Back at it...philosophydoc rebuild By philosophydoc (Read 10,880 times)

[philosophydoc]

At last, graduation is over (daughter out of college, son almost out of high school), and I can get back to rebuilding my scoot.

Original thread here:http://scooterdoc.proboards.com/index.cgi?board=250cc&action=display&thread=3375

In brief, bike appears to be a 2008 Jonway YY250T-2. I am almost ready to return to tracing some cut electrical wires, but first I have replaced all vacuum lines, fuel lines, installed a new starter motor, and now at doing a cold valve adjustment (CF Moto), because the reason the original owner "abandoned" this bike was a broken rocker arm, which I have replaced but gather a new rocker means the valves must be adjusted.

Bike up on center stand; removed left crankcase cover, removed inspection cap from cylinder, and am trying to rotate drive pulley counterclockwise to get cylinder to TDC. Unfortunately, drive pulley goes about 1/4 turn then practically stops. Am wondering how hard I should push at this point...no index mark is visible through the inspection hole yet. I don't have a 19mm socket, so I am using a crescent to pull, and may not be generating sufficient force, but I sure don't want to slip a breaker bar over the crescent and snap something.

I know to expect resistance when one comes to the compression stroke, but how much is too much? Quite a bit (which is what I am experiencing) or less? How hard should I crank on it? And if I am getting too much resistance, what might be the cause?

I have never had the bike running (bought it two years ago in parts, kept in garage), so I cannot attest to it's being able to run.

Thanks in advance

[shufu]

Try pulling the spark plug out, that should make it a little more easy to turn....

[philosophydoc]

Does this require an 18mm spark plug socket? Neither my 13/16 (too big) nor 5/8 (too small) fit, and I can't find an 18mm one locally. Will 3/4 work?

[cptk]

The 3/4 will work for a 19mm but am not sure on the plug. My plug is an 18mm and I would definately find such a socket to remove. Maybe an 11/16 would work instead of 18mm but I am not for sure. But for sure if you remove the plug it will make it easier to turn over the motor.

[philosophydoc]

Went to Lowe's, picked up a set of metric deep well sockets for $10, and pulled the plug. Turned completely, but a lot of gunk came up out of the cylinder (all liquid...I think). Unfortunately, even after I pulled the top off the cylinder to expose the timing chain and cams, I could detect no "index mark"whatsoever. So I replaced everything and will hope that the valves aren't so far out of whack that it will at least turn over.

I will replace the plug -- it is an NGK DR8EA, and looked a little crusty. I know the spec for a Helix clone is the DPR6EA-9...should I go with my original plug size (which I think was original, as the bike only has 137 miles on it).

[philosophydoc]

As I examine the old plug, and look at what got "burped" out of the spark plug hole when I pulled the plug and rotated the drive shaft, it looks a bit more "crusty" than I like, and hence I am seeking advice on how to flush out the cylinder, short of pulling off the cylinder head.

Here's a shot of the plug, with a few specks of what I found inside:

[

Again, I am not sure anything is amiss save for the gunk that can build up in a cylinder when the engine hasn't been fired in over two years...or is that an unreasonable assumption?

I had though to rotate the piston to TDC and then flushing it with solvent (or gas)? I suppose I could rig up a narrow tube on my Shop Vac and suck out all I can...any other advice? Or should I leave well enough alone...?

[tvnacman]

pull the intake off with the carb, diesel fuel down the intake with a plug in it be sure it is on the intake stroke fill it to the top , let it sit over night . In the morning pull the plug drain it down and crank it , put it all back together with a fresh plug and try to start it .
John

[philosophydoc]

tvnacman, I am a little leery of putting diesel into a gas cylinder...any reason to use diesel rather than plain old gas?

A little internet searching seems to confirm that diesel is fine as a degreaser, so I'll give it a whirl...thanks,

[Cruiser]

If you are leery of diesel, use Sea Foam. Sea Foam is a popular product used to dissolve stale gasoline deposits and carbon in the combustion chamber. Also good as an oil additive.

I have read that diesel fuel is similar to one of the main ingredients in Sea Foam. It probably has the ability to soften carbon over a period of time and that's most likely why tvnacman recommended it.

[tvnacman]

the plug looks like it maybe rusted , it that a water cooled bike ? if so did you use water to fill the cooling system ?

diesel is a great penatrating oil (try it on a rusted or squeekie hing) and it is not flamable !!!
spray it around the outside of your house keep the bugs out .

John

[philosophydoc]

It's sitting in diesel now...

