hey, for synching carbs, I found a pretty good way of doing it.. take anordinary engine vacuum guage and a length of that red silicone vacuum tubing, and plug it onto the vacuum port... you can do this with the bike running
then you'll notice the guage flutters like mad (a liquid filled guage may work nicely) but you can just squeeze the tubing a tiny bit at a time until it steadies but still reacts... take an initial reading on #2, then do #1, adjust, go back to number 2, take a second reading... go to #3, and then #4. i did mine, they were nearly within spec of +-1"Hg... they're bang on now (my reading was around 7 in HG, but it doesn't matter what it is as long as they're all the same)


as for cam chain tensioner, i'm intersted in what your findings are with the rattling, mine is a little cluttery when it's cold, particularly under 3000

I really cant complain about the power under 3000, I mena it's not a vtwin, and it's not a big block, but it really has no issues with low arpm

and for the hig RPM bad running... definitely check the plugs and wires... you may also want to check your fuel supply (filter, pump, and shut off valves)

of course we're interested in sites that will save us money by making our own tools

 

"As the cam chain stretches and the CCT doesn't take up the slack, the valve timing retards. That means the engine runs better at higher revs, but worse at lower revs. I'm not sure if a new chain and/or a new CCT will cure it. Advancing the cam timing using slotted cam sprockets could bring back the power down low. Has anyone used slotted cam sprockets?"

Ah, good point. How many degrees of retardation do you think it would it take to make a noticable difference? When I worked my CCT over and put things back together the engine ran noticably different - much smoother idle, where before it had a lumpy, hot-cam type of idle. Unfortunately I didn't check to see if the cams were timed correctly, and wonder if they had been advanced a tooth or two.

Interestingly enough I just synched the carbs today. Got them spot on at idle, then ran the engine up to 5000 rpm. By then carbs one and four were pulling considerably more vacuum than two and three. Is that normal? What might cause it if it isn't? Plugs? Wires? Valves?

 

it could also be a vacuum leak... did they return to all 4 carbs being in sych at idle when you let it idle back down?


it could also be the springs that push the carb diaphram down that are stronger in some carbs than in others... just my two bits, going from theory not form experience

 

Why not try synching them at 5,000 RPM, then see how they are at idle? The only thing I can think of would be the piston slides sticking in carbs 2 and 3.

 

that would be a possiblity... it probably wouldn't hurt to take the top off the carbs and see if anything's amiss there

 

oh, it might be an idea to check the plugs for the coloring, it could give you an idea if some cylinders are working harder/ running leaner than others too

 

Thanks for the ideas everyone. I'll check for vacuum leaks and then start reading up on the carburetors and see what kind of a job it is to go through them. The carbs do come back to being in synch when the throttle is closed. Last time the plugs were out was a few weeks ago when I did the CCT, and they were all fine then, but it is probably a good idea to take a look at them again.

 

hey, let me know what your findings are.. I resyched my carbs again today, it has a bit of a miss at idle, particularly when it's hot. my bike is an 88, I found the idle mix screws for the outer two carbs, but I'll be damned if I can get to the inner ones, or even see them... since I was just resynching the carbs, I decided to do what you did and rev it up a little more and check it, I found that at 2500 rpm they were out as well... , I didn't pay attention to which ones were out though

just out of curiosity, what vacuum does your bike have at idle? mine is about 6-8" Hg

 

I plumbed all four manifold take-off points into one and connected it to my vacuum gauge. It was all over the gauge. But if I hook each one individually to my mercury stick, it is high and steady. Actually, I've tried this with all my multi-cylinder bikes and never got a vacuum gauge to read like on a car.

 

what I did which worked like a hot dam was get 2 lengths of that small red silocone tubing, get a glass bottle (I used a Sobe bottle) and drilled a 9/32" hole in the lid... I inserted a small piece of tubing into it, and then put a tee fitting into it,the tee fitting expands the tubing to make a tight seal.. I had a small restrictor which I stuffed in the hose going from the tee to the guage, and then used the other line to connect to the carbs.. there was just a trace of puslation, not enough to bug me though...

if you want to hook up a vacuum guage like on a car, you will need a similar device with a significant volume to reduce the pulsation, the reason for this is that the car has a large volume intake manifold which does the same thing.

eventually I might get a mercury stick.. in time... first I need more riding gear and other absolute essentials