Pod type filters for VM 30 carbs on GS 1000 ST ( European/Australian spec)

[John Kat]

The rubber junction tubes between my VM 30 carbs and the airbox are getting very old and as they are no longer available, I'm considering using some pod type air cleaners.
Has anyone ever tried this modification?
I'm quite wary of going down this route given how difficult it was to tune another GS 1000 with pod type filters fitted to CV carbs.

[Agemax]

the VM's are SOOOO much easier to dial in with pods than the CV's are.

[GregT]

the VM's are SOOOO much easier to dial in with pods than the CV's are.

Agreed. Probably won't need a needle change - just a tad richer on the pilots.

[John Kat]

Agreed. Probably won't need a needle change - just a tad richer on the pilots.

That's great because changing the needles on these looks difficult.
What about the main jets?
Are K&N's mandatory?

[Agemax]

mains and pilot jets are real easy to change. K&N are good, APE are just as good but a lot cheaper than the K&N's. All the rest are not as good!

[GregT]

That's great because changing the needles on these looks difficult.
What about the main jets?
Are K&N's mandatory?

From memory the 30's are the type with 2 screws holding the plate down over the needle. Do them one at a time, taking out the 5mm screw holding the lifting gantry to the shaft. The slide will come up far enough to get at everything. Just fold back the lifting arm to take the slide out.
Time consuming, yes. Difficult, not really once you've done one.
Adrian - Kiwimacchi - got pretty good at adjusting his...

[Big T]

How about reviltalizing the junction tubes with wintergreen oil?

[GregT]

How about reviltalizing the junction tubes with wintergreen oil?

Kiwimacchi did that on his one. Worked after a fashion but by the time he'd had his carbs on and off several times, they were a lot more flexible - as was he, LOL.
They're an absolute pain to get the carbs on and off with the standard airbox - the 30's I think are just a tad longer than the 26's.

[John Kat]

Here's the microfiche related to my carbs.
The O.D. of the carbs on the filter side is 49 mm.
I wonder if the APE pods for the 1st GSXR at 50 mm I.D. would be OK?

[John Kat]

As I could not get in touch with Kiwimachi, I decided to move the needles up by two slots ( now at N° 4 from the top) and increased the main jets to 107.5.
The bike will now run up to 1/2 throttle but not beyond.
I believe it's too rich as the main's were at 92.5 with my Kerker 4 into 2 exhaust ( down from 97.5 in OEM trim)
I'll try with 102.5 ...

[John Kat]

I installed 102.5 main jets and 22.5 idle jets today but the bike doesn't idle well at all and chokes when opening the throttle???
It seems like the engine is suffering from fuel starvation?
Very strange!

[GregT]

Kiwimacchi is away on a long 4 day weekend ride - and isn't looking at the net often as he's started rebuilding his house post quakes...
He used the stock airbox and got away with moving the needles and changing idle and mains to suit the 4 : 1 pipe.

What you're experiencing sounds like overlapping problems. No or reluctant response cracking the throttle is usually what I call "gulp lean" - self explanatory, getting air but not fuel. Cured by going to either a lower cutaway or a bigger idle jet. Reluctance to pull past half throttle can be either too rich or too lean. Too rich will usually be accompanied by smoke....

What is the OE jetting on those carbs ? mains and idle jets ?

[Agemax]

102.5 sounds very small for pods. i run 130's in my 29mm smoothies with 25 pilot jets

[John Kat]

Kiwimacchi is away on a long 4 day weekend ride - and isn't looking at the net often as he's started rebuilding his house post quakes...
He used the stock airbox and got away with moving the needles and changing idle and mains to suit the 4 : 1 pipe.

What you're experiencing sounds like overlapping problems. No or reluctant response cracking the throttle is usually what I call "gulp lean" - self explanatory, getting air but not fuel. Cured by going to either a lower cutaway or a bigger idle jet. Reluctance to pull past half throttle can be either too rich or too lean. Too rich will usually be accompanied by smoke....

What is the OE jetting on those carbs ? mains and idle jets ?

The OEM setting for the VM 30's is 97.5 main jet, 20 idle jet.
When I fitted the bike with a Kerker 4 into 2 exhaust I had to reduce the main to 92.5.
I followed the sticky advice to increase the main by 4 points and the idle by 1 point resulting in 102.5 and 22.5.
The needle went up by two slots to position N° 4 from the top.
I wonder if the issue is not coming from the OEM vacuum operated fuel tap?
After exchanging fuel tanks with one with no vacuum tap, I noticed a good improvement?
Strangely when blocking off the first carb's vacuum tube the idle went erratic again???

[GregT]

Have a good look at the carb bodies for "vacuum hose" takeoffs. I'm pretty sure that the hoses on those are actually float chamber breathers and the vacuum takeoff should be on either a rubber manifold or the head.
If there's no matching hole through into the slide area it isn't a vacuum takeoff.