Motorcycle mods?

[saunders1313]

Any one have any ideas what I can do about mods for my motorcycle?

[dcb]

Accelerate efficiently.
Use the clutch and kill switch and glide to all stops, leave engine off till time to move again.
Try and glide down the hills, and in slow parts of town.
Put a smaller rear sprocket on it.
Lower it.
Streamline it.
Put fuel consumption feedback instrumentation on it.

[beatr911]

+1 and
Carburate appropriately. Check your mixture with an O2 sensor and a volt meter or an air/fuel ratio gauge.

Using hypermiling techniques works but is wierd on a motorcycle until you get used to it. They are so powerful, going slow is so wierd on a mc that it just feels wrong. But it's right.

[extragoode]

Originally Posted by dcb

Accelerate efficiently.
Use the clutch and kill switch and glide to all stops, leave engine off till time to move again.
Try and glide down the hills, and in slow parts of town.
Put a smaller rear sprocket on it.
Lower it.
Streamline it.
Put fuel consumption feedback instrumentation on it.

This is all great for EFI bikes, but my '81 is carburated, so the fuel consumption feedback will be almost impossible, and I've heard that starting a carburated engine blows a ton more fuel through the engine than just letting it idle for 30-60 seconds. I kill mine, coast to the stop, and pop the clutch to restart the engine as part of my braking.

Also, I'm working on an LED headlight (should save 35w) and front turn signal mods (should save 56w) and have already switched the taillight to LED (saved 28w). Will change the rear turn signals at the same time to go with an electronic flasher, but they won't account for much because they're only on intermittenly. It's still only about 120w, but that's 10 amps! Using numbers from another thread, 1hp = ~720w, so I should be saving ~1/6 hp. My 400cc makes 35 hp at max, but probably more like 10-15 where I run it and let's assume it gets 50mpg (I've only ridden it 100mi so far, so haven't had to fill up yet). By my math this works out to about 1mpg improvement, but that seems low and I know I don't have concrete numbers by any means.

Sorry, don't mean to threadjack. It seemed appropriate, and then I just kept rambling.

[Vince-HX]

Ive been looking into adapting a industrial spag overunning clutch into the rear sprocket so it freewheels like a bicycle. Only downside is that you would lose all engine braking but pulse and gliding would be effortless and you wouldnt have to hold in the clutch the whole time.

[dcb]

I rely a lot on bump starts, especially in town, and I don't notice much difference between gliding with the clutch or digging down into neutral, except that my left forearm seems to be getting larger with the clutch method

P.S. I have carbs too and am trying to figure out the instrumentation part.

[beatr911]

Vince-HX, I've been wanting a freewheel for a long time. Please post your progress on this. This is part of how the Yoshimura modded XL 125 got like 185 mpg, (Craig Vetter site I think.)

This would be a real benefit for aero modded bikes that have the ability to coast well. Most bikes have such a high drag to weight ratio that they do not coast far.

[FastPlastic]

I started experimenting with engine off coasting/bump starting my bike. Anyone have tips on the best way to do this? Gear/Speed etc. I've used the N coasting for the past couple of tanks with good results (38MPG top) I figure by using engine off coasting I could easily hit 40MPG.

[truckncycle]

Freewheeling sounds like a really interesting idea. I tend to just put the clutch in but my commute isn't very long.

I have been considering a couple of aero mods. Some bikes have aerodynamic seat covers behind the driver when there is no passenger. I was thinking about creating a seat cover that is the shape of a large tapered mail box to smooth out the flow behind me (and give me extra storage). I have also considered an aerodynamic backpack to smooth out the flow. If I make one, it will be hard sided and will have some sort of slide on shoulder clips instead of straps. Straps are a pain to remove over leathers.

My carbed bike gets 10 mpg less in the winter than summer so I am planning on installing carb heaters. Hopefully this will help. I was able to find some on a UK website.

I have also been thinking about weight saving. The cheapest would probably be for me to lose a few pounds but I was thinking more about rotational weight. One possibility is to move from 530 chain and sprocket to 520. I would also consider changing gearing at the same time.

A couple of interesting sites on motorcycle aerodynamics are:
Craig Vetter, designer and inventor of the Windjammer fairing and Triumph Hurricane Motorcycle - This is a great site if you haven't seen it already.
Ryno Fender - Expensive ($200) but interesting for sport bikes