More CJ360 Carb Tuning...CrazyPJ, Trek97?

[ncologerojr]

I know there are many of these threads, but I haven't found what I'm looking for...

I'm running pods and short 2 into 2 exhaust pipes with shorty mufflers. I was running stacks for the aesthetics, but I could not even get the tuning close. I'm currently running stock 68 primary jets, 120 secondary mains, stock needles (no shims) and pilot screw 4&1/2 out. The bike still gets rich and sputters at low-mid in 1st and 2nd gear, but seems pretty good once I clear that range. This leaves me with a few main questions:
1. Would going to a smaller primary main help with the low-mid rich mixture? I think I saw that trek97 is running a 62.
2. It's my understanding that this tuning issue is caused mostly by the CV carbs reacting to the extra turbulent air flow of the pods, and dumping fuel early. So if I were to upgrade to a set of mikuni VM carbs would I eliminate this tuning problem?
3. Do most people running pods/stacks just deal with the mid range sputters?

Here is the bike in question:

Thanks in advance for any help!

 

[ncologerojr]

Also I think it's running hot. Although this is my first vintage honda and I'm not sure what constitutes as "hot".

 

[trek97]

I know there are many of these threads, but I haven't found what I'm looking for...

I'm running pods and short 2 into 2 exhaust pipes with shorty mufflers. I was running stacks for the aesthetics, but I could not even get the tuning close. I'm currently running stock 68 primary jets, 120 secondary mains, stock needles (no shims) and pilot screw 4&1/2 out. The bike still gets rich and sputters at low-mid in 1st and 2nd gear, but seems pretty good once I clear that range. This leaves me with a few main questions:
1. Would going to a smaller primary main help with the low-mid rich mixture? I think I saw that trek97 is running a 62.
2. It's my understanding that this tuning issue is caused mostly by the CV carbs reacting to the extra turbulent air flow of the pods, and dumping fuel early. So if I were to upgrade to a set of mikuni VM carbs would I eliminate this tuning problem?
3. Do most people running pods/stacks just deal with the mid range sputters?

Here is the bike in question:

Thanks in advance for any help!

Has PJ modified and restored these carbs ?

1 If you have the stock 35 pilots and 68s - 4 1/2 turns is too much. Start at 1 1/2.

2 send those cheap pods back to china and get uni filters.

3 Talk to PJ or 3dognate about mikunis...I dont know nuthin bout em.

4 yes, Going to a smaller primary main will fix mid range mixture. But you got to modify a pair. cause they dont sell em for the 754s, I will post a link to the jets you need in a moment.

5 And yes, NO SHIMS EVER. the stock needles are already almost a bit too short.

 

[trek97]

W the current jetting, if she is getting hot...its not fuel. Its probably timing.
Using the non-contact on mine. The wrapped headers near the collars gets 500-520 F. On the head, down in there near the plugs gets 320 degrees F .

Give me a few minutes...I am taking pics and gathering links. Im also gonna post this on my blog.

 

[ncologerojr]

W the current jetting, if she is getting hot...its not fuel. Its probably timing.
Using the non-contact on mine. The wrapped headers near the collars gets 500-520 F. On the head, down in there near the plugs gets 230 degrees F .

Give me a few minutes...I am taking pics and gathering links. Im also gonna post this on my blog.

Awesome. Thank you.

 

[ncologerojr]

Has PJ modified and restored these carbs ?

1 If you have the stock 35 pilots and 68s - 4 1/2 turns is too much. Start at 1 1/2.

2 send those cheap pods back to china and get uni filters.

3 Talk to PJ or 3dognate about mikunis...I dont know nuthin bout em.

4 yes, Going to a smaller primary main will fix mid range mixture. But you got to modify a pair. cause they dont sell em for the 754s, I will post a link to the jets you need in a moment.

5 And yes, NO SHIMS EVER. the stock needles are already almost a bit too short.

No pj hasn't modified the carbs, I've done all work.
I started with 1 turn and worked my way out on the pilot screw. Anything before 3&1/2-4 turns the bike runs super rich, pops out the exhaust and sputters like crazy. 4&1/2 gives me the best so far...
The cheap pods are all I have right now. Like I said I was running stacks, I had these laying around.
How would you modify the primary? Fill it and re drill?

Thanks for all the info.

 

[trek97]

First send em to PJ...I hear PJs current recipe, is improved. He did mine 3 years ago. And he has done a bit of tweaking since then.

If they require any additional fine tweaking I did this...

These are the kits I have...They come w a bunch of great stuff. Also some stuff you wont use. ANd still the crappy o-ring bowl gasket. grrr. But, they offer 4 different tapered needles to play with. and 3 pilots. #34, #35 and #41, Stock main primaries and several secondaries, but they are all too small for pod jetting. I think the largest is 112.

