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Does anyone have any pro's and con's about the MOSA's 5th gear OD (or any mod for that matter)? It's basically a gearing kit that changes 4th gear tothe normal driving gear and the 5th gear is used as an over-drive. Supposedly, one of the benefits is that it would take a 1500 from hitting reserve at ~140 miles to hitting reserve at 250 miles :shock: (all freeway miles in 5th gear).

I have been hearing good things about a '6th gear' modfor HD's, so I looked up tranny mods for the GW and found this modification.

What do you think? :?
 

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E. W. Mitchell wrote:
Does anyone have any pro's and con's about the MOSA's 5th gear OD (or any mod for that matter)? It's basically a gearing kit that changes 4th gear tothe normal driving gear and the 5th gear is used as an over-drive. Supposedly, one of the benefits is that it would take a 1500 from hitting reserve at ~140 miles to hitting reserve at 250 miles :shock: (all freeway miles in 5th gear).
What do you think? :?
Seems to me you'd have to drive a hell of a lot of miles to earn back the cost of the mod compared to the price of gas.
 

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E. W. Mitchell wrote:
Does anyone have any pro's and con's about the MOSA's 5th gear OD (or any mod for that matter)? It's basically a gearing kit that changes 4th gear tothe normal driving gear and the 5th gear is used as an over-drive. Supposedly, one of the benefits is that it would take a 1500 from hitting reserve at ~140 miles to hitting reserve at 250 miles :shock: (all freeway miles in 5th gear).

I have been hearing good things about a '6th gear' modfor HD's, so I looked up tranny mods for the GW and found this modification.

What do you think? :?
Mitch, while adding an overdrive gear would lower the engine RPM's at cruising speed & make the bike a little quieter I seriously doubt ANY gearing change would give you almost twice the miles per gallon. It still takes (X) amount of horsepower to push that big bike through the wind so just changing the overall gearing won't change that piece of physics. You might show a slight gain in MPG at light cruising speeds but no where near double.

On automobiles, adding an overdrive adds MPG to the EPA rating but not allthat much in real life MPG.



Twisty
 

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Is such a thing available for Goldwings? A 6th gear might be nice to have, never even heard of it before. Not surprised there's lots of gearbox mods for HDs, any mod has to be an improvement on their stock design. I've had three HD gearboxes blow up on me over the years!
 

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Thanks all. I thought it sounded too good to be true.
 

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GWEddie wrote:
Is such a thing available for Goldwings? A 6th gear might be nice to have, never even heard of it before. Not surprised there's lots of gearbox mods for HDs, any mod has to be an improvement on their stock design. I've had three HD gearboxes blow up on me over the years!
http://lamonster.com/od.htm

I've never heard of a 6th gear, the above modification increases the ratios of 4th and 5th. I kinda doubt that the mpg increases claimed are possible. Automotive ODs, at least the two I've had tend to uncouple the engine from the wheels when you let up on the throttle. I think a lot of any mileage increase with it is due to the lack of engine braking allowing you to retain a lot more kinetic energy. If you were to ride a bike, especially a fuel injected one like an SEI, at a steady 45mph in 4th and then in 5th on a level road I'll bet the fuel burn wouldn't be much different. You probably would see a little more difference with EFI because it's a lot more accurate in metering fuel than a carburetor.
 

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I've seen this overdrive before as well. I would be more than happy to install and give feedback if anyone is interested in sponsoring me :cheeky1::cheeky1::cheeky1:

I actually did the calculations based on 2.50 a gallon gas, and I think it would take about 30,000 miles to get back your money, if you could actually get the mpg they claimed. Next time I have a spare grand, maybe i'll get one.:shock:
 

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The 30,000 miles is the easy part. It's $1,000 dollars I'm having trouble with!!!
 

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BTW, Screamin' Eagle makesa 6th gear kit for HD's
 

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Like it was stated above, you can't count on better fuel mileage just because you lowered RPM. Moreover, if you get out of the range where the engine is most efficient, you may even burn more fuel.

Gasoline engines are variable combustion ratio devices, unlike diesels. The carb (or fuel injection) strives to maintain a stoichometric mixture of 14 or 15 lbs of air to one pound of fuel. When the manifold vacuum drops (engine under load), that baby is sucking in more air and fuel for each charge of the cylinders than when it's under less load - charge the cylinder with a partial vacuum and there's less air in it that charging it under zero vacuum, and less fuel too. If you increase the load at a given rpm, or even a lower rpm because of a change in gear ratios, more air (and fuel) is being consumed.

