1984 Katana 7/11

[Guest]

Seals arrived yesterday, so I've got the second shock back on the Kat. Felt good to sit on last night so I'll ride it to work today and see how it goes.

Next up is to slot a loaner set of stock carbs in so I can do something with the VM33's.

 

[Guest]

Ooops not gotten back to update this!

Rebuilt shock seems good, although I've only ridden to work and back once to verify so far. Pretty confident though as the stanchion is in good shape.

I got the loaner set of stock carbs in but not had time to do anything more than start the Kat and make sure it runs, not even got it warm enough to turn the choke off yet.

Question on the mixture/air/fuel screws on these Kat carbs... the manual indicates they're mixture screws, but doesn't clarify which way to adjust for richer or leaner mixture. I assume in (clockwise) is less mixture therefore leaner idle, and out is more mixture would be richer idle. Is that right?

Is there a trick to adjusting number 2 without taking the tank off? I can get to the other three but the vacuum hose makes number 2 rather tricky to get to...

 

[Guest]

Ok brief update time... got the loaner stock carbs reasonably dialed in at last!

Test ride the other day had a steady 100kph cruise ~3900 RPM showing 11.5:1 on the AFR gauge, and WOT runs going to just over 12:1 then dropping to sit at high 11's.

I've dropped the needle a notch and will have to drop the mains back a size yet (122.5's in it now). Rode it to work and back yesterday and will do again today, and the needle is definitely 100% improved although with traffic there's no way to get a good steady needle reading, will have to wait for tomorrow's fun ride for that.

What I should have added is that the confidence killing lag between throttle closing and opening I had with the VM33's is all gone with the stock CV's, but the one downside is the arm stretching I felt at 1/4 to 1/2 throttle isn't quite the same. At least now I'll get some breathing space to figure out what to do to get them sorted properly.

 

[Charlie G]

We all need a bit of ?arm? stretching once in a awhile. Glad you are getting a bit.

 

[zuluwiz]

I remember well the "arm-stretching" of my old 81 gs1100e. Ya had to have it pointed in the right direction when ya pulled the trigger on that bike.

 

[Guest]

Cheers guys, yes a bit of arm stretching is definitely fun times

Heading out for the usual Katana Australia Saturday morning ride this morning so should get a good read where it's all at with the dropped needles, then hopefully I can leave it alone and just enjoy the ride while I figure out the VM33's.

 

[Guest]

Well it looks like the carbs are at a point where I can just leave them alone and enjoy riding while I figure out what to do with the VM33's

Cruising has the AFR between 12.5 and 13.2 depending on speed/RPM so I'm happy with that, and WOT runs had a fairly consistent 12.5 so I'm going to leave the mains alone now as well.

I probably should post an obligatory pic too...

Untitled by starpoint73, on Flickr

 

[Grimly]

Ok brief update time... got the loaner stock carbs reasonably dialed in at last!

Test ride the other day had a steady 100kph cruise ~3900 RPM showing 11.5:1 on the AFR gauge, and WOT runs going to just over 12:1 then dropping to sit at high 11's.

I've dropped the needle a notch and will have to drop the mains back a size yet (122.5's in it now). Rode it to work and back yesterday and will do again today, and the needle is definitely 100% improved although with traffic there's no way to get a good steady needle reading, will have to wait for tomorrow's fun ride for that.

What I should have added is that the confidence killing lag between throttle closing and opening I had with the VM33's is all gone with the stock CV's, but the one downside is the arm stretching I felt at 1/4 to 1/2 throttle isn't quite the same. At least now I'll get some breathing space to figure out what to do to get them sorted properly.

What AFR gauge are you using?
I nearly went for the Tech Edge on from Oz, but decided to get the 14point7 Spartan (inc gauge and sensor) from Canada. I'm looking forward to finally seeing exactly what's happening inside, after so many years of plug-chops and relying on the seat of my pants.

 

[Guest]

Hey Dave, I've borrowed my mate's at the moment which is an AEM brand gauge with LSU 4.9 sensor. They go on eBay for around the $AU300 mark. The only downside is the gauge is designed to be panel mounted, so the handlebar mount is a DIY effort and it's not really weatherproof.

I've also been eyeing off the Tech Edge one for a few years but recently I also discovered 14point7 and am planning on getting one of the SLC Free ones later this year ready for when I'm tackling the VM33's again.

While the DIY keeps the price down, the main thing for me is the cables aren't pre-made, so I can make them the right length to fit neatly on the kat. I'll also be able to easily disconnect the gauge and sensor when not in use but be able to leave the wiring in place.

I should add you'll never look back once you get an AFR gauge in to figure those ratios out. Unless you're one of those guys who have the magic touch of understanding every different feeling with the butt dyno and have plug reading down to a fine art, it will make your world so much easier.

 

[gs scott]

I probably should post an obligatory pic too...

Pete,
"Your Kat" came out amazing. How does that sound? Your Kat...
Congrats on a superb build, and thank you so much for sharing the excitement - best read in a long time!

 

[Guest]

Thanks Scott, yes I still walk into the garage and see it and realise... yeah I have my own Kat at last

It's quite fantastic and I'm most definitely enjoying Kat ownership for sure! My only issue is resisting riding it to work every day... a good problem to have!