They are kind of a pain in the butt to get. Seem to only be sold in Japan. So, you will have to use google translate to find a place that has them for sale. I checked. the place I get em from no longer has them. And convert Yen to dollars. Mine was like 3000jpy each + 1200JPY shipping. 7200JPY which came to approx $90 total.

Do google searches...The part # is FH-0142N Keyster Tornado. and they make 2 different versions of this kit. I believe Keihin made 2 different versions of this carb...you want the correct one for your carbs. Some things are different.
http://www.keyster.jp/0142nh.htm

Now for the main secondaries...

I have never found anything but 68s. So...I made some. Kinda.

These from Jetrus are correct thread fit...but approx 1.5mm too long. (if i remember correctly)

http://jetsrus.com/a_jets_by_carburetor_type/jets_keihin_99101-124_and_99101-ZF5_air.html

So, get some different sizes, I got #58, 60, 62, 65s and grind, file, sand, cut...whatever you can do to make em right. I have a buddy who does precision machining. He did mine at a fairly reasonable price. The tops are different. this doesnt seem to matter. HOWEVER. The bottoms need to be made the same as stock. So the little venturi, nozzle, whatever you call it acts the same as stock. If you are serious about doing this. I could talk to Stuart and he may modify you some...like $10-$20 a pair...maybe. After you provide the jets.

Stock pair on left. Modified on Right.

 

[trek97]

gonna have a smoke break be back shortly. HA

 

[trek97]

OK, the 4 1/2 turns sounds very familiar. I had mine at 4 1/2 turns once. I cant recall exactly why..
check for leaks. old cracked insulators OR unmodified kit springs on air/fuel mix...

Shut off fuel tap, Drain carb bowls. pull air/fuel needles out...carefully. and inspect em close. If they have brass or aluminum dust (shavings) caught up in the springs. The fix the springs...The ports or pilots may be clogged w this shit. You have to open em up more to get gas through.

Heres the original post AND it mentions the 4 1/2 turns...

http://www.hondabrat.com/2012/05/kehein-754-carbsso-close.html

 

[trek97]

Here is a problem I had w leaking insulators. They were brand new. I over tightened them and they warped. Would not get a seal tween the gasket and head. I filed the rubber flat. a little hondabond on gaskets and fixed.

http://www.dotheton.com/forum/index.php?topic=27417.msg449562#msg449562

 

[trek97]

AND if you really want to go to sleep... Here is a post I made on another page. This guy installed smaller main secondaries...in order to fix the rich mid range.

This is what I believe happens to 754s when you install pods and exhaust.

Pods make stock 754 Keihins really overly sensitive. And cheap steel mesh chinese pods are a nightmare I fought w for two seasons. Pods make her breath easier and allow the carbs to draw the air in big gulps. Everytime the intake valves open and pistons moving down. (GULP) 754 Keihins like a flow of smoother steadier air pressure to operate vacuum slides and jet venturis. they dont like gulps. I havent used the K&N pods...they look pretty much like chinese pods, even though they do include the cotton fabric filter material in them. so I assume they would pretty much have the same effect as the chinese pods.

I can tell you pretty much what is going to happen w your 360 by adding pods of any kind. without crazyPJs fix.
At idle you are feeding fuel through the air/fuel adjusters
when you give it some throttle the added vacuum makes pilot jets kick in to supplement air/fuel adjusters and control mix up to approx 1800 rpms.
Then the added air pressures building in air jets cause main primaries kick in and supplement the air/fuel needles and pilots. Feeding even more fuel as needed w more air flow. building up to approx 3000-5000 rpm
This is when smooth air pressure and vacuum really counts.
Because, the slides begin to rise. drawing the needles out of the emulsion tubes of the main secondary jets. thus supplementing the mix w more fuel necessary to build yet higher rpms at a pre-determined flow metered by the taper on the needle.

Pods gulping air through this system. The needles rise way to early and dump a bunch of gas in the system before its needed.
Your bike WILL run rich at midrange rpm. So rich that as soon as you hit 4500-5000 rpm it will start to sputter and pop. If you hold your throttle steady for a minute or two at this rpm your plugs will foul from being too wet w gas and eventually the bike will completely die altogether. As it running way to rich to even burn. Ideal mix is between 12 to 1 and 14 to 1 ratio. It will be somewhere around 8 to1 or more.

By jetting down, you have put a bandaid on the midrange rpm problem. as you have addressed the issue of the slides rising too much to soon. However you will find, it becomes lean in the upper rpms. Your smaller jets won't feed the necessary amount of fuel and the pods are flowing more than enough air. You wont get any top end speed and she will become hot due to this lean condition. Burning up valves.

When actually what it is begging for is larger main secondaries. to feed the increased airflow you have given her by adding the pods.

OK, now PJ has a secret recipe to help calm all this vacuum air pressure stuff. He has been a Japanese bike mechanic for like 35 years or more. And just so happens...(lucky for us)...to specialize in the 360s. simply due to the fact they are his favorite old bikes. Its a secret cause he does this for his living now.

