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[Rattlebattle]

My take on it is this: the RE is essentially the same as the many 50s pre-unit singles I have owned that all ran quite happily with an Amal carb. For sure there are better carbs but how sophisticated does the carb on an ohv long stroke single need to be? Without emissions regs I very much doubt that RE would have resorted to fuel injection. But we are where we are. I believe the real culprit for poor running is crap fuel. Whilst I take Jefrs point re spark plug heat values ( and I too once holed a piston racing my 250 Suzuki Hustler against a Triumph Spitfire because I forgot that I was using the "town use" plugs) the fact is that back in the day most of us with road bikes stuck with the specified plug grade and adjusted the fuel mixture based on plug chops against the colour charts in n manuals etc. It seems you can't do this nowadays. As for messing around with the EFI I'm quite happy to do this on a bike for which there is a big user base and loads of knowledge and downloadable maps for different exhausts etc eg BMWs, using the GS-911; Triumphs using TuneEcu. I've not yet seen a definitive answer of exactly how the RE EFI works. Whilst I respect those who are sufficiently interested and skilled in cracking this, for my part I'd rather just bung a carb onto this low-revving anachronistic single and get it running as well as it can and I can. To have to pay for at least a PCV to get a STANDARD spec bike to run properly in my book is not acceptable, given the cost. Fair enough I suppose if you want to swap exhausts etc but even then it's still cheaper to put a carb on it. That is what I nearly achieved today; I ran out of time because I went for a ride on it first. Perversely it started first kick.......

[apparently lucky eddie]

You're right on the money Rattle, we simply do not need all the electronic witchcraft on these old machines. The term 'Occams razor' comes to mind, ie., keep it simple with fewer parts to complicate and increase (ironically)inefficiency.
I found a new old stock 1960's Monobloc on fleabay 4 years ago and bought it for 35 quid, put it on my Tiger 90 and have never touched it again. Simple, effective, reliable. Job done.

[jefrs]

Large user base? We are aware that RE produces more of these bikes than the combined weight of BMW, Ducati, Triumph and Norton? Perhaps it's time we got to terms with them.

[Rattlebattle]

The majority are sold in India and have a carb eg Himalayan. It's pretty obvious here in the UK that Triumph and BMW easily outnumber RE bikes. Norton is only a bit player these days. My point is simply that there are relatively few Westerners playing around with the EFI system than with Triumph, BMW and a few others. Anyway, I've now fitted the carb conversion, which went well enough despite the usual sort of snags not mentioned in the generic instructions. Nothing major though. The engine starts on the kickstart and seems to rev cleanly. The weather today is atrocious so I won't be going for a road test/ carb tune. How wonderful not to have to loosen things just to get at the idle screw and for the engine to do what I expect it do when I adjust the carb with a screwdriver. Excellent. I now have what I thought I'd bought - a long stroke single with a lovely gearbox and clutch, decent lights and front brake made to an acceptable standard. In other words a modern take on an old Brit single without the oil leaks. Plus I'll be able to modify it if I choose and to adjust the fuelling to suit. Result.

[zonggong]

Hi again .... all the advise you've provided has been very useful ... thanks. A couple of days ago I came across an exhaust analyser I had years ago ... the sort used to tune ups the carbs on a car ... other than by listening ..... to sort of provide some scientific basis for what you are doing. Anyway , I put it on the bike after coming back from a ride. The AFR was sitting about 13.0 at idle .. it pulsed a little due to the single cylinder but generally centered on 13.0. I guess this is OK for idle and seems to fit in with jrfrs' more scientific measurements.
The bike is going fine at present.