Throttle Syncronisation

Hi All.

I managed to do the TPS adjustment today. The sensor was set to 3800 rpm. I managed to get the line to move betwen 1500 to 1600 rpm after the screws were tightened. I haven't ridden the bike yet so I don't know what difference it has made to the jerky throttle response the bike has been suffering from.

The other job I wanted to do today was check the throttle syncronisation. I have a simple dial type vacuum gauge I used to use on my twin carb cars I have owned in the past. Anyway I managed to remove the vacuum blanking plug on the rear throttle body to connect the pipe. Once connected, the needle was swinging forwards and backwards so fast I could not get a reading. I guess from this I need a mercury type vacuum guage that has a pointer that marks the maximum vacuum achieved. Can anybody recommend somewhere to buy these from.

Also how do you get to the front vacuum take off that is blanked off. I could get a finger to it but not enough room to grab it and pull the blanking plug off. Is it easier with the airbox removed?

When I was a mechanic I was trained to adjust the syncronisation of constant depression variable venturi carbs (SU and Stromberg types) by ear using a small diameter hose placed near the piston and listening to the sound from each carb. Does anybody know if you can use this method on the SV throttle bodies?

Thanks
Tim.

Originally Posted by I'm_a_Newbie

The other job I wanted to do today was check the throttle syncronisation. I have a simple dial type vacuum gauge I used to use on my twin carb cars I have owned in the past. Anyway I managed to remove the vacuum blanking plug on the rear throttle body to connect the pipe. Once connected, the needle was swinging forwards and backwards so fast I could not get a reading. I guess from this I need a mercury type vacuum guage that has a pointer that marks the maximum vacuum achieved. Can anybody recommend somewhere to buy these from.

I also have the dial type gauges, but they came supplied with 2 valves that you can cut into the tube and regulate the amount of movement on the needles. Just a simple plastic tap.

Also how do you get to the front vacuum take off that is blanked off. I could get a finger to it but not enough room to grab it and pull the blanking plug off. Is it easier with the airbox removed?

I removed the airbox, but reconnected the sensors. It was also recommened to get some old tights and secure them over the intakes, just in case anything may drop in. Even with the air box gone, the front throttle body is still a pain to get to - just need small hands!

[Viney]

As above for wobbly needles, 2 valves inlin, but for the front carb, i go the long way round, but after a couple of times, its the easiest. I pop the carbs off, 2 screws, and undoing the throttle cables, pop on the hose, then re-seat the carbs do up the upper throttle cable(I only have the one) start bike and bobs your uncle. Its the easiest way imho.

The vacuum plugs can be a bitch. Sorry. Otherwise it's an easy adjustment to make and well worth it.

does this need doing on the 7500 mile service? i think mines due.

[TSM]

Carb balancing sould realy be done with the airbox on i think. I always have done it like that.

Originally Posted by TSM

Carb balancing sould realy be done with the airbox on i think. I always have done it like that.

It shouldn't make any differnence to the vacuum. Having the airbox off also means you can get the the adjuster screw...

Originally Posted by kwak zzr

does this need doing on the 7500 mile service? i think mines due.

Indeed 7500 miles service.

is it easy DIY or should i get a highway man robber sorry my local dealer to do it?

Originally Posted by kwak zzr

is it easy DIY or should i get a highway man robber sorry my local dealer to do it?

Depends on you really. Apart from the fussyness of having to remove/disconnect/reconnect a lot of things, it was fairly straight forward, and I found it also rather satisfying!

However, by getting in there, there is an Aladdins cave of stuff you probably haven't been able to clean before!!