Certified Clinician
Currently Offline
Posts: 94
Likes: 0
Joined: Nov 30, 2011 16:08:39 GMT -6
|
Post by imnts2 on Feb 3, 2012 17:22:15 GMT -6
As always, I listen carefully to sprocket. I agree weights only change when you get the power.
I think that CVT/Clutch changes are more useful primarily to improve:
1. Durability. long range wear and tear. probably urgently so if you go from 9 Hp nearer 15 or more.
2. gearing improvement when you get your 150 delivering more power than your stock gearing will handle you nay be able to use another gear.. Getting the belt running a 4.5 " primary pulley instead of a 4" is about a 25% increase in the RPM of the rear wheel as the some engine RPM. about a 13% lower (higher speed)gear ratio on the front accompanied with about the same on the rear)
So if you have the power to do it, OK. But if you engine is stock you may not even have enough power to pull higher ratio at the same road speed ( speed on the block don't count)
|
|
Certified Clinician
Currently Offline
Posts: 94
Likes: 0
Joined: Nov 30, 2011 16:08:39 GMT -6
|
Post by imnts2 on Feb 3, 2012 16:31:20 GMT -6
There are 2 very different timing needs in a 4t engine.
Ignition timeing which is typically aseveral digrees befor TOC ( top dead center) on the compression stoke. A GY6 engine typically has marks on the flywheel and the crankase indicating Ignition timing position That is not TDC but several degrees before TDC.
Valve timing is totally different. Each valve ( intake and exhaust) is designed to be opened and closed at 4 different and specifiy points during the 4 stroke cycle. I is controlled by the shape of the camshaft and the linking of the the camshaft sproket to the crankshaft by the timing chain An a GY6 there are marks on the cameshaft sproket that must be liked up with the surface of the valve cover to head joint WHEN THE CRANKSAFT IS AT TDC. There are no factory markes to idicate TDC.
Thats the rub. Using the ignition timing marks to time the camshaft sprocket will screw you up. YOu need to find TDC.
NOt that is not as tough as it sounds. Partly because the cam and sprocket teeth are farely course so are either OK or a long way off. Rmember the Ignition timing is several degrees befor TDC. So set the crankshaft a bout 1/2" after the Ign timing mark and then try to align the camshaft timing mark as you put the chain on. At least that is how I have done it a few times.
|
|
Certified Clinician
Currently Offline
Posts: 94
Likes: 0
Joined: Nov 30, 2011 16:08:39 GMT -6
|
Post by imnts2 on Feb 3, 2012 15:57:50 GMT -6
Sprocket is right. It helps me to think of Volts as pressure and Amps as gallons/flow and ohms as how much resistance you have to flow in a bulb or motor etc. Volts times amps equals watts - how much power is used or generated.
|
|
Certified Clinician
Currently Offline
Posts: 94
Likes: 0
Joined: Nov 30, 2011 16:08:39 GMT -6
|
Post by imnts2 on Feb 3, 2012 15:50:02 GMT -6
::I was wrong! All my theory was just that - theory. Neither the intake or exhaust valves have any discernible leakage. I blocked the head upside down , level, covered both valve heads with lacquer thinner and not a drop leaked. So it is not blowing back into the intake. carefully miked the piston and the cylinder and do not find anything wrong. And no signs of piston scuffing of the cylinder wall or the piston itself. In fact it is so well polished it might even be glazed. and I cannot get any slack movement out of either the upper or lower rod bearings or the crank bearings. So I will run the hone thought the cylinder, slip a new set of rings in and reassemble and break in quickly. The next step after reassemble will be to get a tach on it so we can tell RPMs more accurately than my ears although. I am guessing the clutch engages about 3000 and she runns to about 5 Grand on the highway and about 8 on the stand. Lets find out. Any favorites for a reasonably priced accurate tach? Cheers lefty2  |
|
Certified Clinician
Currently Offline
Posts: 94
Likes: 0
Joined: Nov 30, 2011 16:08:39 GMT -6
|
Post by imnts2 on Feb 2, 2012 18:58:18 GMT -6
Great.
|
|
Certified Clinician
Currently Offline
Posts: 94
Likes: 0
Joined: Nov 30, 2011 16:08:39 GMT -6
|
Post by imnts2 on Feb 2, 2012 9:30:35 GMT -6
The reference to Nash was the old overhead valve Ambassador 6.
Agian thanks to everyone.
I have decided to open today. Pull the head, turn it so I can pour a little lacquer thinner in it and see how bad each valve leaks. I am pretty sure I have a valve leaking and it only takes a little intake valve leaking to lean out hard throttle mixture and cause preignition.. I'll let you know.
While it is open see if I can find any play in either end of the rod. Measure the piston and bore and look for signs of slap. Oil stays very clean
Then make a decisiion. I will keep you informed.
Rich If I lap you will get some good digital pics.
Been fun.
lefty2
|
|
Certified Clinician
Currently Offline
Posts: 94
Likes: 0
Joined: Nov 30, 2011 16:08:39 GMT -6
|
Post by imnts2 on Feb 1, 2012 8:24:19 GMT -6
And please:
1. check the battery connections. Loosen them. wire brush clean and reinstall.
2. get a 2 amp charger/maintainer for the battery. YOu scoot wil start getting emotional over you!!!
You are doing great. Have fun. Learn to cuss like a pro!!
Cheers
lefty2
|
|
Certified Clinician
Currently Offline
Posts: 94
Likes: 0
Joined: Nov 30, 2011 16:08:39 GMT -6
|
Post by imnts2 on Feb 1, 2012 8:18:31 GMT -6
I would feel better if you used one of our venders here or on scoot dawg forum. They really are worth the few extra bucks. Particularly whenever you are not 100% sure.
