K1 ct70 stuck in gear

T

Tuuubbs

Member
Picked up a ct70 this morning. It had a lot of water in the motor, so I drained it and started disassembly. Head came off fine, it had been removed before, there’s red sealant everywhere. Cylinder head and piston and valves look okay but but there’s sludge on everything.

Trying to take the motor apart but I can’t get the magneto off the drive shaft. Bolt and washer came off fine but the magneto is stuck on there. I was only able to loosen 1 bolt from the clutch basket cover.

I don’t believe I can get into the gear box without removing those?
 
JHminitrails

JHminitrails

Well-Known Member
You're gonna need one of these pullers to get the flywheel off after the nut is removed. The flywheel is a tapered interference fit with a woodruff key.

mytrailbuddystore.com

MAG/FLYWHEEL PULLER CT70/Z50

MAG/FLYWHEEL PULLER-CT70 and Z50 models & others Product Name: Puller Type: External Style: Left Hand Application: Flywheel Color/Finish: Oxide Base Color: Black Material: Carbon Steel Measurement System: Metric Diameter - Thread Size: M27 x 1.0
mytrailbuddystore.com
 
T

Tuuubbs

Member
Still can’t get these 3 screws out of the clutch. Stripped one out so I started with a screw extractor kit but I’m not getting anywhere with that either.
 

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dirtbkr188

dirtbkr188

Active Member
Take a 1/4" drill bit and slowly drill the head of the screws until they start spinning. Do all three and then pop the cover with a straightslot screwdriver on the edge. You should then be able to use a pair of needlenose pliers to back out the rest of the screw left in the housing.

Replace with three new 5mm x 10mm long flat head screws.
 
T

Tuuubbs

Member
Okay I’ve got the clutch and shift shaft removed. Had to drill out the stator plate screws as well, now the stator plate is stuck. Can’t get the brass small primary drive gear bushing off either. Im so close to splitting the cases to get everything cleaned up, hopefully it goes back together easier than it comes apart.
 
dirtbkr188

dirtbkr188

Active Member
With a long screwdriver, carefully pry up on the stator plate under the coil winding where it is mounted on the stator plate. Do a bit back and forth on opposite sides of each other, slowly lifting it up from the engine case.

You don't need to remove the primary drive gear bushing to split the cases, the crank bearing normally comes up when you lift and jiggle the crank to remove it.
 
T

Tuuubbs

Member
dirtbkr188 said:
With a long screwdriver, carefully pry up on the stator plate under the coil winding where it is mounted on the stator plate. Do a bit back and forth on opposite sides of each other, slowly lifting it up from the engine case.

You don't need to remove the primary drive gear bushing to split the cases, the crank bearing normally comes up when you lift and jiggle the crank to remove it.
Click to expand...
I already took the points and could off, I can get the screws back in and pull from those though maybe. I can kinda pry up from the bottom side through the timing chain channel, but I don’t feel good about that.
 
T

Tuuubbs

Member
Alright I’ve got the cases split and everything is disassembled. A small bit of rubbing on the inside of the case is the only damage I can find. I understand I’ll need to get new circle clips to reassemble properly, anything else I need to buy for the inside of the motor? Are the complete gasket kits online okay? Do they have new o-rings for the stator plate and it’s screws or will I have to get those separately?

Also I had to hit the end of the coils with a hammer to get the stator plate to spin some to brake the seal, then hit it back and forth it’ll it started coming up, then I could pry it off.
 
T

Tuuubbs

Member
I got everything cleaned up nice but I used a lot of brake cleaner, so I need to pop the bearings out and take care of them. Started working on getting the valves and camshaft out but the exhaust valve cover is stuck, and now stripped. Let the PB sit for about 29 minutes then got it hot and let the impact work, until it slipped. It had been damaged before. What can I do to get this off?
 
dirtbkr188

dirtbkr188

Active Member
Cut a notch on the outside edge of the tappet cover with a cold chisel and hammer, and then tilt the chisel down to get a bite into the cover and tap it off with the hammer counterclockwise.
 
T

Tuuubbs

Member
Valve cover is off. Engine is totally disassembled. Talked with Josh from vintage mini bikes in Orlando and he said to also look out for “smiley faced” shift forks because he replaces them often. I’m going to have to get a new piston and maybe a cylinder. I’m hoping the valve seats can be lapped so I don’t need a new head
 

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OLD CT

OLD CT

Well-Known Member
Take your finger off the fork, that's the area where the smiley would be. Lol! Look on both sides of each fork. As for the lapping of the head, if it doesn't pass a leak down test after lapping and re assemble, don't re install it. These heads can be rebuilt for less than a new head. Ebay heads are garbage and usually the wrong dome. Take two new valves to a machine shop and do the job right.
 
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T

Tuuubbs

Member
OLD CT said:
Take your finger off the fork, that's the area where the smiley would be. Lol! Look on both sides of each fork. As for the lapping of the head, if it doesn't pass a leak down test after lapping and re assemble, don't re install it. These heads can be rebuilt for less than a new head. Ebay heads are garbage and usually the wrong dome. Take two new valves to a machine shop and do the job right.
Click to expand...
Okay one fork had the smiley, the other doesn’t, I assume that I should replace both though.
 
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