StripeySnake
New Member
Hi everyone,
I recently disassembled the engine from my 2006 NE5, and I found vertical grooving in the cylinder wall, as well as a lot of carbon buildup. I am unfortunately pretty new to small engines and motorized bicycles and I'd like to do my best to take better care of my whizzer as it means a lot to mean and I am aware not too many NE5s were made in the grand scheme of things. The current engine modifications are as follows:
minor increased compression with stock NE head (unfortunately my machinist followed my instructions incorrectly so the head was only decked by about .035")
flattened cylinder head with reground valve seats
dremeled restrictor plate & removed intake sleeve to match 22mm carburetor
Camshaft Timing advance 1 tooth
Taiwan made Mushroom lifters
Black cylinder paint for improved heat dissipation
My current plan is to try to find a machine shop or mechanic locally that can bore out my cylinder and switch to an oversize piston and new rings (does anyone know where I can find an oversize piston? thanks.). I've also seen mention of a crankshaft spacer being important, and I would like to get one figured out before I do much more with the engine. My crankshaft does not have an egregious amount of play, but it does move back and forth about half a millimeter if I tug on it. I have noticed a barely audible scraping sound on occasion when running past 5000 rpm for an extended period of time, I wonder if that is related to the cylinder gouging. Additionally, the engine picks up a nasty ticking sound at about 6500 rpm but I don't hit that on the road anyway. Might be valve float. Upon inspection my camshaft looks mostly ok, but the surfaces of the mushroom lifters appear polished but not quite flat. Because of this I am thinking of drilling a perfectly vertical hole in a piece of wood and using it alongside some sandpaper on an old marble slab to grind the lifters flat. Once I've worked out all the kinks, I figure I should take the whole engine apart, clean everything religiously, and then re assemble in as clean an environment as possible.
As for oil, I have tried several different synthetic 40 weight oils but have currently settled on a conventional 50wt non detergent racing oil with pre added zinc. If there is a better option please let me know, I don't mind getting called an idiot for running the wrong oil I would rather know so I don't make the mistake again. I am concerned the cylinder will get gouged again after the rebuild and I can't exactly keep getting oversized pistons indefinitely.
The last thing I wanted to ask about has to do with an old cylinder head sold by Quentin Guenther I recently got my hands on. I believe it was marketed as a "tri pattern" head and was based on the vintage whizzer hi fin design but adapted to early NE stud pattern. I would love to use this head on my engine, but the early NE uses 8mm head bolts in the place of the two 10mm bolts used in the later NE design. Because of this I would either need to modify the head (considering how rare and special it is I would rather avoid doing this at all cost) or to use 10mm to 8mm stepped studs and 8mm head bolts. Stepped studs seem like the best option but I am not 100% sure if they can be trusted. I will make sure to use steel ones of course. The other issue I have noticed is that the valves make contact with the head when it is sat on top of the cylinder. This is only by about 1mm and I tested it with the head just sitting loosely to avoid damaging anything. I imagine that carefully grinding the top of the valves down a couple millimeters could easily solve the problem without affecting how they seat into the head, but I wanted to ask for advice since I am no expert on engine modifications.
Thank you for your time and have a great day!
-StripeySnake
P.S. I am happy to send pictures of anything mentioned if it will help.
I recently disassembled the engine from my 2006 NE5, and I found vertical grooving in the cylinder wall, as well as a lot of carbon buildup. I am unfortunately pretty new to small engines and motorized bicycles and I'd like to do my best to take better care of my whizzer as it means a lot to mean and I am aware not too many NE5s were made in the grand scheme of things. The current engine modifications are as follows:
minor increased compression with stock NE head (unfortunately my machinist followed my instructions incorrectly so the head was only decked by about .035")
flattened cylinder head with reground valve seats
dremeled restrictor plate & removed intake sleeve to match 22mm carburetor
Camshaft Timing advance 1 tooth
Taiwan made Mushroom lifters
Black cylinder paint for improved heat dissipation
My current plan is to try to find a machine shop or mechanic locally that can bore out my cylinder and switch to an oversize piston and new rings (does anyone know where I can find an oversize piston? thanks.). I've also seen mention of a crankshaft spacer being important, and I would like to get one figured out before I do much more with the engine. My crankshaft does not have an egregious amount of play, but it does move back and forth about half a millimeter if I tug on it. I have noticed a barely audible scraping sound on occasion when running past 5000 rpm for an extended period of time, I wonder if that is related to the cylinder gouging. Additionally, the engine picks up a nasty ticking sound at about 6500 rpm but I don't hit that on the road anyway. Might be valve float. Upon inspection my camshaft looks mostly ok, but the surfaces of the mushroom lifters appear polished but not quite flat. Because of this I am thinking of drilling a perfectly vertical hole in a piece of wood and using it alongside some sandpaper on an old marble slab to grind the lifters flat. Once I've worked out all the kinks, I figure I should take the whole engine apart, clean everything religiously, and then re assemble in as clean an environment as possible.
As for oil, I have tried several different synthetic 40 weight oils but have currently settled on a conventional 50wt non detergent racing oil with pre added zinc. If there is a better option please let me know, I don't mind getting called an idiot for running the wrong oil I would rather know so I don't make the mistake again. I am concerned the cylinder will get gouged again after the rebuild and I can't exactly keep getting oversized pistons indefinitely.
The last thing I wanted to ask about has to do with an old cylinder head sold by Quentin Guenther I recently got my hands on. I believe it was marketed as a "tri pattern" head and was based on the vintage whizzer hi fin design but adapted to early NE stud pattern. I would love to use this head on my engine, but the early NE uses 8mm head bolts in the place of the two 10mm bolts used in the later NE design. Because of this I would either need to modify the head (considering how rare and special it is I would rather avoid doing this at all cost) or to use 10mm to 8mm stepped studs and 8mm head bolts. Stepped studs seem like the best option but I am not 100% sure if they can be trusted. I will make sure to use steel ones of course. The other issue I have noticed is that the valves make contact with the head when it is sat on top of the cylinder. This is only by about 1mm and I tested it with the head just sitting loosely to avoid damaging anything. I imagine that carefully grinding the top of the valves down a couple millimeters could easily solve the problem without affecting how they seat into the head, but I wanted to ask for advice since I am no expert on engine modifications.
Thank you for your time and have a great day!
-StripeySnake
P.S. I am happy to send pictures of anything mentioned if it will help.
