Oil Consumption

[wilco]

I have a 1979 X with 45,000miles (62,000km) on it. I am a little concerned with the amount of oil the bike is burning. Can anyone advise me of what would be considered acceptable oil consumption. Currently I am getting about 600mi to the quart (900km per litre). The bike runs great otherwise. Thanks

[Ringnalda]

I think your rings may be gummed up, or your valve seals have hardened. Does it smoke under power or when you let off power?

[Terry]

Sounds exactly like my 79 and I have about the same mileage on it. I've heard that the OE rings on the early models had a tendency to hug the pistons more than scrape the cylinders. This, coupled with relatively high mileage on the internals of the head, valves, guides etc, makes for what I call, an oil (user). No smoke, even under hard acceleration thru all the gears and in my case at least, I run upwards of 5-6-7,000 revs routinely so I've come to accept it and won't do anything about it until I tear it down for a full rebuild, like when it does start smoking or running poorly, whenever that happens. On my 04 tour I took the 79 and used 4 qts of oil in 4,000 miles. Other than that, it ran great and I had no problems except for a flat rear tire in the middle of nowhere. If its not smoking, a few qts of oil is way cheaper than a rebuild.

[Mike Barone #123]

I have a 1979 X with 45,000miles (62,000km) on it. I am a little concerned with the amount of oil the bike is burning. Can anyone advise me of what would be considered acceptable oil consumption. Currently I am getting about 600mi to the quart (900km per litre). The bike runs great otherwise. Thanks

A lot of CBX owners report oil consumption like yours, so please do not rush into any motor work. If you ride your CBX 3k mile per year that is only 5 qts of oil/year.......you can figure out the $ math of this compared to $3,000 plus for a major motor overhaul that may or may not decrease oil consumption.

First fix I would try would be some Mobil 1 15-50...this will cost you $20+ or so with a filter. You do not need the Mobil 1 motorcycle oil...buy the car/regular Mobil 1 at half the price.

My X started smoking on hard acceleration and esp downshifts in the twisties around the same mileage as yours.........and Mobil 1 eliminated the smoking and oil consumption was decreased plus my bike shifted gears alot better.

Below is a video link to the cylinder removal of my CBX at the 75k-100k mileage mark using the car/regular Mobil 1 for 75% of these miles.

http://www.youtube.com/watch?v=O_u-D4vfUjw

I dont know the mileage exactly because the owner did not fix the broken speedo cable for 5 plus years.

Let us all know how it turns out


Mike

[Milt]

First fix I would try would be some Mobil 1 15-50...this will cost you $20+ or so with a filter. You do not need the Mobil 1 motorcycle oil...

Hi Mike,

I agree about not needing the special Mobil 1 motorcycle oil, because conventional Mobil 1 is all that I have ever used in my '79 since it came out. My experience with synthetic vs. regular oil is that the synthetic does an amazing job of keeping the inside of an engine clean, and can also clean one out that has been gummed up by conventional oils. Therein lies a caveat: As my dad & I found out years ago, it can be a delicate situation when beginning the use of synthetic in an engine with lots of sludge because of the potential for rapidly loading up the oil filter.

The relative slowness of the motorcycle industry in embracing synthetic oils has always mystified me. When driving in automotive track events I have seen oil temperatures of 275°F+ and never had to worry with synthetic oil. I'm certain that the oil in air-cooled engines can also reach these temperatures on hot days. Anyway, at 20k miles my '79 uses no oil that I can detect, although I don't ride it that hard.

Best regards,
Milt

[Mike Barone #123]

First fix I would try would be some Mobil 1 15-50...this will cost you $20+ or so with a filter. You do not need the Mobil 1 motorcycle oil...

Hi Mike,

I agree about not needing the special Mobil 1 motorcycle oil, because conventional Mobil 1 is all that I have ever used in my '79 since it came out. My experience with synthetic vs. regular oil is that the synthetic does an amazing job of keeping the inside of an engine clean, and can also clean one out that has been gummed up by conventional oils. Therein lies a caveat: As my dad & I found out years ago, it can be a delicate situation when beginning the use of synthetic in an engine with lots of sludge because of the potential for rapidly loading up the oil filter.

