Tuesday 31 August 2010

Technical Update

Well, I am back to measuring the float height manually and not using the tool! It just doesn't seem to work, and I don't have the confidence or time to mess about with it further. So all the floats are now set at 18mm with the ball valve just closed.

I've been working on replacing the steering lock adjustment, by using some metal brackets hanging down from the fairing bracket, not sure if it is going to be strong enough but we will see.

Testing both bikes has taken a back seat, as they have gritted the road in front of the house - don't want to swallow any grit! But I must get out there soon, just to make sure that everything works before the endurance and racing on the 11/12 September at Croix-en-Ternois.

Monday 23 August 2010

Fuel level


Just writing this to try and get my thoughts clear on the fuel height adjustment. I am using the Suzuki tool, which is basically a piece of graduated tube that screws into the drain plug for each (in turn) carburetor. The idea is that you see on the outside of the carb, the fuel height controlled by the float valve. On the RG the Suzuki manual gives the height to be 5.5mms below the line of the gasket i.e. where the float bowl meets the carb body.

Well first things first. The Carbs do not sit horizontally so there is a difference measuring one side of the carb or the other - so you need to keep the measurement to the rear of each carb. Secondly, if your pit stand lifts the bike too high then this will have an affect on this measurement.

Once you have the idea of what is supposed to happen, it should be very logical that as you bend the tab on the float, the level of fuel should move up (or down). The manual states that the bike should be idling for this measurement, but I didn't see any difference whether the bike was idling or stopped or even if the carb was connected to the engine or not - as long as the carb is at the right height and position. So most of my testing was done with the carb barely connected (just the fuel lines, and then after each change I could turn the fuel on, measure the fuel height and then quickly drain the fuel and then remove the carb, and try a different setting.

Well all of the above is great in theory, and seemed to work well on the right hand side carbs, but when I transferred this new skill over to the left hand carbs, I could not get ANY adjustment! Whether I bent the tabs one way or the other, it made very little difference to the fuel level. I also tried this with the bike running, but to know avale - it just doesn't work!

If I think about it, this means that my fuel height is being controlled by something else other than the height of the float OR bending the tab has an almost invisible affect on the level of the fuel. The float valve DOES however shut off the fuel, as nothing ever leaks out of the overflow pipes, so the float MUST control the inlet of fuel! The above two ideas seem contradictory and they are!

So why am I bothering with this adjustment? Why don't I just manually control the float height ~17-19.5mms (with the carb upside down and the float tab just shutting the valve), well because I have BALL VALVES, and these little buggers aren't the same height as the standard needle valves, so the standard float height needs measuring differently.....

Monday 16 August 2010

Stator Cover photos




Well, a bit disappointed really, still I have produced a serviceable item, but just not very pretty. I think too much gel coat initially, and the mold was not perfect - so I couldn't really expect a perfect piece - never mind you live and learn, and it will do to practice on - I will cut a piece out of this one to make way for the new carbs!

Update

Well back from my hols. in Uzbekistan - interesting experience!

Back to the bikes. The RG is now fully built, and it started easily yesterday, I will need to adjust my carbs, in fact I have bought a Suzuki tool, which measures the fuel level in each float chamber, and I was surprised to find there was a big difference between carbs. in the left 2 carbs the fuel was approximately up to the gasket level, and with the right carbs it was way below, about 14 mms. It should be at 5 mms below the gasket so I will need to adjust my float heights to compensate.
The engine runs OK, although once I have balanced the carbs I will need to run in the new piston, and "hope" I didn't miss any bits of small end hiding in the crankcase - I have bought a new bearing kit - just in case!

I have made a fibre glass mold, and yesterday I layed up the carbon and it should be dry this evening, so if I can remove the carbon from the mold, I may have a new rotor cover this evening - I'll take some photos if it looks good!

The RD350, has a new set of Goodridge brake hoses for the front, I needed to change these because the guys in scrutineering didn't like the fact that I had a brake line splitter which was below the lower yoke on the forks, so now I have 2 lines going directly to the calipers, must have saved at least 50 grams...

Jobs left to do before Croix-en-Ternois :-
Find a fireman (any volunteers?)
Redo the steering stops on the RG500
Adjust the carbs on the 500

At this point I am aiming to do the the endurance on the 350 with Christian, and run the 500 in the other races.

Speak to you soon.

Dave