R65 Project Going Back Together

[flybot]

Finally calling this project complete. I think its full road worthy and I can finally drive it to the DMV to get licensed. Ive put about 20-30 miles on it getting it tuned up.

It was a learning experience getting the carbs right. Ive always been pretty good with carburetors, but it had been awhile since I had messed with them. Thanks for this forum and for all the R65 knowledge stored here and questions answered.

I was getting a bit down on the carb tuning, but they are now pretty darn good. I was thinking I was going to have to tear them down again because I just couldnt get a good idle once it was warmed up. Before removing the carbs, I thought "well, I havnt adjusted the valves yet". I read it over and over that this must be done, before a carb tune. I dont know why I didnt do it. Stubborn I guess. Im glad I did it. Both exhaust valves were tight and one of the intakes. I put it back together and it started right up and went to 3500 rpm! WTH? So, I backed the idle stops both down a full 1.25 turns and she was purring like a kitten. I did a few more tweaks to the idle mixture after riding it some. Long story short, I wasnt even on the idle circuit before. The throttles were adjusted open too much. Im not sure how the valve adjustment is so tied to the carb tune, but it is.

As for the issue with the tank fitting, I had to improvise. Cant seem to get it together with my uncle to make a fitting. I think this set up looks like hairy balls, but it works. I wrapped the fittings in black silicone tape so it didnt look like I had a NOS fitting attached to the bike. The fittings were nice race blue anodized fittings, that did not go with the look at all.

Anyway, I love the ride. Its very easy to maneuver, which will be nice on my commute to work when it gets warm again. Thanks for all the help guys. Ill see you on the forum...

[Barry]

Im not sure how the valve adjustment is so tied to the carb tune, but it is.

The reason is simple. When you adjust the valve clearances you are making small changes to compression, valve timing and overlap which is the duration when both inlet and exhaust valves are open at the same time.  Idle characteristics are particular sensitive to overlap as some of the exhaust gas is mixing with the incoming mixture and some of the incoming mixture is going straight out the exhaust. To combat this the idle mixture has to be set artificially rich to get a good idle.

In the extreme, closed up exhaust clearances will really stuff up idle settings but even a 2 thou change in clearances will make a very obvious difference to idle speed and mixture. Open up clearances and the idle speed will rise which will require backing off the throttle stops and the engine will also tolerate the mixture screws being turned in a touch. I've only experienced the comparative results of a 2 thou change but I can imagine 4 thou or more could contribute to the big effect you experienced.

There is probably another aspect to the effect in your case.  When say the carbs were not on the idle circuit it doesn't necessarily mean the needle jet was flowing mixture as there is another source. What can happen is that if the throttle is too far open at idle it brings the little transfer ports into play adding quite a bit more fuel than just the mixture screw and this will cause idle revs to rise significantly.


Interesting fuel tap.

[livingdeadhead]

love your garages over the pond! are they all like that?

[livingdeadhead]

nice job too!