Another 34 Pic 3 Build!

[dan filipi]

dkl » Today, 10:38 am[/url]":12aodv7r]
The 34-3 is almost impossible to get right with out the Electric choke hooked up and adjusted properly, I did the same thing on the first one I messed with. It also makes cranking so easy. Good Job..

Why do you suppose that is? Since choke shouldn't be needed once warmed up, does it still richen it some when warm?

 

[dkl]

I am no expert, but I believe proper choke adjustment is instrumental in the position of the throttle plate during idle and during acceleration. Also adjusting the accelerator pump can mask problems, get carb adjusted first.

 

[joedrum]

hmmmmmm seems the the choke would just control the position of the choke plate .....but as said ive never worked this carb ....but also the accelerator pump is part of dialing in ....if you get good idle and it wont come off idle good ...that what it dose provide extra gas to move along to main jet and it takes over ....many carbs are adjustable here and with an oldwing high revving capabilities ...im sure adjustment from a car set up might be needed .....it all part of dialing in ...you want no bad spots anywhere in the rpm range .....the get to know your carb program is priceless to having a great old school set up that will compete with new tech easy ....

 

[fivestring]

I get what you are saying, DKL. On these carbs the choke operates the fast idle cam which does move the throttle plate. And, of course the choke plate needs to be wide open before making any adjustments and the fast idle cam needs to be full off. After my fast idle adjustment, the choke is finally completely out of the picture.

I read several VW boards last night on adjusting the accelerator pump. There doesn't seem to be an exact adjustment, more of a "if you have a flat spot off idle give her a bigger squirt" process. VWs have an issue with using a certain distributor (009) that lacks vacuum advancement and gives guys a fit in that off-idle zone. The normal "fix" is to go full stroke on the accelerator pump. So, in a sense, they are masking a problem that is only truly rectified by switching to a better distributor with vacuum advance.

But the engineers of the 34pict designed the carb with a strong accelerator pump because it is necessary, as Joe said, to help bridge the gap from idle circuit to main jet. We are lacking that mid-range adjustment of shimming needles under the vacuum slides of Keihins and Mikunis.

DKL, I am curious where do you have your accelerator pump setting at on both your bikes? Also, what size main jets are you using?

 

[joedrum]

i wouldnt say the carb lacking adjustment the accelerator pump is the adjustment .....im convinced the flat spot can be adjusted out ...not with one thing only but all things tweaked just right ...what i have found is once there..... it hardly ever causes problems again ...nothing like a great gas charge .....

 

[dkl]

Mine is set basically in the middle, I did not mean not. To use the adjustment, I try to get the carb as close as possible to right as possible, then adjust the squirt as needed.....It is super easy to get to and adjust so it is definitely part of the dialing in process. ....my jet sizes are whatever came with the carb...no way can my old eyes read those little numbers.....

 

[dan filipi]

I'm with Joe if dialed in right then accel pump not in much play but dkl the man when it comes to this carb.

 

[fivestring]

I got some time with the project this afternoon. Much tweaking settings and test driving.

The first thing I did was swap out the stock return spring for something a little more wrist friendly. Original spring on left, replacement on right.

IMG 20160816 194554451

• fivestring
• Aug 16, 2016

34 pict 3 stock spring on left, replacement on right

Huge difference in comfort and it still closes the throttle fine.

IMG 20160816 194625439

• fivestring
• Aug 16, 2016

I am now running the idle jet drilled to 0.60 mm. The idle mix screw is at 3.5 turns. The accelerator pump is set at 3/4. The main jet is now a 142 Keihin.

I tried to measure the original main jet. If you remember it had no markings on it at all. Using my micro drill bits, I found the original main jet to be somewhere larger than my 1.30mm bit but smaller than the 1.40mm. I don't have any way to measure any closer than that. I wanted to try a larger jet to get more pull at bigger throttle inputs. I had a Keihin 142 so I put that in. Oh baby! That caused me to get bugs in my teeth, if you know what I mean.

I have learned to adjust one thing at a time until you are not getting any improvement and then move on to the next adjustment. It still needs to be done in order: first idle, then midrange, then top end. On this carb, midrange is an overlap of idle and top end with the accelerator pump helping to fill in the gap.

I did experiment with the accelerator pump today also. It was factory set at the 1/2 point. I first moved it to 1/4. I didn't get any changes, good or bad that were noticeable. Then I moved it up to 3/4.

