I am looking more for just beating around local parking lots. I have already had my fair share of traveling in my lifetime. I turned down Dunlop tires, traveling to all the Camel Pro AMA races back in the '80's, for the same reason.

 

I can do either or both fun for me. There's another member on here from Nc that will be up for some parking lot bashing/racing also.(jrock22)

 

Been painting and working on assembling the chassis. Frame weld are CRAP! Need new steering head bearings. Need to figure out something for handlebars. Straighten one side of the original ones or do something different. Different being aluminum mountain bike handlebars and clamp down through the steering stem.

The better of the two stock motors will suffice for now. I just want to see what I have when it's all together and going.

 

Any suggestions for a pipe? The stock exhaust I have for this thing is a joke. Single tube bend 90 degrees with what I would loosely call a "silencer" on the end. It's an upright piston port engine. I'm thinking, if nothing else, get a stock pipe for the newer Cag and modify.

 

I had to make my pipe custom for mine.......I used an x1 revpipe w/pitbike 4 stroke 1 1/8"ID head/lead pipe



You may get lucky and get one of these to fit.........

jetpro for a sidecar racer....



X7 fatty pipe.........







Eventually I got tired of scraping the footpegs at even at the slightest of angle so I chopped off the engine plate and welded in a reeded engine to raise the footpeg height a couple inches which still wasnt good enough so I sold it for a $175 slapped together with junk parts and a pretty new $20 bone stock mildly modified 44mm bore engine all busted up like this......I bought the cag running for $40 bux and slapped the highly modded 49cc piston ported engine on my homemade r/c buggy

 

You need an over the head Fatty Pipe, if you can find one, seen them on eBay or Amazon under 43cc 49cc pocketbikeparts about $60, and a Walbro WT-813 with boost bottle intake. See photos

 

Sounds like the Fatty pipe is the best way to go. Though, with some cutting and welding, I should be able to get most anything to work. I'll use the stock POS exhaust at first, just to see if everything is working and worth putting more $$$ into. No boost bottle though. Yamaha tried them back in the early '80's, known as YEIS (Yamaha Energy Induction System). Many aftermarket companies followed suit with their own version. After a few years of independent testing, it was widely disregarded and considered next to useless. Yamaha also quit using them after a few years. On the surface, the theory sounds good. It's when you look deeper into it and the principals behind it (Helmholtz Resonator), you will understand why a practical application on a 2 stroke engine is difficult and yields very little gain. It's all about perception. If you think it's a good thing, then your mind will tell you it works. But, the numbers simply don't back it up.

 

Those boost bottles for yamaha worked...I have one on my 83 yz80 and also my 2002 banshee w/421 stroker kit.......For engines w/o manual powervalves it definately works.......I tried both with and without...as you can see how it turned out...........

This thing is alchohol powered and pretty nasty,,,,add a 3-4ft long swingarm w/paddle tire to it and this thing can compete in hillclimbs............

 

Finally got three orders done and shipped to three different continents and can now get back to the Cag.

 

Perhaps they do work better on smaller cc than on full size bikes. I do know that they didn't last long on 125cc or larger bikes, power valve or not. At that point in time (early '80's) I had outgrown smaller bikes and didn't pay them much mind.

 

So, I start to put together the chassis and behold, no front wheel spacers. No problem. Back onto the lathe and 20 minutes later, some brand new 6061 T6 aluminum wheel spacers. FWIW, at least on this old Cag, The axle dia. is 10mm and the spacer width is 10mm and 15mm on the disc side. Considering the condition of this old ratted out thing, I wouldn't carve those width numbers into stone. But they should be close if someone ever needs to make their own.

 

I have to say, out of the thousands of bikes, hundreds of models, from the US, Japan, England, Germany, Italy and from, I'm sure, a few other places, these Cagllaris from China are the biggest dung heaps I have ever worked on. If anything aligns or is the correct size, it surely has to be by accident.

 

You're right china cag bikes are POS's lol but there's a lot of room for improvement. I like to see it as the Chinese came up with a quick and cheap template for a build-it-yourself pocket bike kit, already assembled lol. Leaving it stock is just out of the question.

 

Lol, that was good, doesn't take long to figure out how poor the quality was. But, the're cheap, my first new Cag A1 half fairing was $169, they tell you the bike is just thrown together, and have to check everything before you ride. My New water cooled C1, 50cc Blata copy bike took about 8 days 5 hours a day to get where I would want to ride it.
First thing is good bolts and nuts. I use at least 8.8 and some 15 SS I believe. All SS washers, flat and split.