The relative slowness of the motorcycle industry in embracing synthetic oils has always mystified me. When driving in automotive track events I have seen oil temperatures of 275°F+ and never had to worry with synthetic oil. I'm certain that the oil in air-cooled engines can also reach these temperatures on hot days. Anyway, at 20k miles my '79 uses no oil that I can detect, although I don't ride it that hard.

Best regards,
Milt

Thanks for your reply and tip on changing oil filters often when switching high mileage engines over to Mobil 1.

Mike

[cbxtacy]

I stopped using Mobil 1 because it made such a mess on the bed sheets. Johnson & Johnson Baby Oil works much better. In my bikes though I use Mobil 1 still. And I go the extra mile ($$$) for their motorcycle specific oil. I really twist my motors and want every inch of protection. Mobil makes a 10/40 synthetic for water cooled multi's and a 20/50 synthetic for air cooled V-twins. I use the 20/50 even though Mobil recommends it for V-twins, the CBX is air cooled and has much bigger temperature fluctuations then a water cooled motor. The last time I was in San Diego, Andreas Georgeade came by and we went for a ride. He was riding my wire wheeled CBX (he likes it) and at one point, he came screaming by me. Afterwards he told me that it gets over 10,000rpm real quick. It does. That's one of the many reasons I like to keep the best in my bikes. There's nothing wrong with the automotive synthetic, I've used it for years with good results and have had engines with over 100,000 miles with no major problems. I've also broke 2 rods, 1 cam broke (the intake between 2 and 3 cyl), and I've spun a cam in the head. I have plenty of spare cases, cranks, rods, heads, and barrels to last me into my old age (if it ever gets here).

[Terry]

In re: " I've also broke 2 rods, 1 cam broke (the intake between 2 and 3 cyl), and I've spun a cam in the head."

Doesn't the X stop making power after 9,500 or so? That's when I shift. Are the extra revs just for more speed over distance? I've never looked down carefully enough after 130+ to see what my guages were doing! I've also not held that speed for very far on the X. I agree though that m/c specific synth is much better for any motor sharing a tranny and wet clutch, especially the X. I happen to prefer Amsoil.

[cbxtacy]

The rev's a stock X will pull pretty much depends on the timing and how the cam's are set up. Ideally the cams should be degree'd in, I probably hit on a good setup when I assembled the engine in the wire wheeled bike last time. I've had bikes that would go to 11,000 pretty quick with just individual filters and pipe. Whenever I've dyno'd one the CBX seemed to be a bit rich when it made the best power.

[Mike Barone #123]

CBX motors can be overreved without issue but not much to be gained either.

My gearing was way short for the track day at Beaver Run five years or so ago and half way down the straight I was over redline but kept on going to valve float..........(why......because I am a moron and thought by doing this I would not get run over by the real racers out there).

Only result was my ole X with 85k or so miles vaporized 2 plus quarts of Mobil 1 in 25 miles or so.

Those behind me stated it was not smoking and we could not find any oil leaks.....frankly I dont have a clue where the oil went.

From that session on I kept it to redline and only used one quart of oil the remaining 6 or 7 twenty minute sessions.

Gas mileage was under 10mpg though if I recall this correctly. Top speed on an 80 CBX with 79 cams is .00005 mph slower than an mid 1990s Ducati 900ss which my friend and I found out on a 5 mile straight at the Canadian rally long ago.........tad short of 130mph is my guess, buttttt that is with my bigggg buttttt on it.


Mike

[alimey4u2]

I have a 1979 X with 45,000miles (62,000km) on it. I am a little concerned with the amount of oil the bike is burning. Can anyone advise me of what would be considered acceptable oil consumption. Currently I am getting about 600mi to the quart (900km per litre). The bike runs great otherwise. Thanks

wilco, That is indeed excessive, mine doesn't use oil, period. Well... as we all know that is an incorrect statement, it uses negligable oil... I would "firstly" look at valve guide seals, 45,000 is not a lot of miles but "time" will age rubber....Pull the plugs & look for wet carbon buildup, especially during low rpm use ( IE. around town riding.)

[daves79x]

George:
I think the cams spin in the heads on all my CBXs. Sorry - couldn't resist!

Dave [/quote]