350 running intermittently. Whats your 2 cents?

[cavity.]

Ok, so I’m making this thread in an act of desperation. I have a cl350 I’ve done a lot of work on trying to get it to work right, but still somethings up.

The problem: I can start the bike ok with no choke (sometimes needs the slightest bit of throttle) and go ride for a few minutes (all good). But then I will notice the bike not pulling right and if I pull in the clutch the bike will die. With some throttle I can keep the motor going with the clutch in. If I let it die, I can go to kickstart it and it will start with some throttle but die without it. If I let it sit for a little, it will usually start normally and the cycle repeats itself. Also, occasionally I will see the bike begin to idle at 600-1000 but if I blip the throttle it will go back to normal idle.

About the Bike:
Newtronic electronic ignition, Long baffled straight pipes, Ricks charging system, KN Air filters, Mikuni VM30’s currently jetted with:
Pilot Jet: 30
Main Jet 210
Slide: 2.5
Needle: 6F4 (clip is second from bottom)
Needle Jet: 159 P5
Float Height: 23mm

Things I’ve checked:
New Shorai Battery Reads 13.08V
Timing is spot on (with timing light, not strobe light)
Carbs are clean and fuel lines are clear
Spark Plugs have been changed and gapped properly
Swapped for different set of coils (and plug wires) --no change
I have checked for spark when it isn’t starting right and its there on both cylinders
Compression is 180/180
Checked for intake leaks with brake cleaner



Anybody have ideas or have seen something similar?

 

[krafty]

230 mains? That seems way too big. I think I have 120s or 125s in my 350 right now.

 

[nrcb125]

Hmmm. Have you checked your charging system?

Here's a really good guide to check it: http://www.electrosport.com/media/pdf/fault-finding-diagram.pdf

 

[cavity.]

230 mains? That seems way too big. I think I have 120s or 125s in my 350 right now.

No, 210 mains. I had 180 mains in earlier but wasn't getting enough at high rpm. 210's feel better. Actually, when I got the bike it was used as a race bike and VM32's, short open headers and 240 mains. Jetting absolutely could be the problem, but I've changed the pilots all around from 25-40 and the mains from 180-220 that I'm leaning towards that not being the problem.

 

[coyote13]

Positive that your choke is staying off while you're riding? I was having a similar problem, and when I got off the bike I noticed that either I had brushed the choke with my leg or the wind had blown it into the on position.

Even still....210 seems outrageously large for a 350. Isn't the stock like....105?

 

[cavity.]

Hmmm. Have you checked your charging system?

Here's a really good guide to check it: http://www.electrosport.com/media/pdf/fault-finding-diagram.pdf

OK, I deleted my orignal response when I rechecked this.

Battery reads 13.18 just sitting there.
12.9 with ignition on.
12.98 at idle.
13.3 at 2500 rpm
13.5 at 5000 rpm

This is a problem right? I'm going to try and diagnose this but is it possible that this charging system problem made me overcompensate with jetting? I know that "pre jetted carbs" can be a little off but these came for a 350 with 180-220 main jets i think so 210 didnt seem crazy to me.

 

[twinsorin]

Might want to check your petcock bowl and screen. I was having a very similar problem and it turned out the screen was plugged with debris. It'd let some fuel through at times and at others just enough to idle. If it sat for a while it'd fill the carb bowls and it'd run normally...for a bit.

David

 

[cavity.]

Might want to check your petcock bowl and screen. I was having a very similar problem and it turned out the screen was plugged with debris. It'd let some fuel through at times and at others just enough to idle. If it sat for a while it'd fill the carb bowls and it'd run normally...for a bit.

David

Great idea, thanks. I will check this tonight.

Any other input on my charging system? I would just run all the tests on that link, but my RR is very difficult to probe with a voltmeter. I dont want to cut the wires to get a reading. Maybe i can get a pin in the wire connections?

 

[nrcb125]

OK, I deleted my orignal response when I rechecked this.

Battery reads 13.18 just sitting there.
12.9 with ignition on.
12.98 at idle.
13.3 at 2500 rpm
13.5 at 5000 rpm

This is a problem right? I'm going to try and diagnose this but is it possible that this charging system problem made me overcompensate with jetting? I know that "pre jetted carbs" can be a little off but these came for a 350 with 180-220 main jets i think so 210 didnt seem crazy to me.