 

WOOHOO! The front wheel is tightened and it doesn't hit and thing and it spins! All it took was to machine two axle spacers and cut a new, .5mm longer bearing spacer. The original one was to short and pinched the bearings when the axle was tightened. I hope the rest is this easy!

 

With that lathe it sure makes easy work. Last month I bought one of those mini lathes from H/F tools so I could do such, it's still on backorder....marcelo........

Funny thing is my front wheel spacer on my cag is about 1mm too long so the whole wheel moves side to side lol

I'm stoked today I just finished redesigning and building the rolling frame of my x-games motobike converted bmx/mtb/goped hybrid bike. I still gotta weld up the new engine mounts and a few other things. Made the swingarm out of 3 seperate bike frame rear arms, a hacksaw and a bench grinder. lol

 

Oh yea....having a fair machine shop here is definitely a plus.

Just now got the front caliper cleaned up, lubed, installed and adjusted. Now on to the back end.

I'm still working ideas around in my head for a frame design to build. I'm thinking of using a rod end to have the rear ride height (and thus the rake angle and trail) adjustable. Also, tilt the old piston port engine forward about 45 degrees. The diaphragm carbs (Walbro style) will work at any angle. Unlike float bowl style carbs. Considering getting a small slip roller to make my own cones to build expansion chambers. I think I like that idea better than hydroforming.

Getting close to starting an actual build thread!

 

Are you talking about tilting the piston ported engine forward that sits at a 90* angle? You are right, it will run with the Walbro style carb at any angle but I believe the 90* angle piston port engine produces less piston/ring/cylinder wear than the 20* (approx.) reed inducted engine due to gravity constantly pulling the piston downwards onto the bottom of the cylinder where the exhaust port is.

I was planning on mounting a reeded engine inverted @90* on my bike to clear the front tire and get less cylinder wear. I'm sure Cam would have some input on this one. lol

 

I don't believe that gravity on the piston when tilted is going to play much of a part in piston wear. Though, more influence, the better. The thrust face on the piston is on the piston skirt on the intake side. Tilting it will alleviate some of the load, depending on how much gravity plays into it.

Though I may be new to pocketbikes, I have been playing with 2 strokes since '78.

 

It does on all my 4 stroker horizontals aswell as PW80 2 stroke horizontal engine and has since my first 1972 minitrail50 in 1977,,,,all the piston and cylinder wear is mostly on the bottom..

On my Xr75/80/100 the wear is more evenly distributed....Its sometimes negligable to notice the wear by eye but with a dialbore gauge its very noticeable...



Ive been riding since age 7 and wrenching since age 9,,raced 137cc 133mph 2 stroke methanol huffers at age 12 against full grown adults and had schwinn bicycles that went 100mph and better......When I went to technical school I taught the teacher stuff he didnt know and we had many an arguement with me ending up the winner too...My dad owned a machine shop 40 years and my mom worked in aerospace as an inspector for 23 years...Went mach 2 in a F14 at age 13 too.I Built NHRA aswell as IHRA but mostly NMCA Pro Mod and Sportsman racing engines for 17 years until 2008.........Ive built and owned more than 200 toys in my lifetime just for myself let alone hundreds for others and seen/owned alot of crazy combustion engines in my lifetime too.......

scroll down to chapter 2.4

http://books.google.com/books?id=pk...d=0CDEQ6AEwAA#v=onepage&q=cylinder wear on a horizontal 2 stroke engine&f=false

 

Ahh that makes sense. I never thought the intake side would have that kind of effect on the piston. Thanks man, learned somethin new today:thumbsup: I'll take that knowledge into consideration when mounting the engine.

I like how compact the reeded cag engines are vs. the piston ported engines. They also have more mounting holes in the cases.

 

To explain it a bit more, Right after the ignition fires and the piston starts to go back down, the crank pin is to the front, or exhaust side, of the engine. At this angle, the piston pivots on the wrist pin the opposite direction the rod is pointing. Meaning, the top of the piston will try to go toward the exhaust and the skirt will try to go toward the intake. Between the support of the rings and the lack of leverage (shorter distance from the center of the wrist pin to the top of the piston), the top of the piston is the lesser of the thrust points. It's the unsupported skirt that sees the abuse. The thrust side of a piston will always be the side opposite of the crank pin ATDC.

Now for the stupid question of the day. This old Cag I have has old style forks. Meaning that they are welded one piece with a non clamping top "clamp" on the triple tree and pivot in the steering head by a setup not that different from a bicycle or an older motorcycle (separate races and caged ball bearings).

Now, I look at the new forks and clamps (and I see that the top clamp actually clamps) there is what looks to be a simple bolt running through the steering head. My question is, what style/type of bearings are now used in the steering head?