Glad you enjoyed the read, and again thanks so much for your help, I'm hoping to have the VM33's back on later this year too.

One thing I've always been told about having a Kat is be prepared to allow time to have a conversation about it when you stop somewhere, and I figured that was a bit of an exaggeration. However, I've discovered it's true... you really do need to allow time to chat to people when out and about. If you stop anywhere at all (even just to get fuel), you will inevitably have at least a brief chat with someone. It even happens in traffic when stopped at the lights...

 

[Guest]

It's finally time to revist the VM33 smoothbores.

I really wasn't happy with the low throttle position response with them and everything I've read/heard/been told tells me that VM33's in GSX applications need the 2.0 throttle valves/slides. I have 1.5's and the 2.0's are NLA.

GregT very kindly offered to modify the 1.5's for me if I couldn't find any 2.0's, so I took him up on his offer and they arrived back here a couple of weeks ago and his work is awesome! If I didn't know they were modified 1.5's you'd think they were out of the factory!

Anyway, I was hoping to get them installed again this weekend but I haven't quite gotten that far yet and only ended up getting them bench sync'd and verified the fuel height was good.

To check those I ended up making a stand out of scrap timber which helped immensely.

Untitled by starpoint73, on Flickr

I couldn't justify the cost of a proper fuel level gauge and couldn't find a bolt to modify with the correct thread, so I used a bit of plastic dowel which I shaved down enough to cut the thread of the float bowl into. I glued a bit of rubber around the outside as a sort of a seal and glued a bit of clear vinyl tubing in as the gauge. Worked like a charm! Almost leak free, and certainly leak free enough to be a reliable gauge.

Untitled by starpoint73, on Flickr

I've discovered also that the stock carbs with the Mikuni push/pull throttle setup has an extremely long pull to WOT, and I have a spare R1 throttle tube here which I want to try to see if it works with the Mikuni housing to give a shorter throw.

Anyway, that's a lot of words for a bit of a non-update but plans are afoot!

Starting point for the VM33's:

Pilot jet - 17.5
Air screw - 3/4 turn out
Air jet - 0.6
Needle - 3rd (middle) position
Main jet - 115

 

[Guest]

No pic's yet but I took the stock loaner carbs out last night and started getting the VM33's in.

Got a little distracted by the fact the horn mount is broken and my horn was just sitting on the valve cover... oops! I made it out of steel to prevent vibration cracking etc. but I guess I made it a little too light duty. Should be a simple fix with some extra steel and a welder (and grinder)... and a re-paint of course!

 

[Guest]

Subscribed to your thread. Kat looks stunning! Keep the updates coming.

 

[Guest]

Cheers mate! I still grin every time I ride it

Apparently I now have an incurable disease... I'd like to get a 750 Kat to replace the 450 as my commuter...

 

[Grimly]

Iirc, my original horn mounts were made of three thinner strips of steel sandwiched. They never cracked.

 

[Guest]

Yeah the original ones are pretty strong, this is a hand made mount for the after market (loud) horn, I just didn't make the mount strong enough which I'll sort out this time around.

The VM33's are installed again, need to find time this weekend to get the Kat warm enough to check the pilot jets and set the air screws, then get out for a test ride to check the needle and mains.

I've marked the throttle positions and had to share a photo to show just how quick an action the R1 throttle tube makes it now with the VM33's... happy with that!

Untitled by starpoint73, on Flickr

I also promised my mate I'd make a better mounting system for his AFR gauge which I've finally done now also. It's not the prettiest thing, but I bent and welded some steel to hold the panel mount gauge and utilise GoPro mounts so it's a bit more versatile.

Untitled by starpoint73, on Flickr

Next I need to sort this annoyance out...

Untitled by starpoint73, on Flickr

 

[Grimly]

I also promised my mate I'd make a better mounting system for his AFR gauge which I've finally done now also. It's not the prettiest thing, but I bent and welded some steel to hold the panel mount gauge and utilise GoPro mounts so it's a bit more versatile.

Untitled by starpoint73, on Flickr

Interesting.
I'm currently wiring the 14.7 gauge in a temporary bar-mounted shell.
Reading the destructions, they warn about cold-starts (condensation) chilling the ceramic of the sensor, so recommend starting the engine, then switching the sensor on, and also caution against leaving the sensor in a rich exhaust stream for too long, as it will foul up, even with the heater on.
I suppose that means that any rich conditions have to be attended to fairly quickly, to avoid damage.
Kind of makes me wonder how these sensors survive in cars full-time, but the ECU takes care of the switching and timing.
Whatever, once I set the carburettion up the sensor and gauge will be removed when I'm sure of the stability of things.
Otoh, it will be nice to fiddle with things and I'm seriously thinking of going big carb again, but this time will be armed with some proper data.

 

[Guest]

Are you using a wideband O2 sensor along with this AFR gauge?

 

[Grimly]

Are you using a wideband O2 sensor along with this AFR gauge?

Not sure whether you're asking Pete or me.
I'm using a Bosch LSU 4.9 w/band sensor.