Katana Owners Club U.K.

I think I know the answer to this but thought I’d put it out there just in case...

So, the problem was the revs increasing once the engine warmed up..
But now, after it sitting for a few weeks, it starts up on choke no problem, and then once up to temp and choke switched off, completely dies..

I’m thinking blocked jets..

Does the choke mechanism completely close off at no 2 carb.
650s suffer from this problem when the silly centre of yoke cable is attached .
Also had this on an ES because the oil breather is just above the slide mechanism and attracts grim in to a paste.

Turned out to be a bit simpler than that..
I’d replaced the pipe for the fuel tap vacuum.. but it was a bit too long and had a sharp bend that completely stopped the vacuum reaching the fuel tap... oops

Think I may have also found the air leak which may have been causing the revs to rise..
all the jubilee clips from the carbs to cylinder head rubbers were loose.
Managed to get a steady tickover with warm engine.
Will do a proper test ride later in the week.

Well done Sam. I had a similar issue after rebuilding the TZR250 last year - on first start it would die off choke and I could hear air being sucked somewhere. After mucking about I had forgotten it was a vacuum tap on that and had left the pipe off - as it was it's first startup I had the tap on prime hence it ran OK with choke"! Live and learn

And so the saga continues...

After some more research, a possible cause of the engine revving high when hot is the throttle valve shaft seals.
These are readily available as they’re used on multiple models... but will cost me about 40€ with postage.

Anybody know of an equivalent seal at a better price and regular post in a jiffy bag?
Best I’ve found is €1.97 inc vat each
But €20 postage

Part # 13651-51010-000
And there’s 8 of them

Hi, I have a question, why are the 650's called "pop ups"

Pop ups are 750 s3.. A limited edition kind of , that was only Japan market , with some going to SouthAfrica , Australia, New Zealand , U.K. and a slightly different model for Canada .
It's called a pop up because the headlamp pops up when turned on , like a sports car .
On the banner on the top of the page , it's the one with no headlamp.

Bikeazoid wrote:Hi, I have a question, why are the 650's called "pop ups"

Sam - the shaft seals are the same as on the 1100 Katana so you can get a set of viton ones from Litetek - https://litetek.co/Carb_Kit_Suzuki_GS10 ... 82-83.html - service kit B which also comes with teflon washers and new stainless butterfly screws.

I might have a set though I can send FoC, I'll need to check if I can find it, as I got this set then never fitted it. I did remove the butterfly valves (the screws on those are peened over so take a little to do - use a JIS screwdriver) but the rest of it looked like a world of pain (I think there were roll pins to remove as well on the shafts) and that is as far as I got! Putting the screws back in I used locktite as peening them yourself without a jig looked like it would damage something.

UB

Uncle Bob wrote: ↑

Mon Apr 20, 2020 11:20 am

Sam - the shaft seals are the same as on the 1100 Katana so you can get a set of viton ones from Litelek - https://litetek.co/Carb_Kit_Suzuki_GS10 ... 82-83.html - service kit B which also comes with teflon washers and new stainless butterfly screws.

I might have a set though I can send FoC, I'll need to check if I can find it, as I got this set then never fitted it. I did remove the butterfly valves (the screws on those are peened over so take a little to do) but the rest of it looked like a world of pain (I think there were roll pins to remove as well on the shafts) of that is as far as I got! Putting the screws back in i used locktite as peening them yourself without a jig looked like it would damage something.

UB

Fortunately I have not had to do this on any of the sets of carbs I have cleaned. It does look like a fairly involved job. More for a high miler rather than one sitting with fuel decaying in the carbs