Planet Minis

z50 chopper · 08-20-2009, 03:02 AM

I am gonna get a passport engine to rebuild and then eventually place in a CT70 for street use because I do want e-start.

Where could I source an 88bbk? will one for a crf work?
Will I need to change the crank? the answer to this will depend on if I start from a full engine or just the case.
Will ct70 internals work?

arlindsay1992 · 08-20-2009, 05:30 AM

The older Passports used a shorter con-rod. You will need to get a kit for the older Z50s and use a 50 head from the corresponding year, or you can put together a combination of parts from DrATV and have an 88 kit with your current head. Neither option requires case splitting and crank replacement.

z50 chopper · 08-20-2009, 07:53 AM

I am looking at 81-83 cases one of which is already split and has no internals.

arlindsay1992 · 08-20-2009, 08:56 AM

The cases will accept pretty much anything. If you use a crank from a bike after 1988, you will need to modify the cases for the CDI pickup. But other than that, everything else drops right in.

slimbo · 08-20-2009, 12:17 PM

pretty sure 81 motors were 6v and 82 were 12v. talk to firepower minis. he can put you in the right direction.

z50 chopper · 08-20-2009, 01:38 PM

yup 81 were 6 and 82/83 were 12v

arlindsay1992 · 08-20-2009, 01:53 PM

I learned something new today!

z50 chopper · 08-21-2009, 04:10 AM

Quote:

Originally Posted by arlindsay1992

I learned something new today!

oh what was that?

arlindsay1992 · 08-21-2009, 05:04 AM

Passports got CDI before Z50's.

z50 chopper · 08-21-2009, 05:24 AM

Quote:

Originally Posted by arlindsay1992

Passports got CDI before Z50's.

were there not 12v points setups?

arlindsay1992 · 08-21-2009, 06:35 AM

I don't know honestly. Not for Z's there wasn't. I'll let someone else take over because I obviously don't know what I'm talking about.

firepower354 · 08-21-2009, 07:30 AM

Welcome to the club

Sincerely
Da Prez.

z50 chopper · 08-21-2009, 06:32 PM

Looks like I'll be travelling into new territory with this build as soon as I get the case I'll add some pics and measurments.

z50 chopper · 08-21-2009, 08:47 PM

I just got this response back after asking another member these questions since he has used a c70 passport engine.

Quote:

Originally Posted by s_10onbagz

Basically a c70 motor uses GB4 cases like a crf50, but it has a spot for the electric starter built in. Mine was an 82-83 motor and there is no crank you could swap in directly. The ignition taper is different and the c70 has a gear for the starter chain. The c70 runs a reversed stator setup. This also makes the ignition cover huge. Basically instead of a stator plate it just has a big oil seal, then the flywheel is BACKWARDS, and the stator is mounted to the ignition cover.

At this point you are thinking "ok so on the 82-83 you could swap a crf crank in and you would just use the crf ignition system." This may work, I never tried it, but you will loose your electric start which is the whole reason for using this motor.

I think the 81 motor is almost identical with just a different ignition system. Check it out for yourself if you have one sitting there.

Big bore kits fit right on. It is obviously a 70 head so you just need a BBK made for a 70 head or race head.

For a stroker crank talk to firepower. He might be able to bang something out for you. I have a feeling he could swap your stock ignition side of the crank shaft onto stroker flyweights. If not he could probably just throw an offset wristpin on your stock crank.

You may want to just have him bore your cases so you can run 54mm bore with a 49.5mm stroke and a (69mm) tall jug. Thanks, Morgan.

mexicanyella · 08-21-2009, 11:31 PM

Yeah, that's an interesting point; I recently took apart a Chinese 110cc motor out of a trashed quad. It had the e-start reverse-flywheel arrangement and a different taper than any of my old 6V motors (I assumed it was the same taper as the 12V CDI motors, but maybe not...?) but it was the 52.4mm bore/49.5 mm stroke common 110 arrangement. I got that motor for about $30, give or take, and it had a usable crank that I believe is now being used in a race bike another member here built. If you want to go stroker, check out your local craigslist for people unloading trashed Chinese ATVs or bikes with the 90 or 110 clone motors.

