Scooped up 2 70's- couple questions

[FastZ28]

They are 85 year frames, one has the correct all up shift pattern the other is all down. The one that shifts down will go all the way around to neutral and back to 1st. What causes this?

The other one that shifts up will randomly pop out of gear. What would cause this?

They both run, one needs a pull start and tires. Came with an extra 85 frame and a box of parts. There is a couple cylinders and a head and other random crap.

[KASEY]

the rotary shift is a chinses transmission,, or the star gear on the end of the shift drum is slipping... randomly popping out of gear usually means a wore out transmission,,,

[FastZ28]

Thank you Mr. Kasey:cool:

[FastZ28]

After riding 85#1 more it wasn't popping out of gear, but it would miss shifts once in a while. Well I tore it down to investigate, plus it will be getting some hop ups. More on that later.

First off with its head!!!
http://i915.photobucket.com/albums/ac354/FastZ2884/70%20engine%20teardown/IMG_20110801_184610.jpg

Here it is headless ;)
http://i915.photobucket.com/albums/ac354/FastZ2884/70%20engine%20teardown/IMG_20110801_184618.jpg

Ready to split the cases.
http://i915.photobucket.com/albums/ac354/FastZ2884/70%20engine%20teardown/IMG_20110802_003521.jpg

Cases split
http://i915.photobucket.com/albums/ac354/FastZ2884/70%20engine%20teardown/IMG_20110802_005433.jpg

Pretty much all apart
http://i915.photobucket.com/albums/ac354/FastZ2884/70%20engine%20teardown/IMG_20110802_010512.jpg

Now I did notice a couple things during the teardown that were broken or didn't look quite right. I think one of the broken pieces might be why it was missing shifts??? Any input will be appreciated.

1st I notice this spring not hooked right...
http://i915.photobucket.com/albums/ac354/FastZ2884/70%20engine%20teardown/IMG_20110802_002428.jpg

Then later found this in the cases....another part of the arm.
http://i915.photobucket.com/albums/ac354/FastZ2884/70%20engine%20teardown/IMG_20110802_010458.jpg

While taking the clutch apart the hub came out in pieces...
http://i915.photobucket.com/albums/ac354/FastZ2884/70%20engine%20teardown/IMG_20110802_010622.jpg

So hopefully Mr Kasey you can tell me if that arm was my problem. As for my plans for the hop ups:
88cc Big bore race head kit
stroker crank
cdi conversion
suspended frame kit
Probably a R55 kit since PK and A+ kits are so rare and hard to find.

With the mods it will be 110cc's and have more power than a chinese 125. I cannot take credit for coming up with the plans for this. I rode Steven0196's pk suspended 70 at TF with this same engine package. Had to have one so here goes my attempt.

[ctbale]

I just took two 70s all the way down like you did over the last few days, BOTH of them had issues with the shift stopper arm. One the alum case boss was busted off, the other has slipped off the shift star and was grindin on the back of the big primary gear. I did the CDI conversion on my 83 atc70, got the $99 one, its supposedly had and advancer function programed into it, seems like it winds out more than stock.. I am also surprised that there is only one seller, would be nice to get some competition to drive down the price!

[CRAZY70MAN]

After riding 85#1 more it wasn't popping out of gear, but it would miss shifts once in a while. Well I tore it down to investigate, plus it will be getting some hop ups. More on that later.

First off with its head!!!
http://i915.photobucket.com/albums/ac354/FastZ2884/70%20engine%20teardown/IMG_20110801_184610.jpg

Here it is headless ;)
http://i915.photobucket.com/albums/ac354/FastZ2884/70%20engine%20teardown/IMG_20110801_184618.jpg

Ready to split the cases.
http://i915.photobucket.com/albums/ac354/FastZ2884/70%20engine%20teardown/IMG_20110802_003521.jpg

Cases split
http://i915.photobucket.com/albums/ac354/FastZ2884/70%20engine%20teardown/IMG_20110802_005433.jpg

Pretty much all apart
http://i915.photobucket.com/albums/ac354/FastZ2884/70%20engine%20teardown/IMG_20110802_010512.jpg

Now I did notice a couple things during the teardown that were broken or didn't look quite right. I think one of the broken pieces might be why it was missing shifts??? Any input will be appreciated.

