Just read your post about selling the 400 Matt...
...If you gotta sell for personal reasons then that's what you gotta do.
But if it's because it won't purr like a kitten........then......well.....I would have sold everyting I own by now if I felt that way.
Forgive me if the following is low balling your tech abilities, I just want to help you with the old girl and don't want to leave any stone un-turned:
These old bikes only really run perfectly when all systems involved are tuned to perfection.
Some of these systems tend to cause more headaches than others; refering to the carbs and ignition.
However, these aren't always the source of the problem. Old fuel, loose electrical connections, tight/loose valve adjustment, intake leaks, pluged airfilter/box, bad sparkplugs (cracked insulators), etc..... are some other problems which can mimic both carb and ignition issues.
There can also be mechanical issues such as low compression, worn cams, burnt valves....
SO.....I when a machine is sick, I like to start from the begining with the most basic of basic things and get to the bottom of the problem from there. After all, the best answer is usually the simplist.
You have a bike that partially runs which means that you are very close to perfection. There is a problem somewhere that has not been addressed or a combination of a few problems.
Start by verifying that the battery has juice....lights work, as well as starter.
Check the fuel level, and verify that fuel is making it's way to the carbs........I think you did this already?
Check to see that after the bike has started (or somewhat
) that you have then turned the
choke OFF. I have nearly gone as far as pulling the carbs apart when I discovered that I misunderstud the correct choke positioning
(I left it on..)
DOWN is off (rotated clockwise) and UP is ON. The bike should run when warm with it OFF.
Now, This is where the bike runs poorly right? It revs but wont idle.
Verify that it is running too rich at idle by slowly putting the choke ON, while maintaining around 1200-1500 rpm with the throttle, and see how the bike reacts.
Somewhere close to full choke the bike should either die, or begin to run better. If it dies than yes, it is too rich. If it begins to run a little better than it's too lean.
Now, if the choke did anything at all then this says that it is likely a carb issue. HOWEVER, before diggin into the carbs again, have a look at everything else like the ignition system to verify it is not the problem. (SEARCH: setting points etc...)
Verifty the intake system is clear (no rag stuffed in the intake pipe under the seat or something silly
)
Check the valve adjustment......or as a quick check, at least pull the valve caps off (17mm wrench) and the rocker arms should wiggle a very small amount. You should really adjust these but a little clearence is close enough to rule out them as the cause.
If some or all of the rockers seem tight, or very loose you need to adjust them (SEARCH: Adjusting valves...)
At this point, if no other faults have been found, I'd say pull the carbs off and have another go.
In my own experience with my 350F (virtually the same Carbs) the smallest crud in any of the jets causes havok.
If you didn't already, you should pull the main jets and push out the emulsion tubes. On my bike, every hole in these tubes was clogged and made the bike barely run.
.......well, my fingers are sore so I'll stop here
But if there is anywhere on the web where your mechanical issues can be sorted out with the help of fellow bike owners.......it's here at SOHC4.net.
Matt.
