The owner of this site assumes no responsibility for any adverse results from using any of these tips. They are, to the best of my knowledge, accurate and many of them are put into practice on my own scoots. However, I cannot guarantee that they will work for you.
I received this in my e-mail today (3-19-01) and found it somewhat amusing so I thought I would put it up here:
From: SilverArt
Comments: How to learn bike repair:
1. Buy a new '66 Bonneville, in '66.
2. Seize it up going down the Grapevine.
3. Push it five miles to a gas station that's still open.
4. Get ride to SF from friend.
5. Give what's left away.
6. Ponder for 35 years.
7. Get another Bonneville in 2001 - and restore it.
Send me some some pics of your work in progress I'd like to see them. And post them if you don't mind.
Dismantling Concentric Carburetors
Remove the carburetor from the engine and unscrew the two screws holding the top. Pull out the throttle slide and lift the return spring to enable removing the needle and needle clip. Compress the return spring and guide the cable end out of its retaining slot. Separate the cable and slide.
Remove the air slide by compressing it's spring so the cable end can be freed from it's slot.
Dismantle the banjo connection and the fuel strainer.
Remove the float bowl screws and the float bowl. Lift out the float, hinge pin, and needle valve.
Unscew jet holder and and remove main jet.
Remove all rubber O-rings and clean the remaining components (excluding the float) in carburetor cleaner. Use compressed air to blow air passages and jets clean. Never use hard, sharp objects such as a peice of wire to clean carburetor jets. Instead, use a broomstraw to remove hard blockages from the jets.
Inspect the componets as detailed in the following section and reassemble the carburetor.If possible, replace all washers and gaskets, particularly those in the float bowl, with new ones. Check that the two rubber rings on the float bowl mounting screws are in good condition. These are easily damaged repeated tightening of the screws of the screws and are a common source of leaks. When reassembling the float, check that the needle is correctly seated in the float recess.
Carburetor Components Inspection
Check the throttle valve slide, mixing chamber, and slide for wear. Make sure the needle is not bent, scorn, or worn. Check the throttle return spring and air valve for resiliency. The throttle return spring should have a free length of about 2 1/2".
Check the float for gasoline leaks by shaking it. If any gasoline is inside, replace the float. Check the float vavle assembly for wear and replace as necessary.
On concetric carburetors, the pilot jet is not removeable. If it becomes blocked it will cause hard starting and poor low speed performance. It can be cleared by blocking the low speed air passage at the bell end of the carburetor, removing the pilot air screw, and blowing compressed air into the screw opening.
Carburetor Adjustments
The throttle stop screw should be set so the engine idles at slow speed with the throttle fully closed.
The pilot air mixture screw is used to obtain the correct idling mixture. Screw it in until it just bottoms slightly, then unscrew it 2 1/2 turns to obtain a basic starting point for idle adjustment. Screwing it in richens the mixture while srewing it out leans it.
The needle position and the needle jet control carburetor mixture from just over idle to 3/4 throttle.
Throttle slide cutaway primarily affects carburetor operation from just over idle as the trottle is opened to 1/4 throttle. Fitting a cutaway with a larger number makes this mixture leaner while a smaller numbered cutaway richens it.
The main jet controls the mixture from 3/4 to full throttle.
Twin Carburetor Syncronization
Syncronize twin carburetors by first adjusting the throttle cable play to a minimum and so that both throttle slides begin to move at the same time when the throttle is opened.
Start the engine and remove the left spark plug lead so the motor is running on the right cylinder only. Adjust the right carburetor,using the pilot air screw and the throttle stop screw so the motor is running at as smooth an idle as possible. Replace the left plug lead, remove the right side lead, and perform the same adjustments on the left carburetor. Replace the right plug lead and unscrew both throttle stop screws the same amount until the engine idles just fast enough to keep it running with the throttle closed.
Triumph Valve Timing
Rotate the crank and cam gears so they line up as shown in the pics below. The exaust cam gear should be in line with the intermediate wheel's dot. The crank gear's dot should be in line between the two marks on the intermediate wheel. The intake cam gear's dot sould line up with the long dash for T-120 and TR6 models or the short dash for 6T models. The marks only line up every 94 turns of the engine so if you happen to crank it over while you are working on somthing else and the marks no longer line up this is probably the reason. See the pics below for the propper alignment for 750 models.
