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Post by pistonguy on Mar 25, 2016 10:05:18 GMT -5
Here are some tasty nice valves One Steel that rest TI Some Honda and Yamaha, See any lapping here? A couple of these I had made for HRC of Europe. yup Honda Racing Europe , and they Don't Lapp valves.  |
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Post by pistonguy on Mar 25, 2016 9:50:38 GMT -5
Ok respected OE. How bout factory HD? This is The Cylinder head Guru for Factory HD flat track Go to Any Grand National Flat/Dirt track and look at the Factory HD head's they all have DRS etched in the side. And None are lapped.  Hers is a Honda CRF250R head with Amco-45 alloy seats, No lapping there.  |
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Post by pistonguy on Mar 25, 2016 9:42:47 GMT -5
Per the 2009-2013 Piaggio Scooter Factory Service Station Manual published and distributed by Piaggio - after covering how to check if valves and heads are suitable for reuse they instruct: "If no anomalies are found during the above checks, the same valves can be reused. For better sealing results, it is advisable to grind the valve seats. Grind the valves gently with fine-grained lapping compound. Upon grinding, keep the cylinder head in horizontal position. This will prevent the lapping compound residues from penetrating between the valve stem and the guide (see figure). CAUTION TO AVOID SCORING THE FAYING SURFACE, DO NOT ROTATE THE VALVE WHEN NO LAPPING COMPOUND IS LEFT. CAREFULLY WASH THE CYLINDER HEAD AND THE VALVES WITH A SUITABLE PRODUCT FOR THE TYPE OF LAPPING COMPOUND BEING USED." For checking how the valves are seating: "Inspecting the valve sealings - Fit the valves into the cylinder head. - Alternatively test the intake and outlet valves. - This test should be carried out by filling the manifold with petrol and checking that the head does not excessively ooze through the valves." Bottom line per one of the most highly respected makers of motorcycle, scooter and air craft engines and not by my personal opinion you lap the valves on a scooter if you go by the book. YA I knew someone would come up with a Chinese manual that say to lapp even tho the same OE Does Not at the Factory. Pure Bunk. the "Book" is simply passing down misinformation of Old school thought. Currently the Big Five makers Do not advocate Lapping, were dealing with Allot of TI in Offroad and want to ruin a TI Valve fast lapp it. Why would someone think there perfecting fine machined surfaces with Lapping compound. Unreal and have No Clue what There Doing. I have work with every Factory MC Pro Show and None Ruin a Valve Job with Lapping compound. Yup, I'm one of those who gets Paid to be at races every weekend. You are pointing out that you simply have never done a proper valve job and don't know how or know what you are looking at. Piston guy didn't move from TX to NC for the BBQ. I have been involved with one of the Nations Highest End manufactures of Valves, Valve Seats, Valve Guides and retainers. Turn the TV on this weekend and you can watch a few thousand of that Valve Train Not Lapped. |
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Post by pistonguy on Mar 25, 2016 7:56:41 GMT -5
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Post by pistonguy on Mar 25, 2016 7:47:04 GMT -5
That engine died not long (maybe a week) after posting this thread.... LOL Just lost all compression and would not start. Thought I had burned a hole in the piston or rings had become digested. Finally got the time to tear it down... talk about procrastination.  That not lapping the valves is most likely the issue. Don't know yet but will install to a ready-for engine chassis tomorrow and find out. Exhaust valve was not seating, toasted and a divot had burned (whatever) its way into one portion of the seat ( lots of leakage coming from intake and exhaust. Tried lapping but still had the tinniest bit of light shining through the burned spot and the excessive hiss on compression stroke got on my nerves. Prolly would have run fine but OCD kicked in. Pulled a valve from an older head and lapped it: Takes some quite a bit of effort to turn the crank now and hiss is almost non-existent.  Lapped both intake and exhaust, BTW. Moral of the story? Lap those valves, Ladies and Gents. Don't get too hasty to get that ride on the road. "A stitch in time saves nine"? As always: Any and all input on this is/was greatly appreciated. Sorry I am slow to post and help out here: Lot going on and it ain't all good. Long as it ain't all bad; we good. NO!. Machine those Valves and Valve Seats Properly, 1/2 Degree Difference on the Valve Angle with NO Lapp and she will Hammer Home upon start up to a Near Perfect Vacuum. Pulling a Valve out of another head and Not Machining Either Surface is Butchery, Not to be Teaching others that this is Proper Practice. That Lapping is Not a way to Correct Valve Seats and Valve Face that need to be Machined. You do NOT make it Better when you do after a proper machined valve job. Lapping? this practice needs to be Stopped from being taught. Old timers passing this down for a hundred years. Ever see Any OE in the World lapp Valves? Auto, Cycle, Marine, Diesel, anything with Valves? No Pro racing or Aftermarket Hot Rod heads are lapped. Peeps just don't understand what there doing to the two surface when ya Goop a Glob of Abrasive Paste in between. Lets say my Valve Seat are on the Valve face is .030", All My Spring Pressure is on the contact area and Equally Important that Contact area when Seated is How the Valve Dissipates its Heat. Now take a Glob of crap and Lapp like Heck, You have Now Made the Valve Face Seat area Concave. So Its Only Sealing on the Very Top and Bottom of that .030" Seat Area and NONE in the Middle. Now it Cant Dissipate Heat properly and will Not Seat as well.  |
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Post by pistonguy on Mar 25, 2016 7:14:28 GMT -5
