eBay complete top end kits for PW50?

5/11/2017 8:10pm Edited Date/Time 5/11/2017 8:30pm
No before, but I think this one was $120.

About $350 in it, all said and done. Used to buy every mini I ran across. Straighten them up, and make a few pennies on them.



5/11/2017 8:17pm
This pit bike came complete with a custom racing tire. The grip from it was like no other. I gave $100 for it. It was actually like new.








After a tire, and wash.



5/11/2017 8:26pm Edited Date/Time 5/11/2017 8:28pm
$110 each. Air cooler only needed a tank, as the original was cracked. Did Ok on it. The water cooler was an over heated, seized mess. Money pit. Both had really little run time from new. Original paint on the frames.








5/11/2017 8:34pm
Gave $50 for this cream puff. Had about $250 in it, all told.







The Shop

5/11/2017 8:54pm Edited Date/Time 5/11/2017 9:00pm
No before, got this for $50. Rear wheel was exploded, plastics trashed. Had about $275 in it total.



Four wheeler was $130. Needed a battery, couple of tires, and side cover inserts for plastics.

Kind of miss all these little turds. Oh well, hope some kids were able to use them.

Quite a few more, but no pictures of all them 'lil boogers.






temppp
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5/12/2017 8:59am Edited Date/Time 5/12/2017 9:11am
I could try asking a couple more people if they have a suitable torque wrench. I had one offered to me but the low end of it's range was well above what's needed for this. I could always take the motor in to a dealer/mechanic and ask them to do it if necessary.

I had thought of trying to match the size of the circlip before so I might just do that. I stretched it last time I removed/installed it so it doesn't seat properly now. Wasn't in a rush to replace it but don't want to run it for too long with it in there either. I could buy a few similar sized ones to get the right size and it will still be cheaper than one from the dealer.

The only other things I'm looking to replace at the moment are the carb gaskets and the "absorber" things inside the primary drive gear? When I installed the new crank seal I noticed they had little bits broken off them. Probably not too important but I was just going to replace them next time I had it open and then hopefully I won't need to get in there again after that.

There are a number of missing/damaged fasteners which is why I need to buy some new ones, not concerned with how anything looks.

Plenty of other things could be replaced (bent forks/ripped seat/etc) but I'm going to leave them until a good deal pops up or they get much worse and really need to be replaced. I'm just trying to spend minimal money to get it up and running well, while learning along the way. Could spend a lot more on making it real nice but it's just not worth it.

I'm hoping to have it back together sometime in the next week ready to test.

Unfortunately I haven't seen any bikes like your "before" ones for anywhere near $100 here. Something like that would be great for me because I could easily swap parts around to make one nice bike and still have plenty left for spares.
5/13/2017 2:51am Edited Date/Time 5/13/2017 3:17am
You can get by with a ratchet and socket for the head nuts. You need a torque wrench that measures in Inch pounds, not foot pounds, for that small of torque value. It is over kill for what we are talking of here.

Other than the KTM 50 water cooler, I can't recall ever using a torque wrench on any 50cc engine. Use a pattern, snug things up, and check for head / base gasket leaks after some run time. Recheck the nuts , call it a day.

It is a PW, not an F-18 or space shuttle.

And for what it's worth, you won't find many "good" deals on old bikes on market pages, ebay.

My source was going around to local dealers, and buying bikes that had come in for service estimates, and then abandoned by their owners. Some had minimal work done to them by the shop. I usually would pay just the estimate fee that the shop would have billed the customer to assess the repairs needed.

They really don't care about the bike. They care about getting their money that they were out by paying a mechanic to do the estimate. If the customer abandons the bike and bill is not paid, a letter is sent to the owner of the bike. If no response in a reasonable time, the bike becomes the shops property.

They sell it , and recoup their money for the estimate.

If the shop had any more billed time into a given unit, we could generally come to a reasonable meeting.

I'd say that at least 25 bikes were purchased this way when I was interested in that sort of thing. To a dealer with hordes of bikes in their service area, they love to move the "dead" players out of the picture.

