2 stroke is STILL unlikely, but I will ask! - Page 2

alex_in_az · 09-22-2022, 02:39 PM

Quote:

Originally Posted by Magician16

I rode a Yamaha 2 stroke in the early 70's, and at 250cc I think it had about 25 hp.

I had a early 70s TS185, made about 20bhp

Wild Dog · 09-22-2022, 06:57 PM

That's part of the charm of the 2 stroke.
You can go from a mild 15 hp in a 125cc to 30hp in the same engine.
There is a lot to play with the transfer ports and the expansion chamber.

herbie · 09-22-2022, 07:20 PM

If the sound and smell of a 2 stroke rippin it doesn't get the ole heart pumping, then either you are too young to remember the 2 stroke craze or your dead!

Give me a good ole 2 smoker please, pretty please

kevperro · 09-22-2022, 08:28 PM

We had a CanAm 175 back in the late 70s. It was a beast but totally one-note powerband and we constantly were fouling the plug. Part of that was ignorance but it ran like shit most of the time.

I had a CR250 in 1989 and that was a much better bike. I worked at a Honda dealer at the time and had access to the shop, and help when I needed it. That was a fun bike but I wouldn't buy another.

Personally, I like the 4-strokes. Working on my CR was fun and it was extremely easy to work on. I could have that bike apart almost completely in 15-minutes. The top end was easy to rebuild and it didn't cost much.

But I'll take the few extra pounds for the ease of living with a 4-stroke. They run cleaner, sip fuel, are easy to start (when you have an electric start), and the power curve is more usable.

Magician16 · 09-22-2022, 08:33 PM

Remember the 500 and 750 Kawasaki triples? Those things were some rip roaring fun. The front end came off the ground when you hit the right part of the power curve no matter what gear you were in.

Megadan · 09-22-2022, 09:00 PM

The real charm of a 2 stroke is the power for a given engine size. A CR125R basically makes double the power of a CG250 with half the cc. If I can get my hands on a good cr125 engine for a reasonable price I am honestly considering swapping my Hawk out. Just because lol

Bruces · 09-22-2022, 09:54 PM

You guys thinking that two strokes are “dirty” should do some looking at Evinrude Etec outboards ,they sip fuel ,clean as a 4 stroke ,use almost no oil and they have been around for almost 20 years .Unfortunately ,evinrude gave up on the outboard market a year or two ago ,but the engines were proven ,and the technology could easily be applied to a motorcycle .

Magician16 · 09-23-2022, 07:53 AM

Quote:

Originally Posted by Bruces

You guys thinking that two strokes are “dirty” should do some looking at Evinrude Etec outboards ,they sip fuel ,clean as a 4 stroke ,use almost no oil and they have been around for almost 20 years .Unfortunately ,evinrude gave up on the outboard market a year or two ago ,but the engines were proven ,and the technology could easily be applied to a motorcycle .

Basically the same injection system is used in the Skidoo 2 stroke snowmobiles. Bombardier(BRP) bought OMC which owned Evinrude. Skidoo is a Bombardier company.

Maiphut · 09-24-2022, 03:02 AM

Oils are a lot cleaner burning these days and can run much leaner ratios which helps.

I see the 23 KTM/Husky are moving to a true throttle body injection.

I've had a few 2 strokes over the years, CR125 Elsinore(wish I kept it), 93 DT200R and 98 RMX250. Wish I still had them all, fantastic bikes. I still get to see the RMX250 often as my mate bought that and has looked after it very well, in great condition even after a crash or 2 and some repairs and a new rim lol.

While I have a YZ450 atm it definately does not last any longer than a 2 stroke, you still got to change the rings and possibly piston around the same amount of engine hours. The torque is nice. Then when the head needed replacing, yea that broke the bank.

Looking at prices recently for new 23 bikes my jaw dropped, everything has gone up.. 17k for a WR450

makes the poorer people like me look harder at the other options

Thumper · 09-24-2022, 10:31 AM

I rebuilt a 1976 Suzuki TS250 dirt bike engine when I was 16 years old. I didn't even have a proper tool set! It was just like this one I found decades later:
http://www.chinariders.net/showthread.php?t=30118

I replaced second gear and the drive shaft (or was it second counter gear and the countershaft). It was frozen on the shaft. I had loaned it to a friend that let it run out of injection oil and rode it for a few miles in 2nd gear.

I also replaced all seals, gaskets, bored the cylinder to 270cc, new piston/rings, new bearings on all shafts. And I added an expansion chamber.

HOLY COW! It ripped!! Wouldn't stop accelerating right away when I let off the throttle until I rejet it. It would stall when it finally let up. Way too lean. After rejet, it was magnificent! A real beast for a 16 year old! Screamer!

I paid $250 for the bike (used), and probably $350 for all of the parts when I fixed it. It all went smoothly, very simple assembly. The last step was getting the gear shift sliders in place with the two crankcase halve almost closed. I reached in with a skinny screw driver to push it into place. It took 3 or 4 tries, but when it was right, the two halves closed right up with a deliberate "right" feel. I was a complete novice mechanic, so I guess it MUST be easy to work on 2 stokes!

