Delorto

[8ninety8]

I've never had great luck syncing my carbs and this week I'm going through them for lack of anything better to do. Since I've got them off I was thinking of drilling a hole in the body and screwing in a vacuum take off. Any one do this on Delortos?

Or should I stick to the usual, turn so many turns, wiggle the air adjustment screw around, listen for proper running sound, wiggle and turn other adjustment screw around, get on bike, ride fast enough to get the carb up on the main jet and when waiting at stop light, blip throttle to keep motor running, and make others wonder WTH yer doing?

The carbs look fine for a '74 R90S. A few dings but otherwise clean, smooth up and down, no leaks, just puttering around cleaning things up on the bike and wondering if anyone ever drilled holes for a Vacuum take off.

 

[bikerfish1100]

dude, put the drill down, and s l o w l y w a l k away from the workbench!

 

[8ninety8]

Bikerfish, I know somebody has drilled a vacuum takeoff at sometime to sycronize these carbs, just wondering where they drilled. I probably won't drill any hole, but just thinking about doing it. I'm wondering why the factory didn't do it.

Fiddling around, twist the air jet, twist the idle screw, disconnect this, listen to motor, perform only while hot, careful, don't idle engine for more than ten seconds, listen to left cylinder while connectinig the right cylinder....I never gave a damn for how great a bike sounds when idling anyway. And after a ride it always seems to be idling high, which is a good thing as it keeps the battery charged.

 

[20774]

Snowbum has an article on the Dells...

http://bmwmotorcycletech.info/dell.htm

Towards the bottom it mentions:

"Connect each barrel to the mercury manometer, taking off the blanking plugs provided on the vacuum intakes and fitting instead the proper vacuum connectors."

Not sure if this applies in your situation. Might want to read the article and see if helps any.

 

[8ninety8]

Thanx....

Thank you Kurt, this is invaluable for me. Never would have found all this stuff without the link. Think I'll stick to to tuning by ear and the advice in the links. I've haven't touched them since I first took the bike apart and they are beautiful pieces when cleaned up.

 

[swall]

If you are uncomfortable synching carbs, then leave them alone. Carb synching is not that hard--stick your finger in the left carb so you can feel the slide. Then watch the right slide as you crank the throttle ever so slightly. That way, you know what the left slide is doing when the right slide moves. Adjust accordingly. For the mixture screws and idle speed screws, run the engine (after warm up) one cylinder at a time and see which one is running faster. Adjust accordingly then repeat several times as needed.

 

[8ninety8]

thanx swall...

I finished blowing out and cleaning and mounting today, started right up, after a short spin came in and got them idling at about 1200 RPM, which is fine with me. The best thing about these carbs is throttle response, give it a twist, and vroom. The best two wheeled hot rod around. Not a crotch rocket, better, because it's 34 years old and reminds of things when I was younger.

One thing, however, Kurt, after I got into Snowbum's web, I read almost the whole thing, and beside the point of going in for a PSA, I noticed there was a lot wrong with my '74 R90S that I wasn't particularily aware of, even after owning the bike since 1987, tearing it down completely, and riding with some abandon.

That is the transmission. My serial # Y8629 puts it at about the very beginning of the run of the /6 transmissions. I've never babied this thing, thinking, WTH, it's a BMW, what could possibly go wrong, after all, it's won the superbike championship several times. I've banged on the transmission never giving it thought. How worried should we be of these early /6 5 speeds? Guess I'll take it easy from now on. Thanx again to this site which I have only recently become acquainted with. And to all the participants, people like Snowbum who have greatly expanded our horizons and given us BMW owners the knowledge to breath life into these bikes.