P200 Holed Piston Recovery

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porter
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Re: P200 Holed Piston Recovery

Postby porter » Fri May 04, 2012 10:41 am

This is an offer for timing tools.

If you read up on how scooterhelp finds out where TDC is, its not super exact. I ended up making a plate that sits atop the open cylinder and mounts onto the exposed studs. In the middle is a hole that accepts a plunger gauge, and on that is a nice dial in metric and english units. So, you spin the flywheel slowly by hand and watch the needle move up until it reaches TDC, with the ability to nail that point down exactly. You can do the math and calculate the distance of piston travel for degree change and measure it all out with the gauge, or use a degree wheel to mark your cases.
On something this important to the life of the motor, its nice to be as exact as possible.

Long and short, I have the gauge and two plates, one for vespa, one for lambretta, degree wheels and a strobe.
If anyone wants to borrow, I'd be happy to lend.

porter

My .02 on the rebuild after a holed piston is to split the cases. Seals, bearings, gaskets, a clean out, inspection, cruciform (just cuz), and consumables on the clutch, but I am not sure if they need swappage.
good luck

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toigo
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Re: P200 Holed Piston Recovery

Postby toigo » Fri May 04, 2012 10:55 am

Hey Porter,

Thanks. Once I get the engine back together I'll definitely hit you up for help. Glad I was on the right path as far as tearing everything apart. Are the bearings pretty easy to get and cheap? I was going to look at them to see if there's damage before replacing them. I'm absolutely going to do new clutch and flywheel side seals and a cruciform while I have everything apart. Also have the cylinder base gasket and am going to order the crank case gasket. I'm sending out the cylinder to be bored out to a first over as well to match the new piston. I also rebuilt the clutch about 6 months ago on the bike so everything with that should be solid.

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porter
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Re: P200 Holed Piston Recovery

Postby porter » Fri May 04, 2012 11:39 am

Bearings are cheap, mercato can fix you up with a set, if you call and explain which ones you want.
http://www.scootermercato.com/Scooter-Parts/Bearings

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toigo
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Re: P200 Holed Piston Recovery

Postby toigo » Fri May 04, 2012 11:43 am


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Zeets
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Re: P200 Holed Piston Recovery

Postby Zeets » Fri May 04, 2012 12:47 pm

Make sure you send the piston with the jug, otherwise it won't be properly matched. The clearance for the piston is usually like .002" so there's not a lot of room for error.

For the Lambretta, I made a piston stop out of an old spark plug. You assemble everything, torque it, install the piston stop, run the piston around until it stops, mark the case by the flywheel timing mark, spin the crank the opposite way until its stops again, mark again and than half that distance on the case and you have an accurate tdc mark. The you use a timing wheel or protractor to mark your 19 or so degrees back from that mark and then time it off that new mark. Since the Lammy was points, I just set the timing staticly using a DMM with an audible tone and listened for the points to open.

I also have a plug hole dial indicator that I use to do the timing on my RD, but its only designed for heads that have the plug centered on the top of the piston. That's the most accurate way.
Zayretow

70' Vespa Sprint (2009 LML power)
74' Yamaha RD350 (pinger)
2008 Suzuki DRZ-400SM (thumper)

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toigo
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Re: P200 Holed Piston Recovery

Postby toigo » Fri May 04, 2012 12:52 pm

Thanks Adam. Both the new piston and cylinder are going to Al so he can make sure they're a good fit.

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Harley_Vespa
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Re: P200 Holed Piston Recovery

Postby Harley_Vespa » Sat May 05, 2012 10:33 am

Matt,

Great job on the CBR and I feel for you on the holed-piston.

I was reluctant at first to split my cases but I am glad I did.
Image

I found almost a fine 'mud' of metal (in my case, aluminum) in every crook & cranny. Here is my bike after I flushed and wiped every possible place the little metal 'mud' could be found - including all over the crank and behind it. Basically I sprayed WD-40, wiped it out, then compressed air, then wiped it out, then repeat that cycle at least three times until when I wiped a cloth through I found no debris or particles.


This was it right before I zipped it back up:
Image

Good luck & great job on the CBR.

Take Care,

Erik

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Re: P200 Holed Piston Recovery

Postby dirtyhandslopez » Sat May 05, 2012 11:10 am

If you are splitting the case and rebuilding the clutch, pull(or more correctly push) the crank out and replace the drive (clutch side) seal also. It can only be done with the cases split and crank removed. Flyside side seal can be replaced without splitting the cases, if need be.
That's not going anywhere

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toigo
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Re: P200 Holed Piston Recovery

Postby toigo » Tue May 22, 2012 1:25 am

So I've made plenty of progress and have a couple of questions. I've got the cases split and most of the engine apart. I'm very glad I took it all apart because all around the crank was a fine grain grey sand of ground up piston and I can hear a faint grinding sound from the flywheel side bearing when it spins. So just for discussion, here's where the timing was set to. I'll worry about it more when I'm putting it back together, but I'm assuming when those marks are lined up it's stock timing and this is advanced correct?

