Following is step by step on doing the ear shave (while
doing coasters as well) on a BUBF (1500A/C).
'B' Jet Needles
Step by Step Details:
2. unscrew and remove the round decorative cover located over the right side carbs. locate the silver plugs situated next to what appears to be a brass plug. Use the 3/64 drill bit and drill a small hole in both these plugs. Take a scribe or nail and pop the plug out. Screw these jets all the way in, then back them out 2 1/2 turns on both carbs.
3. undo gas pump (take it off mounting bracket but leave hoses on) and balance carbs
NOTE! Get a manometer to balance the carbs before rejetting. A manometer is a carb sync tool that has mercury in plastic tubes and hoses attach to the other end of the tubes. Refer to a shop manual, Clymers or the instructions included with the manometer for the procedure for carb balancing.
NOTE! If you have a Clymers manual, the picture (in carb sync section) in chapter 3 purporting to show the location of the vacuum ports is INCORRECT! It DOES NOT show the vacuum ports. The hoses shown are actually air vents which connect to a 2 into 1 collector which is routed under the seat. These hoses will not be touched in this job. One vacuum plug is located under the fuel pump you removed. It is joined to a 4 way plastic 'T' which connects to the other vacuum plug located on the right side of the bike on the front/base of the rear cylinder carb. The other two plugs go to the 'EPA cans'. EPA cans are the brass colored cylinders with a bunch of hoses coming out and are tied into the bikes vacuum lines and reed valves.
4. After balancing the carbs, cap the vacuum plugs on the carbs. Then, take off the 2 plastic covers which are directly behind your steering head which cover the thermostat housing. There are three screws; one on each side and a screw on the top.
5. Drain the radiator. There is a plastic plug on the bottom of the radiator. Undo the radiator cap so the antifreeze will flow. Collect the antifreeze in a clean container for reuse.
NOTE: At this point U-Turn says:
6. Remove the 4 hoses connecting the thermostat housing and remove the thermostat housing.
7. Pull all the hoses off the EPA can in front of the front cylinder. DO NOT pull the hose coming from the crankcase off its plug. It is used later. Remove the EPA can.
8. Install the front coaster per the directions supplied. Use the existing gasket if it doesn't break or Hi temp RTV (Form a Gasket) can be used.
9. Connect the crankcase breather hose to the crankcase breather filter and wire tie it to the frame down tube.
10. Remove air box. It is a tight fit but will come out at this point. You may need to cut some wire ties if cables routed down the frame obstruct removal.
11. Install rear coaster per supplied instructions.
12. Remove battery. This is a good chance to top the battery off with distilled water, clean the terminals and put some Vaseline on the terminals.
13. Remove rear EPA can located just in front of where the battery had been.
14. If the airbox inlet ducts which connect the carbs to the airbox are still on the bike, remove them and set them aside. These ducts will be used later.
15. Remove the plastic top from one carb and be aware there is a spring under which will require you to keep pressure on the top during removal so it won't fly out. Take off the top, remove the spring and using needle not pliers, remove the plastic jet needle retainer from the inside the carb. Using needle nose pliers, remove the jet needle. Replace with new needle and reassemble. Take care not to pinch the rubber diaphram with the plastic top. The jet needle part number is stamped on it. There can be two different jet needle numbers so ensure the correct one is installed in the appropriate carb. Repeat for other carb.
16. Using a 7mm wrench remove the two bolts holding on the bottom of the carb. Using a small ratcheting offset screwdriver, remove main jet which is the lowest jet protruding from the bottom of the carb. Replace with new jet. Carefully replace the bottom so the rubber seal doesn't leak gas. Repeat on other carb.
NOTE!: Do yourself a favor and get a small ratcheting offset screwdriver. These are available in hardware stores and sometimes have a hex drive. I bought one with interchangeable hex drive Phillips and flat blade bits. You will need a thin flat blade to remove/install jets. You may also be able to find a very short 7mm hex drive socket which will also fit this racheting tool and you can use it to remove the 7mm bolts that hold the bottom of the carb on.
The small offset racheting screw driver will be very useful for removing the jets. Due to the limited space between the cylinders, a normal offset screwdriver may not have room. A regular flat blade small screw driver doesn't have the leverage to break the jets free easily or tighten them up well (IMHO). Jets; get 3 or 4 ranging from about 125 to 135 or so. The stock application uses 112 and 115 (front/rear). Use the larger jet on the carb attached to the rear jug. Anyway, if you get 4 jets, you have some to swap up or down. Do not over tighten the jets; snug will do.
17. Cut off just the end of each of the two carb to airbox ducts. Cut as little as possible from the end that used to attach to the air box.I like to install a two inch long piece of PVC, 2" diameter (its for 2 inch ID therefor it is a shade bigger outside diameter) in the cut ends. This gives the air filter a more positive clamp surface. Slide a PVC spacer into the cut end of each duct and use sheet metal screws to fasten these parts together. On the longer of the two ducts, you will need to remove about an inch of the rubber divider which is used to keep this longer tube from getting squashed. Apply RTV around the joined area to seal it. You may wish to grind down the exposed PVC end (the one the air cleaner will slide on to) a bit as the filter fits on very tightly or you can work the filter onto the end of the PVC at this point. Use the larger / wider radiator hose clamp you bought, as the one supplied is very thin and may not seal well nor will it be long enough. Install the new filter units onto the carbs.
18. This is a good point to check the routing of cables and hoses and wire tie the stuff so it won't chaff. Make sure that gas hose is kept off the manifolds and route the gas hose from near where the fuel filter is between the frame members so it won't get crushed. Many of the cables and hoses were not routed well from the factory so this is your chance to improve the routing to protect the cables/hoses.
19. Put it back together. George Koppleman has plenty of notes on how to dial in the rejet in the archives. Note the pile of useless junk you removed. The bike should be faster just because of the weight loss.
Hope the info helped. email: firstname.lastname@example.org
George 'wiredgeorge' Lesho~V~2420
Where did you want to be today?