1981 SRX Carb change and Coil Relocate
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xxxbuck19xxx
- Posts: 28
- Joined: Mon Sep 03, 2012 8:12 pm
1981 SRX Carb change and Coil Relocate
I'm deleting the airbox and am wondering if their is kind of a common spot to relocate the coil as it screws to the airbox. I want that airbox goneski
Re: 1981 SRX Carb change and Coil Relocate
Your limited by the length of the wires so, looks like a custom bracket from the tunnel or the steering loop is in order ?
https://www.youtube.com/watch?v=PFb6NU1giRA
"I prefer dangerous freedom over peaceful slavery." Thomas Jefferson
"I prefer dangerous freedom over peaceful slavery." Thomas Jefferson
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chrisrider63
- Posts: 445
- Joined: Fri Nov 21, 2008 12:38 pm
Re: 1981 SRX Carb change and Coil Relocate
Id keep the airbox if you dont it might blow up, im guessing it would......
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Bob Vehring
- Posts: 659
- Joined: Tue Feb 24, 2009 12:42 am
- Location: Milw. Wi
Re: 1981 SRX Carb change and Coil Relocate
ah, i feel like a fish going after the bait 
I will never tell anyone something won't blow up, too many variables. How ever damage from being too lean can come from jetting if your not sure what your doing or where your at.
With all that said, how well your sled performs is relative to how you jet it. From the factory almost all sleds are very rich. This is to protect both the sled owner and the dealers from people burning them down. Factory jetting should be safe for almost all conditions. They jet it for the coldest temps they think you will see.
Did you ever feel like your sled is fast on those really cold nights?, It is faster, your jetting is now much closer to right because the cold temps can use all that extra gas. At 25-30 deg those same jets are so rich, power suffers.
Short of EFI, if you want max power under all conditions, you re-jet to keep it right.
So, how do air boxes fit in here? Some but not all simply don't flow as much air as not having them. Others may be capable of flowing enoff air, but because the engine now has to pull "harder" to get the air to move around the baffles in the box, that can create a difference in the fuel signal through the carbs.
If you don't have EGT gauges on your sled and understand them, I would either leave it stock or start very rich and work your way down to it. Remember main jet is not the only thing to consider here. Certain Needles and tubes can cause very lean conditions in areas other then WOT, on a trail sled, you won't find that by reading plugs or piston wash.
Be Careful
I will never tell anyone something won't blow up, too many variables. How ever damage from being too lean can come from jetting if your not sure what your doing or where your at.
With all that said, how well your sled performs is relative to how you jet it. From the factory almost all sleds are very rich. This is to protect both the sled owner and the dealers from people burning them down. Factory jetting should be safe for almost all conditions. They jet it for the coldest temps they think you will see.
Did you ever feel like your sled is fast on those really cold nights?, It is faster, your jetting is now much closer to right because the cold temps can use all that extra gas. At 25-30 deg those same jets are so rich, power suffers.
Short of EFI, if you want max power under all conditions, you re-jet to keep it right.
So, how do air boxes fit in here? Some but not all simply don't flow as much air as not having them. Others may be capable of flowing enoff air, but because the engine now has to pull "harder" to get the air to move around the baffles in the box, that can create a difference in the fuel signal through the carbs.
If you don't have EGT gauges on your sled and understand them, I would either leave it stock or start very rich and work your way down to it. Remember main jet is not the only thing to consider here. Certain Needles and tubes can cause very lean conditions in areas other then WOT, on a trail sled, you won't find that by reading plugs or piston wash.
