Honda CL70 K2 revival for my big bro

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lukelaw1

Active Member
Ok now for the important part of the head. The valve contact surfaces and combustion chamber. I got the chamber pretty clean, I can go more if anyone thinks I need to, but I stopped here to lightly lap the old intake valve and see what shape the valve contact surfaces looked like. The intake (right) at this point is the only one done.
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Closer up looks like a nice even band. Am I wrong?
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In this photo, I have the exhaust lightly lapped.
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close up but hard to see.
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lukelaw1

Active Member
I am at another stopping point for a little while, one its back to the daily grind for me, and second I will be waiting on a couple of shipments of parts. I currently have $505 in this project. If I figured everything correctly and there are no other surprises, the carb will work along with stator. Shouldn't take anymore parts.
 
motodevo

motodevo

Active Member
Top work, its a pity no one will see how clean you got the insides of the cases, etc. A little bit of effort now pays big dividends in the long run. With all your effort, if your bro looks after it it should be going for another 45 odd years.
 
kirrbby

kirrbby

Well-Known Member
lukelaw1 said:
Update on the transmission. I thought about this for a while and determined that the AHP 4 speed transmission setup is going to the best bang for my buck. I negotiated the seller to $125 with free shipping for a complete setup; new shift drum, forks, and all gears. Even though I read some poor reviews. This wont be a racing bike with a stock 72cc setup so for the money it should hopefully last. Thanks for everyone's input.

Kirbby if you have a buyer for the rest of the trans. I may sell it.
Click to expand...


Agreed. Maybe the best buy to go along with your budget, and it's easy compared to rebuilding the original. The 1d3up should work well with the manual clutch. And, those pitbike racers can destroy even the best transmissions, lol. I think the AHP will hold up to the average CL70 guy.
 
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lukelaw1

Active Member
Does anyone here have a lot of experience with installing the AHP 4-speed transmission setup? This seems to be the age old question that comes up from time to time, but I never seem to remember the correct answer.

Possible important data:
The OEM 4 speed transmission (all down) setup only had the thrust washer/shim on the top side of the counter shaft.
The new AHP 4 speed transmission (1 down 3 up) had included 2 thrust washers/shims. One at the bottom of the main shaft and one at the top of the counter shaft.


My question is:

Do I need to use both thrust washers/shim with this setup? I have them pulled away from the gears and are kind of hard to see in the photos


2017082495170916.jpg
2017082495170920.jpg
 
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lukelaw1

Active Member
I am getting ready to put some time in on the motor rebuild tomorrow and over the weekend. I need some MORE input though.

I bought a new clutch back from dr.atv. I want to use the oem "inner ring" that meshes with the primary gear on the new clutch pack. I don't know the official term of the part I am talking about, so I'm calling it the "inner ring". The machining on the OEM "inner ring" is much better than the aftermarket. Looks like much better surface contact.

Check out the photos.



OEM primary gear with aftermarket "inner ring"

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OEM primary gear with OEM "inner ring"

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Am I being over critical/paranoid here? I'm just thinking that everything in the motor will be turning at a pretty good rate of speed and a little bit of "play" turns into a lot of play over time.
 
red69

red69

Well-Known Member
lukelaw1 said:
Does anyone here have a lot of experience with installing the AHP 4-speed transmission setup? This seems to be the age old question that comes up from time to time, but I never seem to remember the correct answer.

Possible important data:
The OEM 4 speed transmission (all down) setup only had the thrust washer/shim on the top side of the counter shaft.
The new AHP 4 speed transmission (1 down 3 up) had included 2 thrust washers/shims. One at the bottom of the main shaft and one at the top of the counter shaft.


My question is:

Do I need to use both thrust washers/shim with this setup? I have them pulled away from the gears and are kind of hard to see in the photos


View attachment 53841 View attachment 53842
Click to expand...

You may find your answer here if you can get past the loud radio noise:

 
kirrbby

kirrbby

Well-Known Member
I have no experience with them. The TRX/ATC 70 has both thrust washers, and I think your AHP is a copy of them...so I'd say install them, then check how it shifts as soon as you tighten down the case screws.