 

Sealed Ball bearings, 8mm ID. Get the number of the bearing off the seal or outer race. I get all my bearings in a few days online. The www. plus .com on the end. usabearingsandseals , I get all my bearings there or at greatbearings. I get 10 Cag China wheel bearings for $9 shipped. Or for a few bucks more $5 or $6 SKF Nascar bearings. They also have RB from Taiwan, NaChi from Japan or the best SKF from France, Germany or Italy. My Billet Case Cag has SKF bearings and seal.

 

CAM2....Cute link, for the layman. 90% is right. The other 10% is either omitting certain things or is outright wrong. For example, to quote from the "Merits of vertical engine"......"The weight of the piston is carried by the crank. Therefore, the weight of the piston does not wear the cylinder liner during motion." To read this for what it says outright, a vertical bored engine will not ever wear the bore lower than where to rings ride against the bore, conveniently ignoring physics.

I never said that wear on the exhaust side of a piston didn't occur. It would be a matter of degrees, literally, as well as other factors. One being piston weight. CAM2, you know as well as I that a bore will oval on the bottom on a vertically bore engine. And that wear is on the intake, or thrust side. Depending on the degree of bore tilt, this will be reduced and will slowly transfer more to the lower or exhaust side. I have worked on enough small Honda (not cheap Chinese knockoffs) near horizontal bore engine to see this myself.

Get the number of the bearing off the seal or outer race.

EPR.......If I had the bearings, I wouldn't have been asking what style/type they are. When you say "Sealed ball bearings", I am assuming that they are the same type as what is in the wheels, only dimensionally different. Based on this assumption, it is nothing more than a cruel Chinese joke to those unsuspecting. These bearings are not designed for axial loading. This why tapered roller bearings are used when engineered correctly. Steering head bearings have both axial and radial loads applied.

If these are a sealed taper roller bearing, then that is a different matter. Though, I can not find any that have a 8mm ID, after a quick search.

 

The right store is usabearingsandbelts, got my A1 & A2 Cag neck bearings there 10 ea for around $12. I'm sorry, I am working on 4 bikes at once so I am lost, there not 8mm there 10mm x 30mm x 9mm I have RB Tech bearings, the size is 6200Z or ZZ. Metal seals on both sides, pretty sure there ball bearings.

 

That's what I was afraid of. A 6200 bearing is just a standard ball bearing. What a joke. Apparently, those slant eyed SOBs don't know the difference in an axial load and a radial load. marcelo 6200 bearings are intended for a radial load only. Bearings in a steering head see both. This is why tapered roller bearings and standard bicycle headsets load at an angle. Given the cost of, and available sizes of, tapered roller bearings, I will use a standard bicycle headset with machined 6061 aluminum adaptors between the head and the bearing race or cup. Unless I can find the appropriate tubing size to where the race/cup will press in.

I know a 12 year old can grasp this concept, why can't the Chinese? This is beyond shoddy manufacturing, to where one has to go through it to get it right, but a major design failure.

I'm half temped to poke a hole in the fuel tank of this POS CAG and start a bonfire with it.

 

They are supposed to be Toys, you cruise around the parking on the weekends at up to 27mph, lol. 15 years ago these engine where used on backpack blowers. My Cag is 5 years old never had a neck bearing problem in that or any off my bikes. Rod end bearings, now that's a different story, lol.

 

I did some digging on 6200 bearings. Specs, axial loading and so on as well as some educated guesses on front/rear weight bias, angular loading from the steering head angle, etc, and found that they are within tolerance with a static load. Dynamic loading would probably, at times, like under full braking, exceed the load rating. Without testing with an accelerometer, it's impossible to tell for sure about the dynamic loading. While these bearings were never designed to be used in this fashion, it seems that they will live for awhile....depending on how severely they are abused.

All that aside......I now at least have a roller. Now on to the engine and to see what I remember in particular about these engine from my days working in a small engine repair shop. It was only for about a year and after I was in the bike shop.

Also revised my frame design......

 

At USABearings I got 10 China wheel bearings shipped for $8.89 or something like that. I have a lot of extra bearings & seals for the whole bike. Cag reed port & piston port cases are $24.95 a set, ea. At PB Parts in Florida, I just bought one of each to build two different engines. Got all kinds of stuff $107, got 10% off that and free shipping got here yesterday. FedEx is Good, lol.

 

I have a Fastenal close by that stocks all the bearing I need. Had to replace 1 wheel bearing and it was a dollar and change.

My list for PB Parts is growing. Trying to get this Cag in some ridable condition to see what all I need before I place an order.