78 GS1K Carb Rejet? Bad Fuel Economy - KEITH KRAUSE!

[Hoomgar]

I'll check all that when I pull the carbs. I have another set of good boots and the o-rings are new so I should be good if it is that. If it is the slide it will be taken care of when I rebuild the next set.

[TheNose]

I just got it - the dreaded No posts exist for this topic. I went to page 14 to continue reading and that's when I got it.

I hope you guys know that this is in my opinion the best thread ever on the GSResources. Thanks for the perseverance. I'm learning a lot from this thread.

Terry

[Hoomgar]

OK I need some more help guys. I got my Dynajet kit.
It says to put the spacer on top of the clip. But do I use
the stock spacers that the Mikuni needle had too or not?

Basically, I need to know how to (what parts and what order) assemble this?

[KEITH KRAUSE]

OK I need some more help guys. I got my Dynajet kit.
It says to put the spacer on top of the clip. But do I use
the stock spacers that the Mikuni needle had too or not?

Basically, I need to know how to (what parts and what order) assemble this?

The DJ "base settings" say to place their jetting spacer directly on top of the jet needle e-clip. This is for making 1/2 position changes. As I said earlier, I think your bike will run well with the e-clip in the 4th position from the top and no jetting spacer. Hopefully, this will be a good guess.
As for the stock plastic spacers that come on the stock jet needle, yes, you must re-install them as they were.
The thicker spacer, actually called a ring, goes directly on top of the e-clip and the thinner spacer goes directly under the e-clip.
Just for your info: if a jetting spacer was used, it would go directly on top of the e-clip, then the thicker ring would go on top of the jetting spacer, and the thinner spacer under the e-clip.
TIP: Snap in the new e-clip to the new jet needle firmly. DO NOT check for seating by trying to twist/rotate the e-clip as some people do. This can cause the e-clip to eat into the softer jet needle groove and this can later result in loosening and damage to the needle.
Also, the 138 main should work for you. Check float levels. Remove vent tubes.
Now do a good bench synch. Also, adjust the side air screws initially to 1 1/2 turns out. Try 1 1/4 to 1 1/2 on the pilot fuel screws. After warmed up, adjust the air screws for highest rpm, idle is 1,000/1,100 rpm, then shut down, cool off a little, and then vacuum synch. Hope she flys! :twisted:

[Hoomgar]

Rock on! Thanks Keith. I hope to work on it tonight.

[Hoomgar]

I just rode to work after installing the Stage II jet kit. I needed a test ride after setting the air screws and sync of the carbs. It seems to run good and smooth but I am not sure about the power? No backfires, stuttering or coughing out the air filters. It just seems that it is not as strong. But it has never idled like this before. The idle is now perfect...

What order would you like plug reads Keith?

[Hoomgar]

OK here are two chop tests with new plugs after the rejet with the stage III kit.

I also rechecked the intake boots and o-rings. They are good. My high idle thing must have been sticking floats in the other carbs.

I took two reads, one at 1/3 throttle and one at 1/4 throttle.

1/3 throttle chop test:
[img]http://groups.msn.com/_Secure/0SwCZArAWpF0BhkPVAzjgVm9kdJcOtQnVO4xRq4Nrp8oUgku77 n5wfo0*wqRH5AR2fmnKtPXy64yomoUTV3PG2PMXv1qJPgIZku5 7lzREV3IDz5n9f*7mQg/1-3-read.jpg[/img]

1/4 throttle chop test:
[img]http://groups.msn.com/_Secure/0SwCqArEW610iAgjA4y8cZooemvTNkOBH*5n90DmJpnQNMTzNS On8myDoj97k79pDUdF1TJvRJUsrAGgqyoc1uoGWSuD9PdjS7Wy 3V4FCQeJ*sZxfdX3FQQ/1-4-read.jpg[/img]

They look very close. Things to notice different from past plug reads:
1. The number 3 plug that was always lean is now the darkest if anything.
2. The color is very consistent across all the plugs compared to before. 3 and 4 are slightly darker than 1 and 2 and only slightly. You have to look at the insulator to see it.

As best as I can describe it the bike runs like this...

It is smooth. Very smooth and seems to run great as far as even acceleration and no bogging or staging like stuff. No coughing or back firing. It seems about the same the whole way through the RPM range.

It seems weak. It is slightly sluggish to rev off idle but then seems fine. It does require some choke to get it started when cold. Once warmed up it runs smooth. It just doesn't have the power it did before.

Again the photo's don't tell the whole story. Not sure if you could see it or not but the 1/4 read is slightly darker than the 1/3 read. Both seem just a bit on the light side but better than in the past.

WOT seems to pull OK. It has been stronger in the past.

Intake boots cleaned and resealed with good o-rings and some hi-temp grease.

Oil changed - not filter this time around since only 1200 miles since last change.

New plugs, gap checked and set at factory.

Stage III kit installed with the needle clip in the forth spot down from the top of the needle. Spacer on top of the needle but under the stock spacer. DJ138 mains used. Bench sync, air screws tweaked for max idle (barely noticeable change after 1.5 turns out) and carb sync with Morgan Carb Tune II.

The only thing I would like to see at this point would be some of the missing power back. Not sure what the fuel economy is yet?

[duaneage]

Maybe the "seat of the pants" feel is not what you had before but if it idles good, runs smooth, gets decent mileage, and causes you no trouble I would leave it alone. The extra power you may have had before could have been due to carb problems that ruined your mileage.

I guess if your after more speed press on but if it runs decent maybe that is how this bike is going to run. I ws tuning a small block years ago and had the carb jetted way off. The car was quick off the line and seemed to be fast but it wasn't right. Other problems I had forced me to tune it the right way and forego some of the performance I had.

