[Retro48]

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Hi All, I was reading all the threads the other day and one had a response that lead to cyber-cycle.com. I clicked on it and began to read their FAQ's. The link below is their detailed explanation of the Air Cut-off valve. If you own a 75-87 4 banger and most of us do. you might find this interesting reading.

According to Saber Cycle (see attached detailed explanation) all 1975-to 1987Goldwings should be getting 50-58 MPG. The explanation below is a detailed account of what the Air Cut-off Valve does and what happens when it begins to fail. My 1987 1200I runs very well, idles smoothly, starts every time and cruises at 80 all day with little effort. It does not get 50-58 MPG!. It does produce a puff of blueish smoke when it starts up. It also has 118,000 miles on it. I was very happy and content until I read this article about air cut-off valves.

I guess I am asking, is 50-58 MPG a reality? And is the puff of blueish smoke at start up a sign of bad things to come?

http://www.saber-cycle.com/cgi-bin/shop.pl/SID=1120592447.17291/page=AirCutoffValves.htm

 

[rcmatt007]

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I think I once got that many mpg on my '78.... it was all down hill ad I was going 35 in fifth gear!

neither of my my wings ever did that well, and I have owned them both since they were new. And you are right, almost all the 1000-1200's will give off some blusih smoke out the left side at start-up

 

[exavid]

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rcmatt007 wrote:

And you are right, almost all the 1000-1200's will give off some blusih smoke out the left side at start-up

Unless you park it on the centerstand. Seem those fellas who drive on the wrong side of the road ought to have the kick stand on the other side.

 

[77GL1]

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Best I've gotten was 44.5 @ 63mph. This was before my DynaS blew out....it's not as good with points. More like 39.5 @ 63.

 

[axelwik]

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Best I ever got was about 43 mpg... that was driving slow in the rain. I normally get between 35 and 40 depending on how I ride it and how much stuff I have along (camping gear, wife). Of course the riding here is nothing but mountains and curves.

This is all with a fresh air cut-off valve that I installed 8 months ago.

I've never heard of a GL1000 getting 50 to 58 MPG! The blue smoke is from a little oil in the cylinders (usually from being left on the sidestand). Don't know who wrote the article, but I think he's blowing some smoke of his own.


A 500cc bike in good tune and driven slow will get that kind of mileage, but not a GL1000 or bigger.

 

[Hobie1]

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I've gotten consistent 40-42 mpg from my wing.

50-60 mpg is b**sh** in my opinion. My bike runs like a clock, I'm not heavy on the throttle and do everything to be conservative in my riding style.

Anyone else get 50+ mpg (gallons not imperial gallons)

Hobie

 

[Ruaidh]

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The best I ever got on my '85 1200 Aspencade was 48.5 MPG but that was achieved by babying it; no rabbit starts/stops, very low RPMs when possible and no speeds over 70-75. Typically, I get around 45, sometimes a little better, depending on my riding. Most of my riding is commuter traffic on freeways; about 105 miles each workday. After that, it's all just relaxing riding and still not stressful.



My '83 1100 Interstate stayed right around 40 no matter what. And no smoke from either bike at start-up.



Ruaidh

 

[johnmac]

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I had a GL 1000 for 6 years. It had 29000 miles on it when I got it, and 67000 when I sold it. When I got it, it got in the low 40's. Each year it would get a little better milage. Just before I sold it I got 49-50 mpg on a 350 mile trip. BUT, the speed limit was 55 mph at that time.
My '85 1200 gets in the low 40's.

As far as the puff of smoke, I looked in the intakes when I had the carbs off, and by the angle of the intake valves, I don't any advantage to parking the bike on the center stand, unless it's the exaust valve stems letting the oil leak by. Then it would be the right side that would smoke. (Right?)
Mine may puff 2 or 3 times in a row on start-up, then not puff for a long time.
It doesn't cause the oil level to go down, so I don't worry about it.

 

[exavid]

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Hobie1 wrote:

I've gotten consistent 40-42 mpg from my wing.

50-60 mpg is b**sh** in my opinion. My bike runs like a clock, I'm not heavy on the throttle and do everything to be conservative in my riding style.

Anyone else get 50+ mpg (gallons not imperial gallons)

Hobie

I think if you were to travel on a level road at 35mph it's likely you could get mileages in the mid 50s. At least that's what my SEI computer said when rolling through town. That was the reading on the instantaneous mileage. But I agree that 50+ in normal riding is a bit likely to be, shall we say optimistic.

 

[Gearhead76]

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I'm still messing around with the carbs, I just got the carb kit and in prossess of rebuilding them, I also got a air cut off valve kit, but mine got 28 mpg, Not good but it's running to rich, and Idles poor, so I think the kit will help

Mine smokes on start up every now and then, Sometimes it smokes when it sits for awhile, other times it won't, Some times it really smokes after riding, shut it off to fill with gas, other times not a puff, But it's a bluish smoke, so it's oil, If it were coolant like they said it would be whitish and smell sweet.

