New to me 91 Kat 600..on the right track?

[ctandc]

I posted in the Intro thread I think...anyway...picked up a 1991 Katana 600. Nice bike....it will take over commuting duties from my trusty GS500E shortly..

Bike has 28k on it right now. Owner I purchased from had it a month or so...then he found out he was a bit too small for the bike, and a smaller cruiser would be much better for his commute. So that makes him the 3rd owner.

2nd owner purchased bike with 3.3k on it in early 1993. How do I know? I've got owner's manual, cards, and EVERY friggin' receipt from everything ever done to the bike...he let the dealership to everything. He was religous on oil changes, valve adjustments, plugs, air cleaner etc. That's nice to know.


Anyway...bike runs pretty good. Let me rephrase...it idles low. I wasn't going to tear into it until I got my Clymer's in, but since I downloaded the Haynes I Said why not.

I have to replaced the windscreen, mirrors, and the clutch lever...so I ordered all that from Bike Bandit today.

So it idles around 1000 or so. Tried adjusting the idle per specs, and while I can get it to idle way up....another 3-400 RPM is damn near impossible. It seems to just idle back down. But it runs GREAT from off idle to around redline. Pulls hard and smooth like nobody's business. So I know there isn't too much going on here.

Anyway one of the receipts from April of this year was a complete carb / clean / 'repair' and sync.

But the carbs looks pretty dirty on the OUTSIDE to me....

So tonight it escalated...before I knew it, all the plastic was off, the tank was off, and away I go.

BTW...is it standard practice for a dealership to use ZIP TIES to hold the fuel lines to the petcock? Just wondering.

I've also got what I thought was a possible valve rattle at idle. Only really noticeable at idle. But of course it is idling low..but after looking at the stock (oh yeah bike is BONE STOCK) header...I'm thinking I might have an exhaust leak..sounds like a header leak on any hundred project cars I've worked on, so I'm gonna hit Bike Bandit up for exhaust gaskets as well. Couldn't hurt.

So I'm wrapping up tonight, but tomorrow will be pulling the carbs and checking 'em out.

Also on the to get list - The vacuum line that goes in near where the fuel gauge / sender wires come out...it was split so bad it wouldn't stay on. So I'll replace that. I'm thinking it's just a vent hose, since it runs to the bottom of the frame..

Also the air box looks to have some 'gunk' in it..almost like oil..reminds me more of K&N Air filter oil...and I can see a red 'tinted' substance around the neck of the carbs when looking through the air box..????????

Another one to add to the list...the airbox drain line was either twisted or burnt? Almost in half....the cap was still there. Order that too I guess..

Plugs didn't look too bad....we'll see I guess.

So this is the plan.......

Take off and clean carbs. I know I ran across an article on that here....thought one with pics, but I can't find that thread right now...been searching too. I'm thinking since it runs so GOOD from off idle to redline, that it might be the idle circuit. Then again, it IS a 4 stroke 4cyl, so if I do have an exhaust leak that could cause that crap at low RPM too...are exhaust leaks common on these w/ age?

I'll take a gander at the carbs and check 'em out...from the airbox looking in they look VERY clean. But you never know.

So here's the checklist so far, if you got this far in this novel please let me know if I'm missing anything:


- Pull petcock and clean filter (there does appear to be a few VERY small spots of rust in the tank....but I mean SMALL....and no trash coming out of the petoock.

Should I rebuild the petcock WHILE I've got it apart?

Any seals / gaskets that are likely to need replacing once I go to put it back together? (would need to order them now)

I'm going to 'assume' that the 3rd line that ISN'T a fuel line coming off the petcock is the vacuum feed for this thing. So if I understand the operation clearly, in the ON position, the engine turning over would create VACUUM and let fuel travel to the carbs...correct? Not like PRIME which is a direct 'gravity' feed right?

-Replace ANY suspect vacuum / fuel lines.

Can I get just get bulk hose? Or is it easier to use OE Replacements?

Speaking of that I was going to go ahead and make a water driven (I add red food coloring to make it easier to see LOL) manometer, I figure it should do the job to sync the carbs. So ANOTHER question...

I only have two hands...is it practical / safe to get some extra long pieces of fuel line and prop the tank on my workbench next to the bike, and run the long fuel lines from the tank (off the bike) to the carbs? Can this work well enough when I'm adjusting the carbs and sync'ng them? Anyone done it? Seems simple enough.

