Need some FA50 cylinder advice

My FA50 would do 35mph all day. I have the MLM intake, Mikuni VM17, CF reed, and a Simo pipe. I haven't ever done anything to the cylinder (port/polish, milled) or tried to stack extra gaskets. The other day when I kicked it one of the wristpin clips popped out somehow and tore up the piston and stock cylinder.

Now, I don't know if I should; 1. have the stock cylinder bored out and buy an OS:0.5 or OS:1.0 piston and rings.

2. get on treats and buy the 45mm cast iron kit. https://www.treatland.tv/suzuki-FA50-45mm-cylinder-kit-p/suzuki-fa50-45mm-kit.htm 3. get on treats and spring for the 45mm aluminum parmakit https://www.treatland.tv/suzuki-FM50-45mm-parmakit-70cc-cylinder-kit-p/suzuki-fm50-parmakit-65300.00.htm

I'm sure some of you have a ton more experience when it comes to changing bore size and whatnot. I was also planning on getting the malossi red clutch springs too. I'm not looking for more speed. Just a cool, balanced, easy-starting noped set-up. Any ideas or advice would be appreciated. THX

Re: Need some FA50 cylinder advice

If you're satisfied with what it was , why do/spend anymore than what it takes to get it back to that state ?

You might be able to do that for as little as 30 bucks .

How bad is the cylinder and piston ? Post a couple pics of the carnage .

Re: Need some FA50 cylinder advice

The scoring to the cylinder was a lot worse. I did what I could to fix it with a brake hone but the piston is history. I was happy with how it ran and started but the only things I havent done to this thing are what I've always heard improved it the most, more ports and make sure the piston clears them. Thats what I was thinking about on the 2 mile walk home when the circlip locked it up and what I wanted to get other people's takes on. Would one of the aftermarket cylinders do this without the whole extra gasket/head milling thing. I also read boring a cylinder on a 2 stroke really only effects the low end. Is that true? I appreciate you taking the time. TY

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Re: Need some FA50 cylinder advice

Dr. Mantis Toboggan M.D. /

That cylinder doesn't look all that bad in my opinion. You may just want to order a new replacement piston/rings, chamfer the ports and try running it.

Re: Need some FA50 cylinder advice

As much as we want perfection , it's not really needed .

Your piston is far from toast . It's a lot better than the one I'm running .

Just clean the ring lands and make sure the rings move easily . Take any nubs in the lands out that might stick a ring .

The vertical scores above , between and below the rings mean little next to nothing .

The cylinder obviously isn't perfect either , but , I'd simply insure there are no sharp edges to catch a ring and run it .

You'll likely be pleasantly surprised .

If you want to spend money , new piston sets ( piston , rings and clips ) are available . Not OEM , but , good quality from a seller with an excellent reputation for making any problem right .

As for the top end kits , I have no knowledge .

Re: Need some FA50 cylinder advice

What do you think about the whole stacking gaskets to clear the ports thing? I was thinking if I need to get some machine work done they could also mill it down easily. I get all my OEM parts from www.cheapcycleparts.com. Im gonna need a new plus size piston depending on how big the bore gets. This site sells them +0.5 and +1.0.

Re: Need some FA50 cylinder advice

William Johnson /

FA50 requires alot of work for 35 mph. My stock FZ50's do that.

Re: Need some FA50 cylinder advice

> Mike Blaser Wrote:

> -------------------------------------------------------

> What do you think about the whole stacking gaskets to clear the ports

> thing? I was thinking if I need to get some machine work done they

> could also mill it down easily. I get all my OEM parts from

> www.cheapcycleparts.com. Im gonna need a new plus size piston depending

> on how big the bore gets. This site sells them +0.5 and +1.0.

What do you want to mill down and why ?

The stock FA50 top end clears ports nicely .

Re: Need some FA50 cylinder advice

Jack Rutherford /

I wouldn't bother boring that cylinder. You'll pay around $80 to do that and then how much is an o/s piston and rings? You'll have as much or more in it as a new kit.

are you getting most of your info from the FA50 performance wiki page? That article is unclear on many things and needs to be supplemented/changed.

Contrary to what the article says, I don't believe that increased compression increases power across all ranges. More likely just low end.

I've never owned an fa50 but I've ridden one once. ha ha! Anyhow Honda and Yamaha restricted their engines in at least one way. With the piston at bottom dead center, you'll see it still partially blocks (in the Honda Express, for example), all the ports. I'd have to look at the Yamaha but I know the piston still partially blocks at least the exhaust port (3-4mm worth). I would bet Suzuki did the same thing since these bikes were subject to various states' laws limiting top speed.

What the wiki article might be trying to convey is that if you take a metal spacer, shaped like a base gasket, you can use that to push the cylinder forward. The piston will still remain in the same place but the cylinder is pushed forward. So if you take a 1mm spacer and sandwich it in between two base gaskets (that are 0.5mm each), you have pushed the cylinder forward 1.5mm (you only need to account for one paper base gasket and not both). I wouldn't use the alternative of a bunch of paper base gaskets stacked on top of each other. I assume but don't know that there are metal spacers available for the fa50. And I'm telling you to just take two aspirin at a time, and just because they helped that doesn't mean take the whole bottle. So don't get a 4mm spacer and throw it in there and think you'll set the world on fire.