IMG 20160816 194636873

• fivestring
• Aug 16, 2016

Accelerator pump p adjustment

IMG 20160816 194641616

• fivestring
• Aug 16, 2016

Pump adjustment

That was a big help. When riding along at steady cruise, then twisting hard, like you need to pass a car quickly, the bike would begin to pull then stop pulling hard, like it was getting too much air and wanting more gas. If I backed off the throttle a little bit it would pull harder again. This pump adjustment took almost all of that away. I am going to go another step up in main jet to see if I get any more power in that "car passing" range.

One other note. My stock exhausts were cut when I bought the bike. This might explain why DKL and I are ending up with different settings. You can kind of see them in the next picture.
I am really pleased at how this project is coming along. Another time or two of testing and tuning and it will be ready to go, carb wise anyway. I still have more lighting and misc stuff to take care of before it will be complete.

IMG 20160816 194803496

• fivestring
• Aug 16, 2016

Naked as a jaybird

Thanks again for all the help, guys.

 

[slabghost]

This is a great build! Thanks for posting the whole process.

 

[fivestring]

No prob, slab. One of my pet peeves is threads with dead ends.

I need a shift lever for a standard gl1100. Anybody have an extra laying around? The only one on eBay is kind of nasty looking.

 

[dan filipi]

I got that same surge on accelerating when I was too lean on primary with the dft. I went in .05 steps drilling larger until I couldn't feel it anymore.

Step by step progress as the carb is tweaked really does help a lot. Even if not being applied to your specific carb, each change helps us to learn carb characteristics for the next guy.
Keep up the good work!

 

[dkl]

Seems like ur headed in the right direction, nothing better than another single joining in the fun....Congrats !!!!

 

[joedrum]

yes this is going great 5string ....and its a nice thread ....i know on my bike the jetting is so much bigger than the car set up jetting ...except at idle ....that i can tell im getting about all this carb can do ...i just back from a ride where the hooch bike pulled the wheel off the ground like it was nothing in second gear change ....it so nice when things start getting right ...

you are becoming a pict carb expert now and many will read your thread ....it the best pict carb thread ive read i think in dialing one in ...at classic we work hard to figure the SCC thing out ...and this thread shows how much collaberation from all can really ...get it done ...great job ...

 

[Ansimp]

:good: Great job. :good:

 

[fivestring]

I went on a quick test ride just now to see where I am. Honestly, it is running very well. I think I am going to hold off on more tweaking until I can start riding extended distances instead of around the country block. I have an 80 mile round trip to work. That will give me a chance to find any little issues that need addressed.

Once I get the bike fully on the road I will do a little more fine tuning. I just don't want to get a ticket riding an illegal bike. I need my headlight and turn signals before I put official tags on it and begin riding it regularly.

Meanwhile, here's my video for entry into the SCC club

https://youtu.be/7oOg5Qvm2Oc

[video]https://youtu.be/7oOg5Qvm2Oc[/video]

 

[mcgovern61]

That sounds great!! Congrats!! :clapping: :yes:

 

[dkl]

Great Job !!!!!!! PVC Mani & 34 pict 3 Rule !!!!!​

[video]https://youtu.be/pItugbXjrYc[/video]​

 

[brianinpa]

That sounds great! Just curious... Did you, or DKL, see any condensation forming on your manifold?

 

[fivestring]

Thanks for the kind words. Spent most of today cleaning and painting front end and freshening up fork seals. Messy job every time I do it. But it needed it badly. Almost no oil in right fork.

Also bought a shifter off eBay Wednesday and it showed up today. Woot! Now I can actually shift right through the gears without problems. The makeshift lever I was using was modified from a Yamaha and kept slipping. Sure is nice to run through the gears without a hitch.

Brian, I have only taken maybe a 4 mile ride so far but did not notice any condensation yet. I will keep an eye out for it. DKL should have a definitive answer on that. I think he has a bazillion miles on his setup.

Kudos once again to DKL for doing all the hard work in designing the manifold that helped me take the step into SCC territory. :music:

 

[dkl]

Never have seen any condensation, but it would have to be super cold in the manifold to show on the thick sch 40 pvc. Icing up is a non issue on both my bikes,,,,,but remember I am in Louisiana.