PW 80 questions.

Yamaha PW80

591 replies to this topic
  • gmoss357

Posted January 26, 2009 - 11:21 AM

#1

Added an 01 PW 80 to the family this Christmas for my son. Got the carb all cleaned out and running well. I am very familiar with 2 strokes, but not the PW, and not oil injected. I also don't have the owner's manual, the previous owner is looking for it.

Is there a way to control, lean out the mixture other than the adjustment on the carb?

Is it normal for the bike to fall dead with rpms in each gear, before shifting?

87 or 93 octane?

brand of oil preferred, I normally run Motul 710 in my KTM?

I would like to get rid of the mosquito fogger it is right now. It's cool to cold here and expect the smoke to get worse as it warms.

Thanks.

  • matt4x4

Posted January 26, 2009 - 12:16 PM

#2

you can completely bypass the oil injection and just run premix.
many people complain of similar symptoms as yours and find out the expansion chamber pipe is full of crud and that's causing the problem - I think there's a method on how to properly clean them out somewhere here in PeeWee.

  • Smacaroni

Posted January 26, 2009 - 12:43 PM

#3

That little thing will probably run just as well on 82 octane as it will with 100 octane, stock compression is 6.6:1, practically nothing. And that assumes the rings are good.
You can bypass the oil injection, but I really don't think it's a good idea. It's easy enough to add a quart of oil-injection oil every 10 or so hours (I have no idea, haven't gotten through a tank yet). The only complaint I have is you have to unbolt the seat to do it.

The one PW we have kinda farts and puffs when you run out of tachometer. I don't know why, but they do have a rev limiter on them, or so I've been told. I haven't messed with disabling that.

I noticed that when I put that washer back in the exhaust it smokes a lot, but before pulling the pipe, check the plug, it could be fouled. When the KE100 we have fouls a plug it smokes really really bad. That's the only other oil injected bike I've worked with. So far we haven't fouled any plugs on the PW80.
If the plug is fine, then clean the pipe and check for that stupid washer where the head meets the pipe.

Any oil-injection oil will work fine, we're still running out what the PO two POs ago put in.

I'd like to add that from what I've seen and read, these little bikes are nearly undead, you have to try really hard to kill them.

  • gmoss357

Posted January 27, 2009 - 08:27 AM

#4

That little thing will probably run just as well on 82 octane as it will with 100 octane, stock compression is 6.6:1, practically nothing. And that assumes the rings are good.
You can bypass the oil injection, but I really don't think it's a good idea. It's easy enough to add a quart of oil-injection oil every 10 or so hours (I have no idea, haven't gotten through a tank yet). The only complaint I have is you have to unbolt the seat to do it.

The one PW we have kinda farts and puffs when you run out of tachometer. I don't know why, but they do have a rev limiter on them, or so I've been told. I haven't messed with disabling that.

I noticed that when I put that washer back in the exhaust it smokes a lot, but before pulling the pipe, check the plug, it could be fouled. When the KE100 we have fouls a plug it smokes really really bad. That's the only other oil injected bike I've worked with. So far we haven't fouled any plugs on the PW80.
If the plug is fine, then clean the pipe and check for that stupid washer where the head meets the pipe.

Any oil-injection oil will work fine, we're still running out what the PO two POs ago put in.

I'd like to add that from what I've seen and read, these little bikes are nearly undead, you have to try really hard to kill them.


So, the copper washer isn't necessary?

I have talked to a friend about removing the oil injection, but that seems to open up other possible problems.

Will any 2 stroke premix work, or is there a specific oil injection oil that is needed?

Is there a way to check the expansion chamber/silencer, repack, clean?

the plug is good, fires up first kick everytime. The rev limiter explains the revving out. Anyone have any info on raising it or removing it?

What about metal footpegs? Can't stand the rubber ones.

  • barbwire44

Posted January 27, 2009 - 09:06 AM

#5

I had two of them, yes they can run better, and rev each gear out fine. I don't know why but they do run better when you disconnect the oiling system, which is not bad to do, just remove the two bolts on the pump and pump cover, pull the pump out and remove the drive gear, just a snap ring holding it on, then re-install the pump, and make sure and re-install the cable (two throttle cables from a splitter). While your in there, pull the carb and change the main to either a 110, or a 115. Move the clip on the needle up 1 notch. Grind out the expansion chamber washer. And mix the gas 32:1- 40:1 something around that area, replace the stock filter with a piece of UNI foam. Open up the silencer or buy an aftermarket one, also a big difference is dropping at least one tooth on the front sprocket, them things in stock form feel like 1st gear will run 25 mph before they rev out, the sprocket really helped the bike pull the gears better. do all that, and it should run really good. I know some guys have even removed some of the balls on the clutch to raise the engagement rpm. Oh and make sure and get an automotive spark plug cap for it, a good rubber one, the factory one will ground out if they spalsh even the smallest puddle and make the bike miss or stall.

