Service
Service
WHERE DID THE POWER GO?
Q:I am having an issue with one of my bikes. Last year, I purchased 1990 Kawasaki ZX-11C from
a collector in Canada. The bike was flawless and ran well, but over the winter it obviously collected some dirt in the carburetors. We had also moved to the high desert, which is about 2,500 feet higher than my previous residence, so I thought that might be part of the problem as well. At the time of purchase, I also acquired a new era-correct Kerker 4-1 exhaust. With that, and a K&N air filter in hand, I headed to the local Dynojet dealer to have the carbs re needled and synced to the exhaust and air filter. Here's my issue: Based on an old Cycle World test, the 1990 ZX-iiC made about 125 hp new. As my bike has less than 6,ooo original miles and runs really well, I thought it would at least produce similar figures with all of the new stuff added on. But my bike produced only 83 hp and 66 pound-feet of torque. You'd think it has a 6~o engine in it, but it is the original iiC engine. Any suggestions on why the power is so low?
WOLFGANG KIRCHNER FORTIR WIN, CA
We the machine understand runs your well concern. through If B the rev range regardless of
throttle position, look beyond the carburetor setup. The carbs are certainly part of the recipe, but the power is off by a about a third, a huge amount. A compression test and a lealcdown test should be your first priority. If neither of those tests indicates a problem, check the cam timing. It’s possible one of the camshafts is a few teeth off on its chain wheel.
NEEDED: NEW VALVES, REMACHINED SEATS
I have a 2006 Honda CRF250R that cannot be kickstarted. I * can only push-start it. I checked
the plug, timing, and valve clearance. Everything was fine, but the clearance was out of spec. Here are the clearances I measured: left exhaust valve: 0.008 inch; right exhaust valve: 0.008 inch; left intake valve: 0.005 inch; right intake valve: I couldn’t get the thinnest gauge in there, so I assume there’s no gap. I could replace the shims of the other valves but am wondering what I
should do about the right intake valve with no gap. I am guessing I will need the seat cut and/or a new valve?
TYLER SHERMAN
SUFFOLK, VA
wearing Your right into intake the seat, valve thus is B taking up the clearance.
The rocker arm is now holding this valve open, which allows the fuel-air mixture to escape from the combustion chamber, thus creating the hardstart issue. Adjusting this valve by changing the shim will certainly get your clearance back, but you will find that the right valve (and eventually the left) will continue to wear into the seat at a rapid rate. The only cure for this: new valves combined with re-machined seats. The valves on that particular Honda are titanium, which have a tendency to wear through their hard coating and start dishing into the valve seat. With proper care and maintenance, these titanium valves can last quite a while but nowhere near as long as some of the stainless steel options available via the aftermarket.
YAMALUBE, OR JUST ANY LUBE?
My 2005 Yamaha FJR1300ABS owner's manual shows I need * 20W-40 Yamalube oil. However,
my local mechanic doesn’t stock that and wants to use iow-40 instead. He says this will not be an issue in our mild California climate. I have always lived by the owner’s manual. However, could I use this alternative? I checked the Castrol website, which recommended iow-40 specifically for my motorcycle. Should I rest at ease or stand up for the owner’s manual?
DAVID M CCU E VIA CYCLEWORLD.COM
Absolutely manual. Because go by the the owner’s FJR owner’s manual doesn’t list different
oil viscosities for different ambient temperatures, don’t stray far from 20w40. As far as using branded product from a manufacturer, it certainly isn’t necessary as long as the oil you choose is designed for motorcycle use. Motorcycle oils do not contain the friction modifiers found in automotive oil, which can cause slippage issues with a bike’s clutch.