For every bike purchased, there were usually several more that were passed over. I looked for the bikes that needed minimal repair to make run, trying to avoid the total basket cases. The baskets take too much to bring back, but are good for parts if you have similar units.

They are just another pile of crap in the way at that point.
5/13/2017 3:35am
The rubber dampeners in the primary gear are for cushioning the clutch drive. There are aftermarket primary gears that do not utilize the dampeners. If the damps are some what intact, they will do the job.

I have a brand new ebay China PW50 carb and OEM float bowl gasket for the PW. Never going to use it.

I'll give it to you, but shipping would probably be crazy from US to Aus.
dirtdiva
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San Jose, CA US
5/15/2017 10:32am
Camp332 wrote:
Any of you guys rebuild your PW's with these inexpensive kits? Are they complete garbage? Surprisingly good? Let a brother know. Here is a link to...
Any of you guys rebuild your PW's with these inexpensive kits? Are they complete garbage? Surprisingly good? Let a brother know. Here is a link to what I'm talking about.

http://www.ebay.com/itm/Yamaha-PW-50-PW50-Carburetor-Cylinder-Piston-Ring-Gasket-Top-End-Kit-1981-2009-/200938050158?fits=Model%3APW50&hash=item2ec8d7526e:g:nJAAAOSwHMJYNc3C&vxp=mtr
How did this work out for you? I'm looking at getting the same kit too. It seems like decent deal since it includes everything inside the carb too.
temppp
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5/25/2017 10:09am
The rubber dampeners in the primary gear are for cushioning the clutch drive. There are aftermarket primary gears that do not utilize the dampeners. If the...
The rubber dampeners in the primary gear are for cushioning the clutch drive. There are aftermarket primary gears that do not utilize the dampeners. If the damps are some what intact, they will do the job.

I have a brand new ebay China PW50 carb and OEM float bowl gasket for the PW. Never going to use it.

I'll give it to you, but shipping would probably be crazy from US to Aus.
Thanks but I can get them fairly cheap locally if/when I need them. Appreciate the offer though. I'll leave the current rubber things in there for now.

I've been sick so had to put the PW50 on hold for a while. I went to try and match the circlip today but the closest they had was too small. I put the old one back in there for now, will replace it in the near future.

The float bowl is slightly warped so I was going to try and fix that up but the main body looks a bit off too. It doesn't leak too much, I just had a rag stuffed under it before. Do you think it's worth it trying to stop it leaking or just start looking for a replacement?

Should I just have the air screw 1 1/2 turns out to begin with and then adjust it further once it's, hopefully, ready to ride?
temppp
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5/26/2017 10:07am
The bolts to join the exhaust to the cylinder feel far too tight and I don't want to force them in... Are the threads on these cylinders supposed to be the same or are they smaller? Perhaps it's just paint or something in there?

I'll get new bolts and also see how a size smaller fits but that will have to wait until Monday.

I'll ask the seller on ebay but I don't think they will know anything about it.
dirtdiva
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Location
San Jose, CA US
5/26/2017 2:30pm
Thanks for the update temppp. I haven't had chance to put my new kit together. Only installed the carb but still need to work on idling. It was revving too high. I have not yet worked on exhaust /gasket as well as put in the new cylinder kit that came with it. I'll exchange notes when I can ...it will be a few weeks as I have commitments for next few weeks!
5/27/2017 12:46pm Edited Date/Time 5/27/2017 12:56pm
temppp wrote:
The bolts to join the exhaust to the cylinder feel far too tight and I don't want to force them in... Are the threads on these...
The bolts to join the exhaust to the cylinder feel far too tight and I don't want to force them in... Are the threads on these cylinders supposed to be the same or are they smaller? Perhaps it's just paint or something in there?

I'll get new bolts and also see how a size smaller fits but that will have to wait until Monday.

I'll ask the seller on ebay but I don't think they will know anything about it.
The kits I have used all took the standard bolts. 6mm x1.00 ,I believe.

