Roughness Off Idle - Continued from Electrical Thread

[Guest]

This thread is a continuation of another thread I was running in the electrical section:

http://www.thegsresources.com/_forum/showthread.php?t=180059

I fitted the Dyna S electronic setup to my bike thinking this would fix my problem. The coils are 4.1 ohms and 4.2 ohms respectively.

Well I took the bike for a run and it is still running a bit rough just off idle, when the twist grip is barely open not even an 1/8th open there is a roughness where you just know things are not running right.

I have synched the carbs: see below.



I have set the mixture screws at:
Cyl. No. 1 at 2 1/4 turns
Cyl. No. 2 at 2 1/8 turns
Cyl. No. 3 at 2 1/4 turns
Cyl. No. 4 at 2 turns

and this is what the plugs looked like when I pulled them after the ride. I tried to ride at the throttle opening where the roughness is experienced, it was a bit hard as there are a number of cross streets I have to turn down before getting to my place, so could not keep the throttle at a constant setting if you know what I mean.



Left to Right: Cyl. 1, 2, 3 & 4



Above: Cylinder 1



Above: Cylinder 2



Above : Cylinder 3



Above: Cylinder 4


If anyone has any thoughts, don't hold back.

All comments welcome.

BTW I have advanced the ign from 17deg at idle to around 12deg. which is closer to what the 650 motor should be.

[pete]

Hey Don, long time no talk!

I'm gonna stick my newbie plug reading hat on and tell you what I reckon, but remember all I've done is read lots of threads on here as well as some stuff on motorcyclecarbs.com etc., so I'd really recommend listening to someone a tad more experienced

Anyways, looks to me like number 1 and 3 are too rich. 2 and 4 look good.

Given you're talking 1/8 throttle, I think mixture screws need tweeking to lean them up a little, I don't expect the needle will be coming into play that early in the piece...

[Suzuki_Don]

Hey Don, long time no talk!

I'm gonna stick my newbie plug reading hat on and tell you what I reckon, but remember all I've done is read lots of threads on here as well as some stuff on motorcyclecarbs.com etc., so I'd really recommend listening to someone a tad more experienced

Anyways, looks to me like number 1 and 3 are too rich. 2 and 4 look good.

Given you're talking 1/8 throttle, I think mixture screws need tweeking to lean them up a little, I don't expect the needle will be coming into play that early in the piece...

Hi Pete, yeh, long time no speak. I've been busy riding and doing other projects, tuning etc.

I've just come in from outside. I've had the tank off again to adjust the mixture screws to 2 1/2 turns each. And I've nudged the timing back a smidgeon so now I have around 14 deg advance instead of 12. I took it for a quick spurt down the road and it does seem smoother and has a slightly better idle.

I will check the plugs again after the run tomorrow with the European boys and see if the stumble at low throttle settings has gone away.

I have had an issue with just lazily opening the throttle coming out of high speed corners. You know the story, you're doing 110 and back off for a high speed curve and only drop off a small amount of speed and just roll the throttle on ever so gently to get her back up to 110 and there is a stumble or flat spot at this point. If you twist the throttle open further and more quickly you seem to ride over it and hardly feel it, but it can be annoying and i would like to resolve it. I will see what it rides like tomorrow and if the stumble has gone away.

[pete]

Good to see you've been doing lots of riding

Now I have the pipes done on mine I feel like I can get a bit of a move on, see if that ignition is fixed in a couple of weeks, and hopefully get back on the road by the end of the year. I'd love to be tuning by then!

I do know what you're talking about though, that just off idle stuff annoys the crap out of me. Didn't have it on the GS when I was riding it, but definitely had a couple of cars that did it and yeah, giving it a bit of a boot certainly pushes through it, but doesn't solve it.

So, does this mean I may have actually been helpful for once? Or did you read that after you got back inside? Hahaha

[Suzuki_Don]

Pete your posts are always helpful and a pleasure to read because they always have an interesting edge to them. I am waiting on the technical info and "how to" on your home made electronic ignition. I cheated and just bought a Dyna S for mine and modified the auto advance unit to correct the advance from 550 to 650 specs.

[pete]

Cheers Don, I've still got heaps and heaps and heaps to learn about yet, but I'm definitely getting to know so much more as I get further through this rebuild... as to the ignition, I'm hoping to have a much better idea in a couple of weeks as to how that's progressing and see if what's there now works or not.

I just found out this morning that there's a Dyna that should work for the 450's, and I tell ya, I'm tempted! But I'll persevere with the HEI one, very keen to see how that goes...

Let us know how your fuelling goes tomorrow, hopefully it'll be nice and smooth off idle!

[Suzuki_Don]

Well!!!!! Things didn't work out today. My co-worker pulled a sickie and I had to go in to work today. So will have to put the ride off until another day.

[UncleMike]

That sync doesn't look very even.

[tkent02]

The richness on the plugs seems to correlate exactly with your screw settings.
#4 looks the best, why not try them all at #4's setting, 2 turns out?

[UncleMike]

The richness on the plugs seems to correlate exactly with your screw settings.
#4 looks the best, why not try them all at #4's setting, 2 turns out?

Agreed. ...

[Suzuki_Don]

That sync doesn't look very even.

I know it looks bad but is a lot better than it was before I did it. It's very hard to get them all even. They alter as the locknuts are tightened down I find. I could probably have another go at them and see if I can get them a bit closer -- it is really only No. 3 that is off a bit.

What do others think? Does it need to be redone?

Thanks Mike for the comments -- they are all appreciated.

[UncleMike]

Get 'em straight across, it can be a pain, but I think you'll be surprised at the difference it'll make. The carbsync tool helps keep them from turning while you tighten down the locknuts, but you can also compensate for how much they'll turn with some practice. Just make sure you have a fan or two blowing while you get better.

But definitely set your mixture screws to 2 turns like tkent said.

[Suzuki_Don]

MIKE, thanks for the comments. I will have another go at it.

TOM, yes you are right. The condition of the plugs does represent the adjustment on the relevant screws. I had not noticed that.

I have turned the screws out to 2 1/2 turns each and with the alteration in timing mentioned earlier it seems to be running a bit smoother.

I currently have 5C45 needles in the carbs and would like to go to slightly richer needles with the straight/parallel part at the top of the needles a touch smaller to give more fuel to the engine in the 1/8th to 1/4 throttle range. I don't know how well it is known but the 45 on the end of the needle number (5C45) is 2mm + .45mm = 2.45mm O.D. So I would be looking for a set of needles that would be about .005" (.12mm) smaller O.D. So that would be, lets see, !!!!!! .45mm - .12mm = .33mm.

So that would equate to a 5C33, but I think the closest I have seen is a 5C32 needle. All I have to do now is remember what type of carb/bike they were off.

Any help on this would be appreciated.

Thanks.

[pete]

While I've reached the end of my usefulness on this one Don, I'm definitely keen to see how it ends up. I'm expecting some of this fun/pain with the K&N's plus the Tranzac 2 into 1 I got made, so definitely watching how you go...

[Nessism]

Hey Don,

One other thing you can try is advancing the timing a couple of degrees. Mark the current position, rotate CCW to advance, and then go for a good hard ride. As long as you don't get detonation, the more advance the better.