The fact it doesn't smoke right away, and the smoke disappears so quickly often indicates condensation being burned off, possibly from inside the exhaust. It takes a couple of seconds for the heat to start burning it off. Together with the amount of rust on your exhaust, I'm betting on this being the issue. If the smoke starts right away, it's usually oil burning in the cylinder, often meaning valves need to be lapped or rings/jug issues. However, it still could be an oil issue, since it takes a couple of seconds to get the oil pumping up to the head, but the fact it goes away makes me think condensation. If you are experiencing a lack of power, I would recommend a leakdown test on the head and cylinder. If my Valve Face to Valve Seat is Not Sealing correctly how would this cause my scoot to draw some Oil and Smoke? Were is the Oil coming from? Now, with Clapped out Valve Guides and Excessive Valve Stem to Valve Guide clearance Will Suck Oil. |
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Post by pistonguy on Mar 24, 2016 17:17:30 GMT -5
Got the stroker fitted and ncy cylinder kit on only needed one gasket not sure why, i had to use a spacer on my 150 so yo achieved zero deck with what thickness gasket? with no gasket how much was the piston coming out of the hole? |
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Post by pistonguy on Mar 14, 2016 15:40:46 GMT -5
I have a 2013 TaoTao ATM-A 150 EVO. about 3 weeks back I was riding on an expressway and noticed that even at maintained throttle, the scooter would bog down a bit. I stopped at a wal-mart for some things I needed. I came out and the scooter wouldn't start. After getting it back home and doing a whole lot of checking it was determined I had a bad stator. Fortunately. the person I bought it from left a new stator with some other parts. After replacing the stator and getting spark back I fire up the scooter. Everything seemed find so I put it all back together. Now when I drive it and it warms up it bogs down seriously. From about anything higher than 70 kmph it would really bog down. The person I bought the scooter from had also thrown in another scooter that I have been using for parts. I thought maybe a carb problem so I took the carb off the parts scooter and put it on the running one. Still bogs down. It only bogs down after it's warmed up. But I have noticed it seems less responsive than before I changed the stator. So my question is can anyone direct me where to look at fixing this problem? Check the Famous Valve Lash. With milage it closes up. Once close to closed at Temp. valve train expands with the high rpm heat and slightly Hangs Open One or Both Valves. Cools down to ambient temp and starts back up and then repeat. Adjust your valves if you have Not. |
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Post by pistonguy on Mar 3, 2016 19:33:43 GMT -5
If it happens after it warms up, check th valve lash, probably too tight.  She get Hotter at Throttle, Components Expand With Heat, Valve Lash Closes up and Slightly Hangs Open the Exhaust Valve. Then She dies. cools down some then she starts back up, then repeat. Adjust Valve Lash (clearance). Take your time and Triple Check you did his correctly on the Compression Stroke. |
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Post by pistonguy on Mar 3, 2016 15:57:47 GMT -5
Easiest to just put a fuel filter on the end of the vent tube, and zip tie it high on the frame. Ive enjoyed this method for sometime. screw all that jackin around mounting a catch can |
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Post by pistonguy on Mar 3, 2016 7:51:25 GMT -5
I believe that's simply a vent tube. BTW..if your ever going to become a dealer you'll have to memorize these two sayings: 1. "They all do that" 2. "They come that way from the factory". 3. "Its the Nature of the Beast" 4. "It is what it is" |
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Post by pistonguy on Feb 12, 2016 16:48:20 GMT -5
Sweet  I didn't know you could buy a burger in Colleyville for under a couple hundred buck's. Il stop by and check them out the next time I'm back in me DF Dub. |
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Post by pistonguy on Feb 10, 2016 20:54:54 GMT -5
One slightly used Ring fancy Yellow. 101 total diamonds have paperwork, last appraised at $27,000, make you a buddy deal. Includes the Finger it came off of. She gunna love you long time with this rock. NOT!    |
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Post by pistonguy on Feb 8, 2016 21:49:00 GMT -5
By city ordinance all gas here has ethanol, I don't like it but its not practical to have to refuel outside the city. The new chinese carb worked great but started leaking after a few weeks, it had a metal tipped float needle, and I think a brass seat. Couldn't get this one to ever seal properly again once it started leaking. I need to open up the mikuni and see what it has. Both the new chinese and the new Mikuni leaked out the drain tube I'm pretty sure it was from fuel going out the overflow tube in the bowl, and the problem wasn't the drain screw. I wonder if those metal tipped float valves are more sensitive to debris. The original carb that came on the scoot never worked right but also never leaked a drop and it had either viton or rubberized float valve (not metal.) City Ordnance? Gotta love being force fed power robbing, fuel gobbling, engine eating, filth. My Ordnance say I can't make whiskey, ya right |
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Post by pistonguy on Feb 8, 2016 8:50:12 GMT -5
Does the Needle have a Viton tip? or Rubberized?
Got two power equipment buds here doing 300-400 new carbs sales a year and 600-800 carb kits.
ETHANOL is great for the repair and replacement business. write your check
Its a Corrosive. had to Flush my Alky motors with Gas after each race, would Destroy a Walbro in less than a week.
This Filth does Not mix well with Gas and separates, if your supplier has not been filled up mixing the full most likely Much more than 10% EA. more like 35%, Then some chase there tales trying to get a carb, jetted and scoot running correctly. same will happen in you gas can at home.
My scoot, CBR and all power equipment is ETHANOL Free. and these problems Don't Exist
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