Planet Minis

Thumpin90 · 08-22-2007, 08:29 PM

what motors will and wont fit.

turn8a · 08-22-2007, 08:37 PM

Quote:

Originally Posted by Thumpin90

what motors will and wont fit.

I have a 120cc engine from a thumpstar in an 1985 z50

dirtbkr188 · 08-22-2007, 08:59 PM

Any other Z50/XR50/CRF50 engine will bolt right in, and so will any CT70/ATC70/TRX70 engine. Most of the Chinese engines will also bolt right in.
A 1964 Corvette 327CI/365HP small block won't fit...sorry

Thumpin90 · 08-23-2007, 10:57 PM

will a SDG 50cc motor fit

Thumpin90 · 08-23-2007, 11:03 PM

???????????????????????????????????????????????

dirtbkr188 · 08-24-2007, 07:55 AM

probably...

fitty · 02-09-2009, 01:19 AM

On that topic.....

I just entered the scene by buying a 1969 K0 (I think) and a 1976 z50.

I was thinking of trying to make the '76 steetable. That 3speed 50cc isn't going to cut it, or is it?

What engines should I stay away from and what ones would you recommend. I'd like to save money but I'm also willing to spend a fair amount... I guess I just want to hear about the bang-for-buck options out there.

Are the chinese engines that bad?

Thanks!

cdoublejj · 02-09-2009, 01:55 AM

i have a Lifan 125 starts with about 3 kicks every time, unless it's below zero it doesn't want to start. has lots of power and was cheap except for those ignition systems i fried, woops forgot the ground

actually it ran for about 5 minutes with no ground on the cdi ahaha. It is a great engine, and will be even better once i get the high performance parts installed.

firepower354 · 02-09-2009, 03:43 AM

No luck mounting a Pratt & Whitney radial, either.

mexicanyella · 02-09-2009, 07:19 AM

But to be fair, radials--Pratt & Whitney or otherwise--are tough to fit in almost everything.

If you go the Chinese clone route, or the later Z/XR/CRF route, be aware you're talking about 12V CDI ignition, which requires additional external components (CDI box, different coil) to be mounted, and the actual tapered end of the crankshaft where the flywheel mounts is shaped differently than the earlier motors, which had 6-volt points ignitions. Also, Z50Rs after '79 and before the switch to 12V CDI had a different taper than the Z50A motors ('68-'7

.

The rest of the board is probably rolling their eyes right now because I have recently asked a bunch of questions about this myself; I wanted to put a Chinese 107cc clone in a hardtail Z50, but wanted to keep the points ignition, and couldn't come up with a crank that would work, so changed direction. But others willing to defect to the 12V CDI camp have put the more complex later ignition on older bikes and gained more lighting output, etc.

Someone please correct me if I got some of this wrong.

I have ridden a fair bit on the street with a stock Z50 hardtail. I can do that in Missouri because it technically fits into our "motorized bicycle" (moped) law. But it is marginal and you want to avoid streets with speed limits over 30 mph.

fitty · 02-09-2009, 08:41 AM

Nobody has said anything bad about the Chinese engines yet!

I think I'm going to get a 125 or 150cc engine off of ebay and slap 'er in. I like the idea of CDI and 12v. I want it to be fast and reliable.

Will my 76 exhaust still fit? I heard someone say they had a prob clearing the frame with the carb on a 125, know what I mean?

LoudFastUgly · 02-09-2009, 12:33 PM

"Big" Bore engines (70cc plus without alteration to bore or stroke) will require different exhaust a: to run, b: to fit.

You'll most likely want an adjustable rotation mount for your intake as well.

Check out trailbikes or CHP classic honda parts

Or you could go with this...

A Rolls Royce Merlin V12 27 Liter; ~ 2000 HP on AV gas.

Pretty sure it's got torque enough to run a 17 tooth up front...

cdoublejj · 02-09-2009, 12:39 PM

I ran my 125 with stock 50 pipe and it still had power, not as much after the minigunz, not it does wheelies when you crack the throttle.

fitty · 02-09-2009, 12:52 PM

I want a 4speed and to be able to 50mph+

So if I go with a newer big bore 12v I'll need a new harness and swap some bulbs, ya?

So you figure my stock exhaust will not fit then, eh? I can imagine how it'd choke the power out but it would be nice if I could at least run the bike without spending the extra $200 for exhaust.

Do you recommend a particular manufacturer of engine? How much should I be paying for it?

mexicanyella · 02-09-2009, 01:10 PM

I had one guy, a guy I bought some parts from here on PM that goes by the name Oilspot, tell me that he put a bigger Chinese engine...I think it was a 107cc...in a Z50 and ran the stock exhaust, and it did fine for goofing around in the back yard. Might be worth a try.

