Making your next TBS easier

[BkrK12]

On the off chance there are other people out there as dull as I am, I thought I'd pass on this new (to me) technique for TBSing.

For years I have been propping up the tank and reaching under it to put on the vacuum tubes and fiddle with the screws. The authorized TBS is a PITA - but not a real big one. The unauthorized TBS, where you screw with the throttle plate adjustments, is a genuine PITA, trying to get on the screws without opening the throttle and spiking the tach.

Well, when I took my tank off, after getting the new wiring harness, I noticed that I had a good deal more slack in the two connectors that go to the fuel pump. I decided to see if I could place the tank on a table next to the bike while it was completely connected - worked like a charm. Placed a towel on the table, edged the corner as close to the bike as possible and made sure not to kink the fuel line as I put the tank on the table. Voilà, everything is exposed and reachable. Makes the authorized TBS stupid easy and the unauthorized a piece of cake.

For those of you who already knew about this, I'm sorry for taking your time. For others, I hope this will make your efforts a little easier.

Dan

 

[smellthat?]

Great idea about the table. I too feel a little foolish while reading this post. You see I ALWAYS work with a Costco plastic table next to me for tools, etc. DUH! Edge the darn tank onto it! I will definitely do this in the future. Every now and then someone takes another hard edge off the wheel for me . . .

 

[BkrK12]

Great idea about the table. I too feel a little foolish while reading this post. You see I ALWAYS work with a Costco plastic table next to me for tools, etc. DUH! Edge the darn tank onto it! I will definitely do this in the future. Every now and then someone takes another hard edge off the wheel for me . . .

Me too, I have an old dog grooming table which is a perfect height. I put a clean towel over it and use it to lay out tools and hold parts and fasteners that come off the bike. I'm telling you, the first time you do a TBS with the tank out of the way you will be amazed - much quicker and better results. I just took mine out for a test ride and it is smooth.

Dan

 

[BobMercer]

Dan,

Great idea! Which side of the FJR did you put the table, and how high is that grooming table? Did you have much fuel in the tank when you did the TBS? Pics would have even been better. Thanks for sharing.

Bob

 

[HotRodZilla]

You can set the tank next to the bike with the stock hoses and connectors still attached? I don't recall having that much slack, but if I do, I'll sure as heck try it.

 

[BkrK12]

Table needs to be on the clutch side. You need to snuggle the corner of the table as close to the bike as possible, kind of on a diagonal. The grooming table is a regular height table and it keeps the tank just about the same height as when it's mounted. Stock wires and fuel line give you enough slack. Just exercise a little care with the fuel line, the fitting has to swivel a little.

The tank was about 2/3 full. But, here's another neat thing. Because the tank is sitting flat, instead of propped up in the front, you can do it with a lot less fuel in it.

Sorry about the pictures. I was skipping around the garage, inordinately pleased with myself, and wanting to put everything back together so I could go for a ride. Pictures never occurred to me. But, the process is very simple. Once the table is in place, it's obvious what needs to be done.

Dan

 

[RaYzerman19]

I am making an assumption one will only need to do the Unauthorized TBS once, since the physical settings should not change. After that only need to do the Authorized TBS, which can be done with the tank on, say on an annual basis.

Further, after an episode on another bike I was working on, I am considering installing short hoses from the vacuum ports so you don't have to fiddle with those dinky little rubber caps in those tight spots, particularly #2. Of course, this will require some kind of connector fitting and cap at the end, and a way to neaten up the hoses... perhaps a little more complicated for those using the ports for cruise control (I only use #4 for that). I am still mulling this around in my head, wondering if anybody has done that.

 

[Fred W]

Not sure that assumption is a good one. Here's a single data point:

During my 50 k mile maintenance frenzy this past week I re-did the CUATNS as a part of the service. When I closed down all 4 air screws I found that something had changed causing misbalance. Deposits on the throttle plates? Shifting linkage? Dunno for sure. Last CUATBS was at 40k miles. Other things done at this maintenance were flip the air filter end for end and replaced all plugs. Checked valves but no adjustment required.

Rebalanced the throttle plates and then opened all four air screws to 1 turn. Had to tweak a couple of them to get them perfect. Watched the vacuums during throttle roll on, all seem in balance with the world again. Test ride showed turbine like smoothness all the way up to (past) 6k rpm. Before sync it started getting buzzy at ~4500 rpm.

 

[BkrK12]

What Fred said.

For whatever reason, the throttle plate sync can change significantly in as little as 4000 miles.

Fred, can you actually get the plates synced well enough that rolling on the throttle causes then to stay completely in sync during the runup? I have not been able to do that. I can get a perfect static sync. But 1 and 4 always seem to run up higher than 2 and 3. I am smooth as glass at steady speed. Under acceleration, I get significant buzz.

BTW, taking the tank off requires removal of one additional bolt and a hose clamp - takes about 1 minute. You save a lot more time than that just being able to see what you're doing without the tank in the way and easy access to the rubber caps obviates the need for the additional hoses and fittings you're considering.

Dan

 

[Fred W]

Fred, can you actually get the plates synced well enough that rolling on the throttle causes then to stay completely in sync during the runup? I have not been able to do that. I can get a perfect static sync. But 1 and 4 always seem to run up higher than 2 and 3. I am smooth as glass at steady speed. Under acceleration, I get significant buzz.

No, not really. I can only seem to minimize the differences, but there are some both on roll on, and roll off.

FWIW, I believe that the first gen tanks go higher (closer to vertical) with everything still connected. Just disconnecting the two electrical connectors (fuel pump power and fuel guage) and using a tie-down to hold the tank up from the the luggage rack is all I needed. Yes, I still do have to kill the engine to make an adjustment to the linkage between the #2 and #3 butterflies.

 

[RaYzerman19]

Assumptions can be dangerous I know.... Always willing to absorb information from you guys who go digging in there that deep multiple times and your results on subsequent follow-up. If the effort produces a benefit, I am all for it.

BkrK12, if you are having persistent buzz problems, I would tweak some more, but perhaps there is another cause or perhaps it just can't get any better than it is (you reach that level at some point). Now, if it seems it is worth it, one would have the airbox off and pin gauges to physically sync the butterflies (i.e., place pin gauge in one butterfly, set all others to that). Then you are assured of the best attainable sync, with a later TBS tweak at the vac ports.

After reading another thread long ago about grunge building up on the back side of the throttle plates, I wonder if that could affect sync or buzz as well. This of course leads to a whole other set of discussions whether it is preventable, removing the PAIR hoses, effects of crankcase ventilation, how often to clean, etc. Big job!!

 

[fjr183]

I have the PAIR ck'd/cleaned when doing valve ck's. (26k intervals)

Fred

 

[Fred W]

That PAIR is a whole lot easier to clean when it's in a box, sitting on a shelf!

Jus' sayin'