super1c
Super Moderator
Thanks for the advice, i have no idea if the head was machined or not i will have to call. I do know they are stock heads. You guys got me worried now. I might just take it back to stock. I really dont need all that power it was just to good a deal to turn down. The sled is like brand new. He said he never had any overheating issues or problems ( I know you have to take that at face value ). I'm just a trail rider/ditch banger for the most part. With my type of riding would it matter either way? Looking for any thoughts or ideas on this.
Just throw a compression tester on each hole and see what it reads. That will give you an idea if the head was rechambered or not. Does it have the rear heat exchanger? I'm too lazy this time of night to read the whole thread. Don't be afraid of a few mods. Set up properly it will run just fine and the extra 30 horse or so is way fun.
Mac
Member
I agree don't go back to stock. The 118-120 HP was not enough. Back in 2002, 2003 many sleds were blowing engines because the pipe manufactures were not recommending reduced compression. As time went on and everyone figured out how to fix this problem you now benefit from that experience. The engine will run great with 30 extra HP as long as its setup correct. Pulling the head if required is an easy project and be sure your jetting is correct and you are good to go. Are you a mechanical kind of guy that can pull the carbs and check the jetting? We have seen several instances of guys that didnt change all three circuits required when installing pipes. It would be a good idea for you to see inside those carbs and confirm the jetting and clean for next season.
super1c
Super Moderator
Well you guys talked me into keeping the pipes. I'll just start with pulling the carbs and checking my jetting. I've already been looking for heads online. Is one better than the other, and the whole different cc thing is way beyond me but i'm wanting to learn. I have to finnish up the 96 xt first to make room in the back garage . As soon as i know what size jets im running ill post as i have know idea what one means from the other. Thanks again.
super1c
Super Moderator
It looks like the carbs on the 04 are the same as 02, is this right? Just wanted to know if i could go off my 02 viper manual to tear out the 04 carbs to check that jetting. I'm also guessing they have numbers on the jets? Do i need to check both the main and pilot? Sorry about all the questions guys but i'm just trying to get a handle on all this. Some day i'll be the one answering questions but not yet!!!!!!!!!!
The carbs are going to be basically the same. To my knowledge they are identical, but I'm not familiar with anything viper. Redhead and srx motors have been my playground. They are all flatslide mikunis.
Jets have numbers stamped on them. They can be hard to read sometimes, which is why I try to have my 9 year old in the garage with me when I'm doing carb work. She can read them no problem.
You want to verify the mains, pilots, and the needle setting. Fuel screw too, but every sled likes those a little different to be perfect.
Jets have numbers stamped on them. They can be hard to read sometimes, which is why I try to have my 9 year old in the garage with me when I'm doing carb work. She can read them no problem.
You want to verify the mains, pilots, and the needle setting. Fuel screw too, but every sled likes those a little different to be perfect.
Mac
Member
Check the mains and pilots and record your findings. These are found under the float bowl cover. Also check the needle setting found under the top cover. The needle has a 5 position clip groove. Record what position the clip is in. Also look for the shim washers found either under or over the clip. They will be a white color. Let us know what you find? ---Mac---
super1c
Super Moderator
Here's what i got so far. The main jets clutch side carb one has 160, very hard to read them. carb 2 same 160, carb 3 exhaust side 162.5. Piolt jet clutch side carb one 45, carb 2 47.5, carb 3 exhaust side 50. I havent taken throttle valve out yet to check clip position.
Last edited:
super1c said:
Just FYI - Not sure that its an industry standard, but when talking about cylinders and snowmobiles I reference them as:
Driver's/left/clutch side = PTO (power take off)
Center = CENTER (obvious)
Pass./right/exhaust side = MAG (magneto)
Yamaha numbers them 1,2,3 and I can even remember in which direction. I stamp or mark everything (carbs, pipes, etc...) with a P, C, or M before and when disassembling to keep things organized.
Nice find.