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Re: ANTI SURGE JETS; DO THEY WORK?

Posted: Fri Dec 21, 2018 12:40 pm
by yeadon_m
If you're noticing surging while in the higher gears, lord knows what its like in 2nd around town! it can be hard to get rid of it, but you should be able to get it to a level where you can ride around it easily enough.
Cheers,
Mike

Re: ANTI SURGE JETS; DO THEY WORK?

Posted: Fri Dec 21, 2018 5:39 pm
by teazer
Try fitting a set of BS30/97 air jets as described in the service bulletin or on http://www.pinkpossum.com/GT750/carb/BS40carbs.htm

In your case I'd start with #80 (0.8mm) and see how that works. If Baz can supply them that's great, if not, your dealer should be able to order them form their Mikuni distributor.

Re: ANTI SURGE JETS; DO THEY WORK?

Posted: Sat Dec 22, 2018 4:45 pm
by Filly
The idling speed is set to around 1300/1400 RPM.

Re: ANTI SURGE JETS; DO THEY WORK?

Posted: Sat Dec 22, 2018 5:16 pm
by itsnotateapot
Filly wrote:The idling speed is set to around 1300/1400 RPM.
get it down to around 1000 RPM and give it a go.

Re: ANTI SURGE JETS; DO THEY WORK?

Posted: Sat Dec 22, 2018 9:11 pm
by Roger Ackery
Yes agree 1,000 rpm is good,this should make a difference :idea:

Re: ANTI SURGE JETS; DO THEY WORK?

Posted: Sun Dec 23, 2018 3:50 pm
by Filly
OK guys, in the meantime, thank you because I see so many important information that I think will surely bring benefits. I will start by adjusting the minimum to 1000 RPM, after which, I will try to change the jets. However, I would like to understand something that is not clear to me: the main air jet BS30 / 97 which suggests Teazer where it is screwed? Why look at the image taken from Pink Possum seems embedded in the left side of the rear venturi tube inside a tiny hole as you can extract? Forgive the questions that will seem obvious to you but not to me. Thanks again.

Re: ANTI SURGE JETS; DO THEY WORK?

Posted: Sun Dec 23, 2018 4:42 pm
by teazer
Good question. The air jets are screwed into the passage on the right of the carb mouth. It has the larger of the two pressed in jets in it as described on Pinkpossum.com

That hole has to be tapped with a suitable tap as described in the Suzuki service bulletin.

Re: ANTI SURGE JETS; DO THEY WORK?

Posted: Sun Dec 23, 2018 4:49 pm
by Filly
Beautiful, thank you very much for the precious information.

Re: ANTI SURGE JETS; DO THEY WORK?

Posted: Sun Dec 23, 2018 8:25 pm
by BAZ
I made a clip see here https://youtu.be/Ri8SzrxSHzA

Re: ANTI SURGE JETS; DO THEY WORK?

Posted: Tue Feb 05, 2019 3:14 pm
by teazer
Up to now I had never seen a bike with Anti Surge jets fitted from back in the day. I just stripped a set of carbs for a client who said they had been through an ultrasonic cleaner and most of the air passages were still partly obscured. Anyway, in the inlets were surge jets, so I asked him about them.

He and his dad bought the bike in 76 and he described the bike as surging badly when they got the bike (not the words he used but that's what he described). He left for college and his dad put another 27,000 miles on it over the years and eventually parked it in '95. His dad had serviced the bike and had anti surge jets fitted way back in the day. The father passed away a few years ago but the son says that his dad loved how smooth the bike was, so I'm guessing that he fixed the surge.

So the carbs will be rebuilt with all new brass and re-plated parts, barrels will be ported and new crank and so on, and it will be painted in nice bright colors and should enjoy another 20 or so years of service.