Also forgot to mention that the top end bog is gone now and that I now have a slight low end bog followed by a back fire. Not sure what that is, pulled my plugs and they are giving me a cardboard color. Heard that that's what I should see.

 

Check your needles. In the summer when I grass drag mine I put the clip of the needle on the very top which will make it leaner. So, in the winter time when you forget to put the clip for the needle back in the middle like I did everytime I hit the gas the sled would back fire and bog because it is too lean. As far as your low end bog, if you hit it from a dead stop does it bog and you get out a little ways and it takes off like a bastard? Have you done anything with your clutching when you switched pipes? For the longest time I couldn't figure out why my Ultra had a terrible low end bog and it was because the clutch weights I had were way too heavy.

 

I'm still runnin the stock clutch on my ultra. I picked up that parts sled with the slps. And I figured that the parts also was already set up for the slps. The only thing I haven't put on yet is the clutches. I've even notice that the clutch that came on the parts sled had a blue spring instead of red. I don't know much bout clutches, only that it sucks when they dynamite. I will also check out my needles and see where they are at.

 

If you can find a set of slp needles that would be ideal but they are hard to find. I run slp needles in the second clip position. If you can't find any slp needles try some from an spx ultra. 380-390-380 for mains. I run br10es plugs which help with detonation concerns.(learned that from a fella who raced/rode ultras) I believe 30 pilots(i have boysene reeds). As far as the pipes go what slp pipes do you have? the low or high rpm pipes? You need to find that out first before we get into clutching

 

If you can find a set of slp needles that would be ideal but they are hard to find. I run slp needles in the second clip position. If you can't find any slp needles try some from an spx ultra. 380-390-380 for mains. I run br10es plugs which help with detonation concerns.(learned that from a fella who raced/rode ultras) I believe 30 pilots(i have boysene reeds). As far as the pipes go what slp pipes do you have? the low or high rpm pipes? You need to find that out first before we get into clutching

98jultra has it down pretty good i got a xlt with ultra motor spx carbs 3.0 carbs 2nd clip on needle think im tunning real close on jets too but have Psion modblaster high rpm pipes

 

Yeah if you jet it like an ultra spx it will get you real close at least that's where I started with my ultra with slip pipes.... a lot of people that pipe these sleds change the needles but not the needle jets and burn the motor up in mid range so whenever you change something I would keep a close eye on your plug color just to be sure

 

Ok, I'm getting a light cardboard color on the plugs, and I will try putting 380 mains and a 30 or 40 pilot. But before I start that, is there anyway to identify what type of slp pipes I'm running? I've been fighting this thing for three years, and I wanna get it right this time, also I wanna make sure it won't blow up too easy. I have Three other ultra motors and each have scored cylinders. Don't want that to happen to this one. And now I'm just rambling on. Also is there a way to identify what type of needle I'm using? And what the spx needle size is.

 

I was told that you can tell the diff. In pipes by measuring the expansion chamber on the center pipe from weld to weld... I think the high rpm pipes are 8" and the low are 9".... the spx needle is #6ceya and the needle jet is #247q2 the numbers should be stamped on the side of the needle and the needle jet[thumb] oh and the spx slides for the carbs have a 3.0 stamped in the bottom vs. The 2.5 on the sp

 

Thanks a lot every one, now I got to check all my jetting, but I'm sure with this information I will be able to get it pretty Damn close. You all have provided me with what I needed. Thanks again.

 

Ok I did some research, my slides have 3.0 stamped on bottom, 380 mains, and 40 pilots. I'm hoping this brings me close.

My needle also has 6cey6 stamped on that and I'm on the fourth notch from the top of the needle closest to the throttle cable. And I am running the high rpm pipes.

 

Ok I did some research, my slides have 3.0 stamped on bottom, 380 mains, and 40 pilots. I'm hoping this brings me close.

My needle also has 6cey6 stamped on that and I'm on the fourth notch from the top of the needle closest to the throttle cable. And I am running the high rpm pipes.

 

Sounds like that will be pretty close did you check your needle jets? A lot of people change the needle but not the needle jet and it could burn up in mid range

 

I haven't checked them yet, they should be the 247 q2 right. And I just did a compression check and I'm gettin clutch side 126 pounds. Middle 124 pounds rewind side 105. And my plugs are runnin pretty lean. Plugs turning white. Do I have to richin the oil pump with the pipes. I also moved the clip on my needle to the number two position.

 

I haven't checked them yet, they should be the 247 q2 right. And I just did a compression check and I'm gettin clutch side 126 pounds. Middle 124 pounds rewind side 105. And my plugs are runnin pretty lean. Plugs turning white. Do I have to richin the oil pump with the pipes. I also moved the clip on my needle to the number two position.

compression should be within 5% of each other i think that motor will blow if tuned properly poss sucking air on mag crank seal

 

I tested it with a warm engine, plugs in the other cylinder and held the throttle wide open and pulled till the needle quit Movin. I also noticed I wad running the wrong 247 p-4, instead of 247 q-2 needle jet. I'm also runnin 380 mains and .040 pilots. And 6cey6 needle. Plugs still burning lean, so I've been moving the clip down on the needle, thinking that it will richin it. I'm in the third notch now, and noticed that the plugs are starting to richin alittle. Does that work. Doing it that way

 

Ur pilot jet is for idle. Ur needle and needle jet is for mid range and main jet is for like wide open and like I said if you have the wrong needle jet I could burn up in mid range.... might even be why ur plugs are reading lean but to answer your question yes moving the clip down raises your needle allowing more fuel in to rich in it up

 

I took it for a longer run last night and ch ecked the plugs again. And now I finally got the coffie brown. I was putsing around the yard and heard that it wasn't enough to tell plug color. I made sure I put the 2u47q2 needle jet and the 6cey6 needle in the carbs. With 380 mains and .040 pilots. I have a little low end bog and back fire, but that goes away after the sled fully warms up. But I feel pretty confident with the sled now and I appreciate all the help from everyone. Thanks again.

 

105 is low. Pull the pipe on that cylinder and check the cylinder and piston for scoring/cracks etc...Both my ultras are in the 130's across the board(tested with a newer snap-on gauge). The bog/backfire could be indicative of a bad piston.

 

I checked it and its not scored or cracked, I'm guessing that the rings might be worn or my tester is bad. I tried it again the other day and the tester didn't even work. So I think I'm gonna recheck with a better tester, and re ring it just to be on the safe side. Never put rings in it since I bought it three years ago, so maybe its time has come.

 

Before you do anything, get a guage that yo u know is working properly. Do a comp. test and tell us the numbers. We'll go from there.

 

Also, you should test compression with all plugs out and wide open throttle.