Forum

[Thack]

Hey guys, have any of you experimented with "hacking" the EFi system? For instance, I wondered about disconnecting the lambda sensor or the engine temperature sensor and just seeing what happens.



If you do this on a car, it illuminates the warning light, and then loads a default fuelling map so you can still drive it. In other words, it goes into "open loop" mode, where it doesn't try to adjust the mixture based on feedback from the lambda sensor, but simply sets the mixture to the default map.



I don't know whether the Bullet does this, so I thought I'd ask in case anyone here has already tried it. If not, I'm tempted to have a play tomorrow.

[Norm]

Thack I asked these questions 6 months ago but at that stage nobody really knew but hopefully somebody may chip in with a bit of info. From what I remember the O2 sensor is manufactured for Enfield only and costs about $180 au

[Michael]

Norm is right...o2 sensor not available on aftermarket. Cost upwards of 100 GBP.

[Adrian]

Probably the most radical hack so far is the carb conversion kit. There was a time when fuel injection was seen as a performance mod rather than an emissions tamer...

Reagrds,

A.

[Thack]

Thanks, guys. I can't wait until tomorrow. I'm going to disconnect the engine temperature sensor now, ride it for a bit, and see if I can notice any difference. I'll report back later.

[Thack]

Hmmmmm....... that's interesting. I disconnected the engine temperature sensor before starting it. The first thing to notice was that it wouldn't idle when cold, which is pretty much what you'd expect. The second thing to say is that nothing bad happened. Anyway, I drove it for several miles and noticed only one small difference.



Basically, the idle speed is definitely slightly slower. Interestingly, though, it doesn't seem to alter its speed like it normally does. It didn't show any of that tendency to slow down and stop when idling for a long time. It was a short test and I should have done more like-for-like comparisons, but I found it thought provoking, at least.



For now I'll concentrate on getting some miles on it so I can get it past that first service and properly run in. After that, I can just feel my fingers itching to start playing.

[Norm]

Thack, keep up the good work because these bikes get a bit older there needs to be some documented info on how/why they work and what fixes are available. Best to start with something working than trying to fix something that isn't

[Thack]

Yay! Thanks, Norm! A man after my own heart......

[Scalyback]

There's been a lot of posting about converting EFI's to carb, but...



the Indian home market 500 bullet is (or was) a UCE engine with a carb.













Taken from http://www.thehindubusinessline.com/fea ... 756245.ece



"ENGINE AND PERFORMANCE

It’s the heart of this new Bull that makes a world of difference. Yes, it is the same 499cc 4-stroke single cylinder air-cooled mill, but instead of an EFI (as on the Thunderbird and Classic models, and the export Bullet 500 variant), the Bullet 500 has a carburettor. This makes a minor change in power delivery. This carburetted (with throttle position sensor) motor on the Bullet 500 makes a maximum power of 19.2kw (26bhp) @ 5100rpm, and manages to achieve a maximum torque of 40.9Nm @ 3800rpm."



ERM.... their carbureted bullets do work then, don't they?
or are the mods for an EFI to complicated or expensive?

[Thack]

I was in a grump this afternoon after it stalled twice at junctions. Very strange - it wasn't so much the gradual slow down, but a fairly sudden stoppage as I stopped. When starting, it seemed to need a bit more throttle to pick up properly, exactly as if it was running too weak. After a second or three it settled down to idling properly.


I'm convinced there's a glitch in the engine management mapping somewhere, which is OK because it gives me a little project to work on. As I said, before altering anything I'm going to set up some way of monitoring the electrical signals to the fuel injector, to see if I can spot the aberrant behaviour.

I read somewhere that there was a strong preference for a carburettor in the Indian market, so RE responded to that demand. Apparently they want the simplicity and repairability. So, guys, why does it have a throttle position sensor? What does it use it for? My guess is it's to do with optimising the ignition timing. Also, how come we don't get the twin-spark arrangement over here?

Oh, I forgot to say - as part of my grump I was thinking of dumping the fuel injection and fitting the carb off an Electra X; I thought the carburation on mine was virtually perfect (albeit pretty weak, intentionally).