Remember the piston stays in the same place. So if you move the cylinder forward, the piston will no longer reach the top of the cylinder at TDC. So you have to mill the cylinder the same amount you pushed it forward (1.5mm or so depending on how much the paper base gasket compressed). You don't need to mill the head unless you want even more compression which will lead to more problems than solutions.

Now you've exposed 1.5mm more of perhaps every port in the cylinder. Doesn't sound like much but in the world of small engine 2 strokes it can be huge. You'll want to up jet as well.

These changes with the stock crappy exhaust won't amount to much but with a performance exhaust, you'll notice a nice improvement. I had a machinist mill the cylinder for $20 plus postage. They usually want inch measurements rather than mm.

Here's my Express in beast mode after these simple changes were employed:

(edited)

Re: Need some FA50 cylinder advice

Jack,

The piston doesnt clear the ports at BDC on this stock cylinder. I wanted to see if anyone knew if an aftermarket cylinder allowed the piston to clear completely. If you think boring the stock piston will cost around $80 and piston/rings around $75, it would be about the same to buy a whole new setup. The two links in my first post show the two kits on treats. What is your opinion on the two? Do more ports make that much difference?

Re: Need some FA50 cylinder advice

I honed it out the best I could and ran it since I had extra rings. Something was definitely wrong. Not sure if it was the piston or the walls from the marks it left. If i get the scoring removed completely Im going to need an oversized piston and rings (about $75). It looks like its going to be the same price to buy a whole new kit. If I do that I might as well spend $40 more and get the parmakit if people think its that much better to have more ports.

Re: Need some FA50 cylinder advice

Jack Rutherford /

the parma kit needs mods to work. how comfortable are you with doing those? you may want to go with the cast iron kit for simplicity's sake.

Re: Need some FA50 cylinder advice

Jack Rutherford /

I don't think the aftermarket cylinder will allow the piston to clear the ports completely but the ports are most likely bigger.

Remember, I told you to take an aspirin, not the whole bottle. I think you are better off working with slightly more port area than the whole enchilada. 1 or 2 mm in the 2 stroke small engine world can be quite a bit. I'm just sayin' . . . .

Re: Need some FA50 cylinder advice

> Mike Blaser Wrote:

> -------------------------------------------------------

> I honed it out the best I could and ran it since I had extra rings.

> Something was definitely wrong. Not sure if it was the piston or the

> walls from the marks it left.

What exactly makes you say that^ ?

And , do the rings clear the ports at BDC or is just the piston top not exactly at the bottom of the ports ?

Re: Need some FA50 cylinder advice

PD,

Sorry...I was out of town. When I put the new rings on after I honed the cylinder, it fired after a few carb adjustments. After trying to retune it when it warmed up I couldnt get any power. I checked the compression and it was way low. I assume either the cylinder or the piston was causing it since it was fine before I threw that circlip.

As for the clearance of the top ring it almost clears the port but not completely. What would you do? Bore this stock one and buy the oversized piston and rings or just get a larger bore kit?

Re: Need some FA50 cylinder advice

I wouldnt have an issue with the exhaust work needed for the parmakit but if you think just going with the 45mm cast kit would be the way to go I'm leaning that way. Mine definitely needs to be bored because I had almost no compression with new rings. That would take it to 42mm plus Id spend $80 on the oversized piston and rings. Does a couple mm jump really make that much difference and if it does, where?

Re: Need some FA50 cylinder advice

Take a look : https://www.cruzinimage.net/category/item/itemgenre/motorcycle/suzuki/pistons-suzuki/page/8/

That^ might have some influence on your choice . ;)

The seller has provided good service to the big Honda riders for a number of years .

Yes , there have been a few complaints , but , those were resolved quickly and ended with satisfied builders . (edited)

Re: Need some FA50 cylinder advice

Jack Rutherford /

sounds like you want the parma kit. so get it.

Re: Need some FA50 cylinder advice

I have no experience with the parmakit but if its substantially better and worth doing the mods I'd be willing to try it. Same with the cast 45mm kit or fixing the stock one with the bore as close to what it had as possible. That's why I wanted to ask people who have experienced something like this cuz I havent.

Re: Need some FA50 cylinder advice

Damn......Thanks PD.

Re: Need some FA50 cylinder advice

Louis Brunskill /

I'd say put the kit on it! I just did on mine and it's great. All ports are bigger. Just a better jug all n all. Piston just barely in to the port at BDC.. but nice squeeze and deck height. It makes 30% more than my stock setup did. Way worth it!

Re: Need some FA50 cylinder advice

Louis Brunskill /

This is the treat land 140$ iron kit. I did a light clean up on the ports.. but it's good out of the box.

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Re: Need some FA50 cylinder advice

Louis Brunskill /

Here's a few more pic. It cleaned up nice. If you can afford it. Buy it. It's good quality and the extra bore size is noticeable in power.

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Re: Need some FA50 cylinder advice

That does look good. Did you buy the oversized piston and rings from them too?

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