Can 1983 Honda VT-500 Meet the Vetter Challenge?

[redyaris]

The coolent temp is now in the low to midle of the normal range. It seems to run a bit cooler going into a head wind and a bit hotter with a tail wind.

[ldjessee00]

Paint it red and gold and it cold be Ironman's motorcycle!

The opening, do you plan on changing its shape and smoothing the entrance?

Just seems a bet rough with how sleek everything else is.

LDJ

[redyaris]

ldjessee00
The opening at the front, for the cooling air is as good as it will get, Its shape is my version of a NASA duct, and as such its as good as it gets I'm guessing. The area that needs some more work is the upper edge of the tail section which will have to be rounded to reduce the affect of strong cross winds.

[redyaris]

As the ambiant temp has gone up I have had to enlarge the opening for the cooling air to the radiator. I have also rounded the upper edge on the rear section to help reduce the side wind effects. I now believe that the upper section of the rear body work should be a semi-circle in order to minimize the affects of cross winds.

[redyaris]

I have repaired the pluged slow speed jet for the rear cylinder and enlarged the cooling air inlet for the radiator, to ensure adequit cooling for the Ohio trip. I have ordered a new rear tire which I will mount at the end of the week.

[redyaris]

At this stage in the development it would appear that the 100mpg Vetter Challenge standard is far away and not likely to be attained. The reason I say this is that the throatle is less than 20% open at 110km/h [70mph] and there is no inexpensive way to reduce the engine speed with shaft drive and even if it was posible it would not do enough to get to 100mpg.
The bike itself is vastly improved and far more fun to ride. When cruising in 6th gear I no longer have to shift down to pass, go up hill, and/or overcome headwinds. The range on the 10L's of fuel above reserve is much improved. The cargo space alone is enough to convert me to this style of bike, I now find regulare bikes so inadiquit; even big touring bikes with all kinds of bags and boxes. The comfort of being able to lean back agianst the foam covered opening is great. I will continue to develope this bike to see what the upper limit on fuel economy is but 100mpg is not very likely.

[renault_megane_dci]

It's a shame but you are right ...
Bike are meant to have a high power per litre engine wich means wasteful.
Even a tourer like a VT would put most of the cars to shame when considered on this particular point.

Have you considered engine mods and what is your knowledge in this area ?

Mirror polished combustion chamber will reflect more heat making the engine more efficient

If it is a DOHC, you can alter cam timing to reduce overlap.
Overlap is a waste of fuel only required to run the really high rpm bikes usually run.

Higher CR is very important for fuel consumption too.
It is about thermodynamic efficiency of the engine.

You can also run hotter air meaning less fuel in the cylinder and again boost thermodynamic efficiency.

The vetter challenge is not only about high speed so maybe you can consider lightening the bike very much to gain on energy required for accelerating the bike and short shift the **** out of it.

About gear reduction, I assume you already did the obvious taller tire swap ?
What about the rim size ?

[jkv357]

I don't think it would be practical, but if the engine was apart, there are a few things you could do to increase efficiency.

Increasing compression ratio, ceramic coating the top of the piston and the entire combustion chamber (valve faces too), and Teflon coating the skirt of the piston. All moving parts (cams, gears, bearings, etc) could be coated with a Dry Film Lubricant as well.

I still don't think it would get you close to your goal though.

Have fun, and just see what it will do. Best of luck!


Jay

[janvos39]

My suggestion for improvement should be to disable one cylinder. 250 cc is enough power when you have a fairing.
If you place a balance weight on one of the connection rod places you can take of a complete cylinder with head. Like Ducati did once to make a 500 cc out of a two cylinder.

[renault_megane_dci]

I think they also did a new crankshaft to deal with the completely different balance.

Not a cheap idea.