I'll see what I get when I put the carbs back together tomorrow, enough for tonight

 

[Dadoo]

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That smoke is caused by the oil dripping into the cylinders when the bike is parked on an angle(sidestand). It doesn't always smoke because the pistons stop in different positions and more or less oil is allowed into the cylinders. If you parked it on the center stand it is much less likely to drip oil into the left cylinders, hence no smoke. This is a harmless quirk of some horizontally opposed engines.

 

[twisty]

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johnmac wrote:

As far as the puff of smoke, I looked in the intakes when I had the carbs off, and by the angle of the intake valves, I don't any advantage to parking the bike on the center stand, unless it's the exaust valve stems letting the oil leak by. Then it would be the right side that would smoke. (Right?)
Mine may puff 2 or 3 times in a row on start-up, then not puff for a long time.
It doesn't cause the oil level to go down, so I don't worry about it.

John, the oil is entering the cylinders past the low side piston rings. What happens is the bike is laid over on the side stand (in some cases while still running) & some oil puddles in the low side cylinders above the pistons. That oil tends to seep between the rings & cylinder walls as the bike cools. Now if BOTH valves are closed on a low side cylinder that makes the problem worse as a slight vacuum forms in that low side cylinder as the parts cool off & that helps draw the oil past the rings. That closed valve issue is why sometimes the blue smoke is worse than other times.

If the bike is idled for a few seconds while held straight up before shutting down,, then held up-right for a short while until most of the cylinder oil runs off it won't smoke nearly as bad at next start-up (if the side stand is used).

If it's any consolation: my friends BMW K-bike is much worse at smoking at start-up then my Wing & that BMW oil smells awful when burning.

Twisty

 

[dean_3326]

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On my 1200 I get 47mpg per us gallon with 2 riders,and 50mpg and above riding single. The speed limit on most of the roads is 60mph, I ride 60-65mph , I don't hammer down unless I am passing at highway speeds, I don't baby it either, I ride on roads that are hills and valleys for the most part. If anyone wants toprove me to be dishonest about the mileage, then put your money where your mouth is, come on down and ride with me we can have some funand you can check it for yourself. I could use some extra easy money for a few new goodies. I did nothing special to the carbs, I do not have a magic wand.I check the mileage every time I fill up, I always fill to 1 inch from the top of the neck.

 

[exavid]

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dean_3326 wrote:

On my 1200 I get 47mpg per us gallon with 2 riders,and 50mpg and above riding single.

I wouldn't call you a liar, if that's what you get, that's what you get. Wish I could. I probably lose a good bit because I like to feel the bike accelerate! Had a worse problem with that when I had the SEI because it would take off like a scalded cat.

 

[dean_3326]

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exavid wrote:

dean_3326 wrote:

On my 1200 I get 47mpg per us gallon with 2 riders,and 50mpg and above riding single.

I wouldn't call you a liar, if that's what you get, that's what you get. Wish I could. I probably lose a good bit because I like to feel the bike accelerate! Had a worse problem with that when I had the SEI because it would take off like a scalded cat.

I appreciate not being called a liar, I sure have nothing to gain by boasting a high mileage that I can not back up,,,I can not explain it, but I am very happy about it, I do accelerate slow anddrive smooth, I keep the rpms low, I shift around 3000-3500, I don't wind it out. I seldom go above 4500rpms.I like the feel of acceleration also , but I guess I did it so much when I used to race I got my fill for the most part, the bike is so strong it feels good at normal speeds to me. I was only getting 28-33mpg with the original carbs, I always believed a fuel injection system on anything did better on mileage and performance than carbs, I know an expert carb man could probably tweek them and compete with FI. but factory sure doesn't. The main jets in these carbs are a little smaller than the original too. The 84 carbs had either 105 or 108s, these 87 carbs have 103s. It is a difference but I doubt that is the only reason they are so economical.

 

[johnmac]

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Twisty, I have read several times about worn valve guides letting oil leak past.

You are right about oil running past the rings. I kinda forgot about that in my other post.

The biggest puff of smokeI got came after I shut the bike off and put it on the center stand for about an hour to check the bike over.

 

[Patch]

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After reading that link, it sounds to me like someone is trying awful hard to sell air cut-off valves.

Just my opinion.

 

[Dadoo]

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I believe that mileage in the 50 - 55 MPG range can had if one never goes over 55 MPH and accelerates very gently with short, low RPM shifts. I get about 40 at 70 - 75 and less if I go faster. I have a CI single carb on my bike and the MPG is about the same as the stock setup. I think the guy who wrote the article only travels downhill.

 

[axelwik]

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Dadoo wrote:

I think the guy who wrote the article only travels downhill.

Downhill both ways and with a tailwind... He's blowing smoke!

 

[avnsteve]

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he may be referring to some lab tests that were conducted indoors on a dyno, that could account for the "ideal" conditions. I've seen similar claims to my truck (powerstroke) and I've never come close to the factory's claims.