Motorcycle alternators?

Aidan_M_M

Folks, have to admit I'm a car guy primarily, though I love going to the road racing. I use motorbike (Gixer 600) throttle bodies on my rally car, and am considering a motorbike alternator. Any of ye able to tell me about them? Output, how they're mounted and driven etc?

CJhaughey

Aidan_M_M wrote: »

Folks, have to admit I'm a car guy primarily, though I love going to the road racing. I use motorbike (Gixer 600) throttle bodies on my rally car, and am considering a motorbike alternator. Any of ye able to tell me about them? Output, how they're mounted and driven etc?

Most Bike alternators won't make more than 400w, There are exceptions like BMW but generally they will make between 250w and 350w.
There is various different methods, some Japanese bikes have the stator fixed to an engine case and the end of the crank spins the rotor with the magnets in it.
Some have a car like system Yamaha Diversions are like this.
BMW alternators run inside the engine.
The common thing is that they generally all use external regulator/rectifiers to control output.

two wheels good

The BMW 11xx and 1200 boxers have belt driven alternators - behind the front engine cover. According to my 1150 manual it's rated at 560W

Aidan_M_M

Great info , thanks guys.

Hotblack Desiato

If you're not already aware, bike alternators and rec/regs are notoriously unreliable and expensive to replace.

Cedrus

Aidan_M_M wrote: »

Folks, have to admit I'm a car guy primarily, though I love going to the road racing. I use motorbike (Gixer 600) throttle bodies on my rally car, and am considering a motorbike alternator. Any of ye able to tell me about them? Output, how they're mounted and driven etc?

Why?

Motor bike stuff like that is generally specialised/derated to fit into the engine casing and cut weight, given the space in a car engine bay and the carriage load you already have, you have so much choice of standard and custom parts, why would you think of bike gear?

Cedrus

ninja900 wrote: »

If you're not already aware, bike alternators and rec/regs are notoriously unreliable and expensive to replace.

I'd disagree on the first but agree wholeheartedly on the second. Some manufacturers have higher failure rates than others but some (sochiro san) seem to go on forever.

Hotblack Desiato

Really? Some Hondas are as bad if not worse than the worst Suzukis. It depends on the model. Inadequate spec on the parts and inadequate cooling are the usual reasons.

spiggotpaddy

ninja900 wrote: »

Really? Some Hondas are as bad if not worse than the worst Suzukis. It depends on the model. Inadequate spec on the parts and inadequate cooling are the usual reasons.

True enough, the carbed CBR6's regulator was made of toffee crisp,and almost a service item. the 1000f had the secret hidden alternator and when the damper failed its an engine out of frame job.
The car type alternators like the one on oil boiler suzuki's are the best (imo).

Aidan_M_M

Cedrus wrote: »

Why?

Motor bike stuff like that is generally specialised/derated to fit into the engine casing and cut weight, given the space in a car engine bay and the carriage load you already have, you have so much choice of standard and custom parts, why would you think of bike gear?

I fitted a different engine to stock, so space is actually limited. Plus I don't need the high output of the normal car system, nor the weight. And I'm on a budget!

spiggotpaddy

You could get a cheap used one from a bandit 1200, unbolt the drive gear and bolt on a pulley, but why not just get a small car one from a micra or mini?
The one in the pic is from a bandit12.

Aidan_M_M

spiggotpaddy wrote: »

You could get a cheap used one from a bandit 1200, unbolt the drive gear and bolt on a pulley, but why not just get a small car one from a micra or mini?
The one in the pic is from a bandit12.

Because the car ones are still large , and over spec'd for what I need. Also rgey fry at higher rpms. Thanks for the pic. Compared to say a coke can or half litre paint tin, how big is that?

spiggotpaddy

In situ under the carbs. Piston is 1.8 gsr.

Hotblack Desiato

A total loss electrical system (just a battery) probably isn't a goer for stage rallying, but might be for rallycross or hillclimbs...

What happened to that conrod spigotpaddy? Hydraulic lock?

spiggotpaddy

ninja900 wrote: »

A total loss electrical system (just a battery) probably isn't a goer for stage rallying, but might be for rallycross or hillclimbs...

What happened to that conrod spigotpaddy? Hydraulic lock?

The rod was in a doner car(still running) bought for parts, so dont know what happend, but I suppose it was driven through water and sucked it into the combustion chamber and "hey presto compress this"

Aidan_M_M

It's a stage rally car, so definitely need the alternator. Thanks for that pic Paddy, awaiting the price of one from PTS bikes in cork.