting? Thanks again!
Reply With Quote
  #5  
Old 11-18-2009
Gotmud's Avatar
Gotmud
Poo Slinger
Gotmud's Info
 
Join Date: Sep 2007
Location: Bloomingdale, Mi.
Posts: 9,425
Default

Holy shit Ibreakstuff sure answered your question and some lol. Welcome to the club dude, where in lower Michigan are you? I'm near Kalamazoo and also have a 650.
__________________
Rich
"Do not go where the path may LEAD, go instead where there is no path and leave a TRAIL"

Quote:
Originally Posted by Rubi View Post
Nobody on this site likes Ski Doo except Dirty Harry, and he's better at making babies than buying or fixing sleds, so you don't want to listen to him.
Reply With Quote
  #6  
Old 11-18-2009
Ibreakstuff's Avatar
Ibreakstuff
Asswipe Admin
Ibreakstuff's Info
 
Join Date: Aug 2007
Location: Burbs
Posts: 8,466
Send a message via MSN to Ibreakstuff
Default

My technical side outshines my "HOLY FUCK WE NEED SNOW" comments every once in a while.
__________________
You don't have to flinch for me to know that you're scared.
Reply With Quote
  #7  
Old 11-18-2009
CWPottenger's Avatar
CWPottenger
Polaris Guy
CWPottenger's Info
 
Join Date: Jan 2009
Location: Illinois
Posts: 2,056
Default

Quote:
Originally Posted by Ibreakstuff View Post
My technical side outshines my "HOLY FUCK WE NEED SNOW" comments every once in a while.
Both work for us...
__________________
  #8  
Old 11-18-2009
Triple650indy's Avatar
Triple650indy
Czar of the Cheddar Curtain
Triple650indy's Info
 
Join Date: Mar 2008
Location: Appleton, WI
Posts: 1,278
Send a message via Skype™ to Triple650indy
Default

Good Posts IBS. EGT's are the extreme option you have, but even the EGT's aren't an exact science. The best way to check jetting is to go run a full throttle quickly shut it down, pull the plugs and see if they are the correct color and that the piston wash looks good too.

For plugs white is bad, this means you need more fuel or a bigger jet. Cardboard brown is perfect jetting.
Black is too much fuel and you need a smaller jet.

Piston wash is a small area of the piston that the fuel takes the carbon off the piston by the inlet port. It should be about as big as a thumb nail. Bigger means too much fuel. Smaller than a thumb nail is lean and you need more fuel.
__________________
2005 Ski-Doo 600 H.O.
Reply With Quote
  #9  
Old 11-19-2009
VanDamage007's Avatar
VanDamage007
340 Fanner
VanDamage007's Info
 
Join Date: Nov 2009
Location: Michigan
Posts: 52
Default

Ok piston wash is a new one for me. Where do I look to see this? Do I need to remove the carbs to see it? I got the plug thing down. Ive never re jetted anything. The motor when I got it had the middle piston all jacked up. It looked like it got kind of side ways in there because the front and back were jarred along with the ring. The top of the piston looked a lil rough in the middle. No holes tho. I will inspect the plugs when I get home. I hope to start putting the motor in tonight.

Should I use RTV around the joint in the pipes to seal them? I never have had a piped sled. I cant wait, the neighbors are gonna love this one... HAHAHA!

Oh yeah Ibreakstuff, WHERES THE DAMN SNOW!!! Dont worry. I think Gods holding it off for me till I get this sled done. Ill get on it asap!
Reply With Quote
  #10  
Old 11-19-2009
VanDamage007's Avatar
VanDamage007
340 Fanner
VanDamage007's Info
 
Join Date: Nov 2009
Location: Michigan
Posts: 52
Default

Hey the part about the jets compensating for bad lower seals scares me a lil. I had the top half redone. We were assuming the lower is good, but how would I know if I had a problem?