Cheers
lefty2
|
|
Certified Clinician
Currently Offline
Posts: 94
Likes: 0
Joined: Nov 30, 2011 16:08:39 GMT -6
|
Post by imnts2 on Feb 1, 2012 8:13:22 GMT -6
Hi Alleyopp. I am an old mechanic. (81) So I really meant "valve job". I hope to get by with just lapping the intake. Yes, I thnk if I really needed a valve job replacing the head is the best answer. While at it cylinder and piston. Frankly, I an planning to sell it. I have replaced it with a Majesty to keep the 4 wheelers from killing me.
Thanks to allyoop, shalom, sprocket and tvnacman. I have bumped into all of you before and have learned to respect your knowledge and information. Got almost everyone I wanted to hear from. I will bend your ears a little hoping to gather some more wisdom.
First my reason for tackling the valves. The scoot was shipped without cooling shrouds (I think) It had about 600 short trip miles when I got it and I put another 100 before I figured out it needed and got them on. Now have about 1500.
I did a compression check (harbor freight gauges) Only about 110-100 psi (of course that could be the valve on the gauge not shutting as quickly as is needed for on a small cylinder) I also have a "harsh" almost piston slap noise on near full to full throttle and a top of about 48 GPS level/no wind and having wife follow me with a speedo I have calibrated a several different times/places on the interstate (10 mile markers with a good stop watch) I have it holdiing valve adjustment good and starting promptly, hot, cold(about freezing). It also is a real lazy dog on acceration.
I have slipped a 114 main jet in and she runs just a little rich. Seems to like the 110 stock a little better. Does seem to need the idle out 4 turns to idle decent (Maybe a little leakage on Intake? (I have done a propane test for manifold leak)
So part of the reason is to learn what I learn. Gotta know you know.
1. I will find out it the valves are not seating or if the piston is slapping. If I have better compression pressures when assembled etc. Maybe I will get rid of the noise (course she is naked so you hear everything.)
2. I will feel better being able to represent it more accurately when I sell it.
3. It would be nice to get a chance to ride it when it runs right.
I have opened the CVT and made sure it is clean and run in on the center stand and it seems nice and smooth.
Question to shalom. I uses to have a C type comprssor I used to do chevy/GMC/Nash 6's and Jauguar heads. Work or to bulky? Hock shop is a good idea.
Again thanks. really appreciate the expertise. Glad I found where you are all hanging out. Owe you a cool one.
lefty2
|
|
Certified Clinician
Currently Offline
Posts: 94
Likes: 0
Joined: Nov 30, 2011 16:08:39 GMT -6
|
Post by imnts2 on Jan 31, 2012 17:59:02 GMT -6
I have decided to try doing a valve job on my 150CC GY6. Any tips from anyone. I have had the head off before so that is not a concern. I don't have a valve spring compressor. Do I need one or is there a way to do it with out? I thin the rest is pretty straight forward. Thanks of any input. lefty2  |
|
Certified Clinician
Currently Offline
Posts: 94
Likes: 0
Joined: Nov 30, 2011 16:08:39 GMT -6
|
Post by imnts2 on Jan 30, 2012 17:55:35 GMT -6
Surly someone has taken then scoot to a friendly muffler shop and asked about building a custom exhaust to fit their GY6 150cc. With a replacement muffler nearing 150 with little to speak for it except some manufacturers calling it a "performance" muffler there really is a nice bit of work on a slow day. Anyone?
|
|
Certified Clinician
Currently Offline
Posts: 94
Likes: 0
Joined: Nov 30, 2011 16:08:39 GMT -6
|
Post by imnts2 on Jan 28, 2012 13:31:18 GMT -6
Welcome, good start. It would not hurt to have a spare spark plug and try it. You sort of need one anyway.
But I really what to hear what some of the more experienced folks sauy
Cheers
lefty2
|
|
Certified Clinician
Currently Offline
Posts: 94
Likes: 0
Joined: Nov 30, 2011 16:08:39 GMT -6
|
Post by imnts2 on Jan 26, 2012 7:25:32 GMT -6
John.
Glad to see it progressing.
I wonder if your primary focus's are:
mods and upgrades or repairs?
Gy6 150 and or 50?
Seems you know electrical. That is a hole you might consider specializing on for awhile.
First, try to minimize solving individual peoples problems.(of course don't be to apparent with that) Instead find or build a good book or cd or DVD to teach electrics and electrical trouble shooting. Of find someone to do it with a little help from you. Get Sprocket to help. Teach people to use a VOM.
Stock and sell the book/or whatever.
Stock and sell the VOM (your brand) (get harbor freight to supply you)
Make up an upgrade kit with instructions using your lable). How to convert to 11pole. Make up a kit and sell it Include what is needed to provide spark. Again , perhaps a joint venture with Sprocket.
Push your suppliers to guarantee. Charge a little more and guarantee. (See what happened to Hyundai. From junk to setting and industry standard with nothing more than 100,000 guarantee and a little price increase.
Enough of my secrets
Do what you do best. Take charge and manage and supervise.
Good luck
cheers
Welcome to business.
lefty2
|
|
Certified Clinician
Currently Offline
Posts: 94
Likes: 0
Joined: Nov 30, 2011 16:08:39 GMT -6
|
Post by imnts2 on Jan 25, 2012 15:52:43 GMT -6
Good point sprocket.
|
|
Certified Clinician
Currently Offline
Posts: 94
Likes: 0
Joined: Nov 30, 2011 16:08:39 GMT -6
|
Post by imnts2 on Jan 25, 2012 15:50:29 GMT -6
I stumbled on a 4 valve psistons on ebay. I'm certain they were BB for gy6 125/150. Did not take note of vender.
finally
cheers
lefty2
|
|
