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So my parents have not let me get my license yet and I need to get around to gets parts and stuff. Answer: Yamaha CW50 scooter. This is a 2-cycle self-mixing scooter that so far, I am really surprised with the power output and speed. It reaches about 45mph since the speedo has been disconnected and has plenty of power for two riders. Its stupid looking, but with some work and a title and plate, it'll take me around town.. My issue is this: No key. I bought it for $150 from a friend and he bought it from someone for $100 who wired in a switch in place of the ignition. That guy got it form his neighbor who's renter left it behind. The scooter will run with this switch on or off (kill switch on handlebar kills engine) To get it tiled and a plate so its road worthy, I need to get the ignition working either by a replacement key or a new ignition. All wires are cut to the ignition and the switch turned on the power to the signal light switch. Also, the 2-cycle oil was leaking out the carb, through the air filter and onto the scooter. also, it runs great, but its making blue smoke with throttle and the muffler is wet with oil.
(I have new signal lights for it btw) So the issues I have with it summed up:
No key (need new ignition) smokes burnt out headlight- can I replace them with LEDs?
So my latest find is a Moto 4 250. Looked in good shape, started right up but would backfire and die upon acceleration but you
could get it to go if you were good with the throttle. I figured it was the carb. was a brand new Chinese carb, he didn't have original.
I took it apart and cleaned it, only thing I found was some debris in main jet and the main adjustment on bottom was at 41 turns. Cleaned
it out and set at 2 turns, re installed. Starts up, runs better actually drove it but seems really sluggish, once I hit 3rd gear could barely pull
it. Rechecked everything, even ordered a new carb as I had this problem with another atv but still same problem. Now I pull it apart and
decided to check compression, I show only 85 psi. I checked valve adjustment (after aligning up cam gear to mark on case). to make sure not too tight still right at 85 psi.
I assume I need to pull the head and look at the valves, Any ideas I am missing something? motor does not smoke but is super sluggish.
The specs I find are off the downloaded manual of a 94 but figure should be the same. It states compression standard is 128 and Minimum is 114 and Max is 142
Any other Ideas before I tear it down? Thanks in advance Az
I started this project a while ago.. I have decided to make one thread I can continuously update..
So , here we go. I got this Raptor 80 in really bad condition.. Rear end frozen, Engine toast, tires dry rotted, tons of rust..etc.. They admitted they beat on it very hard.
Since they do not make these with a drive shaft anymore I decided to restore it from top to bottom..
These are photos of when I got it home.
Next up, the tear down..
First, I needed to tear it down and determine if the rear end was still good... As we all know... That is where it would be cost prohibitive to restore if it is trashed..
Got it completely stripped down and I lucked out... The rear Drum brake was caked solid inside with dried mud. That was causing the rear end to lock up. Took off the rear brakes and the rear end spun perfectly smooth.
Once I got it all stripped apart I needed to take the finish off all the parts. I am going to be powder coating the frame and many parts.. Once the finish is off each part it will need to be sandblasted to white metal .. The guy I use for powder coating gives me a hefty discount if I bring the parts to him ready to go.
You could just sand blast, but that would take a long time to get the finish off. First I used Aircraft Paint Remover.. That stuff is pretty toxic Goggles and Resperator are required. That quickly gets you down to the metal... Then you can sand blast to white metal pretty quickly...
I had another thread I had started about a problem with the tear down... It has some great info .... here is the link... It is about removing the frame bushings. ....
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By Gary Ferguson
My old Big Bear nearly left me stranded but I managed to limp back to my garage just before it died. Now No Spark. I’ve changed the obvious, inexpensive and easy parts- spark plug & coil without any luck.
Ive stripped it down and traced all of the related wiring, checking as many connections as I can but no luck again.
Next I pulled the cover and accessed the stator housing to inspect and do some resistance testing to ID a possible short.
Here are my readings:
Source coil- 325 ohms
Pickup coil- 225
Can anyone tell me if these are good numbers, and if good, where to go next?
I assume my next purchase will either be a new stator or CDI, but since neither of these tend to be returnable items I want to be as sure as I can I’m gonna get a resolution to the problem!!
Gary in SC
By Dave Ayoub
Ok i am not quick to jump on a forum and post a question without doing my own part and trying to research and solve the problem myself but I cannot find any definitive information anywhere about my problem. I have a Big Bear 350 that I picked up very cheap which had been sitting in a field for years. I am not new to building wheelers but this one has me beat. After rebuilding top end and replacing the carb it fires right up. The vin has some number worn off from being next to the shifter but from the parts in the clutch i assume it is early since 87 parts seem to be the only ones that match. Thats when the plot thickened.
Reverse works fine but when in the forward gears it would not go past 1st and was hard to get into neutral. ie. a it took a million clicks up to thump into 1 and as many down to find neutral. still never getting past 1st. within minutes i could hear metal screeching and whirling around in the clutch side of the motor. I took the cover off to find that 3 out of the 4 springs on the centrifugal clutch had broken and were shredded. Also the black mechanism that the pawl on shift shaft grabs moves was loose so it wasnt always grab to change the gear on the transmission. I tightened that mech, and replaced the springs assuming it would solve the problem since the gears were not actually changing from the lever and the carrier should obviously not only have 1 spring left.
After putting everything back together it did go into 1st fairly easy but then i again couldnt get it back to N without a million clicks down and couldnt get it to go past 1st. I did one time get it into a higher gear who knows what one but i gained some speed and dropped rpm.
If i jack both the front and the back wheels off the ground and run the motor it becomes much easier to shift and i can get it to run through the gears pretty well. Usually going into N without a huge fight. not perfect but it does hit neutral and roar while spinning the wheels instead of gain rpm and with the power.
I have tried every possible position on the clutch adjustment screw without any noticeable result. I think this could potentially be where my problem lies at this point.
does anyone know if the case is supposed to be threaded? because mine is not. obviously it seems as though it should be since every other bike ive touched has been. i even took the cover off my quadrunner to make sure it wasnt crazy.
when the screw is adjusted and the jam nut tightened the screw will just slide back out since there is no threading in the case. accomplishing nothing.
Does anyone have any insight on any of this? Are my plates stuck, Centrif clutch worn out, case stripped or something else crazy im over looking?
By Wolf Studios
Hi guys so I'm looking for any help or advice with a yamaha big bear 350 1997 (i think) it's fairly dirty and just been say for many years, boss says it's a non runner and I've tried and it will not start, ideally would love to do it up and get it running but have been told the engine has gone, cannot find a new engine anywhere. Anything I should check first before just taking the entire thing apart?
Working on my oldest son's buddy's 2000 Big Bear. He was having some power loss at WOT so i thought it worth while to clean the carb and put at kit in it...or at least clean the OEM jets and use the new orings that come in the kit. It starts and idles like a champ, but dies and wants to backfire with any throttle at all. I assume lean because it will run decent with the choke on. Air screw adjusted fine, nice crisp idle. This one has fuel/air screw, low speed jet, mid jet, and main jet. I was assuming just trash in the low speed circuit so pulled it and cleaned again, still does the same.
Two questions I guess:
1. Does it sound most likely trash in the off idle circuit? This one has a few more passages and jets than I'm used to...and a darn diaphragm.
2. It now really wants to leak at the bowl drain screw. It doesn't seem to tighten enough to completely stop the flow. Seat looks good, screw was dirty but cleaned up fine with a touch of 2000 grit paper. First for me. Any idea here?
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