Where do I find the right jug for my engine?

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#1
Hey everyone,

Where can I find a jug that is properly ported for the GT-5 engine's 38mm stroke vs the usual 40mm stroke on every other jug I get? Is it all just luck?
 


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#3
CR Machine has them.
Is there one that doesn't cost a fortune? I know he's good at what he does but $100 for a chrome plated cylinder is a bit much. I wrecked my car recently so I'm trying to get the engine to run so I can at least get to school and back without walking for 3 hours each way.
 

junglepig

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#6
Is there one that doesn't cost a fortune? I know he's good at what he does but $100 for a chrome plated cylinder is a bit much. I wrecked my car recently so I'm trying to get the engine to run so I can at least get to school and back without walking for 3 hours each way.
It should run fine on an eBay jug if that's all you need.
 

junglepig

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#8

junglepig

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#13
https://bicyclemotorworks.com/product/professionally-ported-cylinder-piston/
It's $100.
I'm thinking you're going to have to work with number/thickness of base gaskets.
You've got the long rod and type B piston, right?
Sorry for replying to myself, but, in reference to the $100 ported cylinder for the GT5, they say the following:
You also get a bunch of other goodies with this package. 5 extra head and base gaskets in total allow you to set your port timing how you prefer. It also allows you to run any type of head – from stock to our BMW 6.0cc high comp head.
I really think all the jugs come from the same casting pattern. Fred and others port/machine them some, but the basic dimensions are all the same.
I'm a newbie and do not know this for a fact. In any case, from the quote above, it sounds like setting up the port timing for our engines typically involves some inspection and testing and adjusting the height of the jug. And if you get someone to do custom machining for you, it's gonna cost $.
Again, I'm speculating, but the cheapest way out is probably a cheap jug + a handful of base and head gaskets + glass + sandpaper.
Or spend $100 for a new Fleabay kit and use the new engine.

Please, someone jump in and correct me if I'm off base. I may eventually have the same question/issue as Hell On Wheels.
 
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#14
I have same, with ZAE80, but i have not replaced the jug ever.
I had to replace the cylinder because my first engine had a solid head/cylinder which had no squish gap but had a ledge resembling a small squish band but it just caused it to ping ever so slightly around the cylinder and eventually caused it to fuse to the cylinder (partially my fault for cooling the poorly finned jug because the cylinder would expand and lose compression) once I went from running 8:1 oil to 25:1 oil while still pushing out a fair amount of power. It eventually overheated again then the wrist pin bearing gave out and sent bearing material through the transfers leading to it's death.
 
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#15
Sorry for replying to myself, but, in reference to the $100 ported cylinder for the GT5, they say the following:


I really think all the jugs come from the same casting pattern. Fred and others port/machine them some, but the basic dimensions are all the same.
I'm a newbie and do not know this for a fact. In any case, from the quote above, it sounds like setting up the port timing for our engines typically involves some inspection and testing and adjusting the height of the jug. And if you get someone to do custom machining for you, it's gonna cost $.
Again, I'm speculating, but the cheapest way out is probably a cheap jug + a handful of base and head gaskets + glass + sandpaper.
Or spend $100 for a new Fleabay kit and use the new engine.

Please, someone jump in and correct me if I'm off base. I may eventually have the same question/issue as Hell On Wheels.
I know the GT-5 super engine by CR machine is a 38mm stroke to which he Mills the head down. Don't know if those were originally 40mm heads he added material to the bottom of or he just moved the crank down or raised the deck of the crank case. I would not mind spending more money on a jug if I had the money but tommorow I need to bid on a car I can use to repair my own car with.
 

junglepig

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#16
I know the GT-5 super engine by CR machine is a 38mm stroke to which he Mills the head down. Don't know if those were originally 40mm heads he added material to the bottom of or he just moved the crank down or raised the deck of the crank case. I would not mind spending more money on a jug if I had the money but tommorow I need to bid on a car I can use to repair my own car with.
I get it. If you end up with $100 to spend, I'd just get a new kit off ebay from California for $98 shipped, use the new motor, and keep or sell all the kit parts you don't need.
Honestly I'm surprised that your motor won't even run with the stock jugs sold on eBay. You had a reed setup before. With the new jug and head you have are you just going with piston intake? Or did you try to install the reed again?
 
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#17
I get it. If you end up with $100 to spend, I'd just get a new kit off ebay from California for $98 shipped, use the new motor, and keep or sell all the kit parts you don't need.
Honestly I'm surprised that your motor won't even run with the stock jugs sold on eBay. You had a reed setup before. With the new jug and head you have are you just going with piston intake? Or did you try to install the reed again?
I'll end up blowing it up again. Vibrations at 7k+ rpms was living hell on the carburetor and the engine and myself as the rider. I bought my new bottom end from Fred about a month ago because I know I was going for a screamer simply due to the top speeds I need to not get run over but also the gearing in the back to climb the steep hills around me. But now I don't have the cash or time to spare to get a cylinder from him. I tried my old crank on a 40mm stroke jug and it wouldn't even idle. I just got glimpses of a start up before it died from more bearing material hidden in the case I didn't see while cleaning it out. Just my luck. It was a CDHpower Reed block.

I'm going back to my old setup. Reed block onto cylinder with windowed piston. I prefer the Reed setup simply due to it's ability to give me better top end.
 

junglepig

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#18
I'll end up blowing it up again. Vibrations at 7k+ rpms was living hell on the carburetor and the engine and myself as the rider. I bought my new bottom end from Fred about a month ago because I know I was going for a screamer simply due to the top speeds I need to not get run over but also the gearing in the back to climb the steep hills around me. But now I don't have the cash or time to spare to get a cylinder from him. I tried my old crank on a 40mm stroke jug and it wouldn't even idle. I just got glimpses of a start up before it died from more bearing material hidden in the case I didn't see while cleaning it out. Just my luck. It was a CDHpower Reed block.

I'm going back to my old setup. Reed block onto cylinder with windowed piston. I prefer the Reed setup simply due to it's ability to give me better top end.
Good luck!
 

Tyler6357

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#19
You should just get a stock cylinder and port it yourself if you don't want to spend the money. Usually, you can never be sure it is ported right unless you do it yourself anyhow. A mill makes it perfect but you don't need it to be perfect, just use a dremel tool
 
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#20
You should just get a stock cylinder and port it yourself if you don't want to spend the money. Usually, you can never be sure it is ported right unless you do it yourself anyhow. A mill makes it perfect but you don't need it to be perfect, just use a dremel tool
I don't need a perfectly ported cylinder. I just need something that isn't designed for the 40mm stroke vs the 38mm stroke because then I need to stack gaskets and sand off about 3 mm off the top of the cylinder which isn't ideal because one side may sand a bit too much and cause the piston to hit the head. Raising the head only kills the squish band in the process.
 

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