carb questions

[Phil B]

Hi again folks. I have two questions, one easy and one difficult.

easy: So, I plan to be hooking my abused carbs back up this weekend. Never actually opened. sigh.
From my reading, it seems like if I hook the lines back up properly, I should be able to just put the main petcock on PRIME for a while.... an the floats should eventually turn off the flow when there is enough.. and then I crank the starter for "a while".  Anything else I need to know?
Is it possible to "flood" the carbs? I've heard it could be, but then I read that link that adidas gave, and it sounded like the floats are supposed to stop flooding from happening?

difficult: I'm guessing, sight unseen, that my bike has not bee rejetted to match the K&N drop-in.
But.. what if it has?
If I get the restrictor, and put it on, and it has been rejetted... what are some external (non-take-the-bike apart) signs I can look for?  anything?

There seem to be some good ideas at
http://www.bikechatforums.com/viewtopic.php?t=194975

but I'm also wondering if the change in jet size for merely the drop in, is really going to make much difference in this stuff at all, lol.

[adidasguy]

Stuck floats will flood the carbs. Otherwise, nope.

When the bike is on, the fuel valve is open due to the vacuum. Gas is flowing freely as if the petcock was in prime. What keeps it in check are the floats and needle valves in the carbs. If they were stuck, there would be some flooding even when driving normally because nothing would stop gas from filling the carb bowls.

Make sense?

External signs? Only if they changed screws. Then even that would not indicate changed jets.

I have a K&N on one bike. With or without the restrictor it runs. I suppose after a while I could check the plugs for lean, normal or rich then decide if the restrictor should be on or off.

Run without it until you get one. If plugs show lean, then put it on. If plugs look perfect, don't put it on.

Make sense?

[Phil B]

Run without it until you get one. If plugs show lean, then put it on. If plugs look perfect, don't put it on.

Make sense?

yeah. although I suppose I might need to get fresh plugs, mine look kinda old and ugly now

I found this nice simple comparison chart:


It also mentions that I'm supposed to cut the engine after running at whatever rpm for a while, to properly test.
Is it okay to do that in neutral?  some posts on here I think seem to say its supposed to be in gear only.

[craigs449]

If the carbs are off the bike at the moment, why don't you just open them up and see what jets are in there?

[Phil B]

cant. screws are practically welded in there and Im not gonna attempt to drill them

[Suzuki Stevo]

cant. screws are practically welded in there and Im not gonna attempt to drill them

Agreed...chips from drilling are the last thing you want around a carburetor 

[weedahoe]

When you say "a while", I just wanted to add that when I put my carbs on and set it to Prime, within a few seconds I hit the starter and it fired up. SO it really doesnt take long at all.

[Phil B]

cant. screws are practically welded in there and Im not gonna attempt to drill them

Agreed...chips from drilling are the last thing you want around a carburetor 

Huh... whats that thing between the screw and the pliers?

[Suzuki Stevo]

Huh... whats that thing between the screw and the pliers?

You don't make shavings if you do it correctly 

[craigs449]

use vice grips to take off the float bowl screws, then replace them with allen head ones from home depot.

[salamander]

cant. screws are practically welded in there and Im not gonna attempt to drill them

I'm guessing you've already hit them with WD-40 or PB Blaster and let them sit a while?

[Phil B]

cant. screws are practically welded in there and Im not gonna attempt to drill them

I'm guessing you've already hit them with WD-40 or PB Blaster and let them sit a while?

Yeah. There's *no gap* between the head and the carb body. Just runs right off.

[Phil B]

I need to go to a custom printshop, and order something.
"I took my bike apart, and reassembled it, and all I have to show for it is this lousy T-shirt"

:-}

At least I got it to fire up again, after 4 weeks of being dormant.
It was misfiring like a mad thing until the choke kicked in and raised the revs... which it didnt, until about 5 seconds.... kinda creepy.

and it didnt even do that at first... until I checked the carb bowl drains.... which were empty... which meant of course I'd forgotten the tank petcock

But hey, a running engine is always nice! Now I need to get a hold of a replacement engine bolt before I ride it seriously...

[Phil B]

What.. the.. heck.


GSs are strange, mystical things.

the whole reason I suffered through the "try to take carbs apart" ordeal, was to rejet... to make my jets definitely match my drop-in k&n filter that PO had installed.... so I could get better mpg than my standard 56.


for those who missed the fiasco... it was a failure. I couldnt manage to remove the carb screws, so I ended up just putting the whole thing back together. after re-oiling one little dry spot in the filter.

I noticed how much better it was starting after the reassemble for a while. but that mostly went back to normal.

But now I completed my first standard 3-long-commute days. I put on 138 freeway miles.
and... I got 60.mumble mpg.
What... The.... 
I've *never* gotten as high as 60 before.

I didnt change anything  how can it be performing better anyway??

In some ways, i'm happy.. but the engineer in me is reaaally UNhappy, that I dont know WHY it's doing better.

Oddly, I thought it would be a little *worse*, since there was some amounts of traffic, and I ended lanesplitting a fair amount, going 30-40-ish, at higher than normal  revs to make more noise. 6k-ish, where I usually let it sit around 5k when I'm doing that slow.

I wonder if it was that, more than the reassemble, that did it.

[bombsquad83]

56 to 60 could be anything.  Most likely just the way you drove this time.  You did oil you air filter, which would reduce air flow a small amount.  If you are running lean due to the K&N, then less air would be good for it.

[Phil B]

aha... thanks. so in theory, adding in the restrictor i just accquired, might be even better, if it has not been rejetted.

[bombsquad83]

Theoretically, yes.

[adidasguy]

aha... thanks. so in theory, adding in the restrictor i just accquired, might be even better, if it has not been rejetted.

K&N says with restrictor it performs exactly as stock air filter.
Without it, rejet because too much air goes in and makes it a little leaner.

I tried them. No difference (with restrictor). Then when I found you had to take them out, clean them and oil them up. OOooooohhh - so much work. Decided easier to just throw away stock filter and replace - 20 seconds maybe - than do all that cleaning.

If I did rejetting then maybe. Stock jetting - I'm too lazy to wash an air filter. Would rather be riding or building another bike.

[Phil B]

Wheel .... second full tank refill.
This time, I got 59mpg, with more of a non-stop regular commute riding thing.
(143 miles, 2.42 gallons)

I never get that high, usually.

So, it's not just my riding.
winter blend vs summer blend fuel make a difference?

[weedahoe]

Ive always heard winter blend is supposed to give better mileage but then again, so will non ethanol based gas