[CAM2]

This bike was left in the garage of the home I recently just moved into but I don’t know the make and model. All help appreciated. Thanks in advance

Cateye model FS509 49cc 2 stroke midbike.

Welcome to the forum and good luck with it..

 

[CAM2]

MrKitty: I will see if another carb fixes it. I really don't want to make another manifold to suit the original carby model with it's 2 bolt flange.

EPR: Rubbish casting quality but that's hardly a surprise to anyone. I did consider that the current issue I have is due to an air leak inside cause by the exact same questionable quality. I will find out via a process of elimination what the issue is, or at least I hope to.


Now as promised I have some photos of my custom reed intake. As I mentioned earlier I had a V-block reed housing left over from another project long ago. To use it I made up an adapter to go from it to the crankcase. As for the other end I custom machined up a manifold to suit. To make this manifold I used the lathe and mill to do all bar the internal transitions. I couldn't do the inside as that's not a practical option with a manual mill. So I instead milled a shallow step (marked in orange) as a reference and then later used a die grinder to shape it by hand, it should work well enough.

All things considered I think it turned out decent, well visibly at least. As for how well it works that I will find out. It was entertaining to machine up though.

In this case concerning broken carb mounts knowing all you can about the carb in general will help you in the long run when it comes to sealing those SHA spigot mount carbs....

One thing for sure is you need to put an o-ring in there[pic below] so when the tube gets slid in it bottoms out on something cushy instead of solid aluminum against aluminum where harsh vibes do harsh things.........….

The insulator is another important part as it takes up the finite amount so you don't over-flex the casting causing it to crack under vibes or pressure and helps aid in properly sealing the carb to intake aswell....

Another thing involving the reeds youre gonna notice is a very noticeable flatspot in the powerband transition and depending on how its jetted will either start to gradually foul the plug and bog or it will never reach full rev potential when loaded....

That is unless you up the compression between 15:1 and 17:1 and run it on alky/methanol mix where such a huge volume of fuel is needed all at once due to its stoitchometric offset in weights between alky and pump gas...

With these tool engines in order to produce top notch power you must create a demand thats controlled and thats usually the reeds on a reed ported engine..

When the engine starts the fuel mixes journey towards TDC and if the reed areas are too open and accomodating suction and velocity becomes weak and therefore power manufacturing suffers.


There must be some sort of a taperdown point where it takes a split second for the suction to start but when it does it begins so harsh and violently it properly atomizes and rams a larger mass of better atomized fuel into the cylinder to produce the faithful powerband kick-in we all are accustomed to on highend two stroker engines....


I tried my ADA 4 petal reedblock on a pump gas engine and even though elongating the intake on 2 strokes sometimes improves power in my case it didnt and I tried 5 different sizes aswell as models of carbs too to no avail in getting it sucessfully tuned-in.....Making two 1pc metal reeds improved the setup it still wasn't dead nuts -on point...

I hope you get a better result Sam.........

 

[EPR]

Philly, that is a Cag reed port engine, different than yours. Sam-Q, once again you have out done yourself, lol.
Nice design work, should work great. I have some ADA racing 4 reed V-block setup on my twin engines with Walbro HDA48 16mm carbs cause it only has a gas inlet fitting and no return line.

 

[Kimjon]

Awesome reading thanks. Just read all 5 pages nonstop.

How'd your Reed cage workout @Sam-Q ?

I'd started building something very similar with a left over SQ Reed valve from a seized motor I got in a bulk buy of parts. To be honest I'm still learning this stuff and wasn't sure on why I started doing this...it just seemed like a good idea?

Keen to hear how yours worked out?

 

[EPR]

You should PM Sam, he might not see this.

 

[Sam-Q]

Awesome reading thanks. Just read all 5 pages nonstop.

How'd your Reed cage workout @Sam-Q ?

I'd started building something very similar with a left over SQ Reed valve from a seized motor I got in a bulk buy of parts. To be honest I'm still learning this stuff and wasn't sure on why I started doing this...it just seemed like a good idea?

Keen to hear how yours worked out?

Hi Kimjon,


I no longer have any issues with notifications but I may have delays in replying due to various circumstances.



Unfortunately I don't have any results to share at this point. While I did make some progress I had an issue trying to get my newly built engine running and have been taking steps to rectify that. Just like you I also believe that fitting a V-block reed should be a really good thing and I would like to do testing before and after fitting it to see what result it has exactly. Seeing I have some work to show albeit unfinished I might as well do an update post to show some of what I have done until now.





