Sunday, April 5, 2015

Shimming the Needles

I didn't take any pictures while I had the carburetor partly disassembled. I removed this metal cover (originally held on with phillips head screws) and removed the vacuum controlled slide and needle. There is a mod listed on the Soviet Steeds forums saying that putting two M3 flat washers on the needle controlled by the slide will slightly richen the mixture at mid to upper throttle opening. The rig has some hesitation at around 50-55 mph so I tried this to see if it would help. My gut reaction is that throttle response is improved. It now readily accelerates from 50mph to 60mph. The phillips head screws were upgraded to allen head screws at the same time. I was going to drill the slide enlarging the vacuum port to 7/64" but I couldn't find the correct size drill bit.

Tomorrow evening is the monthly Airheads get together at the Silver Gulch so that'll be a good opportunity to see how it performs on the highway. While at the hardware store, I picked up three grease fittings, a 1/4"-28 tap and drill bit. This is to install grease fittings in the drive shaft splines and the rear brake pedal shaft. All require regular maintenance and the grease fittings will dramatically reduce the time and effort required. But like most things, installing the fittings will take some time and effort. 

10 comments:

Conchscooter said...

Time you have plenty of now, short timer. Effort, well you knew that when you got the Ural! I was on my knees tightening some bolts in a parking lit yesterday. The glories of old machinery that ca never retire.

RichardM said...

Right you are! I went into the Ural eyes wide open and for me, part of the enjoyment is the tinkering. Old bikes seem to need a lot more care and feeding. I suspect that you don't mind that with the new 2-cycle Vespa.

Lucky said...

I'm sure the grease fittings will make life a lot easier. I'd think that'll be a bit of a project, though.

It's great that just adding a couple of shims resulted in a noticeable performance improvement. I'm sure every little bit helps.

RichardM said...

The change from the shims is drivability more than performance. Adding grease fittings to the driveshaft doesn't look that difficult. The brake pedal shaft may be more difficult.

redlegsrides said...

re the grease fitting on the drive shaft, ensure you've clearance once its in place.

thought about the rear brake pedal shaft grease fitting but wonder how much the grease gets moved around.

RichardM said...

In my case there is insufficient clearance to leave the grease fitting in place. Easy enough to put in a threaded plug and swap it for a fitting a couple of times per year. Way easier than removing the driveshaft every time.

The rear brake pedal shaft seemed simple enough and if the shaft has grooves cut, the grease should cover the shaft pretty well. I was going to drill and tap the sleeve from the bottom instead of drilling the shaft like others have done.

redlegsrides said...

I've had to take the brake pedal shaft out before to clean/lube it, no splines, it's a smooth shaft with a splined end where it hooks up to the lever that activates the pusher's brake linkage.

RichardM said...

I was thinking of filing some longitudinal or better yet spiral grooves in the shaft. But I suspect that just having the grease going in under pressure will be sufficient to have it spread. Easy enough to test once the fitting is in place.

Canajun said...

On another site I saw this reference to Moto Guzzis earlier today: "Moto Guzzis, turning riders into mechanics for 90 years". I'm beginning to think that may be more appropriate for Urals. :)

RichardM said...

You don't even want to consider a Ural unless you are willing to be your own mechanic. The maintenance interval is only 2500km. Plus the dealer network is really sparse. Maybe one or two dealers per state.