PNW Riders

Mitch F · 10-28-2009, 12:35 PM

So after cleaning out the carb real well, fresh gas/oil, gear oil top-off and a clean plug, my little Kawi 90cc tried to start on the first kick after 3+ years of sitting. After playing with it I got it to idle, but the throttle has almost no effect besides choking her out. Jet and idle don't seem to make much difference if any. Tried everything I could think of short of tearing the cylinder off and checking my rings. Didn't change timing as I don't see why it would have ever been changed.

Is there anything I'm missing or should I just rip the bitch apart?

ducatichick · 10-28-2009, 12:38 PM

Needle setting - what needle size/number, and what clip is it on?

Mitch F · 10-28-2009, 12:50 PM

Originally Posted by ducatichick

Needle setting - what needle size/number, and what clip is it on?

http://www.kawasaki.com/DefaultFrame...HOWVEHTABS%3d1

Kawi site specifies the needles as
10. 4L6 ("remark" here sounds like it's not for my model?)
16. E-4
17. Main jet 190M

I should probably say, A) I have no idea what these numbers actually MEAN and B) I don't know what you mean by "clip"

ducatichick · 10-28-2009, 01:13 PM

There is usually a clip (#9 is the circlip in your Kawi diagram) that sits in a groove on the needle. There may be a number of grooves on the needle so you can move the clip up or down. Moving the clip down would raise the needle in the main jet causing it to run richer.

Needle number indicates diameter and sometimes shape. Diameter will affect the how rich the bike runs overall, and shape (usually taper) affects how the bike behaves as you roll on the throttle.

My 2-stroke carb knowledge comes from racing two Honda RS125's, model years 96 and 98. So your carburetor might be quite different. The manual had a great chart on carb parts function - I will try to find on the internet and post a link for you.

holypiston · 10-28-2009, 01:40 PM

with old carbs, i straight away shi*can the needle jet. They can have A LOT of buildup. This is an old mother 4ker, so there's bound to be crap that is really hard to get to if there is a LOT of buildup. I remove ALL jets (pilots, needle jets, mains, valve seats, needles, airscrews, idle screws and soak this whole mess in a 3:1 mix of yamaha carb cleaner and gas (per bottle recommendation).

I like starting over with NEW jets (pilots/needle jets/valve seats and needles/replace any air mixture screw o-rings, float bowl gaskets, etc. that need them).

If you know of some kind of ultrasonic wash, use it. That will clean a lot of crap out of there. i then blow out the passages with compressed air.

I'd say the most crucial parts are new pilot jets, main jets and needle jets. It's par for the course that you should replace the float valve needle and seats too.

But the needle jet can screw everything up, so i'd definitely shelve the crusty bastards and get a new set.

Make sure you check your airscrew settings and float height upon assy and set towards stock. Clean/replace any air/fuel/petcock filters too.

Is it timed correctly? I use a dial indicator. Dont' trust the mark on the case.

Fresh battery correct?

james1300 · 10-28-2009, 01:45 PM

Is the air cleaner clean? Did you leave a rag in the filter housing (dont ask)

ducatichick · 10-28-2009, 01:58 PM

Originally Posted by james1300

Is the air cleaner clean? Did you leave a rag in the filter housing (dont ask)

Ha ha, check for duct tape covering the tail pipe too

Of course it won't even idle with said duct tape in place.

Here's a basic carb tuning page:
http://justkdx.dirtrider.net/printcarbtuning.html

I have a 2-stroke tuning book, will see what it has to offer when I get home.

ducatichick · 10-28-2009, 06:28 PM

The 2-stroke tuning book I have is by John Robinson, "Motorcycle Tuning (Two Stroke)" 2nd edition (1994). It has a short chapter on carburetor tuning - I could scan it in as a pdf and send it to you if you want, just let me know. You might find everything you need via google.

pscook · 10-29-2009, 05:47 AM

I have a PW80 that I could only get to run if I completely choked the intake and revved the living snot out of it. After getting it home, I pulled off the exhaust pipe and proceeded to pour ~6-8 ounces of nasty oil all over my garage floor. I then took a propane torch and smoked the rest of the crap out of the pipe. Once I did that it started and ran first kick. I think that the float was stuck and let gas/oil mix seep into the cylinder and then into the pipe (horizontal cylinder). The gas eventually evaporated (or was burned off) but the oil was left behind and choked the bike to death. PUll the pipe and look for a blocking issue, but turn it a couple of times to see if any oil or other crap is stuck in the narrow section.