CURRENT PROGRESS UPDATE


Previously I showed some work I had undertaken as part of my engine build where I was doing some machining to the crowns of pistons to make them all match each other and have a known fixed angle for the outer part of the piston domes. In all my thinking and work to optimise the piston to head clearance I completely overlooked anything to do with the main combustion chamber. Due to the re-cut piston the head dome sat lower down relative to it and I discovered that there wasn't enough clearance for the piston center to clear the spark plugs earth electrode. It certainly wasn't overly smart of me. Looking it up there wasn't another spark plug listed that was a little shorter in reach but with the same specifications otherwise and my compression ratio was too high anyway so I decided to do an unreasonable option instead.


I remembered reading in the performance 2-stroke book I have that having an off-set spark plug away from the exhaust port helps to even out the head temperature, also that there was a reported benefit in having an angled piston to head squish area in 2-strokes. I also wanted more of a contact patch between the dome / chamber insert and the head as well as a means of hooking up a ground cable to the top of the dome next to the spark plug. Figuring that it would be fun and as usual some stress relief I chose to make my own dome that included some mods to the head to make it work.


To allow for enough material for the spark plug offset the top protruding part of the dome insert had to be larger in diameter. To allow for that the first step I took was to bore out the hole larger that goes through the middle of the head. I also cut the main dome recess deeper which let me have a thicker dome as well as more of a contact patch for the heat transfer.



Moving on to the fabrication of the dome insert I started with some solid round 2011 grade Aluminium bar. The first step was to do the top side that would fit into the head. Next up was cutting it off and moving on to the other side. After some facing and external turning I used a fixed angle to cut the main internal shape. With the turning completed in a lot more time than it should of taken I moved on to the milling. Using my rotary table I again started with the top to drill & tap the thread for the spark plug as well as the bolt that would hold the grounding cable. Flipping it upside down a ball nose cutter was used to cut out the area around the spark plug thread for the main combustion area. Finally I crudely die ground the combustion area to blend the machined area into the rest of the dome cut. This completed head assembly has since been re-assembled along with the rest of the engine and so far it looks promising. I don't know if I made the right choices or not so I shall see how it works out once it's running again.



I also did another small frame & fueling modification to how the fuel tank is mounted which much like the assembled engine I don't have a picture of yet. Currently I still have some pending to do on some alternations to my workshop but once that's done I plan to get back to this to see how (if??) it runs.

 

[CAM2]

I tried the ADA 4 petal reedblock on a pumpgas cag engine and it flopped....It ran better on alky..

Put the stock reedplate in the stock spot and use the box as a juice box type intake...

I can't believe you're still following the 2 stroke handbook methods...

You do know the engine you're working with is a tool based engine....The 2 stroke tuners guide covers ski mobiles,jetskus,quads and Japanese made dirtbikes

Another member named Mexicano I'm sure you heard if him followed the handbook and got the same no run results......You're not building enough velocity containing enough atomized fuel mix....

You're gonna need to get that engine in the 17:1 range to build enough case pressure to get it started...With that block you just about doubled your crankcase volume...

The 2 stroke handbook doesn't cover the modification of tool based two strokers like converting chainsaw engines into racekart engines or weed eater engines into r,/c engines..

That is the type of handbook you should be following...

The engines are like apples n oranges and also world's apart even though they share the same 2 stroke principals..

Good Luck Sam,.......

 

[Kimjon]

Nice work on the dome. Thanks for the reply.

 

[Sam-Q]

Well ****...


I hear what you are saying although I am unsure what else I should do to work out what choices to make. I have tried to do my research on here but I ended up with contradictory information everywhere and I didn't know what was correct and what wasn't. If it makes any difference the exact book I have been using as my reference is "Two-Stroke Performance Tuning" by A. Graham Bell, not the two stroke handbook. I know most of it is indeed for very different engines but I figured at the time the fundamentals were the same. Other than the choice of reed block if you feel like it then telling me what I specifically shouldn't of done here and why then I would be interested to learn.



For the time being it's all near on done so when I am able to go back to it I will see how it runs and compare the different part combinations. It's easy to swap between the intakes so it will be interesting to see how it compares. If I am wrong on all fronts which is readily possible then so be it and I will do see what I will do then.