I bought the bike in parts, and never saw it run, so if the old owner allowed water to get into the cylinder, I don't know about it. The bike has sat in my garage for the past 22 months, so I don't know if that had an impact, but the cylinder was never open during that time.

Odometer says bike has 137 miles, and the condition of everything I can see (i.e. rubber parts like belt, hoses, intake manifold, etc.) supports that low mileage. Carb is practically pristine, and the belt (Powerlink 828 x 22.5) is likewise in great shape.

Already bought new plug after pulling old one, and later today I will (following tvnacman's advice), having inserted the plug, opened the intake valve and filled the cylinder with diesel, will pull the plug, hand crank the drive pulley a number of times to purge the diesel, and put it back together.

Doc, I now have everything ready to actually turn the bike over, but I still have six cut wires I need to trace. You've forgotten more about scooter electronics than I'll ever know (!), so should I hook up the battery and start checking those cut wires? If so, what should I check for? Or should I see if it will turn over at all?

Thanks again.

[philosophydoc]

Well, some days you're the dog, and some days you're the hydrant...

After letting the cylinder sit in diesel and then purging it, I went to re-attach the intake manifold. Putting on the second bolt (and having read many posts where errant air leaks have fouled up many a scooter), I decided to give it one more half turn to cinch it up tight...and promptly sheared off the bolt head.

Spent the next two hours (1) running to Sears to buy a screw extractor, (2) breaking off two 5/64 drill bits trying to drill out the shaft of the shorn bolt to insert said extractor, and (3) heading to Home Depot to snag a black oxide bit before finally extracting the bolt. All in a 95 degree garage, with 80% humidity, and a few rather friendly wasps checking my every move.

Boy, I hope this thing is fun to ride.

[Alleyoop]

Damn, when it rains it pours as they say. It is amazing how cheap the bolts are on these things. If you get an america made bolt the damn wrench will break or your hand or arm before the bolt snaps. Don't feel bad many have done it and even to the Valve cover bolts they crank on them and snap them as well.

And YES It will be fun to ride, and I will bet that will be the LAST bolt you break on strip on that puppy.
Alleyoop

[philosophydoc]

Okay, I am reattaching the airbox, and no amount of twisting, turning, cajoling, cussing, etc. seems to be working to get tight connections at the airfilter and the carb. I have loosened the retaining rings on the intake manifold and both ends of the airbox (and I even loosened the bolt attaching the airfilter to the frame) to maximize the amount of "play" I have, but it's as though I can't get the right set of angles to have the airbox fit tightly to both the carb and airfilter.

I can get it tight at the carb, but then this is what it looks like at the airbox/airfilter connection:



I can tighten it up, but there is still a lot of wiggling possible, and I don't know how much is too much. Again, the disadvantage I have in all of this is that I have never seen this bike (or any scoot) all together (I got it in parts), and hence I don't have anything to draw on visually (i.e. "how did it look when you took it apart?"). I'd like to have more of the airbox pushed past the retaining ring (read lots of posts about air leaks, and hence may be overly concerned), but this is the best I can do. Any advice? Does this look normal or not? Should I keep at it, or accept what I have?

[philosophydoc]

Since I have learned a lot on this forum, let me pass along something that may help others one day...

The bolt I sheared off (one of two attaching the intake manifold to the cylinder) was an M 6 x 1.0 x 20 flanged head bolt.

I went to Autozone and bought a box of 3 non-flanged bolts for $2.19...but when I went to install them, it turns out the indentations on the side of the intake manifold are spec'd for a flange head bolt, because the flange head takes an 8mm socket, while the non-flange head bolts I bought take a 10mm socket. In short, there isn't enough clearance to squeeze a 10mm socket around a "standard" (read "non-flange head") M 6 x 1.0 x 20mm bolt, at least when used to attach the intake manifold.

I think the bolt head sheared off because the bolt bottoms out -- it simply can't go any further. This created a second problem -- the non-flanged head bolt (because it is a non-flanged head) has about a 1mm longer threaded shaft than the flanged version, making it impossible for the new bolt to descend deep enough into the hole to get the intake manifold snugged up. Hence I had to hacksaw off about 2 mm of my replacement bolt. And since I couldn't get a 10mm socket (even a thin-walled one) around the new bolt head, (no room around the intake manifold) I could only use this replacement bolt for the top bolt, as I could get an open end wrench around it to tighten it up. Heaven forbid trying to do that on the bottom intake manifold bolt.

MORAL: Flanged or non-flanged heads sometimes make a big difference, even if both are the "same" size bolt.

Lots of info, but it may help someone someday. (My kids say "Ask dad for the time, and you get a history of the clock!")