Image

Here's where I'm at so far and huge thanks to Mike for bringing his custom made engine stand to the NOS xmas party that I managed to snag

Image

The crank seems to move fine so my overall plan is as follows.

1. Completely finish taking everything apart and clean everything since there is gunk in the case half bottoms and the outsides are plenty filthy.
2. New cruciform (the old one is rounding off and I've got a replacement)
3. New Seals (clutch and flywheel side)
4. New bearings (clutch, flywheel side, and wrist pin)
5. Got a gasket kit as well.
6. New Piston 1st over piston when it and the cylinder get back from Hot Rod Al

So next up is getting the crank, input shaft, and output shaft out.

I've got the tabbed washer and nut off the right side of the input shaft. The manual says to tap it out (hitting the end that is hanging out of the left side of the case (where the nut and tabbed washer were) with a mallet, but it doesn't seem to want to come out. Is there something else that needs to happen before this can get removed?

Input shaft
Image

Where I'm trying to tap it out from
Image

Similar question on the output shaft. I've got the gears off, the cruciform out + selector rod, and the brake/hub plate off. The manual says that I should be able to tap out the axle from the side where the brakes pads are. Same deal where I've been smacking it with a mallet, but not getting anywhere.

Output shaft which I'm trying to tap out from the other side.
Image

The end of the output shaft that I'm trying to tap out.
Image

Also, are there any special tools I'll need to remove the crankshaft?

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porter
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Re: P200 Holed Piston Recovery

Postby porter » Tue May 22, 2012 8:35 am

You will create more force if you put a punch into the dimples in the ends of both the input and output shafts. You have to hit them pretty hard, depending on how well they are seated, but you really cannot do much damage to either of them. Just be ready to catch it when it releases, a towel on the part side works.
I start with a rubber mallet and if that doesn't work, I step up to a metal one to persuade them out.

I think that the output shaft might be easier to do first, then there is more clearance for the input to wiggle out from there.

Also, be prepared to catch the needles that are captured under the collar on the end of the input shaft.

nice pictures

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Zeets
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Re: P200 Holed Piston Recovery

Postby Zeets » Tue May 22, 2012 9:39 am

First: You should have cleaned it first to keep gunk out of your rebuild and to keep your hands clean. (I knew an engine builder that would wear gloves because he felt that foreign oils and gunk would ruin an engine faster than anything else. He wouldn't dare touch bearings especially. He was building 1000+ hp race motors, but I figure what's good for the goose and whatnot.)

Second: Go to an auto parts or tool shop and buy yourself a decent soft faced dead blow hammer and put that fucking claw hammer back in the wood shop where it belongs. You can buy dead blow hammers that have interchangeable faces so you get a soft mallet, hard mallet, brass face and steel face all in one. The brass or aluminum face will allow you to wack on the end of shaft without mushrooming the shaft end or distorting the threads. I also second Porter on his suggestion of buying some punches. I'd buy a big set if I were you, they're indispensable. A decent assortment of punches and chisels may run you $30-$50 but are worth every penny when you're trying to knock a little pin out or set something. You should get at least one brass drift too.

In the mean time, you can hack away at it with your 16oz Stanley your dad gave you to hang pictures at college... just get a 2x4 to protect the end of the shaft and use all of your 107lbs to swing that toy you have.

http://www.mcmaster.com/#brass-hammers/=hn847v
Zayretow

70' Vespa Sprint (2009 LML power)
74' Yamaha RD350 (pinger)
2008 Suzuki DRZ-400SM (thumper)

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toigo
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Re: P200 Holed Piston Recovery

Postby toigo » Tue May 22, 2012 10:14 am

It happened to just be sitting there. I have a steel rubber coated mallet that I've been using and haven't been whacking at it with the claw hammer. As I started to take it apart I realized how bad the outsides of the case were and absolutely should have cleaned it first. I'm going to bolt them back together tonight and clean them off completely.

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Mikeh
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Re: P200 Holed Piston Recovery

Postby Mikeh » Tue May 22, 2012 1:08 pm

Whenever pounding on the end of shaft with threads on the end it's a good idea to put the nut on the shaft so that the threads don't get munged up and also keep the shaft from mushrooming. Put the nut on loose enough to allow the shaft to be driven a little ways, then once the nut hits the case loosen the nut more and repeat until the nut will not go on the threads any more.

