Fine tuning '82 GS450L carbs - new exhaust

[incarceration]

I am back!

I replaced the left coil and the bike is now starting!

Now my problem is, after replacing all the stuff I replaced (exhaust, main jet, and pilot jet) I need to tweak the carbs a bit.

I am able to get the bike running now, but it runs a bit hot I think?

I start it up and it'll idle now (I had to adjust the idle screw, before I did that it was revving at super high RPMs regardless of choke position) but when I roll back the throttle and let go, it takes a bit to return to idle.

I believe this is running too lean, correct?

How do I resolve this?

When I put the carbs back together after swapping out the exhaust to a MAC 2-1 system and replacing the main jet from #115 to #130 and the pilot jet to #47.5 from #45, I screwed in the pilot screw (above the carb input to the cylinders) all the way in and then backed out 2.5 turns. Do I need to go more? If so, how? Can I do it by just taking the tank off?

Thanks

 

[incarceration]

TALLAHASSEE AREA - Fine tuning '82 GS450L carbs - new exhaust

TALLAHASSEE AREA - Fine tuning '82 GS450L carbs - new exhaust

Well I got everything going pretty well now, at least enough to ride around and it seems to run better than it did with the old crap I had on it before all of this.

Only issue now I notice, it kinda starts up a little weak. What I mean by that is, I have to pump a little gas in when first starting it up (whether it's hot or not) to get it rolling, then it's fine after that.

Any ideas what that may be?

I plan to do some plug-chops later this weekend if possible (I have a couple things to do to my other vehicle)

Thanks for all the help you guys! I couldn't have done it without this community.

 

[Guest]

High idle can be lean, or it can be an intake leak. Have you got new O rings under the intake boots and are the boots soft and sealing well?

Do you use choke when you first start?

If it's still "weak" when hot maybe richen the mixture screws a quarter turn or so.

 

[incarceration]

TALLAHASSEE AREA - Fine tuning '82 GS450L carbs - new exhaust

TALLAHASSEE AREA - Fine tuning '82 GS450L carbs - new exhaust

Didn't replace boot o-rings, they feel soft and malleable.

I am at roughly 3 turns out from screwed all the way in on the pilot screw w/ #130 main jet and #47.5 pilot.

You think the rough starting is from running lean?

 

[Guest]

Definitely go another quarter or half turn out on the mixture screws, but if you haven't replaced the intake boot O rings I can almost guarantee you have an intake leak, and that will be like running lean.

With the boots, I thought mine were ok too, but the clamps wouldn't really tighten down properly.

I ended up getting new boots and the difference was quite large... the old ones had shrunken, so the clamps weren't clamping and the carbs were hard to get in.

The new ones were able to be clamped properly and the carbs slotted in so nice and easy the difference was amazing.

 

[incarceration]

TALLAHASSEE AREA - Fine tuning '82 GS450L carbs - new exhaust

TALLAHASSEE AREA - Fine tuning '82 GS450L carbs - new exhaust

I take back everything I said about the starting haha

I went to ride it earlier, and got some new plugs while just riding around and when i was taking them out to replace i looked at the electrodes and one was burning rich the other was okay.

Should I just adjust the pilow screw on the one?

Also, are you suggesting I replace the o-rings in the intake boots (boots going from carb to motor) or the intake boots all together? Because that's like a $5 thing vs a $50-$100 thing for something that seems to be ok for now, just needs fine tuning (granted I had previous said I was getting poor start-up)

 

[Guest]

Replace the O rings at a minimum, but for me it was well worthwhile replacing the boots as well. I got them for $US25 each from Boulevard Suzuki.

As for one plug being richer/leaner than the other, sounds like you need to balance your carbs which is quite normal after fiddling with them.

When they're balanced properly, both carbs should be able to run the same jets and mixture screw settings.

 

[incarceration]

TALLAHASSEE AREA - Fine tuning '82 GS450L carbs - new exhaust

TALLAHASSEE AREA - Fine tuning '82 GS450L carbs - new exhaust

Balance the carbs? Never heard of that before.

What is that?

 

[Guest]

Aaah ok... you need to read more

Basically it's making sure that when you open the throttle, the butterflies open the same amount on each carb.

When you look at your carbs and the mechanism that the throttle cable pulls on, you will see a locknut and screw there. That's what makes the adjustment.

Basically, when out of balance one butterfly will open more than the other, meaning one cylinder will get more fuel/air than the other.

I have a Morgan Carbtune Pro to do mine with which is an excellent tool, but do some searching on here and Google to see some other options etc.