A couple members here, including Firepower, explained to me how I could swap the whole longer 69mm cylinder, longer studs, longer cam chain, larger-port chinese E22 head and the 49.5mm crank onto this ATC70 motor I was working on and get a cheap stroker. Then I decided against going with 12V CDI electrics in my old bike, and to keep my 6V ignition I couldn't use the 49.5 crank. But maybe that could be a cheap and sensible route for you...?

doopsx3 · 08-21-2009, 11:35 PM

Quote:

Originally Posted by mexicanyella

Yeah, that's an interesting point; I recently took apart a Chinese 110cc motor out of a trashed quad. It had the e-start reverse-flywheel arrangement and a different taper than any of my old 6V motors (I assumed it was the same taper as the 12V CDI motors, but maybe not...?) but it was the 52.4mm bore/49.5 mm stroke common 110 arrangement. I got that motor for about $30, give or take, and it had a usable crank that I believe is now being used in a race bike another member here built. If you want to go stroker, check out your local craigslist for people unloading trashed Chinese ATVs or bikes with the 90 or 110 clone motors.

A couple members here, including Firepower, explained to me how I could swap the whole longer 69mm cylinder, longer studs, longer cam chain, larger-port chinese E22 head and the 49.5mm crank onto this ATC70 motor I was working on and get a cheap stroker. Then I decided against going with 12V CDI electrics in my old bike, and to keep my 6V ignition I couldn't use the 49.5 crank. But maybe that could be a cheap and sensible route for you...?

ya know there..I gots some of those things...may be available...just sayn

z50 chopper · 08-21-2009, 11:56 PM

I want to keep it all honda but with a bbk.

s_10onbagz · 08-22-2009, 12:35 PM

If you have a complete 82-83 bottom end you can bore your cases and throw a 95cc big bore kit (for a race head) right on with the stock head. That would be fun. I always wondered how much compression the c70 starter or starter chain could handle. Like I said, getting a carb to fit was my biggest battle.

z50 chopper · 08-26-2009, 08:03 PM

grrr as hard as I look I can't seem to find a left side cover for and 82/83 engine. So I might end up going with a 81 6volt engine. Unless ofcourse someone has the left cover kicking around or the 81 c70 side covers can be converted to be used on an 82/83 engine.

08-20-2009, 03:02 AM	#1 (permalink)
z50 chopper 2nd Gear Member Join Date: Jun 2009 Location: Nanaimo, BC, Canada Posts: 504 My Mood:	passport 88bbk I am gonna get a passport engine to rebuild and then eventually place in a CT70 for street use because I do want e-start. Where could I source an 88bbk? will one for a crf work? Will I need to change the crank? the answer to this will depend on if I start from a full engine or just the case. Will ct70 internals work?

08-20-2009, 05:30 AM	#2 (permalink)
arlindsay1992 "High Speed Record Guy" Join Date: Mar 2006 Location: Northern Virginia Posts: 4,369	Re: passport 88bbk The older Passports used a shorter con-rod. You will need to get a kit for the older Z50s and use a 50 head from the corresponding year, or you can put together a combination of parts from DrATV and have an 88 kit with your current head. Neither option requires case splitting and crank replacement.

08-20-2009, 07:53 AM	#3 (permalink)
z50 chopper 2nd Gear Member Join Date: Jun 2009 Location: Nanaimo, BC, Canada Posts: 504 My Mood:	Re: passport 88bbk I am looking at 81-83 cases one of which is already split and has no internals.

08-20-2009, 08:56 AM	#4 (permalink)
arlindsay1992 "High Speed Record Guy" Join Date: Mar 2006 Location: Northern Virginia Posts: 4,369	Re: passport 88bbk The cases will accept pretty much anything. If you use a crank from a bike after 1988, you will need to modify the cases for the CDI pickup. But other than that, everything else drops right in.

08-20-2009, 12:17 PM	#5 (permalink)
slimbo 2nd Gear Member Join Date: Jan 2006 Location: etters, pa Posts: 251 My Mood:	Re: passport 88bbk pretty sure 81 motors were 6v and 82 were 12v. talk to firepower minis. he can put you in the right direction.