Mitch F · 10-29-2009, 10:40 AM

That's a thought, I know when I actually got it to run it warmed up a whole bunch of nasty black residue on the exhaust and dropped it all over my basement floor

Maybe there's a bit more inside.

I'll be adjusting the circlip later today (soaked needles and all that in even MORE carb cleaner last night) and I'll pull the exhaust off too.

And ducchick, that would be wonderful if you could do that. I'll check the web too.

Dave R · 10-29-2009, 11:58 AM

Originally Posted by Mitch F

That's a thought, I know when I actually got it to run it warmed up a whole bunch of nasty black residue on the exhaust and dropped it all over my basement floor

Maybe there's a bit more inside.

I'll be adjusting the circlip later today (soaked needles and all that in even MORE carb cleaner last night) and I'll pull the exhaust off too.

And ducchick, that would be wonderful if you could do that. I'll check the web too.

I have seen exhausts get plugged with oil residue.. check that too. If it is plugged you can try to burn the crud out with a torch... obviously take pipe off bike first..

StageRulz · 10-29-2009, 12:20 PM

Oh......and check the Reed Valves. Thats what is between the Carb. and Cyld. more like an intake manifold. Easy to clean.

Rippn · 10-29-2009, 12:46 PM

"clean" the carb again... including the emulsion tube tiny holes, #18 on the scematic...
define..."clean plug".
Adjusting the needle clip is tunning... your still at the "get running OK" part.
FREE and clean, Ripp'n

Jet City Racer · 10-29-2009, 01:33 PM

Originally Posted by ducatichick

Ha ha, check for duct tape covering the tail pipe too

http://www.youtube.com/watch?v=7e3TYKOVCM0

Mitch F · 10-30-2009, 10:55 AM

These motors are rotary valves, not reeds. There was definately oil in the exhaust, I'm getting it out... slowly but surely.

Big T · 10-31-2009, 06:27 PM

You also need to check the timing

Timing is crucial in a 2 stroke

Maybe the timing advance isn't working

Let it warm up really well at idle, then see what happens

I take it you've never owned a 2 stroke before??

Mitch F · 11-02-2009, 01:35 PM

I've owned 2 strokes before (mainly jet skis), but none have ever fallen out of timing. I keep my shit in good shape and don't let it sit and develop problems as has happened to this old girl.

Drained the oil out of the pipe, re-cleaned all my needles, and leaned my main jet. I also bought a different plug (recommended is B7HS, had a B8HS). Not much change. So right now I've got it all apart for paint/cleaning. I'm planning on just dropping the $30 or so on a carb rebuild kit, and until then she'll just be getting her makeup done.

Compression test tonight. And maybe some pictures just for shits and giggles.

Thanks for the tuning guides as well, I'll do a quick once over and then really get balls deep in them once my rebuild kit arrives. Although that may be a few as I have about $50 to my name at the moment

Big T · 11-02-2009, 02:57 PM

Motors with points are going out of timing from the moment you set them, by definition.

You need to verify that the timing is good, the advance works, the carb (the entire carb) is clean and that there's no air leaks in the intake

You did dip your entire carb body once you took it apart?? And all the parts?

There's nothing to rebuild in a slide carb -new float bowl gasket and you're ready to go.

Mitch F · 11-04-2009, 11:56 AM

She lives! Tried fucking with the carb more last night (to no avail of course) and figuring it MUST be the timing, played with the points. First 3 times it only got worse, but the 4th time she started right up, revved and everything. Pumped up my tires, tied up some loose ends and rode her around the block. So very satisfying. She bogs once the RPM come up, so it looks like more carb tuning (and probably a bit more with the points) will have to happen. But she runs... shifts... stops... the whole shebang. HOORAY.

You guys are awesome.

ducatichick · 11-04-2009, 12:35 PM

Originally Posted by Mitch F

and figuring it MUST be the timing, played with the points. First 3 times it only got worse, but the 4th time she started right up, revved and everything.

Awesome! So you won't be needing me to scan in my whole book, after all?

Mitch F · 11-05-2009, 11:19 AM

I suppose not

However, do you know where I may find initial jet/points gap settings by chance? Without a starting point tuning will most definately take longer than it needs to (especially points).