Im sure they would have check it it out at the shop. I think they took off the fly wheel for something. Does this motor have timing? They said something about all the coils and plugs fire at the same time. Hows that work? Dont the pistons need to fire at seperate times? Weird. All the coils are run from the same two wires. Any info on that?
Reply With Quote
  #11  
Old 11-19-2009
Triple650indy's Avatar
Triple650indy
Czar of the Cheddar Curtain
Triple650indy's Info
 
Join Date: Mar 2008
Location: Appleton, WI
Posts: 1,278
Send a message via Skype™ to Triple650indy
Default

Piston wash is seen with the plug out and you look down into the cylinder with a flashlight or a tool with a light and a optical swivel I guess I'd call it.

To check the lower end seals you can run the motor at idle and observe the RPM. Then take some ether and spray it right on the seals. If either is leaking you'll see a slight increase in the RPM when the ether gets past the seal.
__________________
2005 Ski-Doo 600 H.O.
Reply With Quote
  #12  
Old 11-19-2009
OCR's Avatar
OCR
Summer Sux!!
OCR's Info
 
Join Date: Sep 2007
Location: Groton NY
Posts: 4,642
Default

It is called "wasted spark", the cdi triggers for each piston as it nears the BTDC point that it is set to fire at. All two/three plugs fire at the same time. It's actually easier than setting points for each cylinder.
__________________
Old Cat Rider

'93 Wildcat 700EFI w/ Comet 108 Pro-4 clutch & 01 ZR skid


http://twintiersleddin.proboards76.com/index.cgi


Quote:
we are all given sh*t in life, but some of us learn to turn it into fertilizer and grow from it, and some us try to fling it on others like monkeys
Reply With Quote
  #13  
Old 11-19-2009
Ibreakstuff's Avatar
Ibreakstuff
Asswipe Admin
Ibreakstuff's Info
 
Join Date: Aug 2007
Location: Burbs
Posts: 8,466
Send a message via MSN to Ibreakstuff
Default

My answer? Spend $12 and get new crank seals while it's apart. I have my engine apart right now, with less than 1000 miles on it, and I'm changing mine. Cheap insurance and it's a royal pain to do after the sled is together.
__________________
You don't have to flinch for me to know that you're scared.
Reply With Quote
  #14  
Old 11-19-2009
CWPottenger's Avatar
CWPottenger
Polaris Guy
CWPottenger's Info
 
Join Date: Jan 2009
Location: Illinois
Posts: 2,056
Default

I agree there if apart do it now... Case in point I rebuilt a 440 few years ago, took it apart, new bearings, pistons, rings, checked everything else looked good reassembled, half a day run time seals failed... It was a yamaha..., but still good to replace if apart, lot less headaches!!!
__________________
  #15  
Old 11-19-2009
VanDamage007's Avatar
VanDamage007
340 Fanner
VanDamage007's Info
 
Join Date: Nov 2009
Location: Michigan
Posts: 52
Default

Yeah I just spent enough on it already. Honestly this is my first liquid cooled sled. Im a fan of fan cooled. I dident want to get into the lower half of the engine unless I had too. If they are bad I will deal with it then I guess. I trust the guys who did the work on the engine. It was Irondog, they have been doing it for over 30 years. What kind of power are we talking when porting a 650 big bore with slp pipes? Any clue on HP or 0-60, or top end? Am I gonna be able to ride this out on the back roads and ditches and stuff?
Reply With Quote
  #16  
Old 11-20-2009
Triple650indy's Avatar
Triple650indy
Czar of the Cheddar Curtain
Triple650indy's Info
 
Join Date: Mar 2008
Location: Appleton, WI
Posts: 1,278
Send a message via Skype™ to Triple650indy
Default

Depends on if it is the 707 BB or the 732 BB. Got anymore info for us?
__________________
2005 Ski-Doo 600 H.O.
Reply With Quote
  #17  
Old 11-24-2009
VanDamage007's Avatar
VanDamage007
340 Fanner
VanDamage007's Info
 
Join Date: Nov 2009
Location: Michigan
Posts: 52
Default

A 600 bored to a 650. Now Im looking at the track clearance with the front heat exchanger. I think I am going to have a problem with the 1 1/4 studs. Anyone ever move or remove one of these? Could I remove it and install a radiator somewhere? Wouldent it run cooler with a radiator? I will post that in the tech section.
Reply With Quote
  #18  
Old 11-24-2009
Gotmud's Avatar
Gotmud
Poo Slinger
Gotmud's Info
 
