SPL Viper pipes sea level jetting help, SRXspec-Wolfman or others

Bushman

Bushman

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May 2, 2003
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Indian River Mi.
Guys I have had some pm's on jetting/setup help on SLP Viper pipes but have never played with them. What is the jetting needed to make these pipes run @ sealevel? Weve all seen the dyno numbers the pipes make so how about some setup that work realworld on the snow?

I rode a bit with TY member 2 years ago running the SLP's jetted @ 165 mains & the TempaFlow but his Viper did not run well so I will leave it @ that.

Can you run 158's or 160's & get a good wash/plug color combo w/fuel economy & performance?

Thanks in advance! Randy
 
For sea level riding here is the setup I usually go with (good down to 0*).

Air Jet: 1.0
Pilot: 47.5
Needle: (stock) in the 4th position
Slide: stock
Fuel Screw: 1-3/4 turns out from lightly seated

Jetting: Good down to 0* I go 162.5

Now I don't run this setup with a Tempa-Flow becuase of the underhood heat which can accumulate and then cause a lean condition. He's going to have to adjust slightly.
 
All my jet has been with the CPR head mod or Mega Power Heads. This is what I run with that combo:

Pilots = 45, 45, 47.5 mag

Needles = #4 with 2 washers on top, #4 with 2 washers on top, #4 2 washers under on mag side

Mains = 160, 162.5, 162.5 mag

Fuel screws are at 2 1/4 turns out

Run this to zero deg. but with the above combo not stock head, and I run egt guages.

Wolfman
 
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Spec & Wolfman Thank you! You guys both are pretty close in setup w/Wolfman being a tick leaner.

Have either of you had a chance to run against the new Mach Z or Polaris 900 twin yet? If so how did it go?

Bottom line is jet where you need to be & lose the TempaFlow while running good gas.

How about clutching? Do you clutch for a straight shift @ 8800 RPMs (What RPM's are you running?) Or clutch for bit of a under rev (8500-8600) to let the pipes buid heat & run out to RPM's on the bigend?

Thanks again Randy
 
No Mach Z's or Fusions around here. We just now finally got our first shot of snow. Gotta go break-in a 780 Viper tonight :WayCool:

On the clutching we shoot for 8700 and try to hold it there. The Vipers that have looser compression like the 8700 rpm range, but if you tighten up the compression they like to run at 8900 rpm from my experience. 8DN weights work surprising well, but you don't have the ease of adjustability like the HH or new Super Tip weights.
 
randy, i have the slp/tempaflow set up on my viper with megapower heads. i started with 165 mains (per slp spec for -20) fuel screw 2 turns out, 50 pilots needles on clip #4 (all fatter than slp spec). first morning of riding i started it at about -15* faran. as it idled it was puking fuel and soot out of the exhaust badly. it bumbled and stumbled till about 6000 or so, then cleaned up nicely. i let grape ape ride it and several members of our group all commented on how it didnt sound right until it was at full scream. in this configuration, while using stock 8dn20 weights, it would rev to 8500 and drop back quickly to 8000 and never recovered. we decided to drop the pilots to slp's 47.5 spec and i set the needles on #3 (slp says 3.5) and 1 3/4 on the fuel screws (slp spec). it idled lots better, acted and sounded alot better. grape rode it again and actually said "now its a fun sled to ride". with that jetting corrected, the clutching then pulled a strong 8500 straight shift. the 8dn20 weights had 3.6 mid and 4.5 tip. i put 3.6 in each hole and may go to a stiffer primary to get the 87-8900 needed. i havent tested the clutching since the rivet change but it should be very close. i still think the motor is a little blubbery but i am going to try to lean it with the tempaflow and see if it acts better, if it doesnt i will be going to the 162.5's and it should run good. i have 2 .010 gaskets in the mega power heads, it pulls 132 psi on a snap on guage on all three cyls. i am thinking about going to 1 layer on that as well. still playin, got alot of winter left. but i am in the ball park and heading in the right direction. ski
 
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Ski, Don't be afraid to drop down to 45 on the pilots. It will really clean up the bottom end, and don't seem to have a bog etheir. With the jetting combo that I'm running I also run a mult-range Vari Flow with it and find myself in the number 3 and 4 click while trail riding or the exh temps are at 850 while crusing. With it at #3 I'm at a1000 to 1050 and the sled is nice and snappy. When I come to a lake or a railroad bead then I click it to #1 and let it fly. This is with the Mega Power heads and one gasket, and heavy hitter clutching.


