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Discussion Starter #1
I wanted to do the write up on the mid-bike we picked up some years ago but never got to run. We've been calling it a cateye but know I'm thinking it's an X1 or X2. It came with little plastics so ID was harder, I still don't know if I'm correct. The electrical wiring was a mess, that got gutted...


We've gotten the engine torn down and blueprinted the case halves, and opened up the intake, exhaust, and transfer ports a little, and matched the cylinder to the case.


Also pulled the squeaky bearings and replaced those with budget, chinese, "high quality" (lol) bearings. Damaged pinky in the process of hammering the bearing puller, a bloody sacrifice to the pocket bike gods, ouch!


Sharpened the leading edge of the crank and polished the bearing journal, smoothed out the piston skirt and drilled a couple of oiler holes in the wrist pin journals. Did the base gasket delete.



Opened up the carb and widened the pulse port w/1/8" bit from the carb, manifold, and case.


 

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Discussion Starter #2 (Edited)
Tapped a boost bottle port into the manifold, and constructed a boost bottle aprx. 50cc.
Lots of JB weld.







Opened up the exhaust flange, cut a bit from the flywheel fins, ground up a rocket key, gutted the electric starter.



 

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Discussion Starter #3
Balanced and lightened the clutch arms and polished the cams. Drained and refilled the transmission box with atf.(should work better then the orange stuff that came out)



Rigged up a better flow air filter retaining the original choke plate.



Coming along well so far, had to source my coil but it's ordered..
Here it's almost ready to go.

Compression was a tad higher, I was too slow!
 

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Blata quadard. 2 xhinese copy quads. 3 lucky 7's. 1 lucky 7 trike. 1 cag.
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Good work sir, im doing a lot of this work myself only mine is on the Reed engine this i assume is a piston port. Top work never the less. Shame you didn't get it running bone stock first so you can really appreciate the difference of the mods. Keep us posted.

Max
 

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Discussion Starter #5
These builds are fun, looks like you're doing well with your bike as well.
I wish we had run this first to compare. In line with that comparison, my son does have a stock x7 that's almost the same as this would have been intact with electric starter, fairings, and lights so well feel the extreme weight and restrictions of a stock piston port vs. lightened and modded. It will be a good experiment none the less, which I imagine will lead to my son and I tearing down the x7 this winter for the treatment.

Here's the bike in all its glory.. had to purchase new forks (the new version are not adjustable in construction) and rear tensioners, and we're still waiting for the coil and rear brakes. I rigged up a seat from a Razor Scoot, should do the trick. We'll hopefully be cruising by this weekend.
 

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Discussion Starter #6
It's up and running and sounds great idling, and revs like an angry hornet but dies under load when I give it the gas.
I think it's the stock pipe killing it because it's so restricting as all of the rest has been modded, the top screw/needle is 1-1/2 turns out. I'll need to read up some and go at it again tomorrow.
 

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Discussion Starter #7
I did work up a better carb as the first was a bit overdone. I dug up the original broken one from our x7 and took better care matching and opening it up all the way through.



Hopefully just tuning on the carb will make it right, I'll try without the boost bottle as well just in case that's at fault. I was thinking I might have to throw some $ at a fatty pipe if those don't get it moving, we're getting close.
 

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Discussion Starter #8
This carb tuning has not been going well. I've got it idling and reving good but still won't go under load. I started both jets at 1-1/2 turns out and went 1/8 turn per adjustment and even at its strongest it'll die when I'm on it. It's a new coil gapped w. business card, I've checked for leaks, checked the plug gap .030" on a Champion RCJY6, gas is flowing into the carb...
Any thoughts? Is it the stock pipe choking it out?
 

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Blata quadard. 2 xhinese copy quads. 3 lucky 7's. 1 lucky 7 trike. 1 cag.
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I've seen a few guys on some older threads cutting heads, think it was epr and cam, can't remember what results they got. Fair play mate, ive got a ways to go before I try that sort of stuff but I will get round to it once skills improve, have you had good results? Is it hard to get the head flat and get a good seal? Seen those 2piece heads going for as little as 10quid so might try this. Assume it would still get good results on reed engine.

Going back to the running issues, im going to say it sounds like a fuel delivery issue. I've had it twice on bikes running the old carb. Once it was petcock restricting fuel and the other was a blocked jet. Every time I've had that exact issue its been fuel delivery. Have you got a decent vent to fuel tank, that being blocked can really slow fuel flow. My money would strongly be toward a fuel delivery issue and not tuning. It won't be the exhaust, im sure of it. I've had like 4-5 of these engines brought back from the dead with all manner of dog **** exhausts, unless there's something physically blocking it it would pull you, maybe badly but it would pull. Have you got a bog stock carb you could chuck on yo test?