10-28-2009, 12:38 PM	#2
ducatichick WMRRA Qualifier Joined: Jul 2009 From: Corvallis, OR I Ride: 08 Hypervibrator	Needle setting - what needle size/number, and what clip is it on? __________________ Follow PNW Riders on Facebook and Twitter


10-28-2009, 01:13 PM	#4
ducatichick WMRRA Qualifier Joined: Jul 2009 From: Corvallis, OR I Ride: 08 Hypervibrator	There is usually a clip (#9 is the circlip in your Kawi diagram) that sits in a groove on the needle. There may be a number of grooves on the needle so you can move the clip up or down. Moving the clip down would raise the needle in the main jet causing it to run richer. Needle number indicates diameter and sometimes shape. Diameter will affect the how rich the bike runs overall, and shape (usually taper) affects how the bike behaves as you roll on the throttle. My 2-stroke carb knowledge comes from racing two Honda RS125's, model years 96 and 98. So your carburetor might be quite different. The manual had a great chart on carb parts function - I will try to find on the internet and post a link for you. __________________ Follow PNW Riders on Facebook and Twitter


10-28-2009, 01:40 PM	#5
holypiston Superbiker Joined: Oct 2006 From: Vanquiver, WA I Ride: RD400F Daytonut	with old carbs, i straight away shican the needle jet. They can have A LOT of buildup. This is an old mother 4ker, so there's bound to be crap that is really hard to get to if there is a LOT of buildup. I remove ALL jets (pilots, needle jets, mains, valve seats, needles, airscrews, idle screws and soak this whole mess in a 3:1 mix of yamaha carb cleaner and gas (per bottle recommendation). I like starting over with NEW jets (pilots/needle jets/valve seats and needles/replace any air mixture screw o-rings, float bowl gaskets, etc. that need them). If you know of some kind of ultrasonic wash, use it. That will clean a lot of crap out of there. i then blow out the passages with compressed air. I'd say the most crucial parts are new pilot jets, main jets and needle jets. It's par for the course that you should replace the float valve needle and seats too. But the needle jet can screw everything up, so i'd definitely shelve the crusty bastards and get a new set. Make sure you check your airscrew settings and float height upon assy and set towards stock. Clean/replace any air/fuel/petcock filters too. Is it timed correctly? I use a dial indicator. Dont' trust the mark on the case. Fresh battery correct? __________________ Follow PNW Riders on Facebook and Twitter*


10-28-2009, 01:45 PM	#6
james1300 Track School Dazed Joined: Oct 2005 From: CENTRAL I Ride: When I can	Is the air cleaner clean? Did you leave a rag in the filter housing (dont ask) __________________ Follow PNW Riders on Facebook and Twitter


10-28-2009, 06:28 PM	#8
ducatichick WMRRA Qualifier Joined: Jul 2009 From: Corvallis, OR I Ride: 08 Hypervibrator	The 2-stroke tuning book I have is by John Robinson, "Motorcycle Tuning (Two Stroke)" 2nd edition (1994). It has a short chapter on carburetor tuning - I could scan it in as a pdf and send it to you if you want, just let me know. You might find everything you need via google. __________________ Follow PNW Riders on Facebook and Twitter

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10-28-2009, 12:35 PM	#1
Mitch F Superbiker Joined: Jun 2006 From: The Ham I Ride: too fast to be safe, too slow to be impressive	2 stroke carb ?'s - choking out So after cleaning out the carb real well, fresh gas/oil, gear oil top-off and a clean plug, my little Kawi 90cc tried to start on the first kick after 3+ years of sitting. After playing with it I got it to idle, but the throttle has almost no effect besides choking her out. Jet and idle don't seem to make much difference if any. Tried everything I could think of short of tearing the cylinder off and checking my rings. Didn't change timing as I don't see why it would have ever been changed. Is there anything I'm missing or should I just rip the bitch apart? __________________ Follow PNW Riders on Facebook and Twitter


10-29-2009, 05:47 AM	#9
pscook Pit Crew Joined: Jan 2008 From: Shoreline I Ride: GSXR600, CBR600, YZ444, RZ350	I have a PW80 that I could only get to run if I completely choked the intake and revved the living snot out of it. After getting it home, I pulled off the exhaust pipe and proceeded to pour ~6-8 ounces of nasty oil all over my garage floor. I then took a propane torch and smoked the rest of the crap out of the pipe. Once I did that it started and ran first kick. I think that the float was stuck and let gas/oil mix seep into the cylinder and then into the pipe (horizontal cylinder). The gas eventually evaporated (or was burned off) but the oil was left behind and choked the bike to death. PUll the pipe and look for a blocking issue, but turn it a couple of times to see if any oil or other crap is stuck in the narrow section. __________________ Follow PNW Riders on Facebook and Twitter


10-29-2009, 10:40 AM	#10
Mitch F Superbiker Joined: Jun 2006 From: The Ham I Ride: too fast to be safe, too slow to be impressive	That's a thought, I know when I actually got it to run it warmed up a whole bunch of nasty black residue on the exhaust and dropped it all over my basement floor Maybe there's a bit more inside. I'll be adjusting the circlip later today (soaked needles and all that in even MORE carb cleaner last night) and I'll pull the exhaust off too. And ducchick, that would be wonderful if you could do that. I'll check the web too. __________________ Follow PNW Riders on Facebook and Twitter Last edited by Mitch F; 10-29-2009 at 10:42 AM..


