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Post by onewheeldrive on Mar 16, 2015 1:27:32 GMT -5
A couple things here. You are shooting for .003in for the valve gaps (not .03in). But yeah, there are some great tutorials out there.
I thought you ordered the 83cc (aka 100cc) kit, that comes with the proper cylinder for the 50mm piston and rings, gaskets? Where did the 44mm piston come from that you said you cannot use? I'm a bit confused, sorry.
When you get that new carb it'll probably have a different jet anyway.
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Post by onewheeldrive on Mar 15, 2015 21:47:44 GMT -5
Hmmm, I actually thought most stock carbs were jetted in the mid 70's-- 74-76 range. Clearly that's another reason people should check the size, who knows what they throw in there.
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Post by onewheeldrive on Mar 15, 2015 16:45:44 GMT -5
///////
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Post by onewheeldrive on Mar 12, 2015 5:19:53 GMT -5
Not to beat a dead horse, but it's more of a push/pull motion with the crank rod---- that's how I should have described it when checking for play. I'm not sure I saw that in the video after re-watching it--it's dark down in the case at times. Push/pull, with a bit of force for extra measure, should do the trick.
For the CVT, unless you can get the variator/clutch off, just check the belt and/or for oil leaks---they usually pool at the bottom of the case over time. The belt is probably fine and they usually are until they wear down to around 15mm or so for the width, but note the brand of belt--- usually the stock belts are rather generic and don't have the greatest reputation. Gates Powerlink seems to be the most popular good quality brand around the scoot forums. Bando gets mentioned a lot, too. I'd also note the size marked on the belt, it's most likely 669-18-30.
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Post by onewheeldrive on Mar 11, 2015 13:29:10 GMT -5
It's definitely not normal for top ends (or cranks) to fail at those miles.
The good thing is, your rod bearing looked fine from the video. Definitely wouldn't want to put a new top on there with a bad one.
Did you pull the trigger on the 83cc?
Also, the pic of the head you took that shows the exhaust port, appears to be missing the gasket-- the little ring that fits into the opening. It may have fallen out when taking the exhaust off?
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Post by onewheeldrive on Mar 10, 2015 21:33:14 GMT -5
Nothing is jumping out at me yet. Are there any deep scratches or anything like that in the cylinder? It looked like there was some scoring on the side of the piston. I'm on my phone, maybe the pics will be bigger on my laptop.
Have you looked in the transmission area (cvt) where the belt, clutch, and variator are?
It's a bit challenging here because A) we don't know what the symptoms were beforehand B)The mechanic thinks the engine is bad (still in the back of my head-- not convinced either way) C) The top end is off, so were kind of working backwards a bit
Usually its check the fuel/carb, air, spark and stuff like the valves/compression.... first.
The crank also has two other bearings that can fail-- and can be checked if you take the variator off for one side, and the flywheel off on the other, both by wiggling the shaft on each side checking for play.
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Post by onewheeldrive on Mar 10, 2015 15:13:53 GMT -5
Note how he holds the rod-- the end opposite of the piston location should not be moving in that manner. His rod bearing is toast. EDIT: it's worth checking, even at those miles, since the only way to check for rod bearing play is with everything off.
It's also worth noting that you should be able to start the scoot with the old cylinder, piston/rings, assuming that's not the problem. It may be worth troubleshooting it that way before throwing new parts on it. It MAY.
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Post by onewheeldrive on Mar 9, 2015 22:53:42 GMT -5
They have 63cc top ends for sale, too, with the 44mm piston.
EDIT: NEVERMIND, lol
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Post by onewheeldrive on Mar 9, 2015 19:16:01 GMT -5
If you haven't, you'll need a set of feeler gauges to set the valve clearance(s). A set with .002-.004in at least ( or .05-.1mm).
Also an impact wrench is excellent for removing both nuts on the pulleys in the transmission. Also for the flywheel behind the fan. I use it to remove my rear tire.
A torque wrench is a must, IMO, for torquing down the head bolts.
Really don't need any other special tools for working on these scoots, other than a flywheel puller if you ever need to remove the flywheel.
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Post by onewheeldrive on Mar 8, 2015 20:29:45 GMT -5
Hmmm. Well, it looks to be running rich, to say the least. I wonder what the main jet in the carb is? How many miles on the engine?
Since you have the piston off the rod, I'd check for play in it--- a bit (1 or so mm) of left/right sideplay is ok and pretty normal, but up/down play where the rod bearing is (you cant see it) is not good. I'd at least rule that out before putting back together.
Did the people you bought it off of mention any symptoms at all, other than it just "not running right"?
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Post by onewheeldrive on Mar 5, 2015 21:11:35 GMT -5
I'd ask him what exactly he did to determine that the engine was "bad". It'd be nice if they were a little more specific. Someone saying the engine is bad without telling me what exactly is bad with it, doesn't cut it with me.
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Post by onewheeldrive on Mar 3, 2015 22:26:51 GMT -5
I had a rear Kenda, not sure what model though for my 50(72). I don't have anything bad to say about it. Actually never had any issues with the stock Cheng Shin's that came with my scoot, or any scooter tires for that matter--yet. I'm using Michelin S1's right now.
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Post by onewheeldrive on Mar 3, 2015 1:23:09 GMT -5
I really don't mind changing the rollers and belt, since it always runs a bit different and makes the ride fresh again. Oil change is somewhat obsessive due to past crank failures. I'll wipe it down and make it look sexy a few times a year.
Now, if a few things break or fail within a short period of time, it can get frustrating. "Really? AGAIN?!?" Sometimes I don't even want to touch this scoot. I mean I've had this scoot for almost 7 years, so the only thing that ever gets under my skin is major crank failure--- which is either $320 for a new engine (after shipping) or about $150 for a rebuild. So I'll keep obsessing about oil changes for now. I shoot for about every 500 miles.
EDIT: Although we can minimize some of the frustration by having a spares around: bulbs, belt, throttle cable, the "v" guides in the variator, ignition coil, and maybe even a cdi. Anything that can keep you off the road for a few days waiting on parts, if you have to.
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Post by onewheeldrive on Feb 17, 2015 22:58:27 GMT -5
Where the hole is , the crank would be in the way for any type of bolt to cross the engine case. Yep it would be in the way for sure. |
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Post by onewheeldrive on Feb 17, 2015 4:54:47 GMT -5
Makes me wonder if that is aligned with one of the bolts that actually goes in the engine--- from the other side. It's hard to visuallize without looking at an engine. I wonder if you can see anthing if you look in that hole. Maybe they put a longer bolt in there than what they should have? I know some of the case bolts are of different lengths. Not sure if that would bust through.
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