Throttle Body Synchronisation

I got round to the last bit of sorting out the fuel system on my K6S today - throttle body synchronisation. This is a really simple job made really difficult by lack of access to the two little test vents under the bodies.

I had a look at the manual, which told me to lift the tank (okay) and take the air box off whilst running the motor - and decided that was bunkum, taking the air box off would not particularly help with access and running the motor without the air box seemed a bit of a daft thing to do. I warmed up the motor a bit, lifted the tank and (after lots of fiddling around and a bit of swearing) managed to get the two little rubber caps with their circlips off without losing them (using a pair of long nosed sparky’s pliers and a long screwdriver in tandem).
So far so good, the next tricky bit was getting the rubber hoses from the manometer attached - I resorted to lashing the ends to a long screwdriver with a zip tie like this:



... which worked (I left the screwdrivers in place during the adjustment to make disassembly easier). So, now my test rig was in place, and looked like this:



(note the genuine Suzuki tank prop)... , closed the two damper valves to the manometer gauges and fired the motor to warm it up.

It was obvious that the two cylinders were well out of synchronisation, as you may see from this photo (before adjustment, on tickover):



... adjustment was really simple, but took nearly two turns of the screw (once I’d worked out which was the right way) - and in doing so tickover rose from 1300 to 2600 RPM. I turned the tickover down to the right speed and the gauges looked like this (at tickover):



... this at 3000 RPM:



... and this from 5000 RPM upwards:



I ran through the the procedure a few times for fine tuning, and was pretty happy with the result.

Getting everything back together was a bit easier, although I did have to resort to the old mechanic’s trick of gluing the rubber bungs to the end of a screwdriver, then peeling them off to get them back into place.

I suppose the whole job took an hour, which was 10 minutes reading the manual and formulating a plan 40 minutes getting access, 5 minutes adjustment and a short time to re-assemble the bike.

The throttle bodies were a long way apart and everything seems nicer now. This is a 135,000 mile bike and I don’t know when this job was last done, so perhaps it was no surprise quite a lot of adjustment was required.




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[glang]

now I can see why some owners install rubber pipes (with bungs) on the tapping points to facilitate future balance checks...

Originally Posted by glang

now I can see why some owners install rubber pipes (with bungs) on the tapping points to facilitate future balance checks...

I did think about doing that, but I’m not sure my 135,000 mile bike will need this again.

I was thinking that one could probably achieve much the same effect by just adjusting the screw to get the highest tick over ...the correlation between the difference in body pressures and tick over speed is quite profound.


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[R1ffR4ff]

I recently did my Carbs and chronicled it,

https://cx500.000webhostapp.com/SV650Carb_Balance.html

I removed my Horn bracket ages ago and moved my horn to the left front of the bike.This makes it easy to get to the Front vacuum spigot on the Carby versions by moving the Rad forward.

Orange coiled wire is just Disc lock reminder cable.I use it on the Rear wheel now.

[Craig380]

Be thankful you can sync the TBs manually

I just took the bike out for a run, it is certainly running a bit smoother, which is nice.

It is probably the hottest day of the year so far - well over 30c in the direct sun where the bike was parked - so it is difficult to be sure at the moment, but I think the fast idle I adjusted a while ago may be over-compensating. That is a fairly easy job to correct though, so I just get happier and happier with my cheap, high mileage SV650S.


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[R1ffR4ff]

Originally Posted by Othen

I just took the bike out for a run, it is certainly running a bit smoother, which is nice.

It is probably the hottest day of the year so far - well over 30c in the direct sun where the bike was parked - so it is difficult to be sure at the moment, but I think the fast idle I adjusted a while ago may be over-compensating. That is a fairly easy job to correct though, so I just get happier and happier with my cheap, high mileage SV650S.


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From what you have posted recently I think you got a good purchase.Does the engine use up any oil?

Originally Posted by R1ffR4ff

From what you have posted recently I think you got a good purchase.Does the engine use up any oil?

None at all between changes, which makes me think the rings and valve gear are all in good order.

I’m really pleased with this bike, it gave me just the right amount of project challenge without anything too expensive cropping up. I’m looking forward to getting to 150,000 miles on this bike (in about 5 years time).




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[R1ffR4ff]

Originally Posted by Othen

None at all between changes, which makes me think the rings and valve gear is all in good order.

I’m really pleased with this bike, it gave me just the right amount of project challenge without anything too expensive cropping up. I’m looking forward to getting to 150,000 miles on this bike (in about 5 years time).

That's great

My Curvy uses very little if any between oil changes but I rarely go above 8,000 Rpm as I've found no need.I also pride myself on smooth gear changes/clutch work/Engine braking and love how fast I can get up to,"Combat Speed" without even straining the engine

Originally Posted by R1ffR4ff

That's great



My Curvy uses very little if any between oil changes but I rarely go above 8,000 Rpm as I've found no need.I also pride myself on smooth gear changes/clutch work/Engine braking and love how fast I can get up to,"Combat Speed" without even straining the engine

Excellent, curvies must be getting on a bit now, so it’s good that you are looking after it.


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