Friday, November 14, 2008

Fuel System Mystery

Dug into the BMW fuel system after work the past two days. Drained the fuel tank, removed and cleaned the pet cock fuel screens, then replaced the in line fuel filters. Removed and replaced the carb diaphragms with new ones. The old ones seem good but decided to change them anyway. Bike cold started perfectly and idles perfectly. Still had the high RPM miss though. Talked with Bob Clement (Bobs Motorwerks) and we discussed the problem. He quizzed me about jetting etc. He asked me what the original R75 needle jet size was. I looked and by chance they are a larger jet. I swapped the needle jets out and lo and behold the problem was about 95% healed. The engine still seems a bit weak from 5000 to 6500 RPM so will change the main jets out to a slightly larger jet. Found them on line for about $5.00 each. I'm sure I'm on the right track now. With the modifications I've done it is taking some trial and error to get the engine up to its' full potential. Have had contact with an eBay seller who wants a Toaster Tank.

He has a large 6.2 gallon German Police tank up for sale and we may do a trade. The German Police tank has an upper tool box & lid on the top of the tank. The little tool box was for the Police Radio installation. These tanks are quite rare. My Toaster Tank is in a little better condition than the Police Tank but I think it is a fair trade. The Police Tank is definitely much rarer than the Toaster Tank.

This tank could be used with the sidecar as it has a 5-6 gallon capacity. The tool box takes away
from the normal 6.2 gallon capacity of this style tank. We'll see if we go through with this transaction in the next few days.
I've had conversations with the tank owner and we will go through with the tank swap this week. I completed 6 eBay sales this evening for a total of $140.00. That brings the total sales of parts from the "basket beemer" to over $950.00. Pretty good considering how much of the bike was missing. I still have the frame/wheels/hubs/final drive/engine block/etc. Will probably squeeze another $200.00 to $300.00 out of whats left. I removed the charging system components this evening and will keep for spare parts. Contemplating installing the 280 watt alternator from my R90 engine to replace the 180 watt R75 alternator. Not sure what other components need to be swapped so put a post on the /5 United site to see others opinions / experiences with this type of swap.

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Gila Mtns.

Gila Mtns.