But those Chinese 86cc, 107cc and up have longer cylinders, by about 6mm, than a Honda 50 or 70, so the exhaust port is that much farther away from the frame's mounting points. Might make "does fit" into "almost fits" and you may have to modify the mounts slightly to suit.

What about that, cdoublejj? Did you have to egg-shape any holes or persuade the headpipe of the stock system to get it into the exhaust port with the 125cc motor?

It might be a better idea to leave the stock pipe alone and sell it or keep it around for going back to original someday, and make or buy a pipe for the new motor.

fitty · 02-09-2009, 02:54 PM

Thanks for that wicked info, man!

Stuff like that could cause me serious fun delay if i'm not prepared for it.

I'm going to surf ebay until I find a good plant. I guess that's the only competetive source, no?

2kids1zb · 02-09-2009, 06:09 PM

look at 125's and 110's. fit good with front fender, and go plenty fast. I have a 110 Lifan in a 86 z50 and its great. picked up a sdg pit bike exhaust from ebay for super cheep and modified it to work on the z, super fun bike now. go for it, you can do it.

08-22-2007, 08:29 PM	#1 (permalink)
Thumpin90 2nd Gear Member Join Date: Feb 2007 Location: Chicago Posts: 925	1979 z50 engine swap what motors will and wont fit.

08-22-2007, 08:59 PM	#3 (permalink)
dirtbkr188 3rd Gear Member Join Date: May 2004 Location: New Jersey Posts: 2,972	Re: 1979 z50 engine swap Any other Z50/XR50/CRF50 engine will bolt right in, and so will any CT70/ATC70/TRX70 engine. Most of the Chinese engines will also bolt right in. A 1964 Corvette 327CI/365HP small block won't fit...sorry

08-23-2007, 10:57 PM	#4 (permalink)
Thumpin90 2nd Gear Member Join Date: Feb 2007 Location: Chicago Posts: 925	Re: 1979 z50 engine swap will a SDG 50cc motor fit

08-23-2007, 11:03 PM	#5 (permalink)
Thumpin90 2nd Gear Member Join Date: Feb 2007 Location: Chicago Posts: 925	Re: 1979 z50 engine swap ???????????????????????????????????????????????

08-24-2007, 07:55 AM	#6 (permalink)
dirtbkr188 3rd Gear Member Join Date: May 2004 Location: New Jersey Posts: 2,972	Re: 1979 z50 engine swap probably...

02-09-2009, 01:19 AM	#7 (permalink)
fitty PM Newbie Join Date: Feb 2009 Location: Usually Seattle or Vancouver BC Posts: 30	Re: 1979 z50 engine swap On that topic..... I just entered the scene by buying a 1969 K0 (I think) and a 1976 z50. I was thinking of trying to make the '76 steetable. That 3speed 50cc isn't going to cut it, or is it? What engines should I stay away from and what ones would you recommend. I'd like to save money but I'm also willing to spend a fair amount... I guess I just want to hear about the bang-for-buck options out there. Are the chinese engines that bad? Thanks! Last edited by fitty; 02-09-2009 at 02:20 AM.

02-09-2009, 01:55 AM	#8 (permalink)
cdoublejj 3rd Gear Member Join Date: Oct 2008 Location: St.Joe MO Posts: 1,371 My Mood:	Re: 1979 z50 engine swap i have a Lifan 125 starts with about 3 kicks every time, unless it's below zero it doesn't want to start. has lots of power and was cheap except for those ignition systems i fried, woops forgot the ground actually it ran for about 5 minutes with no ground on the cdi ahaha. It is a great engine, and will be even better once i get the high performance parts installed.

02-09-2009, 03:43 AM	#9 (permalink)
firepower354 Advertiser Join Date: Oct 2006 Location: Flint MI Posts: 11,002 My Mood:	Re: 1979 z50 engine swap No luck mounting a Pratt & Whitney radial, either. __________________ 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.

02-09-2009, 07:19 AM	#10 (permalink)
mexicanyella El rey de los puntos Join Date: Aug 2008 Location: Troy, MO Posts: 984	Re: 1979 z50 engine swap But to be fair, radials--Pratt & Whitney or otherwise--are tough to fit in almost everything. If you go the Chinese clone route, or the later Z/XR/CRF route, be aware you're talking about 12V CDI ignition, which requires additional external components (CDI box, different coil) to be mounted, and the actual tapered end of the crankshaft where the flywheel mounts is shaped differently than the earlier motors, which had 6-volt points ignitions. Also, Z50Rs after '79 and before the switch to 12V CDI had a different taper than the Z50A motors ('68-'7. The rest of the board is probably rolling their eyes right now because I have recently asked a bunch of questions about this myself; I wanted to put a Chinese 107cc clone in a hardtail Z50, but wanted to keep the points ignition, and couldn't come up with a crank that would work, so changed direction. But others willing to defect to the 12V CDI camp have put the more complex later ignition on older bikes and gained more lighting output, etc. Someone please correct me if I got some of this wrong. I have ridden a fair bit on the street with a stock Z50 hardtail. I can do that in Missouri because it technically fits into our "motorized bicycle" (moped) law. But it is marginal and you want to avoid streets with speed limits over 30 mph. Last edited by mexicanyella; 02-09-2009 at 07:40 AM.

