Running rich, I need some advice, please

[gs450sjip]

I've been rereading this thread, and I noticed that (in this thread) there has been no talk of what's happening in the ignition system. I do know (from another thread) that you said you replaced the entire system with a Dynatek.

Question: did that include new coils or just the ignitor?

What kind of voltage are you currently getting at the coils? Has this changed since you acquired the motorcycle?

The pilot jets you have, are they both unmolested (i.e. not drilled out)?

Hopefully switching back to the hole-free jets will work for you. If not, it sounds to me like your problem MAY lie outside the carburetor.

Big D,

A year ago, there was faults in the ignition and fuel systems, hence the long arduous task of sorting through it all. The complete Dynatek system is installed and cured the ignition side of it. Plenty of hot, reliable spark. I did perform the coil relay mod also. The alternator charges the system when running at a reliable rate also.
Thanks, GS450JIP

Pete,

As soon as I get a chance, I'll replace the holed pilot jets with the un-holed originals, they are unmolested. I'm hoping that will get it. It actually runs worse after I replaced the throttle shaft seals and sealed the offending intake boot (pipe). I must have richened it considerably doing those things. It ran smoother (leaner) before I sealed everything.
It makes me wonder what would others set the mix screws at if they replaced the throttle shaft seals first? Stay tuned, Gentlemen, I'm not giving up yet...

[pete]

Good stuff... from memory my mixture screws are somewhere around the 2 turns out mark... but I know my carbs are jetted too rich.

[gs450sjip]

Good stuff... from memory my mixture screws are somewhere around the 2 turns out mark... but I know my carbs are jetted too rich.

Pete and all,

The clouds have lifted over Suzuki land ! I tried it yesterday at 7 degrees below freezing, Starts, idles with 1/2 choke, runs smoothly, very responsive....gee, only took a year. I haven't set the mix screws yet, it will wait till it's a little warmer here. They are at 1 1/2 turns out right now. I think I'm on the home stretch now, the rest is tuning. Swapping to the pilots with no holes did it along with careful positioning of the throttle blades. (Can't uncover the small transfer holes),

Thanks to all for helping ! Great forum. gs450sjip

[pete]

Yeehaa! Glad to hear it

So the next step will be setting the mixture screws properly using the highest idle method, and also you'll want to do a proper vacuum carb sync.

One of those will likely affect the other, so you may need to revisit them another time or two, but you will definitely find it worthwhile.

Very glad to hear you're winning

[gs450sjip]

Yeehaa! Glad to hear it

So the next step will be setting the mixture screws properly using the highest idle method, and also you'll want to do a proper vacuum carb sync.

One of those will likely affect the other, so you may need to revisit them another time or two, but you will definitely find it worthwhile.

Very glad to hear you're winning

Thanks! I really hated the thought of selling it as-is... I'm sure by Spring, I'll have it humming. I have to re-do the brake caliper, it sticks after setting for 3 decades. The tire are hard, etc..easy stuff. gs450sjip

[gs450sjip]

Yeehaa! Glad to hear it

So the next step will be setting the mixture screws properly using the highest idle method, and also you'll want to do a proper vacuum carb sync.

One of those will likely affect the other, so you may need to revisit them another time or two, but you will definitely find it worthwhile.

Very glad to hear you're winning

Pete,

I haven't had much time to play with this after correcting the pilot jets, and it's been cold. I find it will idle between 1200-1400 smoothly, when the throttle is cracked open quickly, it responds well. However, all is not well, the choke needs to be on slightly, the mix screws were at 2 turns out. If it try to richen it by turning the screws to 2 1/2 turns, it runs rougher and I still need the choke on some. If it turn the mix screws in to 1 1/4 turn to 1 1/2 turn, it runs smoother and responds cleanly. Also needs the choke on a little. It is cold here, but I thought it was warmed enough to take it off the choke, maybe not? I'll play with it under warmer conditions and see Sunday afternoon. The motor seems to like leaner mix than richer on the pilot screws. I'm thinking because the throttle shaft bushings were so much tighter than the originals. Just guessing here.
gs450sjip

[koolaid_kid]

If I may interject here:
First, your main jets have no influence on the idle mixture screws. So Pete, you need to adjust your mains and leave your pilot circuit be.
Second, the fastest idle method does not work well with CV carbs. It works for the VM carbs. For CV carbs, you want to use this method: Setting Idle Mixture on CV Cabs
And you almost never need to change the pilot jets; they are almost always fine stock. I have a very radical GPz750/810, and the stock pilot jets are correct for it.
Once you have this done you can do the carb sync.
I have requested that this be posted on BassCliff's site, but he has not gotten around to it yet.