Some of the machining on the ebay cylinders is a bit rough. You need to run a tap through the threads. I believe it is a 6mm x1.00 size tap. Smaller bolts or jamming the proper bolts in rough threads could cause the threads to strip, then you will have more troubles on your hands.

Take the bolt to the hardware store. Find the proper size nut to fit the bolt. The size of the nut that fits the bolt will tell you the size of the tap needed.

The first number of tap / nut/ bolt sizing is the diameter. The second number is thread pitch.

Dab a little grease on the tap. Start it in the threads straight by hand , you may only get a bit of a turn . Run the tap in a turn or two, then back it up a half turn. This will let the tap kind of clean itself as it chases the threads.

Getting the tap started straight is key.

Run the tap in this manner until you feel a light bottoming of the tap. You do not want to break a tap in a threaded hole. Just go slowly, and surely.

5/27/2017 1:02pm Edited Date/Time 5/27/2017 1:05pm
dirtdiva wrote:
Thanks for the update temppp. I haven't had chance to put my new kit together. Only installed the carb but still need to work on idling...
Thanks for the update temppp. I haven't had chance to put my new kit together. Only installed the carb but still need to work on idling. It was revving too high. I have not yet worked on exhaust /gasket as well as put in the new cylinder kit that came with it. I'll exchange notes when I can ...it will be a few weeks as I have commitments for next few weeks!
Do you have free play at the throttle grip ? Check the cable routing and make sure the slide in the carb is closing fully.

Run the cable adjusters all the way in and see if that brings the idle down. Then set them as needed for about 1/8 inch of free play at the grip.

One thing that caught me once was the little junction box in the lower throttle cable, where it splits into two cables.

The bike was always high idling, idle screw made no difference. The throttle cable side in the junction box was not fully in it's seat inside the junction box.

The plastic box is a bear to get into, but can be done if careful.
temppp
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Location
AU
5/27/2017 9:31pm Edited Date/Time 5/29/2017 10:11am
The kits I have used all took the standard bolts. 6mm x1.00 ,I believe. Some of the machining on the ebay cylinders is a bit rough...
The kits I have used all took the standard bolts. 6mm x1.00 ,I believe.

Some of the machining on the ebay cylinders is a bit rough. You need to run a tap through the threads. I believe it is a 6mm x1.00 size tap. Smaller bolts or jamming the proper bolts in rough threads could cause the threads to strip, then you will have more troubles on your hands.

Take the bolt to the hardware store. Find the proper size nut to fit the bolt. The size of the nut that fits the bolt will tell you the size of the tap needed.

The first number of tap / nut/ bolt sizing is the diameter. The second number is thread pitch.

Dab a little grease on the tap. Start it in the threads straight by hand , you may only get a bit of a turn . Run the tap in a turn or two, then back it up a half turn. This will let the tap kind of clean itself as it chases the threads.

Getting the tap started straight is key.

Run the tap in this manner until you feel a light bottoming of the tap. You do not want to break a tap in a threaded hole. Just go slowly, and surely.

Yeah, torque specs from the manual say it should be M6 x 1.0mm which is standard. The bolts I had on the old one were not Yamaha and are a bit smaller at the tip which is why they start fine but then jam. These are 20mm length which is what I was going to replace with unless that sounds wrong?

The seller replied: "The thread size is M6-7H,pore distance is 48mm"

I had read about carefully forcing a high tensile bolt through or using a Inexpensive Thread Chaser but they are probably more suited to when it's just dirt/paint/etc. and not actually cut too small?

I will take it and get someone to run a tap through them, hopefully it only costs $5-10? If I take the assembled motor (out of frame) would they be able to do it like that or do I need to remove the cylinder and take that by itself?

Update:
The first bolt is in now, need to work on the second one. I just used these old bolts and tightened them by hand until they start to jam up, then just work it back and forth on that spot until it makes some progress. Then repeat over and over and over. Every now and then I'd take it out to clean and spray some WD40.
5/29/2017 12:01pm
temppp wrote:
Yeah, torque specs from the manual say it should be M6 x 1.0mm which is standard. The bolts I had on the old one were not...
Yeah, torque specs from the manual say it should be M6 x 1.0mm which is standard. The bolts I had on the old one were not Yamaha and are a bit smaller at the tip which is why they start fine but then jam. These are 20mm length which is what I was going to replace with unless that sounds wrong?

