ed's lemans jetting

[lazlokovacs]

ed's lemans jetting 'recipe'... http://www.guzzipower.com/lemansjetting-ed.html

will this work with these lean-burn carbs?



http://wildguzzi.com/forum/index.php?topic=76666.0;wap2

Or do I need to change my numbers?

Lemans 1000

thanks as usual

[Mark West]

I don't recognize your carb but a variation of Ed's Jetting is what I used in my LMIV with PHM40's and it ran great. Way better than the Euro jetting it had when I bought it or the Euro jetting with a larger main, which was definitely bad.

Seems to me that every situation is a little different and you may need to vary slightly depending on your situation. A good idea is to get a copy of the Delorto manual ( I think they are on thisoldtractor.com) and get an idea for how changing different jets affects running. Then you'll be able to make educated adjustments as you go.

[Aaron D.]

Funny, it sort of parallels my experience on the Sport 1100, except for the main.

[Vasco DG]

This will be interesting to find out. To the best of my knowledge none of the Big Valve motors sold in markets where I've worked on them had lean burn carbs. The fact that Ed has gone so low on the mains alone would seem to me to indicate that American market bikes were equipped with lean burn carbs.

If that is the case I'd use either Ed's suggestions or use stock MkIII Le Mans jetting as a start point but remembering that the MkIV/V series had bigger valves and larger carburettors, the advantages of these are offset against the godawful piston crown and combustion chamber design.

A WAG from me would be mains of about 125-127, a K18 needle on the third notch from the top, AB 268 atomiser, 50 slide and no bloody idea on the pilot

Pete

[guzzibob]

I don't recognize your carb but a variation of Ed's Jetting is what I used in my LMIV with PHM40's and it ran great.

Mark, I thought you were using my jetting on your LM IV. I am pretty sure you told me that at one point you were and liked it. Did you change it later, or are you calling the jetting I sent you "a variation of Ed's?"

[dan_s]

[quote author=Vasco DG link=topic=78619.msg1235074#msg1235074

A WAG from me would be mains of about 125-127, a K18 needle on the third notch from the top, AB 268 atomiser, 50 slide and no bloody idea on the pilot

Pete
[/quote]
Would you suggest similar setup with a 36mm carb or is it a different animal altogether?
I now run the lm2 (850) with 125 main jets with no change in spark plug and butt accelerometer readings.

[Vasco DG]

Depends on what carburettors you are running and what filters, if any. Do yours have the shroud around the atomiser? If not and as delivered they shouldn't have, then no.

Pete

[dan_s]

Carbs are phf36's with  cotton gauze  k&n filters. I didn't look at the atomizer area so I can't tell right now. It's a UK spec bike, delivered with a 140 mains.

[lazlokovacs]

thanks guys, will let you know the outcome

[guzziart]

Lazlo,

I contacted Ed in 2011 to ask if he still felt his recipe, developed several years earlier, was valid.  He said it was a good place to start.  After performing his recommended changes, my Lemans SE immediately performed 100% better...easier starts (cold & hot), no more surging between 2800-3500 rpm, no flat spots off idle through transition to wot.  I'm very pleased with the overall performance.  However, one of these days I'm going to have to get back into those carbs to tweek them a little further.  As a result of plug chops and the use of an air fuel ratio gage, I'm running a little rich on fuel...maybe one of these years I'll give it another hour or so of investigation to get it perfect.

Some of things I did before I got into the carbs were: head re-torque, valve adjustment, compression check, new manifolds, distributor rebuild (new points, springs, condensors, plugs, caps & wires).  Also, I'm running K&N pods and stock exhaust.

Anyway, good luck, the recipe works but it will be up to you to fine tune. 

Art

[lazlokovacs]

Ok... firstly can confirm that Ed's jetting used on 'normal' carbs, (ie without the brass shroud) is absolutely the bee's knees, the dog's b.

So so good, I find it hard to imagine how it could be jetted any better...

Upshot is, I haven't tried it with the 'lean burn' carbs and as its now running like a chicken dinner I doubt I'm going to try them!

thanks to everyone for input.

