Thinking About Re-Doing My Topend

[pondtunes]

Okay last time I checked my compression was on the lowish side on this engine... about 105psi

I'm thinking about re-doing my top end, I know zilch about what's previously been done to this engine if anything.

 

What I *THINK* i'll need to do is this:

1) Grab some cylinders

2) Grab some pistons for the cylinders

3) Get a top end gasket kit

4) tear down the top end and replace parts.

 

That being said

1) What have I overlooked in my list above.

2) Can I do this without splitting the cases?

3) Should I split the cases and check it out anyways?

4) I have a riding trip im supposed to go on May 20, 2010 - Should I wait to tear into it until I return? (the engine is currently out of my bike anyways)

 

 

What do you guys recommend? I've got a little extra cash lying around, this bike is a trail bike. I have a FMF Fatty pipe, and open airbox w/ K&N are the only breathing mods.

[Doddy]

I just rebuilt the top end of my Shee about 2 weeks ago.

 

You don't need new jugs unless you banshee has already been bored out as far as it can go (.65 over I believe is the stopping point). If you take your cylinders off you need to measure the size of your pistons to see what the next size up would be, if you don't know what your doing then send them into a reputable shop and have them measure for you. You will need to take them to a shop to have them bored, honed, and cross hatched any way and they can tell you what size pistons to get.

 

Go on ebay and find a wiseco piston kit that will come with new wrist pins, bearings, the appropriate piston size, and a new top end gasket kit. I bought mine on ebay for $179.99 shipped.

 

You may also think about having a port job done while you have the jugs out, but you don't need it but if you have been thinking about it anyway and you have the extra cash now is the time.

 

You don't need to split the cases if all you are doing is freshening up the top end. But if your crank hasn't been trued and welded now would be a good time for that too.

 

If all your doing is replacing the top end then you should be able to tear it down order your parts take it into a shop and have it all put back together in a week (depending on how long it takes to get the parts).

[Ny-2stroke4ever]

Okay last time I checked my compression was on the lowish side on this engine... about 105psi

I'm thinking about re-doing my top end, I know zilch about what's previously been done to this engine if anything.

 

What I *THINK* i'll need to do is this:

1) Grab some cylinders

2) Grab some pistons for the cylinders

3) Get a top end gasket kit

4) tear down the top end and replace parts.

 

That being said

1) What have I overlooked in my list above.

2) Can I do this without splitting the cases?

3) Should I split the cases and check it out anyways?

4) I have a riding trip im supposed to go on May 20, 2010 - Should I wait to tear into it until I return? (the engine is currently out of my bike anyways)

 

 

What do you guys recommend? I've got a little extra cash lying around, this bike is a trail bike. I have a FMF Fatty pipe, and open airbox w/ K&N are the only breathing mods.

 

whats the bore on the cylinders? asking this cuz u might just need to get them bored to the next size or resleeved instead of getting new cylinders. you dont need to split the case to do just the top end but what year is your bike and how many hours you think are on it. might be time to do the whole motor and check everything. i would do that instead of doing just the top end. otherwise your gunna be doin double the work cuz youll have to take the top end off again and replace the gaskets and itll be a waste of money.

 

id get some v-force 3 reeds for the trails. youll have better acceleration and throttle response

[AKheathen]

why you lookin for new cyls? anyway, i would simply dig in first, since you already have funds, and spec everything out to see where you stand. probably need a bore. order pistons to the next useable size, and have it bored to match them, get your gaskets and sealant, and follow the manual to tear the case apart and check the crank, tranny, and clutch out. digging in is really the only way to know what you need to do.

[Ny-2stroke4ever]

forgot to add that if your doin the cylinders you might as well get them ported. youll get the most hp out of that and itll be more of a beast

[pondtunes]

The reason I was looking at new cyl's just because I know exactly zero about the history of this motor,

I was thinking if I can find a good deal on a set of jugs already machined and possibly with the port work already done I could just bolt them on with a new set of pistons and be back together with no more downtime. Then depending on the condition of the stockers they could be bored and sold or ported for another rainy day.

 

This bike is a 1987 and as far as I can tell it is stock, but then again I haven't pulled the head to look or measure either.

As for the health of the bottom end again I don't really know... I know I SHOULD tear into it and check everything out I just have a riding trip in a couple of weeks that i'm not willing to miss.

[Erwin8r]

The reason I was looking at new cyl's just because I know exactly zero about the history of this motor,

I was thinking if I can find a good deal on a set of jugs already machined and possibly with the port work already done I could just bolt them on with a new set of pistons and be back together with no more downtime. Then depending on the condition of the stockers they could be bored and sold or ported for another rainy day.

 

This bike is a 1987 and as far as I can tell it is stock, but then again I haven't pulled the head to look or measure either.

As for the health of the bottom end again I don't really know... I know I SHOULD tear into it and check everything out I just have a riding trip in a couple of weeks that i'm not willing to miss.

 

Any bad slippage or weird noises coming from the clutch/tranny? If not, I'd do just as you suggest it if you can afford it: Buy a top-end ready to go, bolt it up, enjoy your ride, then tear into it after you return... Just my .02

[Doddy]

If it's an 87 I highly doubt it is on the stock bore. There has to be some thing done to it. I highly doubt that a two stroke engine is going to last 23 years with out having it rebuilt a few time unless it has just sat in a garage it's whole existence. I would take it to someone who knows what they are doing and have them go through it thoroughly that way you will know exactly what has been done to it and can address any issues you may have at that time.

 

If it's still working tight now then just wait until you get back.

Edited May 4, 2010 by Doddy

[Ny-2stroke4ever]

The reason I was looking at new cyl's just because I know exactly zero about the history of this motor,

I was thinking if I can find a good deal on a set of jugs already machined and possibly with the port work already done I could just bolt them on with a new set of pistons and be back together with no more downtime. Then depending on the condition of the stockers they could be bored and sold or ported for another rainy day.

 

This bike is a 1987 and as far as I can tell it is stock, but then again I haven't pulled the head to look or measure either.

As for the health of the bottom end again I don't really know... I know I SHOULD tear into it and check everything out I just have a riding trip in a couple of weeks that i'm not willing to miss.

 

well if your going to buy new cylinders look in the for sale section and buy from a good known person that wont sell u shitty cylinders. as far as the bottom end i would still go through it because once you redo the top end the piston rings need to seat right and if you pull them off to do the bottom end soon after you dont wanna run into any problems when you put it al back together. go through the whole motor now you should have plenty of time before your trip. if the motors out already you should do it right the first time and youll be able to know what the condition of the whole motor is in. post pics of the stock cylinders and whatever probs you run into. im sure we will have an answer for you. but if your banshee is stock from 87 there are gunna be some worn parts that you dont want to fail or break. im sure your crank bearings are gone also. go the safe route man