02-09-2009, 08:41 AM	#11 (permalink)
fitty PM Newbie Join Date: Feb 2009 Location: Usually Seattle or Vancouver BC Posts: 30	Re: 1979 z50 engine swap Nobody has said anything bad about the Chinese engines yet! I think I'm going to get a 125 or 150cc engine off of ebay and slap 'er in. I like the idea of CDI and 12v. I want it to be fast and reliable. Will my 76 exhaust still fit? I heard someone say they had a prob clearing the frame with the carb on a 125, know what I mean?

02-09-2009, 12:33 PM	#12 (permalink)
LoudFastUgly 2nd Gear Member Join Date: Aug 2008 Location: GTA, Ontario, Canada Posts: 383	Re: 1979 z50 engine swap "Big" Bore engines (70cc plus without alteration to bore or stroke) will require different exhaust a: to run, b: to fit. You'll most likely want an adjustable rotation mount for your intake as well. Check out trailbikes or CHP classic honda parts Or you could go with this... A Rolls Royce Merlin V12 27 Liter; ~ 2000 HP on AV gas. Pretty sure it's got torque enough to run a 17 tooth up front... Attached Thumbnails Last edited by LoudFastUgly; 02-09-2009 at 12:40 PM.

02-09-2009, 12:39 PM	#13 (permalink)
cdoublejj 3rd Gear Member Join Date: Oct 2008 Location: St.Joe MO Posts: 1,371 My Mood:	Re: 1979 z50 engine swap I ran my 125 with stock 50 pipe and it still had power, not as much after the minigunz, not it does wheelies when you crack the throttle.

02-09-2009, 12:52 PM	#14 (permalink)
fitty PM Newbie Join Date: Feb 2009 Location: Usually Seattle or Vancouver BC Posts: 30	Re: 1979 z50 engine swap I want a 4speed and to be able to 50mph+ So if I go with a newer big bore 12v I'll need a new harness and swap some bulbs, ya? So you figure my stock exhaust will not fit then, eh? I can imagine how it'd choke the power out but it would be nice if I could at least run the bike without spending the extra $200 for exhaust. Do you recommend a particular manufacturer of engine? How much should I be paying for it?

02-09-2009, 01:10 PM	#15 (permalink)
mexicanyella El rey de los puntos Join Date: Aug 2008 Location: Troy, MO Posts: 984	Re: 1979 z50 engine swap I had one guy, a guy I bought some parts from here on PM that goes by the name Oilspot, tell me that he put a bigger Chinese engine...I think it was a 107cc...in a Z50 and ran the stock exhaust, and it did fine for goofing around in the back yard. Might be worth a try. But those Chinese 86cc, 107cc and up have longer cylinders, by about 6mm, than a Honda 50 or 70, so the exhaust port is that much farther away from the frame's mounting points. Might make "does fit" into "almost fits" and you may have to modify the mounts slightly to suit. What about that, cdoublejj? Did you have to egg-shape any holes or persuade the headpipe of the stock system to get it into the exhaust port with the 125cc motor? It might be a better idea to leave the stock pipe alone and sell it or keep it around for going back to original someday, and make or buy a pipe for the new motor.

02-09-2009, 02:54 PM	#16 (permalink)
fitty PM Newbie Join Date: Feb 2009 Location: Usually Seattle or Vancouver BC Posts: 30	Re: 1979 z50 engine swap Thanks for that wicked info, man! Stuff like that could cause me serious fun delay if i'm not prepared for it. I'm going to surf ebay until I find a good plant. I guess that's the only competetive source, no?

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02-09-2009, 06:09 PM	#17 (permalink)
2kids1zb 1st Gear Member Join Date: Jan 2008 Posts: 139	Re: 1979 z50 engine swap look at 125's and 110's. fit good with front fender, and go plenty fast. I have a 110 Lifan in a 86 z50 and its great. picked up a sdg pit bike exhaust from ebay for super cheep and modified it to work on the z, super fun bike now. go for it, you can do it.