It's time to tear into my Sport and add a Wiseco piston. While it is apart, I thought about having the porting and head mods done. I already have the HPD trail pipe and clutch. Can anyone give me some feedback on the expected power gains after adding the porting, head mods, and an RCR air box mod? I'm also considering boring the stock carb. Anybody done this?

 

well to start I didnt notice a dif with carb bored. get a tmx 38 or a pwk39 and feel the power.
the results of porting = arms ripping from shoulders at 5500 to 7200 rpm. I had rcr do everything an I would do it all over again
I have mine trail ported , head milled for race gas, high rev pipe, v force reeds,flywheel shaved 13 oz., 38 tmx, aaen roller sec, and air box mod. Its a great feeling to never see the back of a banshee unless he loads on trailer befor me. havent had a problem yet with 20 tanks of gas through it
latter
bdscram1

 

I just had the porting and head shave and on the break in, (40:1 premix and oil inj.)she's running FAT and it feels as strong as before at only a 1/4 throttle.

Before the porting, I had the RCR stage one kit, and delta 2 reed cage......now I have the porting, head shave, jet-hot coated pipe and a
"QuadBuster air box mod"......I'm still breaking it in and she rips. Havent' even given her 1/2 throttle yet.

My suggestion is, If you already have the HPD pipe, then have HPD do the rest of the mods. If you have the carb bored instead of going to a larger one, you'll probably have to go w/ rick ritter (i dont believe that hpd does this) The carb boring is more "trail oriented". If you decide to go w/ a bigger carb. the 39 pwk from hpd is said to be an all around better carb. Anything larger than a 39 is no good (waste of $$).

Good luck,

I had a blast rebuilding mine!!!

EC

 

Is there a big difference between just boring the stock carb and the 39mm one? Do they flow pretty much the same?

This whole porting thing. Is the difference like comparing a stock machine to a piped one? More noticable or less?

Does trail porting help low end also?
What exactly does a billet head do?

Thanks.

 

No the 39 will flow more, but anything larger on the 400 is useless (ask rick ritter)

Billet heads/domes flow more coolant and raise the compression giving you more torque,top end, and a cooler engine "according" to which head/dome setup you go w/.

The "trail porting" by HPD is said to give you 8 hp thoughout the entire RPM range! YOu'll feel this more than a pipe. When the man above made a comment about ripping your shoulders out, he was not exaggeratin'.

Since I am currently in college and dont have all the funds for this sport that I would like, I had the .20 shaved from my head ($60) and I'll be getting the carb bored to 35.5mm by RCR ($60) in a couple of weeks. Seeming that I am still on the breakin w/ my new rebuild, I cant give you the full results of trail porting. All I can tell you is that right now I am running double the oil and she is much stouter at less than 1/2 throttle. I havent had her about 1/2 yet. Still got to break her in and then tune her in. I am trying to build a compatable "trail Monster" (I live in NC, there are no dunes here, just trails) If I decide to drag or something, I will do the bigger carb and I still may yet get a billet head (12:1 will still let you run 93oct. anything above is race gas) but until I am out of school, after the carb bore, I am focusing on #1 Riding, #2 handling.........If you have any questions, email me. I will not give you any information that I do not have first hand experience w/. If I cant give you the info. you need, I know people that will.


http://pub8.bravenet.com/forum/show....rnum=612682403

Go here and ask questions!!!! You'll notice that I have....lol. These guys just helped my do my first build! It was a blast.

EC

 

I'm still running the stock carb, but had a problem with the stock piston. While it was apart I had Rick Ritter port the cylinder and modify the head for 92 Octane pump gas. I specified keeping as much bottom end as possible, and am very pleased witth the results. I haven't finished breaking it in, so the carb is very rich and has a lot of lube in the pre-mix. I had Rick do the porting work because I was more confident in his abilities. A larger carb may be part of next years modifications. The quad's in the garage since it's hunting season down here, and don't want to have two stroke smell all over me. After the season's over, I'll turn up the wick on it and see what it's really capable of...

 

Is the Billet Head (12:1) really worth the money for the improvements it gives? I have a chance to get one from Hot seat at a good price...

What about the lightened flywheel? Is that worth the money spent on it?

Thanks again!

 

The last time I remeber that HPD dose bore out the 34mm carb to 35.5mm my friend has all HPD mods on 2 ATV's one is pretty much the race mods now an the other is the trail port an head with the 35.5mm carb. His other motor thr race mode is running the HPD carb 39PWK. It is in a 98 scrambler 4X4 an it flys.

 

a bored stock carb to a 38 tmx (which is what I have ) is like apple and oranges. with the bored carb I didnt notice that much pull when you started coming on the pipe. now with the 38 tmx it is a rocket and it never stops pulling. when I goto badlands and hit the hills I let off the throttle half way up and I have the momentum to carry me the rest of the way up. Im 280 lbs so I need all the momentum I can get.
also Im going to glamis this winter and had a couple questions so if any buddy lives near or has been there in the past can you please e-mail me to answer some ?s. lipp71@aol.com


thanks
bdscram1
thanks

 

I personally believe that an aftermarket head is useless, unless you're going to be running 180+ lbs of compression. Ritter can work wonders with a factory head and some mild porting.

Billet heads are nice, I use one with the girdle kit, but they are expensive! I think you'll be fine with a milled OEM head.

I also strongly recommend an aftermarket carb with the porting as well. I've used both the TMX and PWK, and think the PWK is the better choice of the two.