CL/CB350 Shimming carb needles? Open headers and cones?

[woody1981]

Okay... I installed the other set of CL350 exhaust I bought and chopped the muffler off of. Installed the cone filters as well. Starts and idles well... maybe better then it did before. It does backfire and pop quite a bit after revving it up... I think this indicates that it is running lean. Please correct me if I'm wrong. I rode it around the block and it runs pretty well but there is a kind of dead spot when I first rev it up while accelerating... it kinda bogs... a lot like if you tried to go (in stock form) without having the choke all the way open.

I talked to Chris Faccione and asked him about re-jetting the stock carbs since he has run the open scrambler headers on both his CL350 and his CB360. He said that he discussed it with Greg from Ohio Cafe Racers (Greg, chime in if you're here) and the conclusion is that these little carbs (stock) are pretty insensitive to tuning and the only thing that might be necessary is to shim the needles a bit.

So, that being said... anyone want to give me a tutorial on how to do this? Do you think that will increase the fuel flow enough to compensate for the open headers and cones? I'm open to comments and thoughts.

It sounds like a freakin' moto GP bike now!!

Thanks for the advice in advance.

- Woody

 

[chrisf]

After messing around with the carbs on my RD400, I now understand this a bit better. The needle position adjust the partial throttle, which is where yours is bogging. Let me guess: it's smooth at full throttle and little throttle, but lumpy in between...

Raising the needle with richen the mix at part throttle and smooth it out a bit. Now, as to how much to shim it...that is a bit of a mystery. Let me look around and get back to you because I'd like to do the same.

--Chris

 

[woody1981]

Thanks Chris. I haven't even had these carbs apart cause the bike has always been a good runner. I know there is no clip on the needle on 350s, so you have to shim them with a thin washer. I just don't know more then that. We'll figure it out I guess.

Also, you didn't tell me that the open headers and cones sound like a effin drag bike... it's pretty awesome... but I'm trying to decide if i want baffles before I start trying to dial in the carbs.

Does it annoy the shit out of you on longer rides?

- Woody

 

[chrisf]

The only thing bad about the sound is that I worry it will piss the neighbors off. Living in the Texas heat and having two small children, most of my ideal riding time is early in the morning. But I feel bad firing that bike up at 7AM, you know. Long trips are no problem. The most annoying thing about long trips is the vibration through the clip-ons.

TBH, I haven't ridden that bike in months.

If you find out any more info on the shims, do let me know. Also, I have some exhaust bends coming my way. When I get those, I'll fabricate a prototype exhaust system. Then, duplicate it in staineless. I remember you were interested in a custom exhaust, but forget what you actually wanted done. Let me know if you need some work.

--Thanks, Chris

 

[woody1981]

Thanks Chris.

When I asked about the custom exhaust I was still debating on what to do. This new setup will probably suffice for now... but once I see what you come up with I could change my mind.

I posted this question over on the honda twins forum too... Here is the link if you want to follow it there as well.

http://hondatwins.com/hondatwinsforum/viewtopic.php?f=4&t=26

- Woody

The only thing bad about the sound is that I worry it will piss the neighbors off. Living in the Texas heat and having two small children, most of my ideal riding time is early in the morning. But I feel bad firing that bike up at 7AM, you know. Long trips are no problem. The most annoying thing about long trips is the vibration through the clip-ons.

TBH, I haven't ridden that bike in months.

If you find out any more info on the shims, do let me know. Also, I have some exhaust bends coming my way. When I get those, I'll fabricate a prototype exhaust system. Then, duplicate it in staineless. I remember you were interested in a custom exhaust, but forget what you actually wanted done. Let me know if you need some work.

--Thanks, Chris

 

[chrisf]

BTW, I used to hate Mikuni's because I found them complicated. However, now that I have more experience screwing around with them on my RD400, they are much nicer. It might just be worth it.

I have a set of VM32 that I might put on the CB350. They are supposed to make a huge difference.

--Chris

 

[woody1981]

I was reading from one guy that said he bought some from Sporting for Less that were pre-jetted for the CB350 and found they ran really rich. I thought that they might be perfect for our setup because we need a rich mix to compensate for the open exhaust.

I might have to give them a whirl.

- Woody

BTW, I used to hate Mikuni's because I found them complicated. However, now that I have more experience screwing around with them on my RD400, they are much nicer. It might just be worth it.

I have a set of VM32 that I might put on the CB350. They are supposed to make a huge difference.

--Chris

 

[sclay115]

It's been a while since I've had the needles out of my CB carbs, but I'll say this much. All the other bikes I've had, the FZR, the XS, the Bandit, all had a needle with clips. The distance between the 'settings' is very minute. The trick I think is finding a washer of some type, probably plastic, that won't have an effect on the way the slide drops when you shut the throttle.

Alrighty, quick searching, apparently one can buy incredibly small diameter(what we need) plastic washers(double score) at Radio Shack. They apparently come in a package of a variety of thicknesses, and one can adjust to their liking and needs. It's really pretty simple once she is all apart on how to do it. And come to think of it, I might end up doing this myself, as I am also in the exhaust sans baffle and pod filter club.

Steve

P.S. I'm guessing these are them:

http://www.radioshack.com/product/index.jsp?productId=2103391&cp=&sr=1&kw=washer&origkw=washer&parentPage=search

 

[zimm]

time to dig up an old thread
has anyone had any luck shiming the needles? my 350 with uni's and free flowing exhaust seems to run really rich thue the mid reange idels great pulls hard wide open but wont cruze any help carbs are rebuild with new floats i have never ran it with stock fliters/ exhaust

 

[zimm]

Shimming needles makes things worse.
try 107.5~110 mains and different air correctors in carb top (under diaphragm).
You may have to drill them out to lean out mid range.
The needles are really short, I haven't found anything to substitute them with (yet ;D)

PJ

air correctors? can you please expaline more?

 

[zimm]

thanks it is poss that they are pluged how would it act if they are pluged?