08-20-2009, 01:38 PM	#6 (permalink)
z50 chopper 2nd Gear Member Join Date: Jun 2009 Location: Nanaimo, BC, Canada Posts: 504 My Mood:	Re: passport 88bbk yup 81 were 6 and 82/83 were 12v

08-20-2009, 01:53 PM	#7 (permalink)
arlindsay1992 "High Speed Record Guy" Join Date: Mar 2006 Location: Northern Virginia Posts: 4,369	Re: passport 88bbk I learned something new today!

08-21-2009, 05:04 AM	#9 (permalink)
arlindsay1992 "High Speed Record Guy" Join Date: Mar 2006 Location: Northern Virginia Posts: 4,369	Re: passport 88bbk Passports got CDI before Z50's.

08-21-2009, 06:35 AM	#11 (permalink)
arlindsay1992 "High Speed Record Guy" Join Date: Mar 2006 Location: Northern Virginia Posts: 4,369	Re: passport 88bbk I don't know honestly. Not for Z's there wasn't. I'll let someone else take over because I obviously don't know what I'm talking about.

08-21-2009, 07:30 AM	#12 (permalink)
firepower354 Advertiser Join Date: Oct 2006 Location: Flint MI Posts: 11,005 My Mood:	Re: passport 88bbk Welcome to the club Sincerely Da Prez. __________________ If it has my name on it I did it;) FirepowerMinis.com Custom FPM parts and engines. Parts and service for all makes. Honda Trail Bikes parts and accessories. Pitster/Piranha/Thumpstar bikes, parts, engines and accessories.

08-21-2009, 06:32 PM	#13 (permalink)
z50 chopper 2nd Gear Member Join Date: Jun 2009 Location: Nanaimo, BC, Canada Posts: 504 My Mood:	Re: passport 88bbk Looks like I'll be travelling into new territory with this build as soon as I get the case I'll add some pics and measurments.

08-21-2009, 11:31 PM	#15 (permalink)
mexicanyella El rey de los puntos Join Date: Aug 2008 Location: Troy, MO Posts: 987	Re: passport 88bbk Yeah, that's an interesting point; I recently took apart a Chinese 110cc motor out of a trashed quad. It had the e-start reverse-flywheel arrangement and a different taper than any of my old 6V motors (I assumed it was the same taper as the 12V CDI motors, but maybe not...?) but it was the 52.4mm bore/49.5 mm stroke common 110 arrangement. I got that motor for about $30, give or take, and it had a usable crank that I believe is now being used in a race bike another member here built. If you want to go stroker, check out your local craigslist for people unloading trashed Chinese ATVs or bikes with the 90 or 110 clone motors. A couple members here, including Firepower, explained to me how I could swap the whole longer 69mm cylinder, longer studs, longer cam chain, larger-port chinese E22 head and the 49.5mm crank onto this ATC70 motor I was working on and get a cheap stroker. Then I decided against going with 12V CDI electrics in my old bike, and to keep my 6V ignition I couldn't use the 49.5 crank. But maybe that could be a cheap and sensible route for you...?

08-21-2009, 11:56 PM	#17 (permalink)
z50 chopper 2nd Gear Member Join Date: Jun 2009 Location: Nanaimo, BC, Canada Posts: 504 My Mood:	Re: passport 88bbk I want to keep it all honda but with a bbk.

08-22-2009, 12:35 PM	#18 (permalink)
s_10onbagz 3rd Gear Member Join Date: Sep 2007 Location: Connecticut. Posts: 1,550	Re: passport 88bbk If you have a complete 82-83 bottom end you can bore your cases and throw a 95cc big bore kit (for a race head) right on with the stock head. That would be fun. I always wondered how much compression the c70 starter or starter chain could handle. Like I said, getting a carb to fit was my biggest battle.

08-26-2009, 08:03 PM	#19 (permalink)
z50 chopper 2nd Gear Member Join Date: Jun 2009 Location: Nanaimo, BC, Canada Posts: 504 My Mood:	Re: passport 88bbk grrr as hard as I look I can't seem to find a left side cover for and 82/83 engine. So I might end up going with a 81 6volt engine. Unless ofcourse someone has the left cover kicking around or the 81 c70 side covers can be converted to be used on an 82/83 engine.

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