I am working on ordering all parts I need for the build and I have a question that is pretty far out there. Short back story to the logic here. Beatrice cycle lists a short rod crank for all ct70H's, xl70s sl70s cl70s, 81-85 atc70. Could I use an act70 magneto on the 108 striker crank from TB? Also work with a CDI upgrade?
1972 HONDA CT70HK1 CANDY YELLOW SPECIAL 108 CC STROKER BUILD
- Thread starter lukelaw1
- Start date
I did have a minor set back that I would like to get cleared up by the pros. As you can see I have the HD kick starter installed with thrust washer; however, when I put both case halves together and snugged up the case screws the kick start shaft was binding and wouldn't return. Pulled the halves apart few times. I then noticed that the thrust washer was higher than the case. When I installed the HD shaft I included all parts from this drawing.
Then I looked at the crf50 kick start breakdown.
Its kind of hard to follow, but I did the only thing logical to me to make it work. I took off the #15 circlip. Now the trust washer sits on the step of the shaft. The cases snugged up and everything is turn and moving as it should.
Then I looked at the crf50 kick start breakdown.
Its kind of hard to follow, but I did the only thing logical to me to make it work. I took off the #15 circlip. Now the trust washer sits on the step of the shaft. The cases snugged up and everything is turn and moving as it should.
kirrbby
Well-Known Member
You 2nd parts breakdown is the correct one for the shaft you have. It sounds like you have it right. The thrust washer sits on top of the circlip, and goes on just before you put the right side case on. The thrust washer protects the aluminum engine case from being damaged from the circlip, "thrusting" against it...I think. It also acts as a shim to keep the shaft from sliding too far to the right. Try pull/pushing the shaft in and out...left and right. There should be just a little play...maybe 1mm.
Looking good BTW.
Did you use a little blue loctite on the shift star bolt, maybe a touch on the detent arm bolt? Did you oil everything up with some assembly lube or oil?
And...test the kick shaft to make sure all is well before you get too far ahead.
Last thing...get the oil pump shaft in place and working...and, then see if you can remove and replace the oil pump drive gear, before you get too far ahead.
I've had to modify the threaded end of a couple of the drive shafts when building stroker motors. It was too long to allow removal of the drive gear without opening the center cases. Big ol PITA.
Looking good BTW.
Did you use a little blue loctite on the shift star bolt, maybe a touch on the detent arm bolt? Did you oil everything up with some assembly lube or oil?
And...test the kick shaft to make sure all is well before you get too far ahead.
Last thing...get the oil pump shaft in place and working...and, then see if you can remove and replace the oil pump drive gear, before you get too far ahead.
I've had to modify the threaded end of a couple of the drive shafts when building stroker motors. It was too long to allow removal of the drive gear without opening the center cases. Big ol PITA.
The motor is still pretty much in this state still. I went through again and mocked things up to try and verify I have the parts I need to finish the motor. I am on the 2nd order LOL. I am waiting on a new shift shaft. I have one but for $21.50 I'll have a new one.
Yes I will give everything a light oil coat as assembled, and loctite the shift star and stopper arm bolt.
Yes I will give everything a light oil coat as assembled, and loctite the shift star and stopper arm bolt.
I am at a point I need some help for the experts. I have ordered 2 different intakes and I don't think neither one is correct.
Tb race head intake venturi opening= approx. 26mm
Mikuni carb= approx. 23mm
Tbolt intake #1 tbw0273
Intake at carb= approx. 24mm (good fit to carb)
Intake at head= approx. 21mm (way small??)
Tbolt intake #2 tbw0433
Intake at carb= approx. 30mm (way to big to mount carb)
Intake at head= approx. 26mm (good fit)
Can someone tell me the intake they used on the tbolt race head with Mikuni 20mm carb?
Tb race head intake venturi opening= approx. 26mm
Mikuni carb= approx. 23mm
Tbolt intake #1 tbw0273
Intake at carb= approx. 24mm (good fit to carb)
Intake at head= approx. 21mm (way small??)
Tbolt intake #2 tbw0433
Intake at carb= approx. 30mm (way to big to mount carb)
Intake at head= approx. 26mm (good fit)
Can someone tell me the intake they used on the tbolt race head with Mikuni 20mm carb?
With the whether finally warming up in Iowa I have made some very good progress on the stroker build and finally getting back to posting updates. The motor got finished up with the CDI ignition and a Mitsubishi flywheel. I removed all the springs, advancing weights and advancers cam. I got the rims blasted and painted with new tires and tubes, rebuilt the front shocks, installed TB's HD rear shocks, new handle bars, new seat
Anyways here are some photos;
Anyways here are some photos;
After I got the Petcock mounted and fuel lines ran. I changed out the main jet to a #150 as suggested by Darrel Gunderson didn't change any factory carb settings like slide height or a/f ratio. Dumped in a lil bit of fuel and 4 kicks later (without Choke) it fired right up. I took for a short 10 to 15 minute spin in the back alley for a bit last night and around 9 pm the wife said that was enough of that before the neighbors called the cops LOL. Ran pretty good overall temp only reached 125 degree Fahrenheit, I can't believe the power and torque the motor has-its unreal--almost scary. I have a short video I posted for the guys on the aftermarket exhaust thread. I pulled the plug today once everything was cooled down and the plug was a little wet and black. I'll probably bump down to a #140 and see what happens.
I don't have as many miles on it as I would like yet. I have been busy with work and kid's baseball and softball. I maybe have 20 miles on the build. I just received insurance quotes too, with that said it wont be long before I can tear up the streets. I still have the 150 main in the vm20 which is rich on the plug read but man does that stroker rip. I can't believe the power it has and that CHP performance exhaust sounds beautiful to my ears. I loooovvvvvveeee it!!!!! I hate to admit and say this-going back to driving stock is very hard. I was talking to the boy on the way home from a softball game the other day about building a stroker on the newish-acquired-titled-CL70.
With the jetting, it's not so easy to go by plug coloration...waay too many variables in what used to be a fairly basic equation. What matters is WOT mixture, that needs to be close to the rich limit to prevent burning parts. Aside from that, as long as the plug isn't fouling, you should be fine...with some safety margin for that inevitable tankful of bad fuel. With the motor running this well, I'd be testing different jet needle heights and not even considering changing main jets, unless the jet needle C-clip is at the lean limit. FYI, the rich limit is the point, beyond which, the motor won't rev-out cleanly. Even if you're running overly rich, for the initial break-in period, that'll help keep combustion chamber temps down.
