Thursday, December 11, 2014

Goldwing Single carb conversion - "on the road again"

Finished up some small details today to get the bike on the road again. Now the bike is "wearing" one Weber 32/32 carb. The Weber utilizes a progressive 2 barrel system, with the secondary barrel activated via a progressive linkage.
Completed the air filter installation and plumbed in the crankcase breather to the air filter. 
Rode about 30 miles, 20 of which were on the freeway. Engine ran well and power was good. 
Took a couple of minutes to warm up. Engine wanted to "stumble" a bit when cold when throttle was applied.
Power band isn't as "seamless" as the OEM 4 carb set up but acceleration seemed to be as good if not better. 
I'll rack up some more miles in the next couple of weeks and keep an eye on the spark plug conditions.
As far as a final determination to the set up, we'll see how it performs over time. The idle is stable at 1000 - 1100 RPM. 
I'm just happy to have the bike back on the road...for around $350.00 total cost. 

The bike has been sitting since August and the front brake calipers were a bit "sticky". I removed the calipers, and with a large c-clamp in place, extended the pistons out past their normal travel distance, then use the c-clamp to re-set the piston. Performing this task a few times frees up the pistons. With the fluid sitting "static" for a long time, the fluid must create a "spot" on the cylinder bore walls.  This same scenario happened a year ago when the bike sat for a while. I'll eventually need to rebuild the calipers, and should probably change the brake fluid, although the visible fluid looks as new.
I also changed the oil / filter, I'd only ridden the bike a bit over a 1200 miles since the last oil / filter service about 12 months ago. The previous owner retro fitted the bike with a spin on filter adapter which really makes the filter change easy.

Right side view:
Throttle cable was too short to bring in from the rear, so I opted to bring it in from the front. Made a simple bracket for mounting. Had to drill a small hole through the "firewall" to route cable into place. Purchased a universal throttle kit to adapt to the cable. 
                   ("left click" on photos to enlarge)



Air Filter had plenty of clearance and the OEM Tool Tray still fits in its' place. I ordered a Weber 32/34 air filter but it didn't quite fit, so had to modify the base plate a bit to make it fit.



Left side view:
The carb came equipped with an electric choke assembly which was quite large...not enough room "under the hood" for the assembly. I removed the entire assembly and plugged a vacuum port behind the heat coil. I could have likely been able to plumb in a manual choke but so far the bike started easily with no choke....just a couple throttle twists to prime the system prior to starting. 
One issue I'll need to address is a "preheating" system to warm the manifold plenum. The proper scenario will be to have a chamber welded to the bottom of the plenum and circulate engine coolant to heat the plenum. The carb supplier says this is a "must" for proper atomization of the fuel. He was an Engineer for G.M. and knows his business. Since I have no way to perform the welding / fabrication myself, this addition will have to wait until I hook up with a reasonably priced fabricator who is willing to take it on....then I'll also need to "tap" into the cooling system to access coolant. 
I've also been thinking about alternate plenum heating options. I wonder if one could adapt an electrical heating system...maybe using something like a "heated grip" type element...hmmm....food for thought? Downside would be the additional draw on the charging system, but it might be an easier (cheaper?) option. 
According to the Engineer, the plenum does not need to be "hot", only warm, to achieve more efficient fuel / air mixture atomization.

Plenty of room under the manifold to fit a heating chamber to the plenum if I go that direction.
Initially the carb sat lower when installed....this did not allow room for the fuel inlet fitting up in the shelter area. I eventually fitted some 20 gauge 1 1/2" chrome steel pipe inserts inside the 1 1/2" rubber fuel tubing. The inserts fit tightly in the tubes and also reinforce the tubes as they are not "vacuum rated" and would collapse under throttle application. When all assembled, the steel tubes made the assembly more "rigid" and raised the carb / manifold high enough for fuel inlet fitting clearance.


2 comments:

Richard M said...

Pretty cool setup you have there! And you eliminated the whole multi-carb balance issue. If you pre-heat the intake plenum, do you have to separately regulate the water temperature based on the air temperature?

BMW HACKER said...

Greetings Richard! Shouldn't have to regulate temperature, just have enough coolant flow to "warm" the plenum. That's why an "electrical based" heating option might be viable. I think a "stumble" upon throttle application is a common occurrence without a pre-heated plenum. I'm not experiencing that trait....but then it is in the 70's here in Yuma today. I'll be racking some miles under different conditions in the next few months. I won't have a real feel for over all performance until I run it a while...also I'm keeping the OEM system complete if I want to go back to it.

Gila Mtns.

Gila Mtns.