And as others have suggested.. use a punch or center punch on the bolt.

And YOU DON'T NEED A FANCY hammer.. a standard college picture framing hammer is fine if you use a punch and the above method.

This will work for the input shaft and drive shaft. On the input shaft I like to lightly tap on the end.. it should not need a huge amount of force.. but you should wait to remove this until the driveshaft is out. Frankly I am not sure why you are removing the input shaft since the paste from the melt down should have been in the crank area only.. but if you want to clean everything and check it all out then go for it.

On the crank removal. YES there is a tool. I made one. You should really use a tool to press the crank out. If you don't want to borrow/buy a tool then you can get a copper pipe or any pipe that is big enough to fit around the clutch end of the crank and seat where the washer behind the clutch seats and small enough to fit inside the clutch side bearing and then drive the crank out of the bearing. DO NOT put force on the end of the clutch side of the crank as you will risk messing the threads up or setting it out of true.

Also on the crank.. if you are replacing ALL of the crank bearings have you thought about your big end bearing on your crank? It probably saw more of that piston gravel than any other bearing. Perhaps you should replace the crank or send it with the top end to Hot Rod Al for a rebuild and bearing replacement/ballancing. FYI someone just posted on scoot.net about a longstoke P200 crank for $90. Perhaps you should snag this.. I sent the guy an email to ask more questions (there are good ones and bad ones.. but if it's 60mm and for rotary valve perhaps I'll delegate the purchase you (I have one on the shelft that Hot Rod Al already made for me), You may want to go the longstroke route with a stock setup.. it would be super reliable and go about 7 mph faster.. it turns a cute scooter made for city traffic into a more serious commuter scooter that can easily keep up with traffic out in the suburbs.

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Mikeh
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Re: P200 Holed Piston Recovery

Postby Mikeh » Tue May 22, 2012 1:09 pm

Whenever pounding on the end of shaft with threads on the end it's a good idea to put the nut on the shaft so that the threads don't get munged up and also keep the shaft from mushrooming. Put the nut on loose enough to allow the shaft to be driven a little ways, then once the nut hits the case loosen the nut more and repeat until the nut will not go on the threads any more.

And as others have suggested.. use a punch or center punch on the bolt.

And YOU DON'T NEED A FANCY hammer.. a standard college picture framing hammer is fine if you use a punch and the above method.

This will work for the input shaft and drive shaft. On the input shaft I like to lightly tap on the end.. it should not need a huge amount of force.. but you should wait to remove this until the driveshaft is out. Frankly I am not sure why you are removing the input shaft since the paste from the melt down should have been in the crank area only.. but if you want to clean everything and check it all out then go for it.

On the crank removal. YES there is a tool. I made one. You should really use a tool to press the crank out. If you don't want to borrow/buy a tool then you can get a copper pipe or any pipe that is big enough to fit around the clutch end of the crank and seat where the washer behind the clutch seats and small enough to fit inside the clutch side bearing and then drive the crank out of the bearing. DO NOT put force on the end of the clutch side of the crank as you will risk messing the threads up or setting it out of true.

Also on the crank.. if you are replacing ALL of the crank bearings have you thought about your big end bearing on your crank? It probably saw more of that piston gravel than any other bearing. Perhaps you should replace the crank or send it with the top end to Hot Rod Al for a rebuild and bearing replacement/ballancing. FYI someone just posted on scoot.net about a longstoke P200 crank for $90. Perhaps you should snag this.. I sent the guy an email to ask more questions (there are good ones and bad ones.. but if it's 60mm and for rotary valve perhaps I'll delegate the purchase you (I have one on the shelft that Hot Rod Al already made for me), You may want to go the longstroke route with a stock setup.. it would be super reliable and go about 7 mph faster.. it turns a cute scooter made for city traffic into a more serious commuter scooter that can easily keep up with traffic out in the suburbs.

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toigo
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Re: P200 Holed Piston Recovery

Postby toigo » Tue May 22, 2012 3:16 pm

Thanks Mike. I wanted to take the input shaft and output shaft out mostly because there's a good deal of oil sludge in the bottom part of the case and I wanted to make sure I can clean it all out. I probably could just get up there with a rag and get most of it since it's mostly towards the bottom of the case.

I'd be interested in borrowing, or just seeing a photo of the crank pulling tool you have to get a gist for how it works. I definitely don't want to beat on it at all since such small clearances are involved.

Good point on the big end bearing since I'm doing every other one. Is it fairly straightforward to get one out of a crank or is it pretty difficult?

Also, my timing mark. Am I looking at advanced or retarded timing?

Thanks
Last edited by toigo on Thu May 24, 2012 12:47 am, edited 1 time in total.


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