Service

SERVICE

ATF vs. oil

JOE MINTON

Can automatic transmission fluid be used as a substitute for motor oil in the gearboxes of older Japanese two-strokes? I’ve tried it in several of my old streetbikes and I like the clutch action—it’s much smoother. But I worry that the ATF might not provide adequate lubrication.

What do you think? As the owner of more than 40 old two-strokes, Fd be very interested in your opinion.

Gary R. Toomer

Imperial Beach, California

My personal experience with substituting ATF for motor oil in gearboxes is limited. I have used it in late-model Harley primaries with good results. 1 know of others who have used Type A automatic transmission fluid in gearboxes and swear by it, and Fm led to believe that Chrysler has used ATF in its manual transmissions since the early Sixties. The Type A fluid has slightly better lubricity than the Type F, and may provide a bit more protection. My experience with ATF, gained while conducting comparative tests with fork-oil candidates, led me to believe that the official General Motors ATF was the thickest.

But there are some cautions. In general, thin oils (ATF is about 7weight while hypoid gear oils are about 45-weight) will not offer as much extreme-pressure protection as thick oils, everything else being equal. A gear set that experiences pressures greater than the limits of the oil will wear rapidly.

I gather that lessening clutch drag is the main reason you are tempted to switch to ATF. Certainly, ATF will reduce drag, but may not provide sufficient protection for highly loaded, roughly cut gear teeth. I recommend that you consider using Redline Oil’s MTL (Manual Transmission Lubricant). This synthetic oil will lubricate at temperatures and pressures far beyond what ordinary hypoid gear oils can withstand, and it is much tougher than motor oil or ATF. MTL has a 100-degree Celsius viscosity of 10.2, which makes it only slightly thicker than ATF. Redline Oil’s toll-free number is 800/624-7958.

Pressurized

Help! I don’t trust idiot lights. Any good ideas on an oil-pressure gauge for my Honda CBR1000F? The actual installation isn’t a problem, but finding a high-quality gauge and a line with the proper pitch threads is.

Jim Barnett

Montgomery, Alabama

Your major problem will be vibration: Inline-Fours eat accessory gauges. The most precise and most durable gauges I have used are the 2-inch units made by VDO. However, even the VDO instruments will succumb to the ravages of, say,

Kawasaki Z-l or Suzuki GS-series engine vibration if they are mounted on the handlebar. If you can mount the gauge in your Honda’s fairing and within a soft rubber grommet, it will last.

VDO no longer makes motorcycle installation kits, but the instruments and fittings are still available. You can learn the whereabouts of your nearest dealer by contacting VDO Argo at 980 Brooke Rd., Winchester, VA, 22601; 703/662-1700.

Pipe down

My 1975 Kawasaki Z-l is equipped with an old R.C. Engineering exhaust system. It now needs a baffle, but I am having trouble finding one. Apparently, the company is out of business. Does someone fabricate baffles for this exhaust system?

Mike Murrell Boerne, Texas

Yours is not an uncommon problem. Baffes of many older aftermarket exhaust systems would rot, rust or shake apart far more often than the rest of the pipe. Most of these baffes are no longer available, but there is a solution.

Cone Engineering made most of the cones and baffes for those pipes. In fact, it still makes the majority of the cones and baffles sold today.

When I contacted the company, I was told it does not have any complete baffles to fit your pipe, and because Cone is a manufacturing company, it is not in a position to make just one of anything.

However, Cone has an extensive range of baffle ends, perforated tubing and other parts needed to make a replacement baffe for your R. C. pipe, and will supply you these parts so that you can do the assembly.

Cone Engineering can be reached at 213/429-5533 or FAX 213/420-2702.

Tough tune-up

I just had a tune-up done on my 1986 FJ600-valves adjusted, cam chain tightened and carburetors synchronized. I also had a compression check performed on all cylinders.

The readings ranged from 85 to 95 psi. My service manual says that the standard pressure (at sea level) should be 156 psi. The mechanic thinks my low readings are the result of high mileage. But the bike has covered only 30,700 miles. This doesn’t seem like a lot for a sevenyear-old motorcycle. Your diagnosis?

T.L. Prims

Lubbock, TX

ƒ hope you won’t be insulted if I ask you whether or not the throttle was held fully open-as is proper procedure-while you were turning the engine over during your compression test. If the pressures were recorded with an open throttle, then your engine is in immediate need of a topend overhaul.

Because you didn’t mention any sign of smoking, I assume that the low compression readings are due to valve leakage and not poor ring seal. If you continue to run the engine with this kind of compression, it is possible the head could be ruined. Leaking valves will eventually cause irreparable damage to the valve seats. □