I am only confident that you are incorrect on a single one of your points- it's with the change in crankcase volume in that it definitely hasn't been increased by that much at all. With that block you refer to the only extra volume is what is used for part of the the reeds to be able to open and the tip of the reed block actually extends as far in as to protrude into the crankcase a little. I found an old photo that shows when this block was only partially finished, it's the only photo where I can show how the reed block fits from a side view. As for the volume increase on the other side of those reeds between them and the carb, well that's a different story.

I tried the ADA 4 petal reedblock on a pumpgas cag engine and it flopped....It ran better on alky..

Put the stock reedplate in the stock spot and use the box as a juice box type intake...

I can't believe you're still following the 2 stroke handbook methods...

You do know the engine you're working with is a tool based engine....The 2 stroke tuners guide covers ski mobiles,jetskus,quads and Japanese made dirtbikes

Another member named Mexicano I'm sure you heard if him followed the handbook and got the same no run results......You're not building enough velocity containing enough atomized fuel mix....

You're gonna need to get that engine in the 17:1 range to build enough case pressure to get it started...With that block you just about doubled your crankcase volume...

The 2 stroke handbook doesn't cover the modification of tool based two strokers like converting chainsaw engines into racekart engines or weed eater engines into r,/c engines..

That is the type of handbook you should be following...

The engines are like apples n oranges and also world's apart even though they share the same 2 stroke principals..

Good Luck Sam,.......

 

[MrKitty]

one issue that you have to try to overcome with the CAG engine is its extremely short vacuum duration compounded by the extremely long distance that the mix has to travel before it makes it to the transfer ports that's why the carbon fiber Reeds suck! on a built engine you want the reeds to snap closed in the millisecond that the case pressure goes neutral so when the case pressure goes positive it sends as mutch of the mix up the transfer ports as possible. the more case volume you have increases the amount of mix that gets left behind.

the stock reed stop all so acts as a stuffer...


this is why on my engine I redrilled the intake manifold and reed block to make a line that goes passed the reed block inside the crankcase so the pumper can get good pop off because my reeds snap closed fast and hard and the pulse coming back through the Reeds just wasn't enough at high RPMs and she was wanting to go lean.


since I have pictures I do have to say the hole is in a bad spot I'm going to try to drill the manifold at a different angle or maybe build up one side of the manifold with Autobody fuser so I can get the pulse port more in the center of the Reed cage

 

[CAM2]

Well ****...


I hear what you are saying although I am unsure what else I should do to work out what choices to make. I have tried to do my research on here but I ended up with contradictory information everywhere and I didn't know what was correct and what wasn't. If it makes any difference the exact book I have been using as my reference is "Two-Stroke Performance Tuning" by A. Graham Bell, not the two stroke handbook. I know most of it is indeed for very different engines but I figured at the time the fundamentals were the same. Other than the choice of reed block if you feel like it then telling me what I specifically shouldn't of done here and why then I would be interested to learn.



For the time being it's all near on done so when I am able to go back to it I will see how it runs and compare the different part combinations. It's easy to swap between the intakes so it will be interesting to see how it compares. If I am wrong on all fronts which is readily possible then so be it and I will do see what I will do then.


I am only confident that you are incorrect on a single one of your points- it's with the change in crankcase volume in that it definitely hasn't been increased by that much at all. With that block you refer to the only extra volume is what is used for part of the the reeds to be able to open and the tip of the reed block actually extends as far in as to protrude into the crankcase a little. I found an old photo that shows when this block was only partially finished, it's the only photo where I can show how the reed block fits from a side view. As for the volume increase on the other side of those reeds between them and the carb, well that's a different story.

If you doubt what I say its cool and Graham Bell is just like Gordon Jennings and I wouldn't put your confidence behind anything of any real value...Those guys cover the same type of engines in the same types of Japanese and European 2 stroke engines aswell as rotary engines....Not Chinese tool based engines.....

If you want info on how to properly modfy the cag engine aka the Chinese version of the ROBIN NB350/411 2 stroke brushcutter/auger engine shouldnt you email Graham Bell to see what he says about using his technics to modify that type of engine.......

I guarantee he will say you need to go a different route to building what you want to build...

I dont know if I ever mentioned it to you before about how in the 50's and 60's they converted McCulloch ,Western Bend and Homelite 2 stroke engines into racekart engines....