If the 'EPA' carb plugs have NOT been drilled, is there another A/F adjustment I should be looking at?

- Check 'intake boots' from carbs to airbox as well as intake side.

- Replace plugs, they didn't look that bad, but hell I'm in here now.

- Replace air filter...I need to see what a new OE one looks like, cause this one doesn't look that bad...but again, I'm elbow deep "mine as well"

- As far as trash in carbs.....

- Any spots to really look for? Especially those that would effect the low RPM idle I get.....as it runs SO GOOD further up the RPM range? Idle circuit I'm guessing?

Anything else I'm missing? I'd rather get this thing idling and running RIGHT, so I can drive it.......

Cause although the plastics are in great shape (some were replaced with NEW factory parts a few years ago........."never laid down" my azz...LOL ) the paint on side looks great...the other looks great..but with the factory graphics, lacking on the factory replacement piece + the tank paint is faded....so good excuse for a Winter project. Luckily I have a buddy who does auto body...I figure bringing him the pieces and some beer + paint / clear / reducer should get it done.

Then of course,since I'm anal like that..

Braided front brakes lines, new rear, flush fluid etc etc...I figure when I'm done it should be good for another 25k with only oil changes, plugs, and valve adjustments............yeah right......


Thanks for any and all suggestion and pointers here.

BTW here's the breakdown on the receipt date 4/21/07

4 NGK DR8ES plugs $14.00 (ouch)
Clean carbs 6 hours labor $474.00
Flush fuel sys/fix fuel leak? (zip ties? LOL) $79.00
R/R spark plugs $79.00
Valve adjustment $237.00
Supplies $20.00 (pricey zip ties)

$904.00 and this was 4 months ago. I didn't pay THAT much more for the bike last week.......LOL




Chris
91 Kat 600 -Under the knife
90 GS500E - 52 mpg and chugging along, let's hope it doesn't get jealous :P

[md86]

That's just WAY too much to read . Mind paring that down a tad for those of us with A.D.D ? I got to the zip ties on the petcock (even when I redneck things , I'll go for hose clamps there first ) , then got antsy .

[ctandc]

LOL No problem....

Symptom - idles a couple of hundred RPM low, and idle is not really smooth.

Tried adjusting idle. It's either right where it is or 2k RPM (or more) or slow it down till it dies.

Bike runs GREAT from off idle to redline, good throttle response, no misses, hesitations etc. Just a nagging, low idle.

I'm assuming the I-4 should idle smoother when running correctly than the twin in my GS right? LOL

Symptom: When idling, there is a noticeable 'tick' coming from the front of the engine. Sounds just like one of hundreds of headers / exhaust leaks I've had on project cars. Factory header looks like it's never been off (PB Blaster to the rescue).

NOTE: Valves were adjust @ 1.5k miles ago when carbs where cleaned.

Possible exhaust leak?


Took apart to get to carbs and found:

-Split vaccum hose. Well VENT hose. It's the only hose connected to the fuel sender, right next to where the wiring runs up in it.

-Airbox drain hose was toast. Halfway down it's length it was twisted / busted in h half, with cap still intact on end.

- Spark plugs are recent (again not me) and actually look pretty good

- Zip ties holding fuel lines on petcock (dealership 'mod')


Between a possible exhaust leak and a vacuum leak from the airbox drain line, I'm thinking that's enough to screw with the idle, but still let it run as good as it did off idle.

Inside of carbs from airbox do look spotless. Outside of carbs not so much.

Planning the following:

- Replacing all vacuum hoses including airbox drain line
- Pulling carbs to check for anyother vacuum leaks
- Checking current A/F settings
- Making a makeshift manometer to sync carbs
- Adding extra long fuel lines to the tank (off the bike) to use to sync carbs
- Replacing spark plugs (I'm in here now)
- Replacing zip ties w/ hose clamps
- Replacing exhaust header gaskets (is this common?)

See how it idles from there.

Short enough? LOL

Thanks

Chris

[arsenic]

replacing header gasket is not really common, though things rarely go bad.

[Black_peter]

Symptom - idles a couple of hundred RPM low, and idle is not really smooth.

Tried adjusting idle. It's either right where it is or 2k RPM (or more) or slow it down till it dies.