1st I notice this spring not hooked right...
http://i915.photobucket.com/albums/ac354/FastZ2884/70%20engine%20teardown/IMG_20110802_002428.jpg

Then later found this in the cases....another part of the arm.
http://i915.photobucket.com/albums/ac354/FastZ2884/70%20engine%20teardown/IMG_20110802_010458.jpg

While taking the clutch apart the hub came out in pieces...
http://i915.photobucket.com/albums/ac354/FastZ2884/70%20engine%20teardown/IMG_20110802_010622.jpg

So hopefully Mr Kasey you can tell me if that arm was my problem. As for my plans for the hop ups:
88cc Big bore race head kit
stroker crank
cdi conversion
suspended frame kit
Probably a R55 kit since PK and A+ kits are so rare and hard to find.

With the mods it will be 110cc's and have more power than a chinese 125. I cannot take credit for coming up with the plans for this. I rode Steven0196's pk suspended 70 at TF with this same engine package. Had to have one so here goes my attempt.

Hey Bob Andy here. Interested in your build.....looki like you made a lot of headway in one night. My ?? where or who will you be getting the crank from or done at?? Always have wanted a stroker 70 myself just to have one. I will keep an eye on your thread. Icefest mini????

[steve0196]

Bob, the roller that is broken off the arm runs in the star on the end of the shift drum. It holds the shift drum in postion after you shift. If you need the ring that is broken in the clutch let me know, I'll send you one. Looks like your on your way.

[KASEY]

that is real common in the 70 transmission,,, i have a box of broken ones too... if you want to go bigger on the motor,,,, since you have it apart look into a 95cc setup,, cases have to be bored,, i did it in 20 minutes .. since you are already apart its easy,,, it will look all stock ,if you get a xr70 head with the bearing camshaft,, let me see if i can dig up some pictures,,

http://i1141.photobucket.com/albums/n592/KASEYII/DSC09728.jpg

http://i1141.photobucket.com/albums/n592/KASEYII/DSC09731.jpg

[FastZ28]

Hey Bob Andy here. Interested in your build.....looki like you made a lot of headway in one night. My ?? where or who will you be getting the crank from or done at?? Always have wanted a stroker 70 myself just to have one. I will keep an eye on your thread. Icefest mini????

It will probably be at Icefest, dunno if it will get studded. Crank is available at Beatrice cycle.
http://dratv.com/racr52stforp.html

[FastZ28]

Bob, the roller that is broken off the arm runs in the star on the end of the shift drum. It holds the shift drum in postion after you shift. If you need the ring that is broken in the clutch let me know, I'll send you one. Looks like your on your way.

Thanks Steve, but I was curious if you ever got the HD clutch and how it works.

[FastZ28]

that is real common in the 70 transmission,,, i have a box of broken ones too... if you want to go bigger on the motor,,,, since you have it apart look into a 95cc setup,, cases have to be bored,, i did it in 20 minutes .. since you are already apart its easy,,, it will look all stock ,if you get a xr70 head with the bearing camshaft,, let me see if i can dig up some pictures.

That sounds awesome but I already have the 88 kit from T-bolt USA with their race head. That also has the bearings on the cam.
What would work better, painting the cases or getting them powder coated? You have anymore of those front fenders?

[KASEY]

i paint alot of my motors,with acrylic emanel never have issues,, i am working on another batch of fenders now,,,,

http://i1141.photobucket.com/albums/n592/KASEYII/DSC00236-1.jpg

[tommerp]

i paint alot of my motors,with acrylic emanel never have issues,, i am working on another batch of fenders now,,,,

http://i1141.photobucket.com/albums/n592/KASEYII/DSC00236-1.jpg

Both of these are just SICK!! Nice job Kasey!!!