Best of luck.

[gs450sjip]

If I may interject here:
First, your main jets have no influence on the idle mixture screws. So Pete, you need to adjust your mains and leave your pilot circuit be.
Second, the fastest idle method does not work well with CV carbs. It works for the VM carbs. For CV carbs, you want to use this method: Setting Idle Mixture on CV Cabs
And you almost never need to change the pilot jets; they are almost always fine stock. I have a very radical GPz750/810, and the stock pilot jets are correct for it.
Once you have this done you can do the carb sync.
I have requested that this be posted on BassCliff's site, but he has not gotten around to it yet.

Best of luck.

Koolaid Kid,
I have saved the article as I can not print it. I believe it may be still too cold to run without choke yet. It's supposed to be 70 degrees here Monday, I'll try then. All the jets in the carbs are unmolested originals (pilot jets). The mains are new Mikuni original size. The airbox and exhaust are complete originals. The floats are set correctly, new needles seats, all o-rings and boots are new. There are no air leaks anywhere. With that as a starting point, I believe it's just a matter of tuning now.
Thank you all for staying with me on this ! gs450sjip

[koolaid_kid]

O.K., best of luck.
BTW, bwringer and I did a cross-Indiana run in 40 degree weather this September and our bikes did not need the choke once they were warmed up (2-3 minutes).
Mine - 83 GPz 750/810 highly modified
His - 83 GS 850G completely stock

[gs450sjip]

O.K., best of luck.
BTW, bwringer and I did a cross-Indiana run in 40 degree weather this September and our bikes did not need the choke once they were warmed up (2-3 minutes).
Mine - 83 GPz 750/810 highly modified
His - 83 GS 850G completely stock

Koolaid Kid,

I tried to take the choke off but it wants to stall. It could still be too cold, or I need to do the mixture screw test. It does run cleaner with the screws at 1 1/4 to 1 1/2 turns out. At 2 to 2 1/2 turns, it burbles and generally runs rougher, does not rev cleanly. Much more testing and adjusting is needed. Once I get it to repeat in the tests, I'll post it.
I'll say this, when it runs at 1200-1400 rpm, with slight choke, it sounds and responds great! (at the lean pilot setting) gs450sjip

[koolaid_kid]

I suspect you have a minor issue still outstanding. Will it run at a higher RPM without the choke? If so, I would set it at that RPM and run the procedure, then go from there. It will take a few iterations to get it to settle down. If it won't run at any RPM without the choke, please post.

[gs450sjip]

I suspect you have a minor issue still outstanding. Will it run at a higher RPM without the choke? If so, I would set it at that RPM and run the procedure, then go from there. It will take a few iterations to get it to settle down. If it won't run at any RPM without the choke, please post.

KOOL AID KID,

Yes, I believe it will run at a higher rpm without the choke. When I first started it, it went to 3000 rpm without the choke, before I shut it down and backed the idle speed screw off. I set the screw completely backed off, or barely touching the carb linkage. I haven't had much opportunity to mess with it. I'll post Monday. Thanks, gs450sjip

[pete]

If the weather is cold, it's probably going to need to be running for up to 10 or 15 minutes to really get properly warm. I first got mine going in December last year, and a 5 minute idle and run around the block wasn't actually long enough to get it properly warm enough to accurately set the idle etc.

I found just because it would idle off choke, didn't mean it was properly warm.

Don't forget to put a fan in front of it if you're just letting it sit and idle for that long.

Just a thought anyway...

George, apologies I completely forgot about your tuning method for CV carbs! I have yet to give that a go myself too...

[koolaid_kid]

NP, Pete. BassCliff is going to post it on his site, he just hasn't gotten around to it yet. When I rode in 40F (5C) degree weather, it took my bike perhaps 2-3 minutes to fully warm up so I could take the choke off. Not sure what you call cold, of course.
But it is critical to get everything correct for this to happen. When we muck with our bikes you have to be extra critical when tuning the carbs.
For example, my bike's changes that affect carburetion include:
Pipe
Pods
Dynojet Stage 3
Pretty much the whole shooting match when it comes to the carbs.

[pete]

My issues could've been related to it not being run in after the rebuild yet, but I adjusted the idle and mixture screws after a 5 minute idle and quick run around a small block.

But when I rode it to get it registered, I had to pull over about 1km up the road and knock the idle back from the 3 to 4000RPM it was idling at

Seems I hadn't got it warm enough even though it was happy off choke... after I did that all was well...