1984 ATC300R Fooler build

[El Camexican]

Not going to lie, i am nervous as all hell about the tuning process. and yes it is my first 2 stroke which makes me even more nervous.... i am down right horrified lol.... i am not planning on running it until the spring time when temps get warmer, and so i can read as much as possible on the jetting / tuning process. last thing i wanna do is rush into it and have it end bad... i am working on having my builder walk me threw the process of tuning, i even talked with him about bringing the trike back up to him in the spring time to assist in the initial start up and tune.... i have done research on tuning but i am not about to even say that i am even remotely comfortable with the process....i am much more comfortable with 4 strokes. I am almost positive i have seen your sons trike before daddio, by chance is you and your sons trike on the Flotek website, i am almost positive that is where i saw it. awesome trike by the way!

i wish i even knew someone nearby me that has owned a 2 stroke for a long period of time that i could turn to for help when the time comes to tune. i just need to keep reading up on the subject!

I just posted this for you. http://www.3wheelerworld.com/showthr...67#post1272867 I hope it helps you get that beast up and running.

[bigdaddyvw185]

Daddio: That is ONE SWEET AIR-HAMMER! Very nice!

Now knock it off guys! You are all getting me wanting one BADLY! LOL!

Get that CR125 moving on craigslist , repost that bad boy lol.

[bigdaddyvw185]

I just posted this for you. http://www.3wheelerworld.com/showthr...67#post1272867 I hope it helps you get that beast up and running.

Thanks!!!!!

that was a hell of a write up!! cannot thank you enough.

[bigdaddyvw185]

Well i am going to pickup the engine tomorrow morning! Ken called me this afternoon and said it was good to go. cannot wait to see it!!

[bigdaddyvw185]

the engine looks great! ill tell ya it was great to walk into his shop and to see it assembled for the first time.

[slashfan7964]

Now you just have to file off some of the paint on the cooling fins

[bigdaddyvw185]

got the engine bolted up this afternoon, now i just need to get my hands on a carburetor

[JasonB]

Looking awesome man! So close

[bigdaddyvw185]

i just want to be sure, Can a stock throttle cable be used with a 35 PWK carb? i am pretty sure that i heard a stock cable cannot be used... i am looking to get a new cable and carburetor as a bundle any suggestions on a place to get both besides ebay?
Jets R us has the carb for 186.15, which is good but i am not sure if i can get a cable form them also.

[yaegerb]

so are you settling on a 35MM? I know its ebay, but this is the most competitive price I could find for my 38MM with cable and it comes pre-jetted...(you call the company to get it set up..really nice guy that runs this shop). I still think you should go with 38

http://www.ebay.com/itm/Keihin-PWK-3...24f6f2&vxp=mtr

P.S. I love the work so far. Very nice indeed!

[bigdaddyvw185]

i am still sitting on the fence as far as it comes to size..... tho it is getting down to the wire and i need to make a choice soon. considering the trail port work on the cylinder and all there are more guys suggesting the 38 over the 35. so the 38 may very well be the choice that i go with. way i look at it is if the 38 doesnt work out i could just sell it in the classifieds. its just the talk of the 38 lacking in the low end that keeps me from not springing on it. As the low end is what i am looking for more so than top end being a trail bike. but then again guys running 38's on 250's is a little encouraging that it would be well fit for my situation.

thanks for the tip on the ebay bundle, thats the best price i have seen yet.

[yaegerb]

Lacking in the low end? I don't know about that. My R with the 38 has as much power down low as the stocker did. Where the 38 is going to shine is up top...night and day difference. My opinion is once get it dialed in, you won't go back.

[bigdaddyvw185]

well what the heck im going to pull the trigger on the 38 and be done with it. their is just too much support for the 38 to turn my back on it.

[yaegerb]

well what the heck im going to pull the trigger on the 38 and be done with it. their is just too much support for the 38 to turn my back on it.

Glad to hear it!

[barnett468]

i am still sitting on the fence as far as it comes to size.

well what the heck im going to pull the trigger on the 38 and be done with it. their is just too much support for the 38 to turn my back on it.

Hello bigdaddy;


On a naturally aspirated engine, the engine alone controls how much air it will accept at any given rpm.

The main reason a smaller carb will provide more bottom end than one that is bigger than an engine needs, is simply because few riders rarely roll the throttle on slowly. It is frequently wide open or closed.

When a rider quickly opens the throttle all the way at mid rpm and lower, in general, the engine still sucks almost, if not the exact same amount of air in as it would with a smaller carb but it will not suck in more with the bigger carb. This might cause one to think the engine would still have the same amount of power down low with a 42 mm as it would with a 32 mm. It will actually have less. This is partially due to the poorer atomization of the fuel caused by the lower air velocity/speed.

The velocity becomes lower the more the tube/bore size of the carb is increased. The larger the tube is, the more air it will flow for any given velocity.

If a rider had a carb that was way bigger than the engine could use at peak rpm, in general, the eng would still have the same bottom end performance as a smaller carb up until the point where the throttle slide was opened to a point where the venturi/bore size was larger than the venturi/bore size of the smaller carb.

In reality, you could put a 72 mm carb on it and set the throttle so it only opens 1/2 way which will make it a 36 mm carb. Doing this, will in general, cause it to perform like a 36 mm carb at the same throttle slide openings but not necessarily at the same throttle position on the bars unless it is set up to do so.

In general, the bottom line is, if you get a 38, 39 or 40 mm etc., and think it’s too big, just don’t open the throttle all the way and you will in effect have a smaller carb.



2 STAGE REEDS - If you don’t have these I suggest you get them or ask your engine builder about them.

One of the purposes of dual stage reeds is to improve a 2 strokes performance at low rpm’s without sacrificing top end power.

One of ways two stage reeds improve power over a wider range than a single stage reed is by increasing air velocity at low rpm’s.