  • gmoss357

Posted January 27, 2009 - 09:14 AM

#6

I had two of them, yes they can run better, and rev each gear out fine. I don't know why but they do run better when you disconnect the oiling system, which is not bad to do, just remove the two bolts on the pump and pump cover, pull the pump out and remove the drive gear, just a snap ring holding it on, then re-install the pump, and make sure and re-install the cable (two throttle cables from a splitter). While your in there, pull the carb and change the main to either a 110, or a 115. Move the clip on the needle up 1 notch. Grind out the expansion chamber washer. And mix the gas 32:1- 40:1 something around that area, replace the stock filter with a piece of UNI foam. Open up the silencer or buy an aftermarket one, also a big difference is dropping at least one tooth on the front sprocket, them things in stock form feel like 1st gear will run 25 mph before they rev out, the sprocket really helped the bike pull the gears better. do all that, and it should run really good. I know some guys have even removed some of the balls on the clutch to raise the engagement rpm. Oh and make sure and get an automotive spark plug cap for it, a good rubber one, the factory one will ground out if they spalsh even the smallest puddle and make the bike miss or stall.


Thanks.

  • RootRacing

Posted January 27, 2009 - 10:08 AM

#7

What about metal footpegs? Can't stand the rubber ones.


no problem , did it to every PW I built. find some that will fit or just cut the rubber off those you have and get a peice of 1" or 3/4 flat bar and grind some v cleats on it bend it to shape and weld it to the pegs that you cut the rubber off of.. you can see the metal pegs on those two pics that I posted of those 2 for my boys. posted under (show us your bikes 50 and 65) Oh some of that metal galvinized grading works well too it already has the spikes on it just file them up a little.

  • Smacaroni

Posted January 27, 2009 - 10:14 AM

#8

So, the copper washer isn't necessary?

Is the copper washer where the pipe meets the exhaust port? Is the hole about the size of your pinky? If so, no. The two we have were second/third hand, so I don't know what the washer looks like stock. The one I put in is a 3/8ths inch fender washer.

I have talked to a friend about removing the oil injection, but that seems to open up other possible problems.

Will any 2 stroke premix work, or is there a specific oil injection oil that is needed?

I don't know. I put regular old 2-stroke oil in the KE100's tank, and I haven't added any to the PW80s tanks, yet. But I've been told the plain old $2/pint 2-stroke oil is not the right stuff. I only used it for about 100 miles and in that time there's no noticeable damage, but I'll be switching back to something like Yamalube or it's equivalent from one of the other rebranders. I may even try the "synthetic" (not sure if it's really synthetic or not see Grade IV/V oil)

Is there a way to check the expansion chamber/silencer, repack, clean?

I know the silencer can be disassembled, many people pull the packing out to get more power, but it's damn loud for a tiny bike. I think you'll get more out of an FMF expansion pipe and leave the silencer alone than you would using the stock pipe and gutting the silencer.

the plug is good, fires up first kick everytime. The rev limiter explains the revving out. Anyone have any info on raising it or removing it?

I've read that there's several wires connecting to the CDI, if you pull one and it runs, you've found the correct wire, if it doesn't run, plug it back in and try another.
I haven't gotten that far, it's too blasted cold here for me to worry about that.
I'd still pull the plug and check it to make sure it's not fouled, the KE100 would idle and sort of run with a fouled plug, but smoked like George Burns.

What about metal footpegs? Can't stand the rubber ones.

TTR-90 pegs swap. I haven't done this yet, but from what I've read, they swap.

Good news, pretty soon (1/29-ish), I'll have one PW80 nearly bone stock and one to hop-up so we can do side-by-side comparisons, boy do we have plans for that other one (my step-son is getting all my knowledge hands-on style.)

If anybody has a carb they have laying around for a PW80 or similar (80-100 cc oil injected/case induction) bike, let me know.

  • gmoss357

Posted January 27, 2009 - 10:23 AM

#9

yep, I read the TTR 90 pegs fit. will be gettin' some.

I also read about the reducer. I will give that a look see. The copper washer is a crush ring for the pipe.

I will likely be buying Amsoil by the gallon for both bikes, to make it simple.

