I have a HPD primary red/yellow spring with 58g weights now with a HPD violet secondary in the 2-2 on a 40-36 helix. I was wondering if I should go with a HPD violet primary spring for drag racing? I just ran my quad in some races this last weekend and my best et was 6.4 in 300'. I can't really do any engine mods or sprocket changes to stay in the class I am running. I was hoping to get a little faster acceleration by doing a little clutch work. I am running 8 paddle Haulers also. Please give me some advice. I read a bit when I searched "drag" but I see most of you are race ported or have race mods. You can see in my sig what mods I have. Bubba, feel free to chime in!!
I have a HPD trail pipe on this machine.

 

I used to run the exact same clutching as what you have in this was before my motor work so my bike was set up very close to yours. I would suggest that you put the s-55 stock weights back in and put the secondary in the 1-1 position, that is what i did and i was much faster with that setup. hope this helps [img]i/expressions/face-icon-small-happy.gif[/img]

 

[img]i/expressions/face-icon-small-smile.gif[/img]Thanks Scram, that is what I was hoping to hear. I wasn't sure on the 1-1 so I figured I'd post on here to get some opinions first.

 

I thin you will be pleasently suprised with the change it made a HUGE difference on mine.

 

Do you know how many RPM's you were turning before you engine mods? I just put a tach on it yesterday and it is only turning 6200. According to HPD's chart, with that pipe should be running at 6750 to 6850. I think I will dig into my jetting a little also.

 

no i dont have a tach.

 

Ok, thanks any way for the help. I will have to work on it a little tomorrow.

 

good luck

 

58 gram weights on a stock non-ported motor is a bit too much. I like the red/yellow spring for a high engagement and a better takeoff, but the 58's are probably pulling the motor down a little too much when shifting out. A 6.4 in 300ft sand is actually a good time for just a pipe. I would definitely put the stock weights back in it, then give the 1-1 setting a try. You can also try leaving the setting at 2-2 and putting the stock 40 helix back in it. That could gain you more acceleration about halftrack. I would only run that with the 55 weights, though. It will load the motor a little more from about 150-200 feet on out. If you put a spring with any more top pressure than the red/yellow you will be over the RPM range of the pipe. Tuning and running on the clock will be your only way of really knowing. A tenth or even 2 will be very difficult to tell. By the way, there are ways of getting around "stock motor" classes. You can shave your head .020, it looks completely stock, and it will make more power. A jug can be rough ported, then bead blasted to maintain the stock appearance even if it's torn down. It wouldnt be a full job, but can gain a few HP. Make sure the air filter is breathing good. If you still run the airbox, then put a clamp on filter for the drags if you can, or try to run it without the lid on. Check your jetting carefully. A little rich on the main jet will hurt the performance. Make sure the plug reads a light tan to paperbag color if you can get it there and make sure the pipe itself is warmed up good before making a run. The expansion chamber dont work well when there not fully warmed up. Also on the gearing, there were polaris' made with 13-34 gear ratio's instead of the 13-36. So you would actually be stock even with that gear change. And last but not least, the best way to go faster is to lose weight off of the bike. Lighter is always easier to get moving quicker. Hope this all helps,Bubba

 

bubba i ordered a hpd gold primary do you think this will put me over the rpm range of my pipe?