1985 Gyro X Restoration Help

[johnmc021]

Hi guys,

I have been browsing your forum for help the past month or so as I have been restoring a 1985 Gyro X that I believe was imported from Japan. Most of my work up until the past few days has been cosmetic, which was a pain since every square inch of the bike was covered in combinations of dust, dirt, and oil.

After I cleaned up the front end.

IMG_20120717_174449.jpg (159.48 KiB) Viewed 2681 times

Now I have moved onto the mechanical side, which I thought would be a breeze since the bike was in running order 3 years ago. I cleaned up the carburetor and fuel/vacuum apparatus (not sure what it's called) with a good amount of carb cleaner and compressed air. I also replaced the disgustingly dirty stock air filter with some carefully cut out pre-filter element from Napa. I completely drained the fuel/oil lines and primed them before cranking the motor. However, I could not get the engine to turn over (or even begin to spark), so I started researching other issues. I downloaded a 1984 Gyro (NN50MD) manual from this forum, but it is a very different bike than my Gyro X (I have a vertical cylinder, the manual's has a horizontal). Anyways, I have used it for reference for parts that are similar between the bikes. Here are the things I have done with the engine so far:

I tested the compression of the motor and got a measely 75 psi, which is much lower than the manual's stated 175 psi for the NN50MD. Does anyone know what the recommended compression is for the Gyro X?
I then took off the cylinder head to examine the top end, and found something surprising: the gasket is made out of sheet metal.

Is this hackjob of a gasket normal?

IMG_20120803_165142.jpg (129.64 KiB) Viewed 2681 times

Despite this, the engine ran fine 3 years ago with the same gasket.
The cylinder walls looked to be in decent shape, but I do not have the tools in my garage to check tolerances.

My main question I would like answered is if the 75 psi compression is appropriate to get a running motor. If not, do you think the POS gasket could be causing it? Or could it be that I might have to bore out the cylinder? I can supply you guys with more top end pics if necessary. If 75 psi is appropriate, what else do you think could be causing the motor to not turn over? Because I haven't been able to get any ignition so far. Any help would be greatly appreciated, as I have to get this project done in the next few weeks before I head back to school.

[johnmc021]

O and btw, when I reassembled the carb I put the air screw 2 turns out (as per manual) and have tinkered with different settings along the way, to no avail.

[motormike]

Welcome to the site, johnmc021....
Only member 66SIX has a similar Gyro, and his is maybe a Gyro UP....
You say there is 75 lbs. compression, but the engine isn't turning over. I'm sure you mean the engine isn't "STARTING or FIRING"...if it is spinning, then it is "turning over"
Head gasket is certainly a possible weakness that is allowing the compression to be low.
Not much faith in seeing it run with 75 psi.
This project is sure to take longer than most because parts acquisition will be strictly overseas.
There are a couple members currently in positions to help you with those parts.
Specifically, Madman is in Japan/Okinawa??...believe he is stationed there military.
Best of luck with this fun bike.
I suggest you will need to put rings in this bike to ever get it reliable.

[johnmc021]

Hey motormike, thanks for the help! Yes you are correct, the engine is turning over but not firing... my bad. Do you think it would be worth my time to buy some gasket material to try and cut out a better fitting and sealing gasket in the meantime? And do you know if the engine in my Gyro X is common with any other Honda scooters, specifically ones sold in the US? That would make ordering new rings much easier.

[bradthreee]

Google webike japan, they'll have parts for your GyroX.

[motormike]

http://japan.webike.net/

^^^^^^^^^^^^^^^^^^^^^^^^
There's you a link.....

[johnmc021]

Thanks a lot for the link guys. That will be nice to have if I need any other replacement parts. Unfortunately, the only engine parts for sale are big bore heads and pistons, which I am not looking to spend the money on. Do you guys know if my gyro shares its engine with any other honda scooter that I could find rings for?

[dun rite]

view this topic viewtopic.php?f=3&t=24397 Maybe trafficjamz can let you know how to order, or what needs to be known to get the right gasket.