I am going to go thru the silencer and pipe to see what I can figure out. I am not spending a lot of money on this bike. He just got it Christmas and is just getting to ride a little, had a friend clean up the carb since I was new to the bike. Will be making changes to jetting myself now. The bike had been sitting for over a year, had terrible build up, so I let someone that has dealt with it, deal with it. lol

I may check the CDI.

I have also read much on susp and air intake mods. I will be servicing the forks, making some changes and possibly changing the shock position as well. I will have to post up some video of him riding and maybe do some "how to's" with pics. who knows.

  • barbwire44

Posted January 27, 2009 - 11:04 AM

#10

Wow, ya I forgot about the shock mod, the rear is simple pull the plastic and have a look see....then just drill a new hole for the rear shock behind it, will raise the rear a bit, then just pre-load the front forks with a PVC spacer or whatever you like, kind of tough to get them back in though with the spacers. But seems to definately help..LOL!! then after you are all done with the mods and really happy, you will go and buy an rm65 like I did. But truth be told the boy is still better in the nasty trails with the pw, because of the auto clutch, but maybe this summer if the economy doesn't go totally to the toilet I will put a rekluse in his rm.

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  • Smacaroni

Posted January 27, 2009 - 11:10 AM

#11

Yeah, I admit, it's not the best bike, but it's bullet proof and cheap. Which is what I need for toying in the back yard.
I think it would be really sweet to throw a YZ80 engine in that PW, the pit-bike people would suddenly get some respect for the 2-smokes then. But that would be a lot of work.
I'm not planning to spend a lot of money either, but I plan to not screw with anything I can't undo easily.
Which is why I need a second carb, the replacement one will be nearly useless if what I plan to do doesn't work. I figure $20 or so on a second carb will be much less than jetting kits.

  • gmoss357

Posted January 27, 2009 - 11:12 AM

#12

Wow, ya I forgot about the shock mod, the rear is simple pull the plastic and have a look see....then just drill a new hole for the rear shock behind it, will raise the rear a bit, then just pre-load the front forks with a PVC spacer or whatever you like, kind of tough to get them back in though with the spacers. But seems to definately help..LOL!! then after you are all done with the mods and really happy, you will go and buy an rm65 like I did. But truth be told the boy is still better in the nasty trails with the pw, because of the auto clutch, but maybe this summer if the economy doesn't go totally to the toilet I will put a rekluse in his rm.


he definitely doesn't need more power at the moment, or anytime soon. He has been mtn biking for 3 years, getting ready to turn 8, and riding a bike without training wheels since before he was 3. He is learning to be smooth, and to stand most of the time. He seems to be taking to it nicely. I will try and post up some short video of him soon. He's a little cautious with it till he gets comfortable.

  • gmoss357

Posted January 27, 2009 - 11:13 AM

#13

I'm not planning to spend a lot of money either, but I plan to not screw with anything I can't undo easily.
Which is why I need a second carb, the replacement one will be nearly useless if what I plan to do doesn't work. I figure $20 or so on a second carb will be much less than jetting kits.


I am the same way, don't want to screw anything up.

what about that kit on ebay, stage 1 PW 80. worth the $55 for the reed cage, air filter thingy, etc.? I thought about getting that soon.

Just getting more air to the bike should allow it to run leaner with less smoke, hopefully. :banana:

  • Smacaroni

Posted January 27, 2009 - 11:22 AM

#14

I am the same way, don't want to screw anything up.

what about that kit on ebay, stage 1 PW 80. worth the $55 for the reed cage, air filter thingy, etc.? I thought about getting that soon.

Just getting more air to the bike should allow it to run leaner with less smoke, hopefully. :banana:

That's very likely to be on the to-do list.
But I still need more in the carb department, I sent those guys an email about what I need, they haven't gotten back to me yet.
However, the reeds do interest me even if I don't use the jet kit.
I'm not sure, the jet kit in the Stage 1 kit may be smaller. (.125 vs .120?)

You can also swiss-cheese the air box, I haven't done enough investigation into that to say what or where. To start, I'd try yanking out the snorkel and replacing it with something that is a single tube instead of three.
More than likely, I'll skip that and look for a sheet metal fab solution with a cone filter. BUT... I will do that after the carb mods (jet kit or Smacaroni=kamikaze style) work. I'm not knowledgeable enough to say "we do this that and the other thing" to get to where we want to go, I have to take it one step at a time, the good part is I know which step made the biggest difference. May take longer, but it's also easier to troubleshoot.

Nearly everything I do, I'm self-taught/learn as I go/oh that didn't work the way I thought/CTRL-Z! and for me that seems to work best.