09-22-2022, 07:20 PM	#18
herbie Join Date: May 2019 Location: Illinois Posts: 864	If the sound and smell of a 2 stroke rippin it doesn't get the ole heart pumping, then either you are too young to remember the 2 stroke craze or your dead! Give me a good ole 2 smoker please, pretty please __________________ 2022 Venom KPR 200 Red- the fastest color 16t and 46t sprockets, NGK Iridium CPR8EAIX-9, aftermarket full exhaust system. Top speed 81GPS 2023 Venom SS3 KP mini 150– Nibbi carb, Nibbi air filter, aftermarket muffler, decat 2022 Venom Ghost chopper 250 1997 Honda GL1500 Goldwing 1978 Kawasaki KL250 https://youtube.com/@herbiesgarage681
	1

09-22-2022, 08:33 PM	#20
Magician16 Join Date: Aug 2019 Posts: 472	Remember the 500 and 750 Kawasaki triples? Those things were some rip roaring fun. The front end came off the ground when you hit the right part of the power curve no matter what gear you were in. __________________ 2018 Bashan Storm(sold) 2016 Magician 250
	1

09-22-2022, 09:00 PM	#21
Megadan Join Date: Apr 2017 Location: Omaha, NE Posts: 8,100	The real charm of a 2 stroke is the power for a given engine size. A CR125R basically makes double the power of a CG250 with half the cc. If I can get my hands on a good cr125 engine for a reasonable price I am honestly considering swapping my Hawk out. Just because lol __________________ Hawk Information and Resource guide: http://www.chinariders.net/showthread.php?t=20331 2018 Hawk 250 - Full Mod list here. http://www.chinariders.net/showpost....62&postcount=1 2024 Royal Enfield Shotgun 650 https://chinariders.net/showthread.php?t=34124
	0

09-22-2022, 06:57 PM	#17
Wild Dog Join Date: Dec 2016 Location: Argentina Posts: 756	That's part of the charm of the 2 stroke. You can go from a mild 15 hp in a 125cc to 30hp in the same engine. There is a lot to play with the transfer ports and the expansion chamber.
	2

09-22-2022, 08:28 PM	#19
kevperro Join Date: May 2022 Location: Washington Posts: 25	We had a CanAm 175 back in the late 70s. It was a beast but totally one-note powerband and we constantly were fouling the plug. Part of that was ignorance but it ran like shit most of the time. I had a CR250 in 1989 and that was a much better bike. I worked at a Honda dealer at the time and had access to the shop, and help when I needed it. That was a fun bike but I wouldn't buy another. Personally, I like the 4-strokes. Working on my CR was fun and it was extremely easy to work on. I could have that bike apart almost completely in 15-minutes. The top end was easy to rebuild and it didn't cost much. But I'll take the few extra pounds for the ease of living with a 4-stroke. They run cleaner, sip fuel, are easy to start (when you have an electric start), and the power curve is more usable.
	0

09-22-2022, 09:54 PM	#22
Bruces Join Date: May 2018 Posts: 1,616	You guys thinking that two strokes are “dirty” should do some looking at Evinrude Etec outboards ,they sip fuel ,clean as a 4 stroke ,use almost no oil and they have been around for almost 20 years .Unfortunately ,evinrude gave up on the outboard market a year or two ago ,but the engines were proven ,and the technology could easily be applied to a motorcycle .
	1

09-24-2022, 03:02 AM	#24
Maiphut Join Date: Sep 2022 Posts: 4	Oils are a lot cleaner burning these days and can run much leaner ratios which helps. I see the 23 KTM/Husky are moving to a true throttle body injection. I've had a few 2 strokes over the years, CR125 Elsinore(wish I kept it), 93 DT200R and 98 RMX250. Wish I still had them all, fantastic bikes. I still get to see the RMX250 often as my mate bought that and has looked after it very well, in great condition even after a crash or 2 and some repairs and a new rim lol. While I have a YZ450 atm it definately does not last any longer than a 2 stroke, you still got to change the rings and possibly piston around the same amount of engine hours. The torque is nice. Then when the head needed replacing, yea that broke the bank. Looking at prices recently for new 23 bikes my jaw dropped, everything has gone up.. 17k for a WR450 makes the poorer people like me look harder at the other options
	0

09-24-2022, 10:31 AM	#25
Thumper Join Date: Feb 2021 Location: Kansas City Posts: 2,578	I rebuilt a 1976 Suzuki TS250 dirt bike engine when I was 16 years old. I didn't even have a proper tool set! It was just like this one I found decades later: http://www.chinariders.net/showthread.php?t=30118 I replaced second gear and the drive shaft (or was it second counter gear and the countershaft). It was frozen on the shaft. I had loaned it to a friend that let it run out of injection oil and rode it for a few miles in 2nd gear. I also replaced all seals, gaskets, bored the cylinder to 270cc, new piston/rings, new bearings on all shafts. And I added an expansion chamber. HOLY COW! It ripped!! Wouldn't stop accelerating right away when I let off the throttle until I rejet it. It would stall when it finally let up. Way too lean. After rejet, it was magnificent! A real beast for a 16 year old! Screamer! I paid $250 for the bike (used), and probably $350 for all of the parts when I fixed it. It all went smoothly, very simple assembly. The last step was getting the gear shift sliders in place with the two crankcase halve almost closed. I reached in with a skinny screw driver to push it into place. It took 3 or 4 tries, but when it was right, the two halves closed right up with a deliberate "right" feel. I was a complete novice mechanic, so I guess it MUST be easy to work on 2 stokes!
	1