HPI Racing - RS4 Sport 2 Building Tips

This page has the newest tips listed first, with the date noted next to it.

Many of the tips in the future will have thumbnail photos of what to do, where to put a part, etc. If you click on one of these thumbnails, you will download a larger (5 to 6 inches across, 40K to 80K) photo of the process involved with the tip.

Some racers have told us that they have stripped out the screw hole that is used for the upper arm on the rear hub carriers. If this happens to you, use a long machine screw with a locknut to hold it in. If you have spare HPI screws in your toolbox, use the #A569 15mm self-tapping screw. This screw goes all the way through the hub carrier so the arm won't work its way loose.

When assembling the self-bleeding shocks, fill the shock with oil, then put the bladder concave side down into the shock (dome-side down, as in the illustration in the manual). Put the upper pivot into the aluminum shock cap, and gently screw on the cap. Have a towel handy, because oil will come out of the small bleed hole in the shock cap. When you have the cap screwed all the way on, the shock is complete and bled correctly.

If the belt appears loose, remember that there is supposed to be a certain amount of looseness. If it's too tight, friction will rob you of power. However, if it is too loose you can either purchase the belt tensioner or loosen the four screws that hold down the front end of the upper deck and flex the chassis a bit to tighten the belt, then tighten the screws down again.

Use a small drill bit or sharp hobby knife to put two small air holes in each wheel, opposite each other. This lets air inside the tires in case the tire is glued all the way around the tire making it almost airtight. If a tire that is almost airtight is compressed, the tire may not fill back up with air and expand, giving you a temporary flat spot on the tire. A couple of 1/16" holes will prevent that problem.

Use rubbing alcohol to clean the rims where you will be gluing the tire to them. Doing this will ensure a good bond so that your tires do not come off in a race.

HPI racers have found that Pacer Zap CA (CyanoAcrylate, or Contact Adhesive) works best to bond the rubber of the tire and the nylon of the wheel. It is super thin, and it runs very well between the tire and rim. It may run too well, so don't use too much, and have some debonder (super glue solvent) available in case it gets on your fingers.

For Your Information: The shock clips that are included in all HPI shock sets are 1mm, 2mm, 4mm and 7mm thick. This will allow you to know what the measurement is, instead of thinking, "the third thickest spacer".