tuning

[wingnut]

I’ve had this bike 6 months now. Everything is bone stock. Carburetors rebuilt with K&L kits, tank cleaned and sealed, petcocks rebuilt, fuel lines replaced, new air filter, plugs gapped. Bought a color tune kit (to cool a tool not to have) and a manometer. Bike starts (jump start, still need new battery) fine on full chock runs there for about 3 min and then will run on ½ setting, another 3 min or so on choke and it will respond to throttle and idle at about 1000 rpm with choke off. Yesterday I reread the teck tips and used the procedures to set idle mixture and sync the throttles. Set the idle mixture at light blue headed toward yellow flame color on all cylinders. Then hooked up the manometer. Noticed that #1 and #4 were both higher than middle cylinders but got everything even as per the procedure. On test ride it comes off of idle well but between 1500 to 3000 it just seems a little flat after that it wants to go and I mean right now! You got to love the power these things make. Anyone have an idea on how to smooth it out during the transition? Maybe the weak battery?

[Pat Kelly]

Remove the K&L jets and put the stock (cleaned) jets back in. Make sure the float-height is set correctly for all the floats (remember, there are 2 floats in each carb).
If all else fails then give the bike to me .

[wingnut]

Pat I worked on those floats for a month getting them where the book said they should be. Use the clear tube method and have them within 1/2 mm of where the book says they should be. Hate to take them off again but putting the OE jets back in might just have to be done. As far as giving the bike away don't think so... I'll keep playing with it.

[mro]

Pat " (remember, there are 2 floats in each carb). "

toooo many floats

mro


how about just check both sides of each float

[TopCatGr58]

Hey Wingnut,

Do you remember what the new K&L pilot jets looked like? IF they looked like the OEMS with the holes in the sides, then you may NOT need to remove them? You seemed to be able to get the bike to idle, and run fairly well, which is more than many folks with messed up K&L pilots were able to do. It's just that the K&L kits are notorious for putting the wrong style of pilot jet in their kits, and they run rather rich, which could be bogging down your system in the lower rpms until you hit that 3k range?

What do your plugs look like?? Of course you'll need to put a few more than 6 miles on it to gauge them!!

But, you may also just be experiencing the normal power band transition. These bikes do have considerable torque, but they are not a THUMPER, and running in a higher gear under 3K rpm is going to give you poor throttle response. I don't know why so many people want to run these engines so slow?? I don't hardly ever let my run BELOW 3K!! IT ain't a V-8, or a Harley, let it run in the 3-6k range with the occasional run to 8.5, and you and your bike will be happier for it!!

[wingnut]

Short Shifter

Thanks TC, I remember back when I was rebuilding them and asking you lots of questions you asked and I verified they were the same. The flatness is not really bad and twisting the throttle a little more makes it go away so... this engine may just not like to be bogged. I have a bad habit of short shifting (I know that's a personnel problem, could be related to the large rear tire?) Maybe after I get use to it i'll roll the power a little better. Thats it. I need more miles and more throttle, yep thats what I need. Can't wait for warm weather.

[John]

The problem almost sounds like there may be some blockage in the pilot circuit. The main jet circuit doesn't come into play until around 3-4000 rpm. Pull the pilot jets out and spray some cleaner into the bore where the jet was, and check to see if the jets are clean, and all of the small holes in it are clear. Look and see if the cleaner comes out of the three small holes in the top of the air horn, just behind the throttle plates, and check to see if it sprays out of the pilot screw holes also.

[fxrer]

What John said, pilot circuit! I’d suspect you got bad/wrong pilot jets from K & L (lots of previous comments/criticisms about these), OR there’s dirt/crud somewhere in the pilot circuit. My SG pulls strong, from 1500 all the way up, in any gear - no transition stumble at all.

Nice looking bike - I was thinking the 81’s (SH) had the curved spokes, but I guess that didn’t happen until ’82?

[John]

The 81 LH MNS had curved spokes, ala the 82 XJ. The 80 MNS had straight spokes. I have curved spkoe wheels on mine that I sourced from an 82 XJ.

[John]

Hey Wingnut

One question...What is all that clear space around your bike? It can't be shop floor, as we all know that a clean shop is a sign of a sick mind.
The bike looks good by the way.

[wingnut]

Its not mine

Clear space around bike is the result of SWMBO out on shopping trip and her explorer not in its proper place. She was good enough to let me use the floor space for the photo shoot. Other side of the 2 car garage is relegated to the comfort of the dogs. The bike and I grab what we can as we need it but spend most of our time our corner.

[wingnut]

Think I found it

After putting ten more miles on the bike (I’m really racking them up now) Pulled the plugs and they were all black. After removing the seat I discovered that “somebody” has assembled and installed the air box wrong. The snorkel was not in its retainer and was flopping around loose. It was sitting down on the bottom of the box and cutting off most of the air flow. That may be why it was flat coming off idle. Carbs had to come off to get the air box out so it’s back in the test rig for float level check. I removed the float bowls and changed out the pilot jets with OE parts just to make sure.

[wingnut]

Picture of test rig

http://www.snapfish.com/viewsharedph...3C4C7F135D7D27

[GNEPIG]

.. cool set up, where did you hook the chains too?

[wingnut]

Brackets

Made some 90 degree L brackets with holes in each end. Chains have hook ends on them and other hole in brackets pick up diaphram cover plate screws on all four conners. That way it sits level in both directions and goes on and off easy. There is a lot of on and off using the clear tube method of setting the floats. Only works on carb bowls off of the latter model carbs though Also have a tee fitting in the line so I can check all 4 at once.