Carb and valve question

86 VFR700

Im planning on adjusting the valves and syncing the carbs since i recently cleaned them.

I assume I should sync after, am I correct?

How long does it usually take to adjust the valves, ive done it before just not to this bike.

What was the factory main jet size for this bike? Mine has 118 mains and supertrapps. Curious if anyone every rejetted it in the past.

Ive seen the carb sync tools on ebay that are just vacuum guages. Would it be possible to do it with just one guage and just check them all back and forth and get them even? Where is the vacuum port on these carbs?

 

No, if the bike idles smoothly after the valve checks, a synch job is not necessary unless there is some noticable running issue.

To adjust the valves will take at least 4-5 hours since the cooling system needs draining and the radiator should be removed for best access to front cylinders. Remove top right rad hose, unplug fan and thermoswitch wires and lay the attached rad on the left side. After setting, be sure to rotate the engine 2 or 3 times and check again.

You need to start with the assumption that no clearances need adjusting unless they measure more than .003" off the standard. It's very tricky and time-consuming to reset the screw and locknut to anything better than about a .001" plus or minus, so if the clearances measure within .001-.002" of standard specs, it's best not to touch them.

A very useful test is "go or no-go". Exhaust valves, for example, are supposed to be at .007" (center of proper adjustment range), so if a .008" blade slips in and a .006" is too tight, you're good.

No, synch is not at all possible with a single gauge, and the vaccum access ports are on the carb intake manifold runners covered with a small phillips head screw.

Don't attempt any work without first reading and studying the Honda service manual.

 

Not to contradict Squirrelman, but it is possible to do the adjustments without draining the cooling system (I did it this way a few weeks ago). Albeit, it is a little more cramped, but it is possible to do. This would easily shave 1 - 2 hours off of the time estimate above.

You basically just unbolt the radiator and there should be enough slack in the hoses to move the radiator off the right side of the front of the engine. You'll want to tie off the radiator to something to keep it from hanging on the hoses, but it is definitely possible.

Aside from that, everything else is as Squirrel said above!

 

Without removing the rad access is very cramped, and both measurements and adjustments are far more difficult, but it certainly can be done with rad simply moved as described above.