I think that ahp requires the 3 speed pinion gear too...same as the TRX.
 
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lukelaw1

Active Member
I made some great progress on Friday. I managed to get the head rebuilt;

New intake and exhaust valves
HD valve springs
Exhaust valve guide seal
Rocker assemblies

New seals; IE kick start shaft, shift shaft, counter shaft, motor/stator shaft, clutch disengagement plunger, and stator plate O-rings.
 
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lukelaw1

Active Member
I made even more progress today.

I took a good part of the day measuring up the old transmission and the new AHP transmission. I mocked up the new AHP transmission without the main shaft trust washer. I had quite of bit of play up and down on the main shaft between the motor cases and yes the case gasket was installed too. It also seemed like the secondary gear was very close to the bolt head of the shift drum stop, and with and ever so slightly rock of the secondary gear and it would scrub the bolt head. Long story short I ended up installing the new AHP transmission with both trust washers on the main shaft and counter shaft. This gave me a little more clearance between the secondary gear and shift drum stopper bolt head. Also tightened up the" play" between the case halves.

The only thing I did notice mocking up the old and new transmission several times was after a while the main shaft thrust washer was showing signs of "scrubbing" on both sides of the washer. I may have not installed the same side up every time; but with that said, it just showed me that at some point the washer may turn to star dust.

With everything torqued down the AHP does bench shift.
 
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lukelaw1

Active Member
kirrbby said:
I have no experience with them. The TRX/ATC 70 has both thrust washers, and I think your AHP is a copy of them...so I'd say install them, then check how it shifts as soon as you tighten down the case screws.

I think that ahp requires the 3 speed pinion gear too...same as the TRX.
Click to expand...

Yes the AHP transmission requires a 3 speed kick start pinion.
 
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lukelaw1

Active Member
I have the new kick start shaft installed, AHP transmission installed, new clutch pack, stator plate, honed cylinder with new piston rings (etc.), new timing chain, and rebuilt head. The timing is rough set along with the intake and exhaust valve lash.

The only thing I overlooked was the manual clutch inner cover gasket. Should be here early next week otherwise it would have been all buttoned up today.

Side note does anyone know if Versa change there VG112 kit? I took apart the oil pump and cover to clean. When I went to the new gasket kit I just bought. The oil pump cover and oil pump to case gaskets didn't even come close to working. Luckily enough I had an old gasket sets that I didn't use those gaskets so I had what I needed.
 
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lukelaw1

Active Member
I hope with the long weekend coming I will get the odds and ends wrapped up and get a chance to install the motor and see if I have good spark, then from there see if the carb is clean enough to get the bike running again
 
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Deoodles

Well-Known Member
I'm not sure I fully understand your question but when rebuilding my transmissions i usually look up the transmission with an OEM parts checker. It would apply to any subassembly you're working on and you know what parts go in what order and what parts don't belong
 
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lukelaw1

Active Member
Made great progress of Friday.

I installed a new rear tire, inner tube and rear brakes.

Installed new front brake cable and brakes. FYI the brake cable from dr atv is a little short so it had to get routed different. never the less, cable does its job.

I also got the motor mounted.
 
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lukelaw1

Active Member
Once motor was installed I wanted to confirm spark. This kind of set me back a little bit. With the motor being locked up prior to rebuild, I couldn't verify spark before tear down. If everyone remembers from post 6 &7. The original stator plate had a hole in it , but I miraculously had a spare on the shelf. I also had no idea if this stator was in working condition either. I also had to repair some wires that were slightly nibbled on by some critters. I hooked up all the wires and no spark. I have had a little experience with the external condensers mounted to the ignition coil from SL and XL 70s. (which can run without a battery) I double checked the wiring diagram, noticed that the ignition coil had a black wire coming from it that powered all the lignin. Thought to myself that is a lot of juice needed to run lighting and ignition coil, then it dawned on me. This model requires a battery to run.............
 
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