6V -> 12V @ 25 watt

[Nigel Goodwin]

I have a Honda CG125 and the headlights are powered from the alternator and I have a feeling that this is also the case on my CB500. The CG125's headlights are a bit dim but the CB500's are bright enough. I think having a bigger bike makes sense in lots of ways and safety is probably the main one as the brakes, lights and tyres will all be better. Having said all of that, I don't see the point in getting a really big bike (over 600cc) as it costs more to tax, insure and it drinks more fuel. There again, I suppose I would say that as I'm more of an A to B persone than someone who rides for the fun of it.

I've no problem with a 500cc, the DT400 was the biggest road bike I've actually owned - but your CB500 will have a proper electrical system, with the headlight fed from the battery, and I would expect it to be 12V as well.

 

[Nigel Goodwin]

Nigel, you're awfully close to the mark. It's a like-new (2000 miles) 1978 Yamaha DT175.

By some strange coincidence, I sold my DT400 when I got a car, and I took a DT175 in part exchange, which I then sold. Nice little bikes, but the same crappy lights problem as the DT400 - but I didn't think the headlight was as low as 25W?.

 

[Hero999]

Both bikes have 12V lights, that I'm sure of, I'm not aware of any modern bikes that have a 6V electrical system.

I can't ever see myself not having a bike though, if/when I get a car I'll still have a bike even if it's only a 125cc scooter. I'd never have anything smaller than as 125 though, 50cc bikes are dangerous.

 

[Oznog]

You have stated your question with a detailed description of what you want to do and all the basic specs.

This is against conventions on this forum. To better fit in, perhaps you should stick with "I need 6v to a lot of 12v how do i do this PLZ HELP!!! Thanks!" in the future.

Capacitive charge pump will be nice, but be aware this is a pretty large charge pump. You'll need capacitors rated for double the output current and that's going to be quite a bit actually for a cap.

 

[Blatman Bond]

If you switch it fast with mosfets, no large caps needed. 25 watt is a small thing.

50cc bikes are dangerous for mountain people. They go back when riding. My grand father's is 75cc Yamaha super cup. Full power isn't enough to ride.

 

[Hero999]

I would agree but he is talking about a 175cc machine which should be fast enough to keep up with the traffic.

 

[Nigel Goodwin]

I would agree but he is talking about a 175cc machine which should be fast enough to keep up with the traffic.

A DT175 is a two stroke trail bike, it uses trials tyres (which are only rated at 60mph maximum - although I had my DT400 up to the mid 80's ). But performance wise it will keep up, and probably beat, most mid performance cars up to 60mph or so.

 

[Hero999]

My CG125 (four stroke engine) can easilly do 60mph and I've had it up to 75mph before.

My CB500-S will easilly do over 100mph (I've never done the top speed but I've heard it'll do about 120mph at a push).

Most modern cars will do over 100mph, the 1.2L Renault Clio I sare with my sister will do over 100mph.

The main advantage bikes have is acceleration.

My CG125 can reach 60mph in just over 15 seconds - roughtly the same trime as the 1.2L Renault Clio.

My CB500-S can reach 60mph in 5.2 seconds - quicker than most sports cars even though most sports cars can do over 150mph.

Moden bikes are faster than old bikes even for the same engine size, as soon as I got my Honda CB500, my brother bought a Yamaha Fazer which can do 150mph and can get to 60 in 2.8 seconds, well he had to go one better.

I'm not bothered though as I don't often use all the power my bike has to offer (it revs up to 10,500rpm but I rarely take it past 8000rpm, 7000rpm most of the time) so a more powerful bike would be a waste as it'll cost more to run.

 

[Nigel Goodwin]

The 'fastest' bike I've owned was a Suzuki 380cc two stroke triple, top speed was probably about 110?, but the acceleration would leave a CB500 standing (or a Porsche 911 ). However, only 380cc, and you struggled getting 30mpg from it! Mind you, three carburettors on it, each of which had a jet larger than a 2L car!.

The fastest accelerating production bike ever was the Kawasaki 750 two stroke triple - and those struggled getting into double figures for fuel consumption! .

 

[Hero999]

I bet my brother's Fazer would give it a good whipping though.

I've get about 60mpg out of my CB500 which isn't bad at all for commuting to work though heavy traffic.