Monday, June 1, 2015

Monthly Airhead Meetup



Today was the first Monday of the month which meant that it was time for the monthly meetup of our local Airhead group. Over twenty people showed up with the majority riding. Not everyone who shows up rides an airhead, i.e. BMW motorcycles with the model 247 air-cooled engine, but most have a preference for these machines. On Saturday, I actually got the Beemer out on the road after changing out the studded tires, changing the engine oil and airing up the tires. Even though it hadn't been ridden since January, it started right up and idled smoothly. On the road it was much harder to steer but easier to cruised down the road due to the additional 20 hp.

More air box testing today. I read an article online on how to tune the Keihin CV carburetor. The engine would idle very smoothly when the idle screw was turned all the way in. It was at ¾ turn out. This suggested a change in the pilot jet to one step leaner so I changed both pilot jets from a 42 to a 40 and turned the idle screws out 1½ turns as a starting point. This turned out to be a good guess as it idled very smoothly at this setting and rougher when turned in or out an additional turn. I then used the TwinMax to balance the carbs again at both idle (1050 rpm) and at 2500 rpm. Only very small adjustments were needed. The test ride indicated smoother starts and the engine pulled well in all gears when warmed up. I think I'm done messing with this mod.


10 comments:

redlegsrides said...

man you sure you did go through a lot of variables to tune the carbs to the airbox mod. almost makes me happy with the EFI, almost.

RichardM said...

I do like the ability to do the tweaking provided by having carbs but not needed with efi. I'm still amazed at how hot this engine runs with the stock jetting. Maybe that's what contributes to the bearing failures...

redlegsrides said...

well, I wouldn't discount the heat being a factor but was told unofficially that it was the bearings being pressed in too hard during assembly of the crankshaft...at least where it pertained to the failures I experienced in the 2011 rig.

RichardM said...

I was thinking of CCJon's failure while climbing grades in Idaho. I don't think he ever was told why it failed.

BMW HACKER said...

The ABC Chairman of the board contacted me last year and requested that I remove the "ABC Logo" from my blog site as I was committing a Copyright Infringement. He must not have hunted you down yet....lol

Trobairitz said...

Over 20 people showing up seems like quite a few. Was that a high number for attendance or average?

RichardM said...

Usually, maybe 10 so this wa quite the turnout

RichardM said...

Nope, not yet. Though it does make a nice button on the page for their site.

VStar Lady said...

Wow, great turn out ... says something for your spring weather.

RichardM said...

Yep, though it was down in the high 30s (°F) that morning and it snowed east of town towards the border...