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92 k75rt fuel consumption woes ...

To be honest I haven't checked the valves- I'm scared I make things worse... Is this a reasonably failsafe task?
Cheers for sticking with me on this issue,
Ian.
 
Ian,

CHECKING the valves only involves removing the valve cover and being able to operate feeler gages. The only thing you can make worse doing this is: a leaky valve cover gasket because you didn't replace the 10 $.73 grommets that go on the valve cover bolts or stripped out threads on the head because you torqued the valve cover bolts more than 6 1/2 ft/lb (78 in/lb) Always use an INCH/lb torque wrench for these bolts as a FOOT/lb torque wrench is not accurate at such low torque ($20 from Harbor Freight $9.99 on sale). Engine must be cold (less than 90 degrees) not ridden for the previous several hours.

ADJUSTING the valves IF any are found to be out of tolerance requires $30 worth of special tools. The actual adjusting can be done at a later date once you know that there is one (or more that need adjusting). This allows you to order the tools and set aside time to do the job when convenient.

Follow your manuals instructions.

Valve checking/adjusting is something that should be done at least every 15,000 miles. The more miles that are on the bike, the higher the odds of the valves needing adjustment. If you don't stay on top of it, it can cause all kinds of problems.


PM me with your phone # if you want me to talk you through it and tell you my "easy" method.


:dance:dance:dance
 
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K100RS Poor MPG fixed

I did a trip with low mileage. When I got back my K bike rec'd afuel filter and then a fuel pressure regulator. Old one had not worked correctly, pressure too high.
Next I changed the temp sensor, went well with a sawed off (short) 19 mm open end wrench. These things might have helped but then found (myself) some tight valves, esp exhaust. Had them adjusted (by a dealer) and mileage went back up over 40. Your K75 should respond similarly.
 
Poor mileage isn't just related to the engine. Bad wheel bearings, rubbing brake pads or a failing bearing in the drive line can all reduce mileage. Might be worth looking.
 
One other thought to leave you with..

Winter mileage is typically poor. The L-Jetronic system uses an intake temperature sensor to richen the mixture when there is cold air. It actually tends to run a bit too rich IMHO even on a correctly adjusted/working bike. Since there is no feedback (02 sensor) in the system, it has no way to correct for the rich mixture. The use of a simple air-flow-meter instead of a MASS-air-flow (MAF) meter compounds the problem. The system doesn't know the density of the air, so the fuel map is purposely biased toward rich as the temperature drops to avoid running the engine lean.

The nice part of this is - how great the engine feels with cold dense air and a rich mixture. The bad part can be the fuel mileage suffers. The winter-mix gasolines also tend to do this to some extent.

Really a case of YMMV - but on a K75, if it's running good, and the temperatures are below about 45F, IMHO, 35-38MPG is about normal. At least it was on mine.
 
thanks

Forgive my delay in replying, I've been having computer issues as well :(
Thanks for the on-going advice- I'll let you know how the valve clearance check goes.
Cheers,
Ian
 
update..

checked the valve clearances today and they were okay, also balanced the throttle bodies and installed another set of spark plugs.
Still no change in MPG so I'm now looking at rear crown bearings- anyone have any experience of problems here, as there are two different bearings and I don't want to replace both if not needed.
The brake pads don't appear to be rubbing, wondering if an out of adjustment clutch might be a factor in this ongoing equation??
Thanks to all for your continuing input.
Cheers,
Ian.
 
k75 fuel consumption

Glad yours was so easy to fix. I've been battling poor mileage on mine since I got it. Normally around 35 mpg but on highways with moderate speed, I can get 39 or so.
Replaced temp sensor - to get the fan working, intake rubber, new injectors, lots of gas treatment, balanced TB, checked and adjusted valves, new plugs and went over every thread on several forums regarding bad mileage. Pretty sure the brakes are not dragging. It has always started and run like a sewing machine.

Let me know how yours turns out.

I had fuel consumption problems.Replaced most everything replaceable finall did compression check on advice of a auto mechanic.BIKE HAD POOR COMPRESSION REMIDY i REPLACED ENGINE FROM beemer bONE YARD.hARD FIX but problem solved.
Rod
62342
 
I had fuel consumption problems.Replaced most everything replaceable finall did compression check on advice of a auto mechanic.BIKE HAD POOR COMPRESSION REMIDY i REPLACED ENGINE FROM beemer bONE YARD.hARD FIX but problem solved.
Rod
62342

To be honest, a compression check scares me but I guess before I replace every part on this bike, I should do it. I find it pretty easy to work on and enjoy wrenching and learning. I ordered some plug wires and plan to do a spline lube in the next few weeks, to find a transmission drip. Did the FD drive splines and they were well lubed so I'm optimistic. Valves checked and shims replaced. New rubber on the TB's and new temp sensor. Bad part is poor mileage is the only bad thing about the bike, starts and runs great. After the splines, maybe replace front wheel bearings.

I don't enjoy spending money, I just feel certain things 25 years old need to be replaced.
 
If you can get a dealer to put it on the exhaust analyzer you might find the CO level is out of spec (rich) and they should be able to adjust the sensor in the air box accordingly. Rich will give better performance but will hurt mileage.
 
next step...

Okay, I finally had enough time to remove the front wheel and check the bearings- they turn smoothly with no noise or signs of hesitation. Didn't have a puller to remove them so left well alone and reassembled. Also have checked for brakes rubbing- discs not getting hot and pads showing little to no sign of wear.
My next thought is the airflow sensor- I can get a used one for a reasonable price, anyone have any thoughts on this? I haven't found anyone that is set up for exhaust gas analysis so haven't persued that avenue yet.
Thanks for your ongoing input,
Ian.:scratch
 
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