About to torn the motor open

[Jramos13]

I have a cl350, i recently change to vm28 roundslide i tried all the posible jets combination, i have set the time correct with a timming gun, pamco ignition float bowls to specs but no matter what i do the bike just keep smoking whitish with heavy black and the plugs alway are extremely rich, the carbs currently have

2.5 slide
N-8 needle jet
5f21 nedlee leanest setting
35 pilot
140 main
No air jet
Air screw 2 out

I have 2 into 1 mac exhaust

Im just about to open the engine to see if i broke a ring or something, and i dont think so because im getting a solid 165 - 170 compression

Any more ideas before i open the engine?

 

[SONICJK]

Have you set the valves?

 

[Jramos13]

Yup adjust them correctly like more than 3 times 10mm and 5mm if my memmory serve me right

 

[Jramos13]

My plans are if the rings are not broken and its all good maybe relap the valves

 

[teazer]

Yup adjust them correctly, like more than 3 times. 10mm and 5mm if my memory serve me right

I don't theenk so...... More like .010" and .005" or something like that. Valve clearances are typically very small. Maybe 0.004 and 0.006" check teh service manual for the correct numbers.

Unlikely to be rings or valves leaking but anything is possible. Oil usually smokes blue. White and black smoke suggest too rich. What air filters are on it ?

What needle jet series is it? 175/182/?

Are the plugs oily wet or dusty carbon covered?

 

[Jramos13]

Im positve on the clearence manuals calls for .05mm intake and .10 for exhaust, im gonna dpuble check tonight, could that cause smoking? as for the needle jet im gonna open the bowl tonight because im not sure, i know they are not 159, but not sure, im thinking the same that it should not be a ring since the smoke is not blue at all, but maybe its burning berry little oil? My othe guess is that the valves were not lapped correctly at the machine shop, i forgot to mention i have 65.5 pistons and stacks

 

[crazypj]

0.05mm is about two thousandths of an inch (0.002")
5 and 10mm would probably destroy something through hammering.
(I know, it's just semantics )
Get the correct float level and check carb, could be too low leading to high fuel level?
You need to check the needle clip position as well, someone may have set everything to max rich?

 

[Jramos13]

After messing with the vm30 i switch to vm 28 roundslide the manual call for 15-17mm float height from surface i meassured them both and they ar at exactly 17, i change the needle to the leanest setting, the top one, i dunno of the valves might be the issue, but im getting good compression, and the bike accelerate super smooth throught the whole rpm range, this is what baffles me the most, im about to call an exorcist :'(

 

[crazypj]

How well does carb fit into boot?
If the back end drops it causes a rich mixture.
If it isn't that, may need smaller main jets
The choke isn't partially on? (plunger all the way down, Suzuki had some issues with them sticking, 30+ yrs ago)

 

[Sonreir]

Also... your needle jet is WAY too small. I'd go up to a P-6. And make sure you replace the stock 159 series with a 176 series. The 159 series isn't a bleed type, it's designed for a two stroke engine.

 

[Jramos13]

I got the mikuni boot, vm28-200, the match almost perfect the intake ports!
I though of smaller main jets but how low should i go? Im in 140 mains and 35 pilot in the vm28 and wetting b7es plugs

For the needle jet is this one:

169 N-8

The thing is im extremly rich at idle and all the ranges, to the point that the bike will die from carbon deposits in the plugs, might the needle being so small cause a rich condition?

Heres a pic of the plugs at idle for like 1 minute

I really apreciate your help guys!

 

[crazypj]

Drill a 1/16" hole through the shroud part of needle jet that sticks into airstream.

 

[cxman]

you have to jet the mikuni from the bottom up to top end not from the top down

your pilot is to rich

look at the 6 oclock position of the air intake side and see if the air corrector jet is still in if so remove it

set your needle back down

then try it dont worry about wide open throttle yet see how the plug look in driving to say 5-6k rpm

if they are still wet try a 30 pilot

once you get it starting /idling and midrange good the start playing with wide open throttle

 

[Brodie]

What PJ said. He is the master of Cl350/360.

 

[Jramos13]

Will drill tonight and report back! Working with the bike on a sunday and having a wife is not compatible lol,

I removed the air jet, it had a .05 one!

 

[Jramos13]

Ok i found a spare sec to drill them, heres a pic:

Ill try to start it tonight and report back!

 

[teazer]

That's an interesting VM28. 169 needle jet is a standard 2 stroke part and ideally should be replaced by a 175 series in say P-4 size.

Just out of interest, what size is the outlet of that carb and what diameter is the venturi and the slide.

As CXMan suggested, start by getting the pilot jet right. On the street running slowly we spend most time at less than 25% throttle - even on the highway and few of us use 100% throttle ever unless we ride a moped. That's why messing with main jets when we are still on the pilot jet doesn't work.

Keep the air jets that you took out. Two strokes like big or no air jets but 4 strokes often need an air jet to richen the fuel slope.

When you get to that, remember to come back and read this again. Main jet applies at 3/4 to wide open throttle across al revs, BUT the air jet changes the way that fuel jet work and it changes it more at high revs that low. So a correct main jet at say 4000 may not be right at say 10,000 and that's where the air jet comes into play to change the fuel slope.

For now focus on low to mid throttle.

 

[crazypj]

Opening up that hole 1/32" at a time also makes it run 'less rich' at higher rpm but doesn't affect extra fuel delivery much on acceleration

 

[Jramos13]

Ok, i just started it and the bike feels a lot better but still smoking whitish black not as much but smoking, i check the plugs and one is sooty black the other is kind of wet but im not sure if gas or oil.... Heres pics

I have some 25 pilot jet lying around somewhere, i will try with them to see if its gets better

 

[Sonreir]

Also... the B7ES is the wrong plug. Try a B8ES.