fitting piston back in lower cylinder

[lksseven]

ok, no one told me how tedious it is to get the rings to line up juuuuuuuuuuust right in order to slip the cylinder head back on the piston (removed and painted cylinder head and replaced cylinder gaskets).  It's 35 degrees, and I was sweating and so keyed up after I finally got it to slip on that I paced back and forth for 15 minutes.

Hello warm milk !

Is there a trick to it, or is it just plain minutely tedious?

Larry Seale
I choose to ride

[fasmith]

And are you absolutely sure you installed both circlips to keep the wristpin in?  

I had an experience one time...  had worked 20 minutes to get the rings lined up, and after slipping the cyclinder over the piston, and had just taken a swig of cold beer in celebration when I spied this circlip on the workbench.  Cold chills ran through me..as I thought... now is that the new circlip I possibly had not installed or one of the old ones left over?  Knowing I usually toss the old ones away, then that would have to be a new one which I didn't install and should have.  Oh the agony. what to do? I examined the clip... didn't look new, and there was not a scratch mark on it..as if it was brand new. I dug through the trash and found one of the old ones...yep it was definately scratched from where I had pried it out when I removed the old piston.  I compared it against the one on the bench.  I started gambling.. ok ..do I take a chance?  I think I had really installed both circlips but I couldn't remember... for sure.  So... in the end, I removed the all the nuts and the cylinder .... only to see I had indeed installed both circlips in the piston.   That called for about a six pack to calm down and then another six pack along with another 20 minutes of cussing to re-install the cyclinder.

Freddie

[lksseven]

There's two rings, right?  One at the very top, and one about 1/4" below the top one.

They're both on there, I know for sure.  

Now I'm getting nervous again!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Larry Seale
I choose to ride

[Rocket]

I take a small vise grips and clamp it onto one of the cylindar studs.  Place the cylindar on the studs, the vise grip keeps it from sliding down and now you can pinch the rings and push the piston up into the cylindar.  Sometimes you need to use 2 visegrips to keep the cylindar level.
Rocket

[cubfan1968]

Larry this is a very easy task. First get an 18 year old to help you. If you don't have access to an 18 year old, for a fee I will rent you mine. Please.

Rod Whitman
1972 6 Day (Rider)
1972 6 Day (Project)

[KJDonovan]

Larry,

I also found this to be a tedious undertaking.  I found when I enlisted a second pair of hands (the wife) to hold each ring in place that things went more smoothly.  

KD

Kevin J. Donovan
Foster, Rhode Island

[sachsmx]

Larry, my trick is to install the piston in the cylinder with the cylinder sitting upside down on the workbench. I install the wrist pin clip in one side of the piston and push the wrist pin in from the opposite side until it just starts to break through the hole on the side it is installed from. I then install the piston into the dry cylinder (two strokes only - I know this might open up a can of worms, but I firmly believe it is best to use no oil on a two stroke piston during assembly)with the cylinder upside down on the bench until the wrist pin nearly stops against the cylinder base or liner cut away, depending on the particular engine design, this way you are not fighting the weight of the cylinder. Be sure to get the piston aligned fairly close when doing this to eliminate the chance of snagging a ring later. I then install a new base gasket onto the lower end and a new wrist pin bearing in the rod (lightly oiled). I also stuff a clean, lint-free rag in the crankcase to catch any falling parts or debris and to also help center the rod for assembly. I then install the preassembled cylinder w/piston down over the studs stopping to align the wrist pin and rod. Push the wrist pin through the rod bearing until it stops against the clip, then install the last clip and double check that both are fully seated. All thats left to do is to drop the cylinder all the way down and torque properly. As others have suggested, a pair of vice grips clamped to a stud or two may help.

[lksseven]

Thanks, guys!

- my wife is a sweetheart, and looks like an athlete but actually has the athletic ability of a drugged canary, so enlisting her help next time will be a desperation move  (if she's ever told about his comment, I will of course deny it, and start rambling about non-secure websites, imposter posters, and such [8D])

- vise grips on the cylinder posts .... duh - that's a simple and brilliant idea (no wonder it hadn't ocurred to me) [)]

- Rod - regarding your offer of the eighteen year old helper ... I thought we were friends!  [:0]  It's my opinion that the 18th year is Nature's way of making the "college freshman move-out" an event to be gleefully anticipated by both parties  



Larry Seale
I choose to ride

[john durrill]

Larry,
 We use a piece of wood. Its something a lot of manufactures recommended and some sold as a special tool.
Slide the shaped wood between the cylinder studs and resting on the base gasket surface. Rotate the crank till the piston  rests on the wood. Slide the cylinder down over the studs. Slip the top of the piston inside the cylinder bore making sure the ring is aligned so the pin is center of the ring ends. As the ring enters the cylinder bore you can squeeze , Compress the ring through the transfer cut outs in the cylinder liner.
The wood holds the piston square to the bore and the piston will not be flopping around on you. ( always stuff the cases with a rag to keep  things from falling into engine cases) The wood will not damage the base gasket and you just lift the cylinder ,with piston inside, up to remove the wooden plate. I uploaded a picture to this web addy. The wood can be any clean wood from 3/8 to 3/4 inch thick. Plywood works great for this. The picture shows some dimensions in mm. It may be for a 250 or 400 ( I am not sure) but all you need is something  wide enough to just clear the studs and a slot deep enough for the rod to sit straight up and down.
http://pg.photos.yahoo.com/ph/sachs175/album?.dir=875d&.src=ph&store=&prodid=&.done=http%3a//pg.photos.yahoo.com/ph/sachs175/my_photos%3furlhint=actn,del%253as,1%253af,0

 Hope this is a help,
John D.

[AndyL]

I couldnt agree more with John's advice.

I cleaned out several boxes and drawers this weekend and I found I have half a dozen or so of the little wooden spacers for various bikes.  Little 50cc stuff up to my Jackpiner and even for my KTM 300TXC.

Seems like I always used 1/2" CDX plywood to make them.  Too bad I cant seem to keep them all in one place.

Andy
#14u MOVMX and AHRMA
75 Jackpiner
92 KTM 300