jetting opinion

[jetmechmarty]

Well, I know the floats are all at an identical setting. So, if I check one, they should all be the same. That is assuming those 30 something year old plastic floats still float the same. If what you folks are telling me is true, I expect to have to change the float level.

[bikerphil]

Marty, after rejetting, I would re-check the float level and also open up the mixture screws another 1/2 turn or so and go from there. If it is running super lean, you will know for sure just by the feel of the engine, it wont pull as hard, it will shake more, it will just feel overall thin. My guess would be it isn't getting enough fuel at lower rpm (mixture screws too far in) which will whiten the plugs pretty quick. my 2¢.

[skids]

Marty, after rejetting, I would re-check the float level and also open up the mixture screws another 1/2 turn or so and go from there.

That is true for idle rpms and up to the transition (ie, 3000 rpms or so). There is some guidance out there for CV carbs that says to tune to the high rpms and make compensations for the lower rpms after that...

[Rasputin]

I think this may be the tuning guide Skids was referring to.

http://www.factorypro.com/tech/carbtune,CV,high_rpm_engines.html

[jetmechmarty]

I think this may be the tuning guide Skids was referring to.
http://www.factorypro.com/tech/carbt...m_engines.html

That's interesting. I can definitely tell that I'm too rich in the mains as I have given up power. I'll put it back to the 110-120-120-110 that was working well, or maybe 115 across as many of you suggest.

As I recall, (I haven't seen my bike for 2 weeks) I have no issues on the bottom end. I turn the throttle and it pulls hard without a stumble.

The white plugs confound me. I will start by looking at the fuel level in the bowls when I get home.

One symtom that I do have is a lot of popping on deceleration. It seems to have quieted down a little when I opened the mixture screws 1/2 turn.

I don't know if it matters, but I have the stock airbox in place and 4 into 1 exhaust.

Thank you for that link.

[jetmechmarty]

JAT. Chould this condition have anything to do with my exhaust not providing enough back pressure? There certainly isn't much restriction in that thing.

[petejw]

JAT. Chould this condition have anything to do with my exhaust not providing enough back pressure? There certainly isn't much restriction in that thing.

it could, would also explain the popping on decel,
id still change the main jets to 115, check ur float
levels and as phil stated adj the mixture screws.

[skids]

With 4-1 exhaust, a slight popping on decel is what I would call "normal." You try to get rid of that and you screw-up everything else that is good! At least that is my story and I am sticking to it!

[jetmechmarty]

With 4-1 exhaust, a slight popping on decel is what I would call "normal." You try to get rid of that and you screw-up everything else that is good! At least that is my story and I am sticking to it!

I never worried about it. I worry about white plugs.

[motoman]

Those viton needles may look good, but replacing them will get you even fuel levels across the board. Iknow you don't have the convenience of the bleeder drains like on the 81carbs to check ACTUAL fuel levels when bike is running, but having the spring loaded needle will allow a float to come up, compressing spring more till it seats tight enough to shut off fuel flow. The actual fuel levels in my Venturers fuel bowls were all over the place, never the four carbs being the same, and different levels at different times. This has went on for three+ yrs. now. Finially, couple weeks ago replaced the float needles ONLY. All fuel levels in all carbs are the same, and runs like a total different bike. This was the only time I chose to not use Genuine Mikuni. The OEM cost was $100! Went with the K&L needles, re-set floats and checked that running fuel levels were the same across all four carbs. BTW, 110main jets IS stock on your SG if it still has the original carbs, but with 4into1's, IMO, 112.5's outside cyls/115's inside cyls. Actual fuel level will change approx. 2mm for every 1mm of float level change. You stated that you know ALL floats set the same, but unless those viton float needles are new, you'll find that all four ACTUAL fuel levels are not the same.......BTDT....

[skids]

I never worried about it. I worry about white plugs.

Point taken.

[motoman]

I never worried about it. I worry about white plugs.

Well, unless fuel changes,......... worry it is.

[jetmechmarty]

Thanx motoman! I replaced all of the needles & seats. I used the kits from Georgefix.

[jetmechmarty]

OK, I'm back home and after the bike. I installed new Mikuni jets 115 across the mains. New 42.5 in the slow. #2 is stripped, so I left it alone.

Jeff came over with his "cave man" float gauge and helped me get the fuel level set across the board. It worked well. I reinstalled the bank and it fired right up. Idle was a little rough. #2 header was not as hot as the other three. I opened all of the mixture screws another 1/2 turn and it smoothed out nicely. I hope I'm done for a while.

[motoman]

Glad to hear it's "alive" and runnin,' at least close to normal again.............