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Post by florida on Nov 7, 2016 10:49:36 GMT -5
Thx for the advice about head.
I've not got the money for a hoca head.
I bought all Scorpion brand products from a North Carolina EBay sellar. They had nice packaging.
My scooter (GMW) service manual describes replacing the crankshaft as the last thing to fix.
I am certain my scooter has been modified to run well!
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Post by florida on Oct 28, 2016 8:07:27 GMT -5
Where's a good place to buy a crankshaft?
I was thinking about eBay for $45 free s&h
I have a 100ccbbk with all the performance goodies. It does 52mph all day. 62gps top speed downhill.
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Post by florida on Oct 28, 2016 7:44:54 GMT -5
My timing gain fell off.
The crankshaft bearings metal seal is in a few pieces. What do you think would have made the bearings metal seal break into pieces? Was it the chain whipping around?
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Post by florida on Feb 26, 2016 15:19:37 GMT -5
There is the cause of the derailment,,,is that part of the chain tensioner? Or part of the funky anti kick back device that sits up by the cam area? It doesnt have an anti kick back device. |
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Post by florida on Feb 26, 2016 15:14:59 GMT -5
I think it's from the bearing cage on the variator side of the crankshaft. The "rivets" are the only reason I think that. I've never seen a cam stopper/holder in person, although I've seen them before on forums and after searching for "gy6 cam stopper" it doesn't look like those have rivets at all. Do 139qmb engines even have cam stoppers? I can't say I've ever seen one on a 50 (in forums), but who knows things change. I always thought those were only on 125+cc engines. Florida--- was your scooter engine running louder than normal the last week or two before the chain came off? Hmmm, good point, didn't realize it was a 50cc. Unfortunately, now that you've found that piece, it means you need to split the case to dig out anymore debris. I believe it was running a little louder the last time i rode it. |
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Post by florida on Feb 10, 2016 6:54:16 GMT -5
Ok great. thanks a lot
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Post by florida on Feb 7, 2016 0:49:38 GMT -5
I'm going to bring it to the Local retailer of this brand scooter. They are knowledgable and might be able to identify the metal piece.
I'm certain that the broken piece of metal caused the chain to jump off the cam. One link of the chain had been stressed enough that I had to flex it laterally so it would loosen up and become unkinked.
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Post by florida on Feb 6, 2016 20:50:48 GMT -5
I found the cam to have no damage and the chain is whole. The cog down in the engine looks like it has no damage. When I turn the flywheel it turns like normal. I did find this metal piece in the timing chain area. It has 3 tiny rivets. What could this be?   I took out all the motor oil and it came up 200ml short of the 800ml i had put in a few weeks ago. There was alot of oil around the valve cover seal. Also some around the gasket on the cylinder. Im wondering if the oil leak was enough to cause damage in the engine. |
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Post by florida on Feb 5, 2016 19:49:55 GMT -5
urbanmadness I used the .004in/128mm by mistake It calls for the .004mm.
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Post by florida on Feb 3, 2016 11:51:16 GMT -5
Urbanmadness, I read your bikes stats that appears at the bottom of your posts, did you happen to get "upgraded valves" after they were damaged by the piston?
What does the manufacturer say about performance gains?
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Post by florida on Feb 3, 2016 11:44:52 GMT -5
The only problem with all of that is...... Was it running? I think these motors are interference and if they loose valve timing, pistons hit valves and cause all sorts of nice things to happen. I would think about pulling the head and make sure the valves are ok and not bent. OK, piston could hit valves if valves have lost timing. Heres something you may be able to help me with: If you read my entire first post, -My valves were mistakenly adjusted to .128in rather than .004 by me. Both intake and exhaust. If they were adjusted to a bigger clearance than manufacturers recommendation, would the valves be going further "down" than normal, enough to hit the piston and get bent? I'm new to small engines so this is exciting to me. How much room is there in between the top of the piston and the valves? 10cm, 1 inch? Would I have heard any terrible noise coming from my engine with the misadjusted valves? What would it sound like? |
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Post by florida on Feb 3, 2016 11:31:42 GMT -5
IDK yet if the tensioner had failed.
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Post by florida on Feb 2, 2016 13:47:55 GMT -5
OK steve, thank you. Ill get back after I'm done. Is Columbia the capitol of SC? I used to live on Hilton Head in the mid  's. My little sis and I used to walk with my father as he pushed his ducati from our new house and past the main gate of the plantation we lived in. |
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Post by florida on Feb 2, 2016 1:04:58 GMT -5
scooter is a 2011 139qmb longcase Gorilla motorworks 50cc with 8000 miles. Modified to 100cc bbk, a9 cam. orange cdi box, cone filter etc. I did all the work myself and have a tidy workspace so it was rather easy for me.
The other day I mistakenly used the .128mm/.004in. feeler gauge to adjust my valves rather than the .038mm. on both the intake and exhaust.
The result was my bike ran rather badly and at about mile 10 the timing chain came off.
After inspecting the bike and verifying that the timing chain came off I am prepared to fix it.
Can someone familiar with this repair please give me a rundown of what I need to do?
thx, I have all the tools including a beam style torque wrench.
The timing chain tensioner and guides ( the two long black plastic pieces ) were inspected when I installed the bbk 1800 miles ago and they are in good shape. Since the scooter was only driven for 10 miles with the valves misadjusted I don't think that they could have been damaged.
I plan on:
-removing the engine from frame and taking the head and maybe jug off. I would like to inspect whatever the cog is that turns the timing chain and in turn the cam. I want to make sure that the chain didn't damage anything down in the engine. What could have been damaged?
-inspecting the timing chain for wear and damage.
-taking out the timing chain adjuster and inspecting it for wear and indication of malfunction causing the chain to fall off.
-inspecting the chain guides for malfunction and wear.
-Should I space the piston rings again?
-inspecting the cam for damage.
-reinstalling chain and installing the chain adjuster.
Is there anything I missed or something I should address?
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Post by florida on Feb 1, 2016 23:35:39 GMT -5
ebay. $12
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's.