Doesn't sound like anything is wrong to me. As long as it's getting 13.5 volts when your engine is at a reasonable cruising RPM it should be OK. Check the resistance between windings and voltage between phases of the alternator. If it's single phase check the line to ground voltage. Both of these steps are on the 2nd page of the document.

Again, it doesn't sound like that's the problem to me.

 

[cavity.]

Both petcocks seem to flow freely. I didnt pull them to clean them, but I let each of them flow for 30 seconds or so and both were smooth.

Then I moved onto the wiring. It's something I've always wanted to redo on this bike (kinda a mess) and I was surprised I was getting such a low voltage reading when it has an upgraded charging system. Everything seemed electrically correct, though I found that the bike still had the stock regulator in addition to the ricks R/R (at least i think its ricks), so i pulled that out but i dont think that will solve anything.

 

[coyote13]

How do you have a stock reg as well as Rick's? One or the other, I'd think...

 

[VonYinzer]

Is there air in your fuel lines?

 

[cavity.]

How do you have a stock reg as well as Rick's? One or the other, I'd think...

Right, seems like overkill but I believe it is electrically correct. This bike was modded by previous owners and im trying to save it. I drew up this diagram while watching TV last night. The stock reg is X'ed out on the right between the black live wire and ground (yellow wire wasnt connected to anything)

 

[cavity.]

Is there air in your fuel lines?

I don't see anything noticeable. I will try to pick up some wider fuel line and secure it well while I'm out today though and try it out.

 

[Sonreir]

Next time the bike dies, try coming to a stop and opening the gas cap. Check if you can hear air rushing in. Could be a vacuum forming in the tank. Same thing happened on my 360.

If that's not it, I'd double-checking your jetting. That main jet is super big for a 350 with 159 needle jet..

 

[cavity.]

Next time the bike dies, try coming to a stop and opening the gas cap. Check if you can hear air rushing in. Could be a vacuum forming in the tank. Same thing happened on my 360.

If that's not it, I'd double-checking your jetting. That main jet is super big for a 350 with 159 needle jet..

Thanks for the response. I will try to start it up with throttle when it's not behaving and listen. The gas cap has a good vent hole in it though.

As for the jetting, I had a 180 main jet (the smallest main I have) and the needle on the second leanest setting a few days ago. It had the same problem and was very hesitant accelerating. Now i've got better acceleration but same problem. I'm not opposed to buying smaller jets though. Maybe try 140s? I've seen people post similar jetting for these bikes.

Today I rewired the whole bike. Used seperate grounds for everything, pulled the second regulator and eliminated that "Lights Only" part of the ignition switch. I'll start it up tomorrow and see if theres any changes. I considered maybe the ignition might be acting funky with a bad ground.

 

[Sonreir]

Jetting with slide carbs can be a bit funny. Sometimes going too big shows all the symptoms of being too small as the amount of air rushing through the carb isn't enough to pull fuel through such a large opening.

The jetting I usually recommend for a 350 comes from a post on another board:

200 Main Jet
#176 P-8 Needle Jet
5F3 Needle at the lowest clip
30 Pilot Jet
.5 Air Jet
2.5 Slide
Two turns out on the mixture screw

It'll probably take a bit of cash to buy the brass you need, but this a very good setup as it uses a 176 needle jet instead of the 159. The 159 jet is designed for two strokes, but because it comes stock in the VM30s, that's what a lot of guys end up using.

 

[cavity.]

Jetting with slide carbs can be a bit funny. Sometimes going too big shows all the symptoms of being too small as the amount of air rushing through the carb isn't enough to pull fuel through such a large opening.

The jetting I usually recommend for a 350 comes from a post on another board:

200 Main Jet
#176 P-8 Needle Jet
5F3 Needle at the lowest clip
30 Pilot Jet
.5 Air Jet
2.5 Slide
Two turns out on the mixture screw

It'll probably take a bit of cash to buy the brass you need, but this a very good setup as it uses a 176 needle jet instead of the 159. The 159 jet is designed for two strokes, but because it comes stock in the VM30s, that's what a lot of guys end up using.

Again, thanks for the help. Do you know if my setup will work well with this (KN air filters and baffled straight pipes). I'm going to switch to a 2-1 over the winter when I have more time to do some welding. Not sure if I'll have to start tuning from square 1 again.

I'll probably buy the new brass tomorrow though if I find the rewiring didnt improve anything.

 

[Sonreir]

Yeah. This should be a good starting place.

I don't think you're going to get away from tuning entirely, but this should be closer than were you currently stand.