 

[incarceration]

TALLAHASSEE AREA - Fine tuning '82 GS450L carbs - new exhaust

TALLAHASSEE AREA - Fine tuning '82 GS450L carbs - new exhaust

Ohhhh you mean carb sync?

Yeah I know which lock nut and screw that marries the 2 carbs together that you're referring to.

What's the easiest way to sync them? I know of some tools that are like 90 bucks, are those necessary?

 

[Guest]

Sync/balance, yep same thing

You can get cheap or expensive tools to do the job. As long as the two dials/gauges/whatever read the same then they will work.

If there's someone on here in your area that has a tool they may be willing to give you a hand too.

 

[incarceration]

TALLAHASSEE AREA - Fine tuning '82 GS450L carbs - new exhaust

TALLAHASSEE AREA - Fine tuning '82 GS450L carbs - new exhaust

Yeah I don't know if anyone is in my area. I'm in Tallahassee, FL

Do I just plug in the hoses into the vacuum lines from each carb that go to the gauges?

I suppose I'll look around online and maybe call some places like Advance Auto and O'Reilly's Auto

EDIT:
I'm gonna try and make something like this:
http://www.youtube.com/watch?v=iG8oM-XcmeM

Where do I attach the 2 hoses though from my homemade manometer? My 2 carbs have one vacuum line going to the petcock and that's it. I have 2 vent lines coming off the carbs between the 2 but I don't think those are the ones I want are they?

Also, I see that guy has a 'home made fuel bottle', how would I go about making one of those when my fuel tank has a petcock on it that has the fuel line + vacuum hose?

EDIT #2:
Scratch that idea, if my carbs are too out of sync it could be disastrous.

I'm gonna probably see if a local shop here will do it for me or if any friends in town have a manometer i can borrow

 

[Guest]

Just in front of your carb intake boots on the head you'll see a philips head screw each side with a gasket under it. You take these out and put the nipples for the manometer hoses in there (don't forget to put them back in!):



For fuel, I went to a mower shop and got a fuel tap, bit of fuel hose, and an old whipper snipper fuel tank:

 

[incarceration]

Great! Thanks!

I'll see what I can come up with

 

[Guest]

No worries... just realised how old those photos are and how long since I've sync'd my carbs! I really should give that a check soon after all the carb fiddling I've done...

 

[incarceration]

This is driving me nuts!

I have the slow startup, SOMETIMES. It can be driven around then stopped and go to start up again and it'll take rolling back on the throttle to get going cause of it being a poor start up at first. Other times it'll crank right up when pushing the button.

I notice it gets worse as the engine and engine area gets HOT, like, riding it for about 20min or so. On my way home from work I noticed after a lot of stop-go traffic it was idling at 2,000RPM after it was idling perfectly just before heading home when I took it to a shop here to see what they had to say about it.

The guy at the shop even took it around and congratulated me on the work I did and said it's running beautifully and that he hasn't seen a bike of its age running so well before. We tried shooting it with ether around the boot openings and it didn't do anything, he even shot it around them with a LOT of ether and didn't do anything (sputter, rev higher, etc)

What the hell is going on? Why is it idling so high @ 2,000RPM only when really hot and being driven? And why is the start up sometimes really, really weak?

 

[Guest]

You didn't answer earlier on your choke... do you start with the choke on?

What's the current status with your jetting? Don't be surprised if the 45 is too rich and you need to back to the stock pilot.

One thing I noticed when I first rode mine after the rebuild... I thought I had warmed it up nicely on choke for a few minutes, then started riding with choke off. I had adjusted the idle to 1100RPM at this point.

About 1 km up the road I had to pull over and wind the idle way back down as it was idling at around 4000RPM.

Since then the idle is fine, lesson learnt... don't bother adjusting idle til the bike is nice and warm.

 

[incarceration]

Yeah I start it with the choke to the left about 2\3 of the way and ease my way back as it warms up until eventually taking off with the choke off (completely to the right.)

I tried taking it to the shop here that said they could sync the carbs for me and they didn't find anything wrong with it. I asked if they even had a monometer and the guy said they didn't have one so I have to find another shop with one.

I usually wait a few minutes before taking off so it can warm up. But I'm riding it and it seems to be running great; I rode around town not too long ago for about 30-45min and it idled fine at every light.

 

[Guest]

When mine was stock you push the choke down to put the choke on from memory and lift it to turn it off... been a while though!

Good news it's been running nice