If it pops after letting off full throttle, it could just be a characteristic of the pipe. I know that sounds funny, but it can happen, look here on Mikuni's website, #4 and you will see what I mean. The best thing to do is call HPD ask them if it is normal or what they think, we could tell you do this and do that, but every machine is different and you can only know from your own testing. I would check with the maker of the pipe though and see if it is considered normal or not.

 

That makes sense about the exhaust. Thanks for that link. I guess I'll just leave it how it is. This is what HPD recommended with the pipe so I guess that is what they found runs best. If anything, I would rather be rich than lean. I wish I could do the spark plug test with killing the engine at different ranges, but it is just such a pain in the *** to get to the spark plug that it isnt really worth it. Thanks for the help

 

I agree with you and you are welcome for the link. If anything, just call HPD and ask. Can't hurt to do it anyway.

 

if your quad is popping when you let off the throttle then you may be sucking raw air from one of your exhaust gaskets mainly the donut up by the head check that out before you cuss someone out for not telling you about thier pipe chances are you WILL find your problem here

 

The exhaust came with a new donut gasket. I can live with the popping, its not a big deal. My only concern was that my jetting was off and I didnt want to damage the engine in the long run

 

I had the Hpd on my scrambler and really liked it. Dont fall in love with the shiny headpipe because mine slowly turned to a brownish color. Mine popped a little after a few seconds of letting the engine slow it down from a higher speed. If your exhaust gasket is leaking, you will notice a ton of popping after revving it up out of gear. Mine did this because i let it backfire in reverse by not using the override switch and it blew out the gasket. I dont know if the price has gone up but i only paid 240 for my full system from hpd probably 2 years ago.

 

My Scrambler also pops after I let off the throttle from a fast run. I was worried there for a moment, but thanks for all the posts, they're very informative. I have an 02 Scrambler 500 4x4 with the HSP 500 Speed Kit recently installed (header, muffler, hypershift clutch kit, K&N Filter, & Aaen clutch belt, total cost about $850.00 including labor ). Although I don't think I gained any noticeable top end speed, it does pull like a mad man so I'm happy with it. And I'm able to pop wheelies a lot easier. Any suggestions on any other mods that would help top end?.......nitro perhaps?

 

Tyler33,
I paid $305 for my complete system. Its the new Powermaxx system. I dont know what the difference is between the new and old one. I am glad to hear that I am not the only one with the popping. It must be the high performance exhaust. I overrode my override so I dont have to worry about the backfirring


2002Scrambler4x4,
I didnt notice any real gain in top end as well, but like you said, I got there a lot faster. I think that the only way to get more top end is to go into the engine. You could always get a 42mm carb, or have your bored and have a high flow intake from HPD installed (Which I am thinking about). If my engine ever goes and needs a rebuild, I am going to get the 628cc big bore kit from Four Stroke Tech. And if I win the lotto, I'll get a turbocharge from Aeorcharger. They are only 3 grand
[img]i/expressions/face-icon-small-wink.gif[/img]

 

Yea i looked it up and can see why they charge a little more for the new one. They didnt call the old version the ugly duckling for nothin. It looked like a car muffler but sounded good and worked well. I have a predator now because the scram just didnt take well to abuse. The motor has too much torque, i think, for the belt drive. I think i went through 2 clutch assemblys in 3 years. That was with beating the **** out of it, it would have probably been fine if i took it easy.

 

Yeah, but where's the fun in that?[img]i/expressions/face-icon-small-cool.gif[/img]