[guzzibob]

My 91 1000S came with 40's, same motor & carbs as LMIV & V, and I went through my own process to get something very similar to but not the same as Ed's results. From there I also tried some of what Ed had in his final, and found that mine was better-for my bike under the conditions under which I ride. Ed's bike is not even remotely stock. All kinds of heavy engine work-ie higher compression, cam, valve & head work-all of which Ed says do not much influence jetting considerations-but also Mistral exhaust. He doesn't say anything about air filtering, but I have talked to Ed and recall him saying he ditched the stock air box and filter. Exhaust and air intake generally do influence jetting. My 1000S is dead stock except for Dyna ignition, which should have no effect on jetting and I also have the stock exhaust with the end caps drilled just to make it sound throatier-no perceptible performance difference, and a K&N replacement air filter but with the stock airbox. The latter might flow a bit more air, but I would think the stock airbox would be a lot more restrictive than what Ed has for his purposes. Also while Ed says he jets for sea level, I live at sea level but ride a lot on Angeles Crest Highway which goes as high as 7900 feet, with lots of it over 5000'. So I require my bikes to run at least decently without threatening to explode over that entire range.

When I got my 1000S almost new it had Guzziology's (if you talk to Moto International about jetting for altitude they point out they live at sea level and have zero experience jetting for altitude) Euro plus jetting which is all too near stock. As Ed points out that jetting is way too lean at low throttle, way too rich at more open throttle. In fact my S with this jetting would not even run over 5000 rpm in any gear at anything over 5000', though it wan't too bad at sea level. So I found someone who had the same motor & carb living at 3700' and riding higher who had gone through the exercise and found jetting that worked for him, using that as a starting point.

Ed says he at first decided to stick with the Euro spec K19 needle and change other stuff. I decided to stick with the stock 60/5 slides and make changes around that-because my bike ran well enough just off idle-the main thing changing slides would influence-and slides are way, way more expensive than anything else in there. Looking at prices now, about $150 a pair for slides (a hell of a lot to pay to experiment with something unlikely to help the things I was unhappy with), versus about $8 a pair for idle and main jets, $20 a pair for needles, $20-40 a pair for needle jets. So pretty cheap and easy to do a lot of experimenting with those other bits. I did that by changing 1 thing at a time and riding up and down altitude from a 5000' starting point, so that way it was easy to tell if the change was making it too lean or too rich at a given throttle position-then go back to 5000', make a change, try again.

I wound up with this: 266 needle jet (aka atomizer), 60/5 slide, 65 idle jet, 128 main jet, K19 needle at 3rd notch (of 4 total) from the top. At this setting it runs just fine from sea level up to 7000'. For sure more strongly but a little lean at sea level (pops a little on a trailing throttle, but not bad), but is willing to pull to or near redline way up there, which it for sure wouldn't come anywhere near doing when I started. This is pretty close to Ed's final K19 settings, and even closer to his final K4 settings, exc for the needle.  After seeing Ed's final specs, I tried both his 265 atomizer and K4 needle, both separately and together, and at varying needle positions-and always came back to my settings above, mostly because I got a much better midrange that way.  Again, this on a bike way, way closer to stock than Ed's and one expected to run at least reasonably well over a much wider altitude range than what he wanted.

At one point after all this I ran in to Ed at MG Classics (very near sea level) and asked him to ride mine. He said it was good, and that I should leave it where it was. He guessed that the stock airbox I was still using was why the K4 and 265's didn't work for me, but did for him. I have had 2-3 others try my jetting, and they were a lot happier with that than what they had.

So your bike is your bike not mine, with whatever mods you may or may not have, and you ride at whatever altitudes you ride. Just saying if your bike is stock and/or you ride a significant amount of time at altitude, my jetting might be a better place than Ed's to start from. No matter what, you can do a lot better than the miserable jetting EPA (and Europe emissions as well for that matter) forced MG to send them to us with. I wound up with a much better running bike at all altitudes, and with about 10% better gas mileage (about 47mpg now). It is very cold blooded, needs a couple minutes at idle to get to a point where it will not bog just off idle without the choke on. Once warm that completely goes away. For sure a real joy to ride now, way better than what I started with.

     

[lazlokovacs]

thanks bob, good info...

[groundhog105]

I have Eds jetting in my Lemans 5 and it worked much better. I am going to change to leaner pilot jet though as the 65s are way too rich for my bike. Everything else works great n