  • Smacaroni

Posted January 27, 2009 - 11:25 AM

#15

Another thing you may want to consider that's a cheap and easy mod is advancing the port timing.
Use two base-gaskets and aluminum foil for a head gasket (Aluminum foil puts the compression back which adding a base-gasket takes away). Unlike grinding the ports, this can be un-done in about five minutes.

  • jeffyballs

Posted February 04, 2009 - 03:31 AM

#16

Hey im new hear and I need some help.

I ride a YZ450F but I have endevoured to do the top end in my little brothers PW80 and Im stumped with the rings. theres 2 one is dark and the other is dark with a 2nd lighter layer on the out side. which one goes on top?

any help would be much appreciated

  • Smacaroni

Posted February 04, 2009 - 09:32 AM

#17

Just a guess, the lighter one goes on top, solid dark one on the bottom?

Didn't the piston/rings come with any instructions? If not, what brand so I know to avoid them in the future.

  • gmoss357

Posted February 04, 2009 - 10:17 AM

#18

I assume many of these 'mods' are for adults turning them into pit bikes? I will be adjusting, improving my PW for my son, but he doesn't need a hopped up mini bike at this time. I little more height would be good, and so would a few more small things, but otherwise, it works well for now.

I am thinking that by the time he is good enough to mod the PW much, he will be ready for a bigger bike.

  • Smacaroni

Posted February 04, 2009 - 11:21 AM

#19

For me, I actually have two PW80s. One is bone stock, including the famous fender washer in the exhaust. My nine year old daughter is riding this one.
She had a little incident with her previous bike because it was too small (frame wise) and when we told her we got her an 80, she was scared of it.
So that's how I got the second one, the first one was blue. The second one was white and purple and a basket case. We told her it was a PW50. It was in pieces, so I had to "rebuild it" (move the white parts to the blue frame). She's now content with her "PW50".
The thing is this bike is still too small for her, even though power wise it's probably about right. So any suspension mods I'm talking about are primarily for this bike.

The second PW80, is a play toy for my 13 year old, who's just barely taller than his sister. (little sister is 4'8", he's 5'0"?) While this bike may get similar suspension mods, the end goal is to tweak the crap out of it. Why? Well for starters it was cheap ($75), it's a 2T, so doing things like changing the port timing, compression ratio, are much, much easier on a 2T. It's small enough to ride in our back yard, which his DRZ-125 is not. The DRZ has been slightly modded, it's too loud to run in the neighborhood.
Plus, I'd rather spend time tweaking something that doesn't have to be running on any given day than tweaking something that needs to be running this weekend.
This fills the final "need" he has a play bike.

I've since bought a salvaged engine instead of rebuilding the basket case engine (cases split, parts in a box, who knows if they're all there), because that's much easier. Supposedly the cases were split because the crank needs a new bearing (the one that needs to be pressed in), but I think the PO was a little too adventurous for his skill level.

  • gmoss357

Posted February 04, 2009 - 11:26 AM

#20

For me, I actually have two PW80s. One is bone stock, including the famous fender washer in the exhaust. My nine year old daughter is riding this one.
She had a little incident with her previous bike because it was too small (frame wise) and when we told her we got her an 80, she was scared of it.
So that's how I got the second one, the first one was blue. The second one was white and purple and a basket case. We told her it was a PW50. It was in pieces, so I had to "rebuild it" (move the white parts to the blue frame). She's now content with her "PW50".
The thing is this bike is still too small for her, even though power wise it's probably about right. So any suspension mods I'm talking about are primarily for this bike.

The second PW80, is a play toy for my 13 year old, who's just barely taller than his sister. (little sister is 4'8", he's 5'0"?) While this bike may get similar suspension mods, the end goal is to tweak the crap out of it. Why? Well for starters it was cheap ($75), it's a 2T, so doing things like changing the port timing, compression ratio, are much, much easier on a 2T. It's small enough to ride in our back yard, which his DRZ-125 is not. The DRZ has been slightly modded, it's too loud to run in the neighborhood.
Plus, I'd rather spend time tweaking something that doesn't have to be running on any given day than tweaking something that needs to be running this weekend.
This fills the final "need" he has a play bike.

I've since bought a salvaged engine instead of rebuilding the basket case engine (cases split, parts in a box, who knows if they're all there), because that's much easier. Supposedly the cases were split because the crank needs a new bearing (the one that needs to be pressed in), but I think the PO was a little too adventurous for his skill level.


good to know, I printed off all the mods I could find, but some seem out of place for me. I don't want to ruin resell, so I likely won't be making drastic changes to susp, mainly just to get it to run cleaner and better.

Thanks.:)





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