Cold beer works great with a big head of foam between your lips and the brew. The same can't be said for motor oil.

Fact is, any foam, also called or known as aeration, in your oil delivery system will severely compromise the oil's ability to lubricate properly by reducing the amount of surface tension between it and the parts it flows over. Foam also decreases oil's ability to conduct heat away from friction inducing parts, and -- because of air's high-compressibility -- foam can cause micro-interruptions in oil flow throughout the system.

End result? Increased engine wear, decreased performance, louder lifters and, if you're really unlucky, catastrophic engine failure someplace about as far from a friend with a truck as you can get without crossing an ocean or two.

As everyone knows, Indians of all vintages (as well as Harleys) have dry-sump lubrication systems.  Instead of storing oil in the engine via an integrated wet sump, dry-sump systems use a dual-purpose oil pump. The supply side of the pump sucks oil out of an external tank (in other words: the oil bag), and the scavenger side collects the oil that's run through the system and returns it to the bag. 

Used in air-cooled motorcycle engines, dry-sump lubrication has many advantages over wet sump. Routing the oil out of the engine for part of its flow increases oil cooling and improves engine heat dispersion. Pushing less oil through the system consumes less engine power and can increase performance. Last, but definitely not least -- slipping a dipstick or fairly long finger into an American bike's oil bag is a hell of a lot easier way to check the level than trying to make sense of the inscrutably oriental sight glass mounted at the bottom of the engine on many wet-sump Japanese bikes.

The stock Gilroy PowerPlus 100 oil pump is a Gerotor type (generated AKA geared rotor), which is good because gerotor pumps contain geared inner and outer rotors. In theory this enables designers to produce a balanced supply side/scavenger side system just by changing the number of teeth on one or both of a gerator's rotors. 

Unfortunately, either the theory or the engineers proved faulty in regard to the Gilroy PowerPlus. As in many lubrication systems, the scavenging side of the PowerPlus has more pumping capacity than the supply side. Since there isn't enough oil coming out of the engine to fill the return pipeline and keep air out of it, the trapped air gets dumped into the oil bag where it mixes with the oil, becomes aerated and gets pumped back into the system as foam.

The only practical cure for oil foaming in Gilroy PowerPlus motors is to have the return oil bypass the oil bag.  And, as with the similarly named heart surgery, there's a good way and a bad way to do a "bypass" on a PowerPlus.

One not-so-hotzo system is based on eliminating the scavenger side of the Gilroy factory system altogether in favor of pumping used oil directly back into the engine. This method can actually create more problems than it cures by pumping more oil into the dry sump system than it's intended to hold, thus increasing pressure and wear while reducing performance. Another potential problem with this system is hydraulic lock caused by dumping the returned oil, which is actually a non-compressible liquid, directly onto the lifters and rockers.

To solve the problem of oil foaming without any negative side effects, Crazy Horse's patent-pending True Internal Bypass (T.I.B.) oil pump for Gilroy PowerPlus motors incorporates a bypass circuit inside the pump housing itself. (That's why we call it a True Internal Bypass, duh.) The re-circulated old is routed back to the engine exactly as Indian's designers intended except for one thing: It no longer gets slammed into the oil bag and aerated.

The CH T.I.B. pump is simple, reliable, effective and, perhaps most important, it doesn't throw any baby parts out with the soapy bath water.  All the good elements of the original lubrication system remain intact; all you're "giving up" is the foam.

There are two ways to upgrade to a CH True Internal Bypass pump. You can send your old stock or modified rebuildable condition pump to us for conversion to T.I.B. configuration or you can purchase a brand new replacement pump outright. Please call us at 253-872-3602 (8-5 PST M-F) for details on either option.

How to Identify Your Oil Pump:

Note: If you intend to make any changes or repairs to your oiling system, you should be aware that the routing information in the official factory manual is incorrect. The proper way to route the oil lines and optimize oil flow and venting is depicted below.  Remember to plug the hose that’s no longer used, make sure there are no sharp bends or kinks anywhere, and check the oil line clearances to avoid chaffing which may lead to a leak.

Another Note: ALL our new and rebuilt engines recieve T.I.B. configured pumps as standard equipment.