Motorcycles

mrbell · Post by **mrbell** » Thu Jun 08, 2006 3:45 pm

I know many of you are interested in using this for your motorcycles, but most motorcycles do not have fuel gauges and you simple hit the reserve when you need to fill up. This is probably going to be an issue as EFI pumps do not like to run out of fuel. Are you guys going to address this or just try to be very careful on not running out of fuel?

mrbell · Post by **mrbell** » Thu Jun 08, 2006 3:49 pm

Another question I just thought of... what about power? Most bikes I've been on have trouble keeping a headlight on at idle, how will you run an EFI system?

mrbell · Post by **mrbell** » Thu Jun 08, 2006 4:11 pm

...and finally what injectors are you guys going to use? My numbers suggest a 2 100cc/min injectors, but I don't know what else might even come close to running that low. I don't think throttle body injection will work due to the uneven firing. I dealt with this in my Mini. It's possible, but adds alot of complexity.

newtyres1 · Post by **newtyres1** » Thu Jun 08, 2006 4:11 pm

If the engine runs out of fuel MS will switch the pump off since the engine is not running. Most riders keep an eye on the odometer to know when they are going to run out of fuel, but if there is no low fuel warning light, I guess the old standard reserve tap would still work OK. I don't know how long a fuel pump can run without fuel without damage but I would think a few seconds would be OK. With the electrical system, the owner has to do an assessment of that for sure. Some people have fitted higher capacity alternators, some carbed bikes can handle EFI loads without mods, some bikes you simply wouldn't attempt it, and some bikes are already equipped with EFI and the owner would be fitting MS to be able to tune the fuel and/or ignition timing.

Ian.

mrbell · Post by **mrbell** » Thu Jun 08, 2006 4:52 pm

Ahh... good point about upgrading EFI to EFI... I had forgotten about that case.
Most riders I know will run their bikes till they sputter and flip to reserve. A fuel pump SHOULD be ok... but I've personally seen 2 die the first time they ran out of gas, so that concerns me.
In my case, the only way to get a higher capacity alternator(reasonably, anyway... I'm not going to run a GM alternator off the drive chain like some setups I've seen) is to rewind the coils. Unfortunately, nothing else seems to fit.

BrentP · Post by **BrentP** » Thu Jun 08, 2006 6:03 pm

mrbell:

Have you been out of the loop with motorcycles for a while?

Many built in the last 5-10 years have quite a bit of alternator output, I don't think anybody builds with Lucas components anymore.

Many motorcycles don't even have petcocks anymore, or they are very difficult to get to and meant for storage. They use a low fuel indicator that is a level switch system.

The injection size you mention is quit off for modern equipment. Most motorycle engines have quite a bit higher output than automobile engines, so they need larger injectors. On my 650 twin I am running about 400cc/min injectors.

Placement is a misconception as well. Many high-performance motorcycles run "shower" injectors, which is even further out than normal throttle-body injectors. This works fine with individual throttle bodies, if you are using shared runners (not used since the 70's on motos) then you could have problems.

I have done four bikes now, and the biggest single problem has been where to put a fuel pump.

Hope to do the beta MicroSquirt soon!

newtyres1 · Post by **newtyres1** » Thu Jun 08, 2006 6:08 pm

I've heard of Buell motorcycles running out of fuel with no ill effects on the pump, but that's just one brand.

I think it's the fuel pump that seems to draw the most current (not including ignition) so if you can find one that draws the least current that would help. If you're running a points ignition, that will draw a fair bit of unnecessary current at idle compared to electronic ignition due to the long dwell at low rpm. The current required to drive four high impedance injectors at idle or cruise throttle would be less than 14W, and the MegaSquirt box itself uses negligible current.

Ian.

hybrid · Post by **hybrid** » Thu Jun 08, 2006 6:49 pm

I've thought about most of these problems on my bike.
I have bought a fuel light sender from ebay for a random bike, and I intend to modify my fuel tank to fit it.

Current is an issue for me, as I'll be using an '85 RZ500 engine. If the alternator cant handle it, I'll see about having it re-wound. No massive problem.

I'm using fuel pump, and quad TBI from a Kawasaki GPZ1100.

mrbell · Post by **mrbell** » Fri Jun 09, 2006 8:29 am

BrentP wrote:mrbell:

Have you been out of the loop with motorcycles for a while?

Not out of the loop, I just don't like newer bikes. Sure, they make lots of power, have cool features like electronic ignition and fuel injection and fuel indicator lights. But they're certainly not as pretty (or in my opinion) as practical as pre-70's bikes. Sure I could have a new bike that will do 150, makes 100hp and revs to 15 grand.... but why would I ever want to do that? I'll never drive close to 150, I'll never use but maybe 50 of those hp, and high revs like that are unneccessary.
Not that I'm on the other end either. I'm not a harley fan, really. Too big, too heavy, too loud, too... silly.
Nice simple, reliable lightweight, comfortable, gets me to 80mph reasonably, good handling, good fuel economy, good looks(ie: NO plastic), no more, no less. That's my kind of bike.

BrentP wrote:Many built in the last 5-10 years have quite a bit of alternator output, I don't think anybody builds with Lucas components anymore.

Ah, lucas... the memories... but alot of bikes(even new bikes from what I've been reading) do not really charge at idle w/ the headlight on. Add another 80 watts to that load(pump + EFI computer) and you'll be killing those poor batteries in traffic. It takes a few thousand RPM to generate excess current.

BrentP wrote:Many motorcycles don't even have petcocks anymore, or they are very difficult to get to and meant for storage. They use a low fuel indicator that is a level switch system.

The injection size you mention is quit off for modern equipment. Most motorycle engines have quite a bit higher output than automobile engines, so they need larger injectors. On my 650 twin I am running about 400cc/min injectors.

Placement is a misconception as well. Many high-performance motorcycles run "shower" injectors, which is even further out than normal throttle-body injectors. This works fine with individual throttle bodies, if you are using shared runners (not used since the 70's on motos) then you could have problems.

I'll have to look up shower injectors, but I still only need 100cc/min injectors. My bike is a 350cc inline twin and only makes 35hp. 1 injector per cyl(I can't share a single injector easily due to the 180 degree crank) I CAN use higher rate injectors and not run them out, but I'd rather not, if I can help it. It tends to compromise low end fuel control

BrentP wrote:
I have done four bikes now, and the biggest single problem has been where to put a fuel pump.

Hope to do the beta MicroSquirt soon!

Yeah, I am a bit concerned about where to put things, but since the carbs are larger than throttle bodies w/ injectors, I bet there will be room.... it just may not be so pretty...

mrbell · Post by **mrbell** » Fri Jun 09, 2006 8:37 am

Ok, so I know what you mean by shower injectors. Just really standard injectors outside, but aimed into the horns? I still don't see how that lets you run a too large of injector on a low power/displacement motor... there's still a lower limit on the MIOT and for a large injector/small motor, this would not idle, or it would run extremely rich...