Dirty idle circuit. or FA screws need adjusting. The idle adjuster works on the throttle links once you crank it up enough you get off the idle circuit and into the main circuit. (1800RPM~)


I'm assuming the I-4 should idle smoother when running correctly than the twin in my GS right? LOL

This engine has a notorious "sewing machine" sound. Rattles that smooth out could be the cam chain tensioner.

Symptom: When idling, there is a noticeable 'tick' coming from the front of the engine. Sounds just like one of hundreds of headers / exhaust leaks I've had on project cars. Factory header looks like it's never been off (PB Blaster to the rescue).

Well then you should have plenty of experiance in finding it!


Took apart to get to carbs and found:

-Split vaccum hose. Well VENT hose. It's the only hose connected to the fuel sender, right next to where the wiring runs up in it.

Throw it away..

-Airbox drain hose was toast. Halfway down it's length it was twisted / busted in h half, with cap still intact on end.

Fix that, Unless that hose is tight it is changing the air box pressure.


- Zip ties holding fuel lines on petcock (dealership 'mod')

Up to you. A bit of a pain to cut them off when working on the tank.
Those should be spring type hose clamps.

[ctandc]

Dirty idle circuit. or FA screws need adjusting. The idle adjuster works on the throttle links once you crank it up enough you get off the idle circuit and into the main circuit. (1800RPM~)

yeah I was kinda hoping that I wouldn't have to yuck the carbs off LOL just because I know I'll go overboard.....

you don't think the airbox drain being pretty much open could cause idle issues?

And the bike does 'smell' a bit rich at idle and when running it. So off come the carbs.

You think I should try adjusting the FA screws FIRST? Since the carbs were cleaned and they actually look clean on the inside...

Can those screws be reached without removing carbs?




This engine has a notorious "sewing machine" sound. Rattles that smooth out could be the cam chain tensioner.

Hmm.. I'd heard about that. So I'm guessing the exhaust gaskets aren't a 'common' part to fail. Any true telltale signs of the cam chain tensioner?


Well then you should have plenty of experiance in finding it!



That's what it sounds like. I want to sand / paint the exhaust anyway, so I guess I'll find out it....

Throw it away..

I was thinking that one was purely a vent, plus the other one is just an overflow vent of some kind....so leaving them open fine? Shhh don't tell the EPA...


Fix that, Unless that hose is tight it is changing the air box pressure.

I plan on it. I can order the O.E vent hose w/ cap...for like $12.00 but I figure I can match up some hose and make it work.

Up to you. A bit of a pain to cut them off when working on the tank.
Those should be spring type hose clamps.


I'm going to go buy the local shop and pick up a handful of the fuel line clamps.......it just struck me as odd...the zip ties I mean[/b]

[Black_peter]

If you have incredibly tiny hands you can adjust the FA screws with the carbs on.. Or get my favorite tool:


I would plug the air box and adjust the FA screws (based on the rich smell) and see if you can get idle back. Also check the carb synch. You might have one so far off it's effecting idle. If you are clever you can synch the carbs with out a tank. Just warm up the bike, set the idle up and pull the tank. Then synch with the gas left in the bowls.

About the under tank hoses:
Since only one of them goes back to the intake, the rest are not are EPA issues.
There are 11 hoses total:
Two for gas (needed)
One from the #4 carb to the fuel valve. (needed)
One to vent the gas tank to equalizes pressure (not needed but must be open!!)
One from the filler neck to drain rain water out or gas over fill (not needed but a good idea)
One for the fuel gauge sender (I have no idea what it is for... Stray electrons? So it feels part of the team under there? No clue!)
One to drain the battery (needed!! Should be routed well below all metal parts..)
One to drain the Air box (needed and must be plugged)
Two vents from the carbs that loop up over the air box. These do not run all the way down.
One from the crank case vent (box on top of valve cover) to airbox (needed!)

[ctandc]

Okay so I want to tear into this thing tonight. Of course no one stocks the airbox vent hose or even the 'correct' fuel hose clips..

So I'll go with some good hose clamps and just match the hose size up and install the cap on the end.

I'm going to go ahead and make a homemade manometer and try the sync. It can't hurt. If it helps idle after fixing the airbox vent, we'll go from there. If not...

I'll go ahead and yank the carbs and get to cleaning and check for any missing O-rings or anything else...

I will then check the current adjustment of the Air / Fuel screw and go from there. I think I'm gonna try right at 2 turns out from everything I've read. A bit leaner, regardless, of where they are now.

