Exhaust Manifold, on Bintelli Fury 150 ( GY^ Engine )
 

I have a Bintelli fury 150 One stud in the exhaust Manifold is broken off, the other one is stripped out. Can the manifold itself be replaced.

I stripped the stud out of the head on my 150cc scooter. I just ran a 1/4-20 tap into the head and used a bolt to hold in the pipe.

I drilled and taped for a 5/16-18, it is holding for now but I don't know for how long with only one bolt. There is no way of drilling out the other side that has the broken stud, it is hardened.

What I would really like to know, is it possible to purchase just the EXHAUST MANIFOLD.

sure, just type in google "gy6 exhaust manifold" ... scootdawg gets a little back if you buy from Amazon. I guess I'm missing something .. why the need for an exhaust manifold if the problem is a stud broken in the head? Me, I'd probably just get another cylinder, it's not a big deal to change them. Or once you have the old cylinder off you could take it to a machine shop and they will get that broken stud out.

I know I am not familiar with the terms for a scooter but on an auto there is a block that contain the cylinders, connected to the block is the intake and exhaust manifolds, the exhaust pipe is connected to the exhaust manifold.

Are you saying the exhaust pipe is connected directly to the CYLINDER.

Oh, I see the problem ... first I should have said cylinder head. The exhaust flange is welded to the exhaust pipe and yes that bolts using 2 studs that are already in cylinder head. There are long exhaust nuts so you don't have to use a deep socket to tighten and remove them. Look on e-bay and you will see whole exhaust systems, which would be the exhaust pipe from cylinder head to muffler and muffler for less than 100 dollars. Notice the bends and the bracket locations on them. There are also just some individual exhaust pipes for less than 20 dollars. For most chinese scooters the parts are pretty much interchangeable. The whole exhaust system moves with the movement of the engine so no flex joints. The trick seems to be to make sure nothing is under stress when it all bolts up so the flange doesn't break at the weld where it attaches at the cylinder head. There are many youtube videos showing the installation of exhaust pipes and systems on GY6 scooters. Here is just one .. you'll see what they ran into https://www.youtube.com/watch?v=6zfRX7sT4AE . Lots of parts on e-bay and Amazon with photos of the parts, if the part comes from China it takes a while to arrive if you are in the states and get a state side shipper usually less than a week.

Well I do not follow many scooter types anymore, so take this with a grain of salt. I did not know/realize there was a GY7 scooter. So I did a simple cut n paste of your title. What I found is your Bintelli, could be one of the best damned scooter producer web pages, I've run across.
I mean the pdf's are gold!
When compared to the scooter sites I've looked in the last 10 years or so.
http://bintelliscooters.com/150cc-bi...-fury-scooter/
The engine diagrams, and parts diagrams are great IMHO.
http://bintelliscooters.com/wp-conte...17/04/Fury.pdf
All your electrical parts labled, and shown, on ONE page!!

It may not be a full blown service manual, but DAMN, that is one of the nicest sources of information on a scooter type, Bintelli, and then to have piece part bolts sizes and what not, you should be able to keep her in tip top shape man. You are blessed in the scooter world. It's all there!

Thanks Roscoe, now we are getting somewhere. The CYLINDER Head is where The studs (that the flange bolts to) are located. I have no problem with the Muffler,Pipe or flange, there is no stress whatever, it fits up very well. So if my one 5/16-18 bolt does not work I will replace the Cylinder Head. I don't understand why with only 3500 miles this happened. I bought the scooter used and it was like this when I bought it. One stud was missing and the nut from the other side missing. It was making vibration noise and too much exhaust noise.

Thanks Everyone for all the help.
James Hood

cheapeto caught that fact that this is probably not the typical GY6 engine. But from I've read it's pretty much the same. Measure and double check if you order parts. The studs and nuts holding the exhaust pipe to the cylinder head. I'm guessing maybe someone had the exhaust off for what ever reason, I think mine had to come off when I removed the back wheel. Anyway it's just a stud and nut, lots of heat/cool cycles and vibration. It's a rather common problem for these to loosen over time and it's not one of the easier locations to reach when the scooter is setting on it's wheels. Not hard to get to but awkward. Tighten the nut "just right" and you shouldn't have problems. "Just right" tight enough to hold forever but lose enough to not strip the threads or break the stud. Actually you ought to torque it to specs and of course don't use an impact wrench for tightening. For what it's worth on a 50cc scooter I have I made a copper O ring from some soft solid copper wire for an exhaust gasket. The way the pipe was welded to the flange on the after market exhaust happened to make a perfect seat for the O ring. So far it's worked just fine.

Make a habit of checking for snugness at each oil change. You're under there with your ratchet, removing and installing the drain plug.....just take the 10mm socket and extension with you......as Roscoe said, don't go crazy tight....just nicely snug.

Fastening the exhaust to the exhaust stud bolts... yeah.

It is quite possible, when the engine is properly designed, to hold the exhaust flange to the engine with only appropriately torqued down nuts.

"Real" manufacturers, who hire real engineers, specify the material that the cylinder head is made of, specify the stud bolt thread tolerances, and specify the torque values so that the stud bolts are stretched into the plastic deformation point of tensile stress. They also ensure that production lines are set up so that these items are manufactured to their specifications before the product is shipped.

Most of the cheap Chinese crate scooters are not assembled by real vehicle manufacturers, they are assembly houses which have none of the engineering expertise in-house. As a result, bike quality will depend almost exclusively on the oversight of whoever is placing the order. When companies like Kymco and Sym have a scooter built in China, you'd better believe that they send over manufacturing engineers to train staff for as long as it takes for them to do the job correctly. If your scooter happens to be assembled at the same plant where a Taiwanese/Japanese firm has already run the gamut with getting the assembler up to snuff, your odds are substantially improved of having a bike that will last longer than 2,000 miles without needing major repairs.

In any event, at a low quality chinese manufacturer, compromises can be made which otherwise make ANY engine service an exercise in frustration; in many of these cases, you are using the service manual for the engine that was cloned, and that manual has torque values suitable for the design of the original manufacturer, and will just snap or strip out the same threaded part on the Chinese clone.

In any event, Bintelli has a reputation on the scooter forums for being one of the better Chinese scooters (disclaimer: I have never owned a Bintelli scooter, so have no personal advice about it, just hearsay), so it may just be a case of someone going crazy on the muffler flange nuts without knowing (or caring) what the nuts should be torqued to.

So, finally, now to the information that the OP is really looking for.

The good news, if you can call it that, is that the cylinder head is already unusable as is (you won't have an exhaust seal, so you'll be poisoning yourself whenever the engine is running and you aren't moving), so nothing you do to it can screw it up more. You can attempt to extract both the stud bolts and install new ones. For the stripped one, if you have enough unstripped threads adjacent to the cylinder wall, you can put two THIN nuts on, then use a thin wrench on the nut nearest the cylinder to attempt to get the stud out.

For the snapped stud, if there is still some protrusion of the stud above the surface of the cylinder head, I recommend using a Dremel with a cutoff wheel to cut a slot through the center of a bolt, which should allow you to use a flat bladed screwdriver to extract the bolt. Otherwise, you would need to drill out into the center of the bolt and use an easy-out, however that is a difficult operation for a typical mechanical novice to perform.

Finally, if you do succeed in replacing the stud bolts, MAKE SURE you replace the gasket.