Max
 

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I would start checking things out like the key on the flywheel could be sheared and the timing could be off
 

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Discussion Starter #11 (Edited)
I've a carb rebuild kit coming.. in the mean time I'm going to swap the stock/functional carb from our x7 on it for a try, that might fix it and figure out the source of my trouble.

PB56- I like the chop top conversion y'all do there, I've seen that thread in the past and I'm working my way up to such. I've got one back up piston kit for this cylinder as it looks in good shape. I don't know how old the piston/rings were that we just rebuilt, so if the carb swap/ rebuild doesn't cure it, I'll go one more try on this cylinder. When it's toast, I'll get out a saw and try some practice for that conversion, though turning down a crank would be some sort of task.

Mr.K- I'm running a bought rocket key, I'll look at that as well, maybe try stock key to see if it makes a difference
 

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Discussion Starter #12
I've got the bike pulling now, though just in the drive, it's been raining for days..

Flywheel magnets were aligned, plus I added larger spark wire and cap.
Ended up the carb rebuild was somewhat successful, though still not perfect. After sitting overnight hooked up to the fuel my tank drained into the cylinder and case hydrolocking when I tried starting the next day. Do the needles get stuck open on the pumper carbs?? My fuel lines don't have the proper hose clamps so they leak very slowly as well which might be the case (I have some ordered).
Otherwise it's having trouble keeping the exhaust bolts tight, and two of the four engine mount bolts are working their way out already due to vibrations. I'm thinking how I can add an extra motor mount to amend that situation, looking for scrap metal to fab something up..

Hopefully I'll get this running against our x7 this weekend, the weather looks good for the next couple days. I'll keep y'all posted..
 

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Nice job getting it sorted out better...Yes the pumper needles get stuck and they also lift off their seats due to being deformed or being uncalibrated...Ethanol is the culprit that hinders perf and causes problems in that dept..

Sounds like you need to take the carb apart and adjust the pumper needle lever a lil or replace the pumper diaphragm because its already warped by ethanol fuel...Theres also a gauge that helps get the lever height for the pumper needle set right.........

Theres also a process called adjusting popoff pressure its a way of finetuning the spring pressure exerted on the pumper needle too so it allows perfect timed pumps everytime..Its done with a popoff pressure tester....


As far as the exhaust make exhaust studs with modified nut backers and use lock nuts to secure the pipe.........An extra brace where the headpipe and exhaust pipe come together is a good thing to add too

As far as the engine bolts..It appears you dont have any forming taps....Im not talking about fluted cutting taps either...They are taps that realign the threads so they can be retorqued......Plus Forming taps are a more high tech way to thread new holes too...........

Just know that forming taps out price the regular taps 2:1 but they dont cut away valuable material needed for the threads to be able to be re-torqued properly without stripping out........

Using brand new better quality screws with brand new threads is also a must in this hobby as the crude and crappy chinese potmetal screws wear down via vibrations............

Real screws have a service life and must be replaced after being over torqued or torqued more than twice in some instances..The Chinese potmetal screws need to be thrown in the trash and replaced with grade8 or grade10 hardware as theyre non-conforming and snap easily.......

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And like PBRider56 said you also need loctite............

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Now for the engines mounting...........You actually need to strengthen the frame better by adding a much stronger brace at the transmission front by drilling and tapping into the transmission case as its plenty thick to handle it because rider weight and the extra torque cant hold it in there stiff enough.Id use 2" x 2" angle steel standing up then weld the end to the engine mount plate and re-do the original mounts with 1 1/2 x 1 1/2" l angle steel too............

Good Luck
 

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Discussion Starter #14 (Edited)
We've seen our share of crap chinese bolts and have been hitting Ace Hardware pretty frequently, need to pick up one of the Doorman metric kits or buy more in bulk to save $. I'll also look into the forming taps.

The bottom/right bolt that secures the transmission/bell housing to the flywheel housing and doubles as the engine mount has its threads stripped out of the flywheel housing/case. That will have to be tapped bigger or maybe I can fill the thread with some JB Weld 🤔 and sort of re-thread the hole.


To remedy this a little, and support the transmission case from shifting under throttle I added a metal bracket using existing threads in the frame with two of the transmission bolts threading through the bracket. I think this will help a little where the other is giving up, I'll have to wait to find some angle iron and try some welding when my buddy gets some time to get me started.