Add to that new plugs and we'll see how it goes

Thanks for the input

[ctandc]

HOLY CRAP.................wtf?

So I decided to go ahead and pull the carbs....and they're off. And they are VERY clean inside, damn near spotless....

So I clean 'em off a little more, blow air through everything, carb cleaner, then more air.

I'm also replacing the fuel lines with my own extra long ones, so I can use it for my homemade carb sync tool, then just cut them off to the correct length when I'm done.

So I go to check the A/F screws.

Carb #1 was FOUR turns out
Carb #2 was FOUR turns out
Carb #3 was THREE and 1/2 turns out
Carb #4 was FOUR turns out

Might explain the rich smell from the exhaust

I'm going to back them back out 3 turns each and start putting them back in.

No varnish anywhere, slides move freely, everything looks good actually...

Here's a couple of pics







I'm gonna get 'em back in tonight, and hopefully at least give the sync a try.

Wish me luck

[ctandc]

Okay so that was quick...

Turns out I got 5/16" fuel line instead of the 1/4" that came off of the carbs...lovely.

So it will have to wait until tomorrow night...and then into Friday...

Jeez.......

[arsenic]

yeah 4 turns out, that would be a problem. What jet kit is in them, what air filter are you using?

[ctandc]

NO Jet kit, stock pipe, stock air filter / airbox.

That DEFINITELY explains the RICH smell I was getting.


Chris

[ctandc]

The plan is this (for sync)

I'm going to run new fuel line from the carbs (replace the vacuum hoses too they look pretty brittle...) and run it EXTRA long. The two hoses will run to the tank (Which is off of course), which is up on a rig I made sitting on my workbench. The plan is to hook everything back up, including airbox etc...and feed the carbs from the tank in the PRIME position, so the vacuum isn't need it.

I'll do this to warm the engine up / get it running, then to sync the carbs.

Anyone think this will cause any issues? I will cut the petcock back to ON (no vacuum / no fuel feed) when the engine isn't running, in between syncing the carbs etc.


Any thoughts?


Chris

Bikebandit shipped today...will be here Friday (Express cost me an extra $14) new windscreen, mirrors, clutch lever, windscreen bolts.

[md86]

All I do when I synch mine is just twist the tank sideways and let it lat across the bike . No need for extra long lines .
And I'd go with maybe 2.5 or even less on the pilots . Stock it 1 5/8 . Jet kits seem to usually call for 2.5 for stock engines , and those kits tend to run rich anyway . If it STILL don't wanna idle after that , you have to have some crap still jammed in the little holes in the carbs . The pilot circuit is a BITCH to get clean .

[ctandc]

Okay so the fuel line I got tonight was the right diameter, but too thick walled to fit down to the carb inlets with the vacuum hoses that come out of there as well.

So I used the lines that were on the bike to begin with.

Got the carbs back on, airbox, filter, throttle cable, choke cable etc etc.

New plugs in, plugs wires are snug.

Just sat the tank on top of the bike w/o the bracket / seat etc.

Petcock on PRIME.

Bike turns over easily enough....NO fire at all.

So I made sure I was getting gas.

Tank off the bike, petcock to PRIME gas flows from both outlets.

Checked for spark with tank off. Pulled #1 spark plug wire, put an old plug in it next to the engine, NO spark. WTF?

It started ran fine before. Checked all connections and fuses. All good.

The gas in the tank is low, but not low enough that it wouldn't start and run before I took it apart w/o being in RESERVE.

Battery is almost drained now. Need to go tomorrow and buy a charger...LOVELY.

When I took the tank back off I noticed a wire near the two main harness connectors right in between the coils.....it's not plugged in to anything, but there is NOT a wire to plug it into . Coils are all plugged in etc.

I'm stumped. And I don't have enough slack on the fuel lines (not the factory lines ) to turn the tank sideways to sync carbs anyway (Assuming I get it running LOL) so I still need fuel line..

I'll try again after work tomorrow. Take the battery out of my GS and try...

What am I missing?

Took #1 plug out, (brand new) seems to be a tad wet with fuel, but not really...I could smell gas that's about it.

Any ideas? I think I'm gonna pull it back apart tomorrow, change all the fuel lines (long enough to give me room to move the tank around at least) and then go from there.....

Thanks

Chris