Join Date: Sep 2007
Location: Bloomingdale, Mi.
Posts: 9,425
Default

So you've got 650 cylinders on your 600 bottom end? 1.25 is a BIG stud, I thought studs were suppose to be 1/8" taller than the lug?
__________________
Rich
"Do not go where the path may LEAD, go instead where there is no path and leave a TRAIL"

Quote:
Originally Posted by Rubi View Post
Nobody on this site likes Ski Doo except Dirty Harry, and he's better at making babies than buying or fixing sleds, so you don't want to listen to him.
Reply With Quote
  #19  
Old 11-24-2009
VanDamage007's Avatar
VanDamage007
340 Fanner
VanDamage007's Info
 
Join Date: Nov 2009
Location: Michigan
Posts: 52
Default

Well not exactly. The 600 heads were bored over to 650. Its the big bore kit. The heads have been ported and the carbs were bored however they were three different carbs for some reason. I am going to revert to stock bore carbs and change the jets.
Reply With Quote
  #20  
Old 11-24-2009
VanDamage007's Avatar
VanDamage007
340 Fanner
VanDamage007's Info
 
Join Date: Nov 2009
Location: Michigan
Posts: 52
Default

Oh and it is a 1" lug track. Paddle track. The track only has clips and windows on every third opening. Other than that it is a 121 by 15 track. Aggressive for sure. The studs are at lease 1 1/4" Im sure it will hook up well. I hope I dont flip this bee-otch over.
Reply With Quote
  #21  
Old 11-25-2009
Gotmud's Avatar
Gotmud
Poo Slinger
Gotmud's Info
 
Join Date: Sep 2007
Location: Bloomingdale, Mi.
Posts: 9,425
Default

There are a few of us on the site with piped 650s, we should have any info you'd need.
__________________
Rich
"Do not go where the path may LEAD, go instead where there is no path and leave a TRAIL"

Quote:
Originally Posted by Rubi View Post
Nobody on this site likes Ski Doo except Dirty Harry, and he's better at making babies than buying or fixing sleds, so you don't want to listen to him.
Reply With Quote
  #22  
Old 11-25-2009
VanDamage007's Avatar
VanDamage007
340 Fanner
VanDamage007's Info
 
Join Date: Nov 2009
Location: Michigan
Posts: 52
Default

Great, thank you. Whats the top speed, and horsepower any idea? I bet these things get up and go huh? Do you trail ride yours? Im wondering if the big port job is gonna be ok to rip around back roads. Do these mods make them run hotter? I assume so. I may have just enough room under there after all. If not I may get a new heat exchanger and try to shave it down some. IM really leaning towards putting a radiator in. I dont want to overheat and burn the motor up. If all else fails I will get a 440 fan motor for this thing.
Reply With Quote
  #23  
Old 11-25-2009
Gotmud's Avatar
Gotmud
Poo Slinger
Gotmud's Info
 
Join Date: Sep 2007
Location: Bloomingdale, Mi.
Posts: 9,425
Default

With triple pipes hp should be about 120. Stock I've buried the speedo with ease on gravel roads.
__________________
Rich
"Do not go where the path may LEAD, go instead where there is no path and leave a TRAIL"

Quote:
Originally Posted by Rubi View Post
Nobody on this site likes Ski Doo except Dirty Harry, and he's better at making babies than buying or fixing sleds, so you don't want to listen to him.
Reply With Quote
  #24  
Old 11-26-2009
VanDamage007's Avatar
VanDamage007
340 Fanner
VanDamage007's Info
 
Join Date: Nov 2009
Location: Michigan
Posts: 52
Default

Wow. 120 Hp should be sweet! Im wondering if I should plan on this being my racing sled then maybe. I dunno if I am gonna be back road and ditch riding it too much. Ill be jumping mail boxes....


Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 02:25 AM.


Powered by vBulletin® Version 3.6.8
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright 2007 Slednutz.com