Hi all - I'm new at modding sleds, thus I have a lot of newbie questions.  I'm asphalt racing (1/4 mile) my 97 Ultra SPX.  It has a stock motor and clutch.  I put PSi pipes on it today, and it's not going any faster than it was with stock pipes - possibly even slower.  With the stock pipes it was revving to 8000 rpms pretty quick, dropping to 7800 and then quickly getting back up to 8000.

The PSI pipes are supposed to run at 8600rpms.  I made a few passes today - it revs to 7500 at a medium pace, and then very slowly climbs to 8100 by the stripe.  I stayed in it a little past the stripe and it climbed a little more before I shut it down.

>>Edit:  on the jackstand it pulls to 8800

Being new to mods, I'm not sure where to start.  Lighter weights in the primary?  If so, how radical of a change should I make?  Stock is a 10-54 (which I assume is 54 grams)

I also think I want to increase the engagement to get it out of the hole faster - it seems more sluggish with the pipes - I think this makes sense - I assume the pipes move the powerband up, so I'll want a higher engagement.  Is my thinking right?  It's engaging at 4800rpm right now.

I asked about my gearing last week, but a few guys told me they was just right.

Thoughts?  Suggestions?

Did you put the pipes on and not change anything else at all?  What is your jetting?  Where are your needles set (which clip), and what is your clutching besides the 10-54 weights?  No matter what, I would not go any lower on the clutch weights... If anything I would like to see you run more.  Its tough to say what those pipes are doing for your motor if you didnt change jetting or anything else in the carbs.  It might be wanting more fuel on top so that is why it is falling on its face up top (given you didnt change anything else).

I had a 1996 Ultra asphalt sled.  This was my set-up that I ran...  10-58 weights, Polaris Almond Black primary spring, 44-34 or something close helix, and EPI Black Secondary spring.  This was for 8100 SLP torque pipes (which I ran a little higher because it e/t'd better, somewhere around 8400)... little different than those PSI's...  you should still be close other than you can get your weights to probably 10-56's.  IMO the spike that you are seeing is an overshift because of your already high engagement.  Engagement that high is OK for asphalt, but if it will leave lower, then give it to it.  .020 belt to sheave clearance in the primary (i think that this is more common problem for too much width there than people tend to see... if it is too wide then it grabs hard to begin with, loses the belt somewhere in the middle of the shift because of load, then gets it back again one the load lessens with speed and RPM's come back.  With tight clearance it loads the clutch and stays with the belt all the way.)  Of course, if you are running a trail helix like a 48-36 or 50-36 then an overshift is almost expected with a helix like that.

If you need more fuel then give it, but I would try a Polaris Almond Black (or something close to 165-320) with 10-56's, an 42-34, 44-34 helix (something close to that), and a secondary spring close to 50-90.  This should be a pretty basic set-up to get you close to what you need.

After three years of running my Ultra it would run 10.70's... 15" wide track, and no lightweight parts, all stock except for pipes and some porting.  Just to give you an idea.