Triumphrat

Lobo74

42 and 125 jetting, A Uniflow air filter, and Stainintues were already installed when I bought my 2003 Bonnie. She also had the New Bonneville oil temp gage in the oil filler cap installed. On a typical day in the 60's to 70's she ran 185 degrees F to 200 F, depending on the type of riding. Also, I looked at the old spark plugs (changed out April 2009) and they have a light coating of dry black residue, indicating a slightly rich A/F ratio.

I removed the snorkel a few weeks ago. Once warmed up the throttle response is fine and she has noticeably more power than when the snorkel was in. Since the snorkel removal she runs about 200 degrees F to 220 F or so. That indicates to me that its a leaner mixture, but is the 200 - 220 F too hot?

In an earlier post when I asked about the cold blooded nature after the snorkelectomy I was advised by knowledgeable board members that 42/125 was too rich, go to 40 and 118 (or so). I believe them, but since she runs hotter now I am concerned that the leaner jets would raise the temp even higher. Oh, I run 91 octane gas, that might increase it too, I will go to 89 octane on the next fill up.

She "pops" a bit on deceleration now. More that she used to, but not too loud, and not severe. Isn't that another indication of a leaner mixture?

I know, I need to get her on a dyno and see the A/F ratio and jet accordingly, but the closest one is hours away and I don't have the time or money to do that right now. Seems to me the evidence points to a leaner mixture than before, but I am concerned with the temp increase.

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2003 Bonneville. Cardinal Red. Tach Package. Tank Pads. AI removed, Snorkelectomy, Staintune reverse cones, rejetted 42 & 125. Ikon Progressive fork springs, Ikon 7614 Progressive rear shocks, 18 tooth front sprocket.

Forchetto

220F seems fairly high for oil temperature, but I suspect those filler cap gauges are not really monitoring the actual oil temp as they don't have a probe dipped into the oil. The hot blast from the cylinders will give much higher temperatures than the actual oil.

Lobo74

I thought 220F was about the limit too, hence my concern.

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2003 Bonneville. Cardinal Red. Tach Package. Tank Pads. AI removed, Snorkelectomy, Staintune reverse cones, rejetted 42 & 125. Ikon Progressive fork springs, Ikon 7614 Progressive rear shocks, 18 tooth front sprocket.

Baltobonneville

I have the almost identical configuration as you--see below (note I have Thruxton needles, which might reduce the jet size I need). I don't have any hard numbers, but it's been running nicely with 120s and now I'm trying 118s, still good. I also have slight popping on decel. I'm going to leave it there unless I do a dyno run--not likely--or come up with a good reason to change it.

I might still fiddle a bit with needles and shims because I can't leave well-enough alone.

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Marty
2005 Bonneville Blue 790cc, AI removed, Staintunes RC, Unifilter, no snorkel, 118/40/Thrux needle/1 shim/3 turns, tachometer, Ikon 7610s in back, Ricor Intiminators in front, Pirelli Sport Demons, D9 gauge panel.

Skull Crusher

Exactly, the pick up more the ambient case temp and the blow by from the cylinders. They don't have an internal probe and can't sample the actual oil temp. If I were you I'd forget about the temp gauge for nothing more than a novelty. You will run slightly leaner and could do with a Norman Hyde bellmouth if you decide to keep the airbox. Throttle application, length of run or idle time all have a factor on temp. These are air cooled engines and temperatures from 225 range are not uncommon. Just the nature of the beast.

Cheers

Jeff:

Forchetto

I wasn't too sure so I've just done a search and for air-cooled engines the optimum oil temperature is given as 180°-210°F. This is measured in the sump by a probe sunk in the oil pan.

Lobo74

Hmmm. It looks like the actual probe sits in the middle of the round gage/oil cap assembly, and when the cap is installed is positioned in the case just above the gears visible when the cap is open. The gage/cap assembly is anodized black, and sits fairly close to the right cylinder cooling fins. All in all, without the benefit of oil flow cooling off the probe it appears to me that the heat of the right cylinder as well as the engine case and crankcase gasses internal will influence the temp reading on the high side.

No evidence of the oil cooking or shellacking that I can see or smell.

As you say, I might use the gage as a novelty item that indicates trends, but does not give accurate oil temps inside the wet sump.

OK, now I only have to deal with jetting , unless of course it IS more accurate than I have surmised and indicates oil isn't flowing through the oil cooler . . .

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2003 Bonneville. Cardinal Red. Tach Package. Tank Pads. AI removed, Snorkelectomy, Staintune reverse cones, rejetted 42 & 125. Ikon Progressive fork springs, Ikon 7614 Progressive rear shocks, 18 tooth front sprocket.