The seller replied: "The thread size is M6-7H,pore distance is 48mm"

I had read about carefully forcing a high tensile bolt through or using a Inexpensive Thread Chaser but they are probably more suited to when it's just dirt/paint/etc. and not actually cut too small?

I will take it and get someone to run a tap through them, hopefully it only costs $5-10? If I take the assembled motor (out of frame) would they be able to do it like that or do I need to remove the cylinder and take that by itself?

Update:
The first bolt is in now, need to work on the second one. I just used these old bolts and tightened them by hand until they start to jam up, then just work it back and forth on that spot until it makes some progress. Then repeat over and over and over. Every now and then I'd take it out to clean and spray some WD40.
The factory making those cylinders has probably made a zillion of them by now. They are probably using the original tooling, which by now is totally worn out, hence the rough threads.
temppp
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AU
5/31/2017 10:52am
Yeah, I guess you should almost expect this for the price. Both bolts are in now, everything back together. The exhaust didn't seem to line up quite right but it's on. Just need to fill up the tank and see how it goes...

Using the kickstarter requires noticeably more effort now. Hopefully that's a good thing and not just because it's all too tight. Unfortunately all I have to compare it to is the "before" with the trashed top end, there was little to no kickstart resistance trying to start that.
temppp
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AU
6/1/2017 9:16am
Tried to start it today but unfortunately it did not go well. Gave it a number of kicks to start with and nothing happened. Then tried with the throttle slightly open and wide open which made it sound different but still wouldn't start. Realised something was wrong and stopped.

To remove the motor (while installing the new top end) I had just unplugged the two connections that come out from the flywheel area and the two from the start switch. I reconnected all of them just to be sure.

I removed the spark plug and rested it on the head while kicking (with switch set to start) and I could not see any spark? This plug is almost brand new. I also tested with the old one and another brand new (no name) one that came with the kit. Couldn't see spark with any of them. First time I tried that but I think I did it right haha.

While I had everything apart to install the top end I had bent/moved the spark plug lead to keep it out of the way, perhaps I damaged that?

The possible causes I've thought of would be:
- Damaged spark plug lead
- Damaged (previously mentioned) wire/connection while disconnecting to remove motor/frame
- Something else has just happened to break at this time

I haven't done anything else to it since it was last running.

Am I on the right track here? What else can I do to find the problem? I don't have a multimeter so will do whatever troubleshooting I can without one for now and then borrow or buy one if/when it's required.

Any help is greatly appreciated.

Thanks
temppp
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AU
7/15/2017 6:46am Edited Date/Time 7/15/2017 6:48am
dirtdiva wrote:
Thanks for the update temppp. I haven't had chance to put my new kit together. Only installed the carb but still need to work on idling...
Thanks for the update temppp. I haven't had chance to put my new kit together. Only installed the carb but still need to work on idling. It was revving too high. I have not yet worked on exhaust /gasket as well as put in the new cylinder kit that came with it. I'll exchange notes when I can ...it will be a few weeks as I have commitments for next few weeks!
How is your PW50 going now dirtdiva?

Started mine up today finally... I believe it was just the dodgy old spark plug cap that was giving me problems. Started quicker than it used to and is much quieter now too. The rattle noise seems to be sorted which is great.

Next problem is that the exhaust isn't sealing properly with the exhaust port on the cylinder. I assume the OEM exhaust should still match up the same with the new cylinder? If I line up the cylinder end first, the rear mount is out of place. Might just need to force it a bit. I'll take it off again and try to see where the exhaust gasket was making contact.

One thing to be careful of is the spark plug that comes with the kit. Mine was longer than the (correct) NGK plug I have for the bike so it would hit the piston if you install it.

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