Thumbs up for carburetor balancing/synchronization.

[racefactory]

First time I've really done any proper spannering on a bike and am very pleased with the results. I have just completed balancing the carburetors and would just like to let fellow n00b spannering folk know it is definately worth it if you want to make your engine that much more like it was supposed to be when it came out the factory. If you are put off by very high price of a mechanic to do the work for you, it's worth learning it.

I have the Honda VFR400 NC30 which is a V4 and is a devils own job for any maintenance short of pulling the whole engine, I found everything pretty difficult at first but I can honestly say it was worth every bit. I now know when I went down to the shops and asked them for a quote, they didn't want anything to do with me. In fact they wanted about 800 bucks for the job. The bike was not running poorly or anything, i just figured that it would need doing at some point.

First of all I had to borrow some vacuum gauges which took quite a while (thanks a lot vifferman).

I had a lot of trouble locating the blanking screws which you need to take out of the inlet manifolds to attach the vacuum gauges, in the end had to get someone to take pics and show me where they were since there were many screws and all so foreign and far away inside the 'V'. Amongst the confusion I ended up taking off air box, tank, bit of the carburettor tray too. Then when i took the vacuum hose from fuel tank off of the number 3 cylinder it ripped leaving the end of it on the blanking nipple, this cost me about an hour and a bit of time trying to get the rest off. I then lost the blanking screw in the V when it came out (the screws are in so far away amongst a sea of wires and pipes) . At this point I almost gave up... I had spent so long just trying to prepare things. Very daunting! The next hour or so I spent trying to get the gauges attached in the next to no space available around the motor. All this while, people telling me ''see, there's much more to go wrong than to make right''.

After the initial problems I finally got the gauges connected. Then I had to put back air box fuel tank etc and then had to make a vacuum and seal off the fuel tank vacuum hose. Saw that cylinders 1 and 2 were a little off and cylinders 3 and 4 were quite a bit off. I was pretty damn pleased at this point, even having done no actual tweaking! Then I realised how the f*** was i going to get at the balancing screws, and more to the point- where the hell were they in there? Spent another hour or so trying to locate them and figure out how the hell i'd adjust those things. Turns out they were covered in dirt/dust so i couldn't see them easilly. Tried a flexible screw driver to no use, then realised there was a thing called a 90 degree bevel screw driver... but that was over 200 bucks and no way can afford that expensive a screw driver. In the end I asked around and sure enough someone was kind enough to lend one to me (thanks a lot sarge) .

After i got this incredibly impressive screwdriver it still seemed near on impossible to get to the screws and adjust them. Only after nearly another hour of practice and poking through different sections of piping and wiring, squinting eyes and killing my back to turn these screws, was i ready to do the real work.

Turned motor on, let it warm up till normal running temperature... got someone to read out the gauges whilst i tried to turn these screws. After about 15 mins I got them all perfect. It was so cool to hear the bikes engine tone change slightly and become smoother and more crisp!

Another hour to bolt her back up and get rid of the gauges and took her for a spin:

Immediately noticed less vibration (not to say it wasn't smooth before) , like through your seat and legs and hand you just feel it's that much more smooth. Didn't expect this.

More low end power- definately noticeable at speed limit or below... shit loads more mid range.

Smoother sound for sure as well...

Give it a go- definately worth it!

I can honestly say that the bike has never shifted like that before... feels like this is what it was supposed to be like when it came out the factory.

[Gubb]

Fork seals next eh?

Easy by comparison.

[racefactory]

actually no the valve clearances next. and changing a water pump seal... I think after doing this those will be easier tasks...

fork seal thread is for my brothers bike eh.

[vifferman]

Um... you should've done the valve clearances first. Although as long as none of them are way too small, it shouldn't affect the carb synch.

Sounds like getting hold of a workshop manual could be a good idea too!

Some of the 'bits' on bikes are really hard to get at, like mixture adjustment screws on the bottom of carbs, of all places.

So - you dsicovered the black hole that lives deep in the V of a V4 bike, huh? There's a lesser one on v2's as well. They have a ferocious appetite for screws, nuts, grommets, widgets, washers, and (if they can't get any of the above), dust, dirt, fluff, small animals, insects, etc etc.
This is where a telescopic magnet, some of those claw thingies, and a mirror on a stick are all useful.