I bought both a RCR Stage 1 Kit and a pipe & clutch kit from HPD for my 2000 Scrambler 400 2X4. I did not have a GPS or Radar gun available to quantify my feelings, all I can offer is what the seat of my pants tells me.
If there is enough interest in the forum, I may be persuaded to do a little more scientific testing, ie. GPS speed results.
The comparison results are as follows:
The RCR Stage 1 Kit is very complete, comes with a pipe & silencer, plain color code primary clutch spring, air box modification kit, UNI foam air filter element,two richer main jets for the carburetor, a shifter linkage extension, a few RCR decals and well written, easy to follow instructions.
I modified the airbox with an additional air inlet venturi, and cutting out most of the front wall, however, I installed a K & N air filter element for the testing and the UNI was never used. I installed the Pipe & Silencer, the # 270 main jet, the clutch spring, and the shifter linkage extension. The exhaust note was very loud, with a "tinny" sound from the pipe. The clutch spring raised the initial engagement RPM, which made the quad even louder, moving it around in the driveway. The shifter linkage extension made the throw between gear positions shorter and required slightly more effort. The pipe is routed behind the frame, and the the shift linkage must be moved, as well as a coolant hose and a coolant hose clamp to prevent interferance. The pipe is formed with some indentations to clear some obstructions in the pipes path to the rear. The heat shield requires trimming at the rear of the shield.
There was a very noticable difference in the power of the quad, and Ricks claim of 8 to 10 HP improvement is very realistic. Unfourtunately, the pipe was extremely loud, rattled on the recoil starter housing, the welds on the pipe were somewhat lumpy and unsightly, did not have a USFS spark arrestor ( available for an additional cost ) and the stock muffler / spark arrestor was not easily adaptable ( it also did not quiet the pipe down appreciably ). The pipe is more at home on a race track than on a trail / sport quad.
I then reinstalled the stock pipe with the RCR silencer, and was pleasantly surprised with the performance and reasonable exhaust tone with no "tinniness", I also installed a # 250 main jet to compensate for the reduced air flow through the engine. I would estimate the silencer and rejetting to be worth 2 to 3 HP over dead stock.
I bought a HPD Trail Pipe only ( no silencer ), along with a standard clutch kit.
I then installed the HPD trail pipe which did not require any rerouting, rearranging or extension of components, as it followed the stock pipe routing. The pipe came with very good instructions and all associated hardware. The pipe uses a different exhaust outlet with two rings similar to piston rings, and in my case the mouting holes needed some slight elongating with a rat tail file to fit over the studs properly. I used Permatex Ultra Copper on the gaskets and the rings to keep from spitting oil on th frame. The heat shield required additional trimming along the inboard top edge.
I installed the clutch kit, the same plain color code primary spring as in the RCR kit, an additional set of centrifugal weights and a lavender secondary spring. The primary spring is easily installed after removing the clutch cover. The secondary clutch was removed, disassembled, the new spring installed, reassembled and installed on the quad. A significant note here: the snap ring that holds the helix in is a bear to remove without a large pair of snap ring pliers. I used a section of all thread with nuts and large washers along with the clamping portion of my Black & Decker Workmate workbench to compress and hold the clutch together while the snap ring was installed.
I used both the stock muffler / spark arrestor and the RCR silencer on the HPD pipe. The pipe is still somewhat "tinny", although not to the extent that the RCR pipe was and did not rattle in the slightest. There is a small rubber bumper and a spring to hold the pipe bumper against the frame.
The HPD Pipe / RCR Silencer combination was equal in performance to the all RCR setup. I rode this weekend with the HPD Pipe / Stock Muffler combo, and the quad was very quick and fast, had plenty of power throughout the RPM range and wheelied easily. The HPD Pipe appeared to have better welds, and was built with more attention to detail.
I would estimate that there is very little performance differerce between the RCR and HPD pipes. The HPD pipe is more at home on a trail / sport quad and could be used on a race track as well.
It looks like the RCR airbox mods are staying, along with the HPD pipe, however, I'm probably going to wrap the pipe with header wrapping tape to quiet the "tinniness" down a little more, and an HPD spark arrestor. I can see that some additional fine tuning with the carb and clutch will be required before I'm satisfied. I hope this helps, and I'm very willing to answer any of your questions and I'll keep everyone updated as the fine tuning gets to a razors edge.

 

Now THAT was some excellent info! Thank you Capt. Nemo and keep us updated.

 

CaptNemo,

I should have been paying more attention to your posts. I did the same thing last summer with similar results. The only reason that I kept the RCR pipe on mine was because of the trick HPC coating on the RCR pipe. This coating helped deaden the tinny sound somewhat, helped keep the pipe cool to the touch and just plain looked better than the HPD.

You're right, the HPD and RCR trail pipes are almost identical in performance. So much so, that if the pipes had the same volume level, I couldn't tell them apart. Just my two cents worth.

 

Sorry for the long post, but it's a lot of information.....

 

I took the quad to the hunting camp yesterday and what a great machine !!! Almost too fast for the conditions. I never got to really open it up and make a top speed run. They had done some logging and really tore the roads up.

 

I just changed out the pilot jet from a 35 to a 30 to clean up a burble and stuttering that I was having at less than 1/2 throttle. It really made a difference in the way that it runs. This thing will pick the front wheels up with less than 1/2 throttle now.

 

There's been a lot of questions about the HPD and RCR Parts this week, so I dug this up and re-posted it.

 

Thanks for all your detailed info. I have been mainly watching this site for all of its excellent topics & posted only a few items. I think I am going to get the same setup as you; HPD pipe and just the springs. Also, my '99 Sport still has stock jetting (230), and spoke to the dealer who said a 210 with 2.5 turns out on the airscrew will be ideal for 3000-6000 feet. Between HPD Pipe & springs, rejetting, and a UNI, the thing should show enormous improvements. Is there a recommend service manual out there, such as Clymer, that shows how to do this stuff? I am not sure what the easiest way is to get to the carb, whether to take the airbox out and/or take the plastic off. It seems awfully buried in there. Even the clamp that holds the airbox to the carb is impossible to get to unless you've got a foot long little screwdriver! Thanks everyone, again, for all the information provided by this Forum !!

 

CaptNemo, I just thought of something...Going to a 210 main from a 230 due to altitude probably won't work with an HPD pipe. You mentioned you installed a 250. What altitude to you ride? Leaving the stock 230 in at 3000-6000 feet might just work...

 

I put the RcR Stage 1 kit on my Sport. Amazing difference. I do like the look of the HPD nickel plated pipe, plus the fact that they have forestry approved silencers. I started with the .270 jet RcR included, but it ran rich, so I switched to the .260 I have no idea what my elevation is. I did notice that the scenery goes by a lot faster.