Your bike can run better w pods of any kind if he "fixes" them. I wont tell you its a perfect out of the box fix everytime. Because after 35+ years of wear and tear on all these motors, coupled w riding styles and geographic locations. There will be differences. No two 360s are alike these days. But his fix will provide you w a workable base line that couldnt be achieved otherwise. And he continues to tweek his recipe. Talking with other guys, the Carbs hes doing today seem to be better "out of the box" than when he did mine 3 years ago.
But since he doesnt have your whole bike in front of him to perform all tweaking. You may have to play w the jets a bit on your own. But PJ is the king of customer service. any additional help you need after you get the carbs installed and your machine running, he will be there to help w advice on final tweeks.

Heres the list of what I currently have.
carbs modded by PJ
21mm float height
#41 pilots
#62 main primaries
#120 main secondaries
D44Z-L needles
Uni-filters

far off in the future I may consider a little more experimenting w even larger secondaries and needle sizes. Just for fun. Cause working on carbs is just so much fun...not really.

 

[trek97]

I knew nothing about Carbs or Hondas when I started this. I have been working on these carbs 3 years to come up w all of this from scratch. boxes of plugs and 100s of chops. tons of hours removing changing and reinstalling my carbs.

My machine is running great. And I believe yours can to. Between PJ and what I have done. It shouldnt be too terribly difficult to get her running great.
I havent fouled a plug yet this year. She did die once inside the tunnel down in Kentucky. I installed the #41 pilots since then, however I now believe it was timing related. so I may go back to the aftermarket #35s.

When PJ reads all this. he knows he is absolutely welcome to correct me on anything.

Also. I may consider attempting to make a pair of custom needles from scratch.

PS
I HATE WORKING ON CARBS.

And yes. All these pretty 360s you see online or otherwise w Keihins, pods and exhaust. Chances are its not running as good as it should. Unless its been to PJ. First. And thats a fucking fact. Believe me.

 

[trek97]

Please let me know your plans after reading this. Or make any changes to your carbs. find a leak, etc.

I would like to use this in my blog.

 

[ncologerojr]

Please let me know your plans after reading this. Or make any changes to your carbs. find a leak, etc.

I would like to use this in my blog.

Will do. I am at work now for the night, hopefully I will have some time tomorrow to sort things out.
I think I am going to start by re-checking my timing, points and valve gaps. I want to make sure I have a good baseline before going any further. It also seems like the right side gets hotter than the left, so hopefully I can solve that problem first. I'll also check over the carbs, and make sure there are no vacuum leaks. Then I'll focus on getting smaller primary mains in there. I'll probably go the same route as you and modify some different jets.

The only question I still have is about swapping carbs. I actually found your post a few days ago explaining what happens in the cv carbs causing the rich mid range. If I were to switch to vm carbs with a mechanically operated slide wouldn't I eliminate a lot of these problems? The extra air rushing in wouldn't cause the slide to lift early and dump too much fuel...?

Thanks again for all the great advise.

 

[trek97]

Things to check and do list before carbs...

scroll down a bit and you will find it.

http://www.hondabrat.com/search?updated-max=2012-06-13T04:09:00-07:00&max-results=7

 

[trek97]

be super careful messing w secondaries...Things can go real lean real quick. Especially in the higher rpms. Before you know it. You could burn a valve.

And I really like the look of your bike.

Kiley If I remember correctly also has Mikunis on Gretta

 

[ncologerojr]

be super careful messing w secondaries...Things can go real lean real quick. Especially in the higher rpms. Before you know it. You could burn a valve.

And I really like the look of your bike.

Kiley If I remember correctly also has Mikunis on Gretta

I understand that about the secondaries, that's why I went up to a 120.
Thank you, I'm happy with how it's turning out.

 

[ncologerojr]

Well...
As I mentioned the bike was running hot. I took it out for a short ride and it ran well, until it got too hot and began to stall. So I let it cool down and babied it home.
After letting the bike cool I decided to do a timing check...it was way off.

So I fixed the timing, and went out for a ride. The bike felt great, almost no mid range sputter and great power. But....the bike started getting hot again. So back into the garage.

After it cooled, I pulled the tank and tappet covers to check the valves. I gapped the tappets, and put her back together.

Now it's running on one cylinder, left only...I'm done for the night.

Oh and a spark plug before any work was done.

 

[ncologerojr]

This thread describes my heat issue exactly.
http://www.dotheton.com/forum/index.php?topic=50060

 

[ncologerojr]

After a bit of brain storming I'm beginning to think that my "overheating" issue is in fact a fuel issue as others have suggested. So I am going to begin by re-adjusting the tappet clearances, and getting the bike firing as usual again. Then I'll take it for a ride and monitor the fuel flow from the tank. I also want to double check the breather tubes on the carburetors for clogs. I'll keep everyone posted.