YCIS tool help

I can't seem to isolate out carb #4. I built my tool based on this website, can anyone tell me if there is something wrong with it?

http://home.westman.wave.ca/~jbe/YICS.htm

 

How do you know you aren't isolating #4?

 

because I can't get the Vacuum on that carb anywhere close to the other 3. I have checked for vacuum leaks and I don't seem to have any.

 

Have you checked compression yet ?

 

Did you try checking it without the tool? It doesn't sound like you have an isolation problem, it sounds like you have a problem with that cylinder. Try checking the synch without the tool. If four is still off you will know it was your tool. But I doubt it is.

 

I will check the vacuum without the tool first then...

 

Yes, the problem with the diagram for the home-made tool is that it does not include any type of seal on the far end of the tool (where the tool enters the YICS passage......just before the 90-degree bend occurs for the "handle"). Thus when you insert the tool into the passage, there will be a vacuum leak there. If you inserted the tool from the RH (#4 cylinder) side of the bike, you will have a vacuum leak that will affect only the #4 cylinder (and if you inserted the tool from the LH side of the bike, you'll have a vacuum leak and low reading from the #1 cylinder).

The home-made tool diagram is wrong in that regard, and I don't know why it hasn't been corrected after all these years, and why it keeps getting linked to (from all over the world, no less!). It simply won't work the way it is illustrated----actually, it's worse than that, since depending on unknown and unknowable variables, you will have either a big or a small vacuum leak, and thus you'll be over-compensating for the #4 (or #1) cylinder when "synching" your engine, thus making a huge mess of your synching efforts, and, if you also then adjust the idle mixture screws, you'll have an even bigger mess on your hands!

LUCKILY, you have run into the situation where you just can't get that #4 cylinder to come into synch with the others, and stopped, and asked questions.........I can only imagine how many other people who may have had a smaller vacuum leak just plowed on through, thinking they were getting a good synch, and in the process ending up with a bike that not only still doesn't perform right, but is actually way out of whack as far as tuning is concerned. And an out-of-synch engine not only performs poorly, but it eats itself up in the process.......

Although many people will disagree, and feel that I'm just an enthusiastic saleman, there are reasons why I say to do things the way the factory manual instructs the user to perform such tasks. Trust me, the factory engineers had both the theoretical and the practical knowledge at hand when they wrote their instructions, and also provide the bare minimum amount of steps necessary to do the job right---no "stand on your head and juggle BB's with your toes while you adjust this screw" type of extraneous steps are included.

I think what puts people off is that in order to do a proper engine synch, you must go through (or have gone through) ALL of the following steps BEFORE you get to the stage where you are ready to "synch" and/or colortune:

a) valve adjustment
b) compression test
c) carbs cleaned (internally) and functioning absolutely properly (slide drop "clunk" test passed, correct air and fuel jets, diaphgrams good, no vacuum leaks at the throttle seals, idle mixture o-rings replaced, intake manifolds checked for leaks and repaired or replaced, same for airbox boots).
d) coils, plug wires, plug caps, and plugs are checked and are performing properly.

Only once all of the above steps are taken, and any problems identified AND CORRECTED, are you ready to synch the engine.

And the use of the proper tools to do the above is just part of the game!

I know that many people will find it surprising (and then frustrating) that you bought a bike for $500 and then realize that oh-my-gosh, I'm going to have to spend another $500 or more JUST TO DO A TUNE UP! and getting discouraged.....well, that's one reason the bike was "only $500" and the cold, stark reality is that 20+ years of previous owner's (and perhaps dealership service department's) neglect, incompetence, and inexperience is now your problem to deal with.

Remember, you are working on a high-performance, multi-carbed engine....if you can successfully work on these, everything else is a walk in the park.....ask yourself, how many other multi-carbed engines do you know of? Old Ferrari's? Maserati's? Old Triumph TR-models? Mopar "six-pack" engines with 3 holley 2-barrels? Race engines? I mean, you're kind of in a small, rarefied area with these bikes and their multi-carb systems, and with that rarity and complexity comes a cost!

If all of the above sounds tough, please also take a moment to reflect that on the bright side, at least you can get the parts you need, and you can get the tools you need, and of course these forums are available to get the advice---no matter how discouraging the reality of such advice may be---to allow you to do a proper job. And once you invest the time and money to acquire the right parts and tools to do the job properly, you most likely won't ever have to spend much more on those items ever again.

Welcome to the world of working on classic vehicles! It's not always easy, it's rarely inexpensive, but you'll not only take great joy and pride from doing what other mere mortals are not able to do, but you'll also have a beatuiful classic bike that will outperform most other bikes of any vintage.

One final caution: beware of people who "advise" you on taking shortcuts, or downplay the need to do a job properly or thoroughly. Their techniques may work for them, but of course they may only be planning to hold onto their bikes for a few months or so. Those old Fram oil filter commercials summed up things nicely, and truthfull (imagine that, truth-in-advertising!): you can pay a bit more NOW to do it right, or you can pay A LOT MORE later by trying to take the most inexpensive route now.