Port matching

Youllbe2nd

Youllbe2nd

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Joined
Feb 14, 2015
Messages
425
Location
Canada
Does anyone have experience porting a viper? I'm no expert. The sled I have has two ported cyls and one that was replaced and never matched. I know its hard without looking at the cylinder but if I posted some pics and some measurements could someone tell me if I'm in the ball park here? Im going to be doing this myself. So far I've cleaned up the exhaust ports and polished. Matched the port exit to the exhaust flanges and that's it. All that's left is making the port wider to match other the other two. The auxiliary ports are wider too...any help is appreciated.

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Main port is widened to 55mm and auxiliary ports widened to 15mm. What are the stock measurements? 48 and 11 is it? Theres also some work done on the intake side. It has slp pipes. 47.5 pilots, 165 mains. Smoked my mag piston. Middle piston was smoked before at some point. Although the pistons were out of spec and due for replacement, The sled had a lean idle hang untill I Turned idle down to 1400. I haven't had a chance to test yet but should I try 50 pilots and go from there? Fuel screws maybe 2 and a half turns??

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I'll post some pics but I matched the stocker on Saturday night so there won't be a comparison

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I think your pilot jets are small. I would increase to 50 pilots minimum. Tripple pipes love fuel.
The porting on the Viper cylinders was very good from the factory. Most companies claimed porting increases HP by 6 to 7. Thats only two HP per cylinder. If you have matched as best you can...... bolt it on and run it.
---mac---
 
Ok thanks I'll start with 50s. The jetting is spot on the slp specs right now which, I figure, doesn't account for the porting.

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