Dellorto issue - 75 R90S

Thanks to the forum I now have spark. So - added gas. Again, bike is clean but has not run in 8 years. Right side carb drips/runs gas out of what looks like a overflow hole as fast as it can make its way down from the tank. I figure the float valve needle thing is stuck but I can't get the bowls off. They both hang up in one corner where it appears a tube / passage runs into the bowl. Found a schematic on the web but can't locate info on removing the bowls. Other threads discuss carb cleaning but nothing on this little problem. Advice appreciated.

berniematic said:

Thanks to the forum I now have spark. So - added gas. Again, bike is clean but has not run in 8 years. Right side carb drips/runs gas out of what looks like a overflow hole as fast as it can make its way down from the tank. I figure the float valve needle thing is stuck but I can't get the bowls off. They both hang up in one corner where it appears a tube / passage runs into the bowl. Found a schematic on the web but can't locate info on removing the bowls. Other threads discuss carb cleaning but nothing on this little problem. Advice appreciated.

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I've never had this problem on the Dell's I've rebuilt. Remove the large nut on the bottom of the float bowl, make sure the gasket comes off with it, and drop them down. Be careful, the nut is easily stripped and finding replacements may be hard. Once the bowls are off, pull the pin securing the floats and the drop them down, along with the needle valve. The pin only comes out from one side, it is machined on one side with with groves, pull that side out.

No need to press it back in with any more force than finger tight, the bowl will not allow it to back out. There is also a very small spring connecting the needle valve to the float assembly, do not lose that.

Wayne

Alright. I've got it now. Theres an o-ring at the bottom of a brass tube that fits in a socket in the corner of the bowl. The ring has sort of 'grown" onto the metal. I just needed to tug harder but didn't want to break what I didn't know about. I've got a feeling this is the beginning of troubles from these hibernating carbs. Thanks!

Glad you got it off. The carbs work well, but are complicated with the accelerator pumps. Be careful of the plastic lever that operates the pump, it is old and can break. Once set up correctly they will provide years of service with little maintenance. They also provide instant throttle response thanks to those pumps. Rebuilding them is no more complicated than any other carb. Most parts are available, but the last time I looked, finding that bottom nut was difficult.

What was the issue with spark?

Carbs are pretty simple once you understand how that particular one works, just plan on a complete rebuild with an ultrasonic cleaning to start. I picked up a 90S that had sat for 30 years, it fired but wouldn't idle or run long with a little fresh gas and a battery, picked up a set of carbs with a fresh rebuild and that bike came alive after its long hibernation. Its in line for a full restoration.

What did you find with the spark issue, you might want to post it on your other thread so others can learn from it.

OK, I'll go back to that one.
Yes, I figure the carbs will require serious attention. But we'll see. Am in the process of finding tiny o-rings locally. Also - I've had some remarkable experience with Sea-Foam doing good things to old carbs. Don't know yet in this case.

Hucky's spare parts has lots of Del stuff. Scroll through the Bing parts.

berniematic said:

OK, I'll go back to that one.
Yes, I figure the carbs will require serious attention. But we'll see. Am in the process of finding tiny o-rings locally. Also - I've had some remarkable experience with Sea-Foam doing good things to old carbs. Don't know yet in this case.

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Max BMW has rebuild kits for less than 25 dollars. Other parts are also available from them individually. They were very helpful when I rebuilt mine.

Deliortos

Guzzino.com in Ca. has everything Dellorto.