I don't know enough about where the sweet spot might be for a goldwing, and finding with proper gearing might net you a modest improvement in fuel mileage - for all I know, it may already be there. I'd guess that your local terrain would influence things as well, since load at a steady speed might be steady in the plains states, but vary widely in hilly country. Any additional throttle activity is going to burn extra fuel as a result of the enrichment necessary when openning the throttle.

What is certain is that RPM does not determine fuel mileage, and it will not double or even improve by a quarter just because you're running at 1,500 rpm instead of 3,000. Fighting wind resistance and hauling the cabbage around requires a certain measure of energy, and there's only so much in a gallon of petrol.

I'd ask for a test ride on one of the vendor's fleet . . .

Jack
 

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I'd be willing to sell a magnetic, fuel flow turbulator, with water injection if you need to double your gas mileage.

Does anyone remember the fad in the early 70s that had a bunch of people putting a water jug under the hood and running an aquarium tube through a needle valve into a vacuum port under the carb? It was ridiculous, the rate of water injection was less than the vapor you'd get on a rainy day!
 

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I'm not looking to change the world. Just thought it was interesting and wanted to know what you guys (and gals) thought.
 

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I've been interested in this mod too - my Wing is remarkably unstressed at 3500rpm will all 130lbs of me sitting on it... :p
 

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$950 seems to be expensive for some gears, more expensive even than Honda gears, but if it gives better performance it might be good for some people.
 

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Thanks for letting us know about this EW. I never knew about the gear set, so it's new news to me. :)
 

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Well I have spent more $$$ on lesser crap than that overdrive. I am going to explore other avenues to increase my mileage, before I do the overdrive.

Yesterday I put in a K&N air filter. I will run a tank to see if it makes a difference. After that I will install my Extractor manifold I just got off ebay.

When I got the bike I was getting about 30 MPG. I removed and cleaned the carbs, andfound one bad vacuum piston and replaced it. I also added the 4 degree trigger wheel (which I understand is only good for the 88 and 89 1500's). I also have the pilot screws set out to almost 4 turns (as opposed to the factory 3 1/8? ). Right now I get 33 to 34 MPG at mostly hwy speeds of about 75 mph.

I am also thinking about replacing my windscreen with a Tulsa. The one I have now (unknown name maybe a Markland) is pretty darn huge. Since it has some light scratches I figured it wouldn't hurt to replace it with a size closer to stock, and see if that helps. I was also wondering if the Tulsa 2 piece belly pan would help with mileage by smoothing out the air flow.

We all have questions, and I'm going to try to find answers.:action:
 

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John, the xtractor will make a difference. You should notice a lively and lighter throttle response and a slight difference (throatier) in the sound. I had one and while I can't say of it made the 1500 go any faster or consume less gas, it did feel a lot livlier.
 

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jprodko wrote:
Right now I get 33 to 34 MPG at mostly hwy speeds of about 75 mph.

We all have questions, and I'm going to try to find answers.:action:
I just got back from a 200 mile run on I-90 which is a 70mph freeway, most of the time I was running 70-75mph. This route goes over Snoqualmie pass so a good part of it is uphill. There were pretty strong Westerly winds coming home so I lost a part of the downhill advantage. The point of this is that I got 40.2mpg on my 1993 Aspy for the trip. Around town and on the road I pretty consistently get 39-40mpg. I don't see any reason your bike shouldn't. I do have a stock windshield which I leave at it's lowest position unless it's raining, but other than that the bike is stock. I weigh just a little less than 1/8 US ton on the hoof.

I don't know how you ride, I don't push it very hard, usually use 2500-3000rpm as shift points and rarely exceed 75mph usually slower since most of the speed limits around my place are 60mph (which means 65 cruise).
 

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exavid wrote:



I don't know how you ride, I don't push it very hard, usually use 2500-3000rpm as shift points and rarely exceed 75mph usually slower since most of the speed limits around my place are 60mph (which means 65 cruise).



I usually shift like that too, unless I am getting on the freeway (onramp). Mostly I commute to work on it 30 miles one way, no traffic, averaging 75 mph.

I do know I need more carb work. The one thing I notice is that when the bike is ridden and fully warmed up, if I let it sit for say 15 to 45 minutes and I go to restart it, I have to give it some throttle to get it started, and it runs kinda crappy (loaded up) for a minute or so until I rap the throttle a few time to get it cleaned out. I was thinking of settin the floats to 8mm. I think they are at 7.5 right now. Otherwise I don't know what causes this to happen.

Sorry if I'm hijacking this thread but it seems like info people would want with gas going up like it is :baffled:
 
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