Forum

[Norm]

Hi Paul sounds good but it doesn't have the right thread, apparently it is a tread specific to Royal Enfield so aftermarket ones can't be used, complete bastard act

[trevorch]

Hi Norm,

How do you know it is a different thread? By any chance would it be the same thread as the PAV plug?

I bought a Bonneville T100 EFI last year which unfortunately has, of course, two O2 sensors. For any stage of tuning, you can buy blanking plugs and remove the sensors, then have the EMU reprogrammed to cancel out the sensor and incorporate maps for any changes to silencer and air filter. Total cost, in UK 60 GBP.

As yet, I have no need of this, but when I change to more open silencers, it will be necessary.

According to Bosch data sheet, the sensor output ranges from 0 to 1 volt between rich and lean. At the ideal ratio (approx. 15:1), the output is 0.5 volts, so in theory, applying that voltage, would fix the problem of a failure, though losing the ability to maintain the optimum running mixture.

Just a thought.

Cheers Trevorch

[Norm]

Hi Trevor, I have been told the thread is different buy someone who has tried. Only problem with all these mods is the bloke who has the problems just wants to get it going and sell, he is cured of Enfields

[trevorch]

Hi Norm,

i got this answer from Magnum:

A seller answered your question, "Is the Bosch thread size the same as fitted to the factory EFI B5?" about BOSCH O2 Oxygen Sensor Royal Enfield Bullet 500....
Magnum answered:
"Thank you for considering Magnum Tuning as a potential source of your online purchase. If the OEM sensor on your Bullet 500, you are about to replace is screwed in a M18 x 1.5 mm thread, this Bosch oxygen sensor fits. As description reads, it installs universal.

Does that help anyone.

Cheers TrevorCH

[apparently lucky eddie]

I know nothing of this O2 sensor business being an old git with an old bike and a simple to tune, adjust and repair Amal, but if it comes down to threads is it not a simple case of taps, dies and helicoils if required?

[Norm]

Hi Trevor and ALE, I believe the sensor on these bikes is M12 not M18 no way you could tap it out to M18. I'm only going on info this bloke has provided to me, he knows what he is on about and has been chasing this quite hard but is beginning to admit defeat

[trevorch]

Hi Norm,

I will write back to Magnum and tell them their advertisement breaks the Sale of Goods Act by making false claims, according to what we believe we know (M18 did seem a little large, unless someone know of a suitable adapter.)

Cheers TrevorCH

[apparently lucky eddie]

If the RE original sensor is smaller than the "pattern" type part, surely it is not beyond the capability of any halfway decent spannerman or home engineer to make some sort of adapter (if one is not already available)? It looks like a commercial opening just waiting to be exploited if it saves a punter £100 over the rip-off RE item. Maybe this is one for Mr Hitchcock to look into.

[bikerhifinut]

Seems to me in the UK at any rate, it makes economic sense to buy Mr H's Power Commander if and when the O2 "sniffer" goes.
That and a less restrictive silencer and release a bit more power. And the great JuJu knows the poor old bike needs a power boost.
Incidentally does anyone know just how much extra can be squeezed out of Modern EFI and still keep the big end and mains etc intact? And at what cost?

A.

[cliffy]

Hi
It all depends on the type of efi system fitted to the machine.
For example I have a Moto Guzzi V7 Classic which runs a closed loop circuit EFI , the O2 sensor only governs the fuel to air ratio up to around 4000 rpm after that the ecu runs with the pre installed mapping.
The Guzzi's run extremely lean at low rpm in the range of the O2 sensor purely to be within emission regulations.
To get around this I installed an inline resistor to basically ' fudge' the signal to richen the mixture in the low rpm range !.
Not sure if the Enfield runs the same type of set up but if so it could be one way to help low range running ??
It was a game of lots of plug chops and different resistors until I found a happy medium !