Cobra XR-1010 User Manual download pdf (Page 11)

XR250L Project

September ‘94

Page 11

Spark Plug and Resistor

Use an NGK DPR9Z spark plug, the same as the XR plug, if you do any of the

intake, carb, or exhaust system mods. Remove the resistor in the spark plug

cap and replace it with a piece of stainless steel. I cut the head off of a #10-24

stainless steel bolt and cut the bolt to the right length.

As a side note, the September ‘83 issue of Cycle World had an article that

advised using a brass or copper rod as a replacement for the resistor. I did just

that in my ‘86 XR250R. Just out of curiosity, I checked the brass rod in my XR

to see what it looked like after five years of use. It was black and had a very

high surface resistance. An engineer buddy told me that brass and copper

oxidize at high temperatures. The new advice from my engineer buddy is to

use stainless steel.

Protection

I don’t plan to ride in the rocks very much with my XR-L (I’ll use my XR for

that). I mounted a blue plastic Maier skid plate over the stock aluminum

brush guard. Gordo plans to ride everything with his XR-L, so he’s holding out

for an MS red anodized aluminum skid plate. It completely replaces the

aluminum brush guard and is the hot setup for rough riding.

Maier blue plastic skid plate .................................... CHAP 63005

MS red anodized aluminum skid plate .....................MS 268-405

Big Red - the Ultimate

In early ‘92, Gordo, of the NASA budget, had Powroll do a 330 cc bore and

stroke job on the XR-L for about $500. After a dyno run, he put in a main jet

three sizes larger but otherwise made no other changes. Gordo says the bike

isn’t appreciably faster. However, on steep, gnarly hills, it never runs out of

bottom end, and pulls and pulls.

330 bore and stroke................................................. Pow

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Cobra XR-1010 User Manual Page 11