Be Careful
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xxxbuck19xxx
- Posts: 28
- Joined: Mon Sep 03, 2012 8:12 pm
Re: 1981 SRX Carb change and Coil Relocate
TYVM for the reply bob. I have a vintage racing buddy that works at the local supply store for sled and atv stuff. He hooked me up with the proper needles and such. I am running UFO's to try and kill some of the temperature variance. As far as main jetting is concerned, i'm starting out with 380's and working my way down. I have size 20 pilots as the sled had size 40's and it says in the manual to use half size pilots as compared to the stockers. That needle above the main jet is the proper one. He looked and says it matches the needles i'm going to be using. H4's and H7's
I am going to be syncing the carbs the RIGHT way and plan to use K and N filters behind where the airbox was. I believe that at the moment i'm in the ballpark for a starting point and that it shouldn't do anything bizarre on me. I'd love to know some ways to put this damn thing on a diet though. I'm trying on my own to diet myself. haha
I am going to be syncing the carbs the RIGHT way and plan to use K and N filters behind where the airbox was. I believe that at the moment i'm in the ballpark for a starting point and that it shouldn't do anything bizarre on me. I'd love to know some ways to put this damn thing on a diet though. I'm trying on my own to diet myself. haha
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Bob Vehring
- Posts: 659
- Joined: Tue Feb 24, 2009 12:42 am
- Location: Milw. Wi
Re: 1981 SRX Carb change and Coil Relocate
Sorry, I can't offer anything directly on jetting The engine that came in my sled has been a nightmare since day one, all that is chronaloged in the My Prodjects sec. under VooDo Max,
My SRV which makes around 80 hp runs taber bored 38's, uses normally 340-350 mains. There will be some differances but, as far as having 535 cc's make 80 hp, you should be rich enought to start
I did dump the power jet system on mine, just never liked that plan. I did also find after being hit in the foot with several SRV pistons, that the relation ship between needles and tubes is often the limiting factor. After loosing several pistons almost instantly after a long blast on the lake. then backing down to a cruse position on the throttle.
Because of my kids racing, we have had quite an asortment of really good data actuistion systems around here for years. These of course made their way on to my trail sleds. Download the info and graphing it, it was easy to see the problem really happened as soon as I backed down the throttle. At WOT it is running off the main jet entirely. Now as soon as you roll off the throttle, the slide, and with it, the needle drops and the needle now sits inside the tube (needle jet). This now becomes the limiting jet sytem. It was easy to see on the computor that the engine was plenty safe running WOT, but when you backed off, EGT would sky rocket when the needle when in the tube and the piston overheated.Changing the needle and needle jet solved the problem, haven't hurt it since. The piston is cooled by the incoming rush of cold gas, When you back down this cold gas, the piston overheads and goes away.
Some people will tell you, you can gage jetting based on plug color and piston wash because thats how some racers do it, or at least used to do it. In racing or at least most racing the carb is either WOT or shut. On a trail sled the plug or piston will color up from everything that happens so a rich or lean condition will really not show up as anything other then part of the over all picture, you can't pin point a smal problem area, which is what was eating my pistons.
My SRV which makes around 80 hp runs taber bored 38's, uses normally 340-350 mains. There will be some differances but, as far as having 535 cc's make 80 hp, you should be rich enought to start
I did dump the power jet system on mine, just never liked that plan. I did also find after being hit in the foot with several SRV pistons, that the relation ship between needles and tubes is often the limiting factor. After loosing several pistons almost instantly after a long blast on the lake. then backing down to a cruse position on the throttle.
Because of my kids racing, we have had quite an asortment of really good data actuistion systems around here for years. These of course made their way on to my trail sleds. Download the info and graphing it, it was easy to see the problem really happened as soon as I backed down the throttle. At WOT it is running off the main jet entirely. Now as soon as you roll off the throttle, the slide, and with it, the needle drops and the needle now sits inside the tube (needle jet). This now becomes the limiting jet sytem. It was easy to see on the computor that the engine was plenty safe running WOT, but when you backed off, EGT would sky rocket when the needle when in the tube and the piston overheated.Changing the needle and needle jet solved the problem, haven't hurt it since. The piston is cooled by the incoming rush of cold gas, When you back down this cold gas, the piston overheads and goes away.
Some people will tell you, you can gage jetting based on plug color and piston wash because thats how some racers do it, or at least used to do it. In racing or at least most racing the carb is either WOT or shut. On a trail sled the plug or piston will color up from everything that happens so a rich or lean condition will really not show up as anything other then part of the over all picture, you can't pin point a smal problem area, which is what was eating my pistons.