[KEITH KRAUSE]

Mark, Mark, Mark...what am I gonna do with you? :?
Do I type in Spanish?
Your lack of power as you put it would almost certainly be a lean condition.
First of all, you didn't put the jet needle position exactly as I suggested. I said put the e-clip in the 4th position with NO jetting spacer. Then be sure to replace the stock plastic spacers the way they are...thicker on top the clip, thinner below the clip. By using the DJ jetting spacer on top the e-clip, you're 1/2 position leaner than I wanted. This could matter a lot. Remove the jetting spacer, leave the e-clip right where it is (4th position from top), and be sure the stock plastic spacers go back as above. Because you have to disturb the jet needles, you must re-bench/vacuum synch again. Re-test.
Also, I'm assuming you did check the float levels? Where are they set? Very important they be at .94" or even .93/.92 works.
Also, floatbowl vent lines must be tossed and vent ports left open.
And are you POSITIVE the timing is correct and advancing right?

[frosty5011]

Mark, Mark, Mark...what am I gonna do with you? :?
Do I type in Spanish?
Your lack of power as you put it would almost certainly be a lean condition.
First of all, you didn't put the jet needle position exactly as I suggested. I said put the e-clip in the 4th position with NO jetting spacer. Then be sure to replace the stock plastic spacers the way they are...thicker on top the clip, thinner below the clip. By using the DJ jetting spacer on top the e-clip, you're 1/2 position leaner than I wanted. This could matter a lot. Remove the jetting spacer, leave the e-clip right where it is (4th position from top), and be sure the stock plastic spacers go back as above. Because you have to disturb the jet needles, you must re-bench/vacuum synch again. Re-test.
Also, I'm assuming you did check the float levels? Where are they set? Very important they be at .94" or even .93/.92 works.
Also, floatbowl vent lines must be tossed and vent ports left open.
And are you POSITIVE the timing is correct and advancing right?

?Qu? dijo usted? 8O 8O 8O

[Hoomgar]

Mark, Mark, Mark...what am I gonna do with you? :?
Do I type in Spanish?

Well you might as well. You know, one of the things I have always been complimented on was my ability to follow directions exactly :?

I read and re-read what you said to do and went off to the garage thinking you said to use the spacer. Shoot me now :roll:

I usually print out your instructions and take that out with me but my printer is down. That's my story and I'm sticking to it!

anywho...

Your lack of power as you put it would almost certainly be a lean condition.

What I was hoping you were going to say. This is the nicest color we have had yet. It was just a tad lean looking to me.

First of all, you didn't put the jet needle position exactly as I suggested. I said put the e-clip in the 4th position with NO jetting spacer. Then be sure to replace the stock plastic spacers the way they are...thicker on top the clip, thinner below the clip. By using the DJ jetting spacer on top the e-clip, you're 1/2 position leaner than I wanted. This could matter a lot. Remove the jetting spacer, leave the e-clip right where it is (4th position from top), and be sure the stock plastic spacers go back as above. Because you have to disturb the jet needles, you must re-bench/vacuum synch again. Re-test.

Ohhhh!!! You didn't want me to use the spacer?!?
All stock spacers were installed correctly and will be again once the DJ spacer is removed.

Also, I'm assuming you did check the float levels? Where are they set? Very important they be at .94" or even .93/.92 works.

Set right in the middle of the range as before. All four the same. I did not test with the clear fuel tubes in the drain holes this time.

Also, floatbowl vent lines must be tossed and vent ports left open.

Gone! I use them as drinking straws to drink beer from long neck bottle now

And are you POSITIVE the timing is correct and advancing right?

No I am not. I haven't checked them since I set them spot on 2000 miles ago. I hope they don't need checked every couple thousand miles? If so they are going bye bye really quick.

Thanks for your enduring patience Keith. I'll post results after the changes.

[Hoomgar]

Maybe the "seat of the pants" feel is not what you had before but if it idles good, runs smooth, gets decent mileage, and causes you no trouble I would leave it alone. The extra power you may have had before could have been due to carb problems that ruined your mileage.

I guess if your after more speed press on but if it runs decent maybe that is how this bike is going to run. I ws tuning a small block years ago and had the carb jetted way off. The car was quick off the line and seemed to be fast but it wasn't right. Other problems I had forced me to tune it the right way and forego some of the performance I had.

I appreciate that Duane but were not talking about an acceptable power loss here. If that were the case I'll gladly pay at the pump.

[duaneage]

Points wear out, high speed runs tend to walk them out of adjustment as well, one of the less endearing qualities of mechanical ignition. I would check them often during the tuning process to make sure they are spot on.

Every jetting change or major adjustment should be followed with a quick timing check just so you KNOW they are not causing a problem.

[KEITH KRAUSE]

Yes, points and timing have a huge effect and they lose their settings easily. They pit, they burn...always check points condition/gap/timing before vacuum synch.

[duaneage]

The plug reads WILL be affected by yhe points. The dwell angle (120 degrees if I recall for this bike) is what sets the charge and discharge parameter for the coils.

Buy this

http://www.7453217467431.com/products/productDetails.jsp?PRODUCT%3C%3Eprd_id=1775329&FOLDER%3C%3Efolder_id=3642147&affID=39901&bmUID=1123553111093

Picture here:

http://www.tradervar.com/wwwold/CP7605.jpg

If your gonna play with a points equipped machine you need the right tools. I don't know if this will work for the bike but if you can somehow use it it is worth the money. Reading dwell on a meter is more accurate and faster than measuring the gap (old points are really hard to measure, the feeler gauges never get it right) and then moving the timing around throws it all off.

Keith - will a car dwell meter work if you read the scale differently or is a specific motor cycle one required?

When I worked on Mark's bike last May I had a tough time setting the gap and getting the timing right, I was not able to check the dwell either.