Wolfman

P.S.
I have been thinking of going to 42.5 pilots but afraid of a lean condition when I back of the throttle into the pilots. With the setup I have I'm getting 11.5 to 12 mpg normal trail riding 40-70 mph.
 
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Wolf,
Are you running SLP pipes or CPR. Also are you a flatlander and at sea level. Reason I ask my friend just bought a 02 Viper here off TY with SLP pipes. The sled was never ran though. Sled has 1600 miles and the pipes were recently installed. The guy says its set up with the SLP specs. I'm recommending my buddy to go through everything to make sure we know whats inside. We run in Quebec cold, fast, and flat. The head is still stock I'm thinking head mod CPR. Just pd $4100 clean as a whistle.
SRXSPEC whos 780 did you buy. That 780 runs great from Jeff S
 
Mac,

I use to run CPR, and now run SLP, and Aaens. I run anywhere from 800-2000ft of elavation. I have always ran the CPR head mod never ran the stock head, but now I'm trying out the Mega Power heads. If you want any piped viper to be durable I would recommend doing the CPR head mod.

Wolfman
 
Wolfman,
You have experiance with three different pipes. Which one do you like best. I agree with the head Mod for durability. I run jeffs 780 kit with SRX brass and bored carbs and gutted box. Can't seem to wipe the grin off my face.
 
Mac,

I had the CPR the longest and put 3800 trouble free miles on. Always worked good and fast. Then tried the SLP's because they where suppose to be pretty quiet, but there wasn't much difference between the CPR and SLP in sound. The SLP's seem to have a little more bottom end, but the CPR seem to have a little more on top. Hard to say because i really never got the clutching perfect on the SLP, compared to the CPR pipes. Then comes the Aaens that I'm trying this year. Haven't had that much time on them yet. the vertic is still out on them. The one thing they have in coming is that they all seem to create alot of egt temp at 80 - 90 mph going down a railroad bed or road for a long time. That dang viper timing!
Do you notice any difference in mileage or EGT temp running the SRX carb setup with the big bore compared to the stock motor and stock carbs with pipes?

Wolfman
 
Wolf - You asked about EGT temp at high speed I havent a clue I don't run guages I'm sure I should. I ran 800 miles with CPR pipes stock head and sqeaked a piston verrry long pull. Then did CPR head mod and ran 3200 miles trouble free. Then CPR 780, stock carbs, head mod of course, stock air box running the vent, ran all last season 3800 or so. This year 780, bored carbs, SRX brass, gutted box, and no experience yet this year. I run 1000 mile trips in quebec with 10-12 guys and need to test before we ride. I don't know whats wrong I can't stop changing stuff. Anyone else having this trouble? --Mac--
 
I know what you mean. The CPR ran flawless, but still had to try the SLP, and then the Aaen. Who Know I might be right back where I started and run the CPR again. Just can't leave alone.


Wolfman
 
Mac, I'm running my own 780 kit. My thoughts are that the Viper motor with pipes actually gets more forgiving and less fussy when you big bore it than when it's stock! This thing just flat out rocks!
 
well here is mine again

slp's, tempa flow at 1/4 cc, cpr head mod, carbon tech reeds, opticool, rear exchanger, 8DN-20's, stock secondary, 1200ft. elevation, 8,900 rpm's, an jetting below. 12.05 mpg last weekend on trail. It was weird. I bleieve I got better mileage on the lake that had some powder and I was turning 8000 just to keep up and alot more WOT than trail. Thought to myself the mileage is better the more I stay on the mains as opposed to the needles.

160 across
47.5 across
3.5 across
2 1/8 fuel screws

Ran it to at least -10F and it just keeps goin. Can tell at -10F it close to the edge though. At -10F I am close to the edge too.

I think Jeff said my head was at 21cc's now, all the way across. Seems a little low, but hey the thing runs. Maybe I will add some weight and get it closer to 8700-8800. Spent a year trying, but I am truly impressed with this ride.
 
900 fusion-Mach Z???

Bushman, you better try to top the F-7 first. That is the benchmark around here anyway. They won't line up, but when they do it's gonna be close.
 
koodat said:
Bushman, you better try to top the F-7 first. That is the benchmark around here anyway. They won't line up, but when they do it's gonna be close.
Click to expand...

;)! Got the F-7's coverd for myself.... just thought the Big twins would run better.

Like Spec said (The 780 flat out rocks) ;)!
 
you Got a 780?

If you do, that i'll do it. Saw some fusions and heard about a 1000 that will eat up all the gas in the tank at 88 miles. Nothing at the line yet.
 
Bushman,

Still running the Aaen with the bigbore, If so sounds like it is working nicelly. Whos BB is it yours or someone elses?

Wolfman
 
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