I also pulled the two part exhaust and matched the four mating surfaces and added the missing gasket in the middle, using some red Loctite on those two bolts so it's more a one piece, no leak in the middle. I'm still thinking how to add another support/hanger for the pipe. I'm looking into the exhaust stud idea as well, that should be an easier fix, I'll hit Ace for those.

Hose clamps are here for proper fuel line sealing. I looked into the carb and the float level is set at proper spec and diaphragms are new and in proper order, gas is ethanol free, maybe the leak was from the fuel lines/gravity.. I'll see soon enough.

Updates to come.
 

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You can tap the hole to an american thread or an M8 and drill the passage open with a drillbit a lil bit..

I like the bracket...Quick n dirty and will serve its purpose plus do extra if you can find a way to attach it to the motorplate in the front too......

Yeah if youre gravity feeding the pumper carb it will cause those problems too but getting a calibration tool doesnt hurt either....as you can see on my mini supermoto I put a shutoff valve


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Another tip is to put genuine rebuild kits into the rep carbs and to take the mounting flange and true-it flat to eliminate the rough casting thats so porous that even thick gaskets cant seal them totally and you get some sort of an airleak ever so slight as it will be a leak none-the-less that will overtime get incrimentally bigger..
 

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Discussion Starter #17
CAM2- I'll snag one of those metering adjustment tool. I'll hit the mating surfaces of the carb for the proper seal. The fuel shut off valve wouldn't hurt, I'll snag one of those somewhere. I did get a decent rebuild kit from the looks (Raisman- made in Brazil), though not official Walbro.

Pb56- that banshee looks awesome, haven't seen any engines with oil coolers or radiators, just air cooled so far. I bet the performance is that much better and then less wear from heat/friction for longevity.. one of these days.
I'll get our hardware swapped for SS or grade 8 hex for sure.
 

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Discussion Starter #18
Good tip for those gaskets, I've got the .025 sheet I cut for most other areas, haven't got any thinner. I used some gasket maker, no base gasket for this build, should squeeze the most compression out of this cylinder. I'll dig into my other options when I wear this cylinder out, I've one more piston/ring set I'm about to trim up when this original piston doesn't hold up any more, I guess you get more than one use from the jug(don't know the hours on either).

Busy with the youngsters today, I'll try to get this up and running right in the next day or two.
 

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Good tip for those gaskets, I've got the .025 sheet I cut for most other areas, haven't got any thinner. I used some gasket maker, no base gasket for this build, should squeeze the most compression out of this cylinder. I'll dig into my other options when I wear this cylinder out, I've one more piston/ring set I'm about to trim up when this original piston doesn't hold up any more, I guess you get more than one use from the jug(don't know the hours on either).

Busy with the youngsters today, I'll try to get this up and running right in the next day or two.

A jug has unlimited hours if it doesnt crack or shatter....Ive had a couple bottomends that have had a dozen heads each and the head studs also made the transition from M6 to M8 to 1/4"sae too........LOL

Thats the best part about blueprinting the bottomend...You only have to do that once...The cylinders are a different story and also 1/3 the work but will say I put new bearings every rebuild wristpin bearing included.....

When youre having fun and are budget minded the bearings posted will get you by and last you a descent amount of time...Another thing I change religiously are the clutch bearings and the wheel bearings aswell......Sometimes very high quality bearings are a waste of money when you always ride in dirty environments....

If you save the worn out cylinders you can send 4-5 of them to US Chrome to get them re-chrome plated and honed to specs....Back when I was racing racekarts that were McCulloch chainsaw powered the cylinder and case were 1pc so we sent 5 cases into be rechromed in the cylinders and we only paid for 4 and got 5 cylinders done as a deal......

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Another worthwhile mod and tip is if you want to eliminate the cylinderhead from walking around and wearing down the basegasket causing a leak or wearing away the yamabond using nylon locknuts on the bottoms of the cylinder studs will hold it down as the holes are somewhat larger than the studs diameter giving the ability for it to walk around at very high rpm's....

The mod can be done either way...For mildly modded engines installing the nuts the right way does good but in higher revving engines I suggest countersinking the holes at the flange and flipping the nut and using the rounded shape to deadlock the cylinder and secure it totally to the base with zero chances of walking around...

The mod even works with the 1pc heads too as the countersunk area keeps the screw in place without a way to walk.

One thing Im adamant about is crank seals...I believe in using high quality low drag ones...It makes a huge difference in everything and if you want them to glide simply take some metal polish and polish the areas of the crank where the seals ride..........

I also posted a pic of my handy modified hacksaw blade I use to modify the split transferport center divider...
 

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