My mother worked in the aerospace industry in the A-10 Warthog program in farmingdale Long Island for Fairchild Republic...The engineers that worked there heard through my mom that I was getting into kart racing and such so they gave my mom the formula to building the stoutest 2 stroke engines out of chainsaw engines that rival the high dollar racing engines in the Jr racing circuit and also keeps costs associated with racing at a minimum..

My dad owned a machine shop with gun drilling machines,,CNC Milling machines, CNC laser mchines, trepanning machines and a whole slew of honing machines so doing the machine wrk and making the pieces needed from scratch was an easy task..........

Today its alot easier with the chinese making the parts but the trick is making them work right by picking and choosing the right parts and modifying the rest plus knowing what mods work and what mods dont.......


Doubt on SamQ but until I see a video of that extended reedblock setup the way I see it pictured working on a pumpgas engine from deadstop to redline and gain performance Im afraid you have no basis to say Im wrong until you prove the guy with way more time and experience in these small engines starting from back in 1980 than youll ever fathom to be wrong and not hypothesize he is.......LOL

Ill say it before and Ill say it again...The fastest you can inhale a super stupid amount of correctly atomized fuel into the intake and throughout the engine without losing that mass all the way to the exhaust with enhanced velocity and very low to zero turbulence is how you build power in a tool based 2 stroke engine...….

In my 2 stroke builds you can equally hear the intake suction being almost as loud as the exhaust...…

https://flic.kr/p/22vscKf

https://flic.kr/p/24bMkE7

https://flic.kr/p/FBnPs8

Take a stock 47cc 2 stroke engine...Make a homemade blockoff plate with a nipple and add a vacuum gauge.....Pull the pullrope and watch the gauge.....

Put the same contraption on the engine youre modifying with reedbox with the 2 petal reeds at the rear like you have pictured and note the differences,,,,,,,The outcome might surprise you wholeheartedly when the needle wont move not even a quarter of an inch of vacuum...….

Maybe if you stuck a drill on it and cranked it up to about 1800-2200 rpm's like a turbine engine and feather the throttle you might get enough velocity and case pressure to get it to pop off but it will run awefully lean...Same principal as giving a fat guy half of his regular meal daily..Eventually hes gonna start to whither away...…….LOL

Take notice in the pic below of the type of exhaust this 80cc 20hp 2 stroke chainsaw engine has....Theres no tuned pipe;-just a megaphone....In quickly and out just as quick is how its done....This engine that once had roughly 3-4hp and was used to cut down trees propelled racekarts to 80-85mph spinning 20k rpm's tuned on methanol/alky mix.......LOL

Good Luck revolutionizing the Chinese 2 stroke tool based engine in the Japanese 2 stroke methods SamQ…….......LOL

 

[Sam-Q]

CAM2: As always thanks for the detailed answer. I am particularly interested in that electric ignition setup you have pictured but that's a discussion for another time.

We seem to have an ongoing theme of misunderstandings between each other. I never said I doubted any of what you have ever said and the only time I ever remember saying that you were wrong was in regard to your statement about my reed block doubling the crankcase volume. In that regard it's only because I have seen it fitted up and I didn't show a photo of the inside on here so it would of been hard for you to estimate the physical result. Otherwise up until now I only remember my comments made to you along the lines of "but shouldn't it be like this..." and making a statement of what up until that point I thought was correct. I have continually followed your advice over what I have read, after all I changed various plans because of it. For example going away from a full circle crank.

I also don't pretend I really know what I am doing, hence my disclaimer on the #1 post of this thread where I say I experiment but don't know that much and am open to input.

What I was trying to say in my last post is that yes I am well aware you have lots of knowledge, I don't have any doubt about that but how do I get some of the same knowledge without tinkering around for years? I tried to work out the answers by doing reading on here and it only helped to some degree as well as giving contradictory information. So the only thing that comes to mind that I can do is look up your post history on here, start from your most recent posts and then slowly work my way backwards through your post history. I am not being sarcastic, I am frustrated at seemingly always doing the wrong thing and I can't think of any other way to find out what I want. I have no problem being wrong, better than making the wrong choices.

 

[Lord_Loaf]

Do you (or anyone) have a link to the wheels used on this build by chance?

 

[MrKitty]

are you talking about the X7 wheels the mini chopper wheels or the CAG wheels??? any way look on ebay or amazone all the shops selling pocket bike parts have closed...

 

[Lord_Loaf]

Both actually, I'm comparing wheel sizes. I'll check out amazon too