U.S. Chrome Cylinder Repair
U.S. CHROME CYLINDER REPAIR Remedy for battered bores
CW EVALUATION
WHEN DAMAGED OR WORN-OUT, NIKASILplated cylinders function best as avant garde paperweights, right? After all, the Nikasil process used to line the cylinder bores on most modern dirtbike engines eliminates replaceable liners.
There is, however, one aftermarket company that provides a solution. U.S. Chrome (650 Oak Park Ave., Fond du Lac, WI 54936; 414/9225066) offers an affordable replating process, called NiCom, that reconditions damaged cylinders and promises good-as-new condition.
NiCom is U.S. Chrome’s trade name for nickel silicone carbide composite coating, which is essentially the same process as Nikasil. The benefits of either coating include increased heat transfer, reduced friction, tighter tolerances, less wear and lower weight than a steel sleeve. As a result, the engine runs cooler, lasts longer and performs better.
To evaluate U.S. Chrome’s repair process, we sent the company the cylinder from a 1991 KTM 300 D/XC that had grenaded in a local desert race. Too-lean jetting and a long straightaway conspired to fracture the bridge between the exhaust and subexhaust ports, scar the cylinder wall and leave piston fragments throughout the engine.
After chemically stripping what was left of the original plating, U.S. Chrome’s technicians examined the barrel for additional damage. Finding none, they welded-up the cracked bridge, chamfered the ports and relieved the bridges. The cylinder then was electrically plated with NiCom, and the renewed surface honed to the correct bore size and finish.
Aside from some minor flashing deposits in the powervalve holes, the cylinder looked brand new. Replacement Wiseco Pro-Lite piston ($98) in
place, cylinder-wall clearance was .003 inch, just like stock. Moreover, performance was comparable to new. U.S. Chrome attributes this to its double-diamond honing process, which duplicates the factory finish.
Most important, though, is the cost savings. A simple replate without any repairs costs $150. If damage to the cylinder isn’t catastrophic, the total charge, including all repairs to the cylinder, won’t exceed $200. Cheap, compared to the cost of a new barrel-which in the case of our KTM was $514. Just as impressive is the lightning-fast turnaround; our cylinder was in-hand exactly one week after we had shipped it halfway across the country.
Suffice to say, U.S. Chrome has its act together when it comes to breathing new life into damaged Nikasilcoated cylinders. Which don’t make very good paperweights, anyway.