10-29-2009, 12:20 PM	#12
StageRulz Doom Crew Inc. Joined: Jan 2006 From: Spokane Valley Chapter I Ride: 2002 Silver/Grey & 2008 Black/Grey Vespa's on Steroids!	Oh......and check the Reed Valves. Thats what is between the Carb. and Cyld. more like an intake manifold. Easy to clean. __________________ Follow PNW Riders on Facebook and Twitter


10-29-2009, 12:46 PM	#13
Rippn MotoGP Champion Joined: Apr 2007 From: soap lake wa. I Ride: 00kaw12r, 97 tls1000, 96gsxr1260 turbo freakshow, kz1300gt, 88gsxr1100, 86gsxr750, 82gsx1100ez, 79kz1300, 75 ducati750gts, 72 gt550 cafe	"clean" the carb again... including the emulsion tube tiny holes, #18 on the scematic... define..."clean plug". Adjusting the needle clip is tunning... your still at the "get running OK" part. FREE and clean, Ripp'n __________________ Follow PNW Riders on Facebook and Twitter Last edited by Rippn; 10-29-2009 at 12:50 PM..


10-30-2009, 10:55 AM	#15
Mitch F Superbiker Joined: Jun 2006 From: The Ham I Ride: too fast to be safe, too slow to be impressive	These motors are rotary valves, not reeds. There was definately oil in the exhaust, I'm getting it out... slowly but surely. __________________ Follow PNW Riders on Facebook and Twitter


10-31-2009, 06:27 PM	#16
Big T Newbie Joined: Sep 2006 From: Beaverton	You also need to check the timing Timing is crucial in a 2 stroke Maybe the timing advance isn't working Let it warm up really well at idle, then see what happens I take it you've never owned a 2 stroke before?? __________________ Follow PNW Riders on Facebook and Twitter


11-02-2009, 01:35 PM	#17
Mitch F Superbiker Joined: Jun 2006 From: The Ham I Ride: too fast to be safe, too slow to be impressive	I've owned 2 strokes before (mainly jet skis), but none have ever fallen out of timing. I keep my shit in good shape and don't let it sit and develop problems as has happened to this old girl. Drained the oil out of the pipe, re-cleaned all my needles, and leaned my main jet. I also bought a different plug (recommended is B7HS, had a B8HS). Not much change. So right now I've got it all apart for paint/cleaning. I'm planning on just dropping the $30 or so on a carb rebuild kit, and until then she'll just be getting her makeup done. Compression test tonight. And maybe some pictures just for shits and giggles. Thanks for the tuning guides as well, I'll do a quick once over and then really get balls deep in them once my rebuild kit arrives. Although that may be a few as I have about $50 to my name at the moment __________________ Follow PNW Riders on Facebook and Twitter


11-02-2009, 02:57 PM	#18
Big T Newbie Joined: Sep 2006 From: Beaverton	Motors with points are going out of timing from the moment you set them, by definition. You need to verify that the timing is good, the advance works, the carb (the entire carb) is clean and that there's no air leaks in the intake You did dip your entire carb body once you took it apart?? And all the parts? There's nothing to rebuild in a slide carb -new float bowl gasket and you're ready to go. __________________ Follow PNW Riders on Facebook and Twitter


11-04-2009, 11:56 AM	#19
Mitch F Superbiker Joined: Jun 2006 From: The Ham I Ride: too fast to be safe, too slow to be impressive	She lives! Tried fucking with the carb more last night (to no avail of course) and figuring it MUST be the timing, played with the points. First 3 times it only got worse, but the 4th time she started right up, revved and everything. Pumped up my tires, tied up some loose ends and rode her around the block. So very satisfying. She bogs once the RPM come up, so it looks like more carb tuning (and probably a bit more with the points) will have to happen. But she runs... shifts... stops... the whole shebang. HOORAY. You guys are awesome. __________________ Follow PNW Riders on Facebook and Twitter


11-05-2009, 11:19 AM	#21
Mitch F Superbiker Joined: Jun 2006 From: The Ham I Ride: too fast to be safe, too slow to be impressive	I suppose not However, do you know where I may find initial jet/points gap settings by chance? Without a starting point tuning will most definately take longer than it needs to (especially points). __________________ Follow PNW Riders on Facebook and Twitter

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