Zongshen 200, OHC, or pushrod? - Page 3

red2003 · 10-09-2007, 02:59 PM

Quote:

Originally Posted by Phil_R

Honda describes the engines in all their current utility ATV models as OHV. Most flathead/side-valve/L-head engines were/are "pushrod" engines... Much easier to adjust pushrods/tappets, instead of removing valve and grinding stem to length. (Some engines used adjustable pushrods, some adjustable tappets/lifters.)

Moto Guzzi currently produces some nice "pushrod" OHV engines... BMW's current "boxer" twin is a "high-cam" (not OHC) engine with short pushrods. Quite modern OHV engines, and impressive performance.

Good info!

Nate · 10-09-2007, 03:15 PM

Ya for larger engines, especially for V's and boxers pushrods make a lot of sense.

With those type engines you can get away with having a single cam in the middle of the motor and having pushrods going out to rocker arms (or whatever). This makes the motors less expensive, lighter, simplier and more compact.

Imagine having a V-8 with a single cam in the middle, in the valley of the 'V'.

Now imagine instead with a OHC V8 motor with the complex arangement of gears, pulleys, and belts needed to power the cams at the far ends of the motor and keep the timing accurate and expensive materials needed for long-life and such things. Expensive, large, and heavy.

Now with Inline fours and Inline six motors then OHC makes much more sense and with smaller engines they will work better with the high revs needed to compinsate for lack of displacement.

With thumpers. though, I don't know. I think it's a wash either way. Your only dealing with a single cylinder and it's not like pushrods are that heavy. I personally don't care and I probably would lean towards the OHV : ) because it would be easier to replace the exhaust valves and such (which I would assume would be the first things to go on these air-cooled motors.)

tzrider · 10-10-2007, 12:38 PM

Quote:

There are still lots automotive engines using pushrods, but other than the Chinese, no bikes that I know of.

HD/buell
Moto Guzzi
BMW R series boxers

Three modern bikes that come to mind. Buell has stressed the old OHV Sportster motor beyond design limits over the years trying to get horsepower with a 6K rev limit (the valve train), so now they have a new Rotax motor sourced from Austria designed and built just for Buell, a DOHC 8 valve twin. The old 2 valve per cylinder OHV motors made just under 100 horsepower for 1200cc. The new motor is advertised at 148 horsepower and is a little over a liter in size, I believe. It revs to 10,500 rpm IIRC, or at least a lot higher than the old motor. That bike is all the buzz in Buell circles right now and they had a Buell day at a track near Fort Worth recently. I thought about signing up for a test ride, but don't have the time. 7 hour ride to that track for me.

tzrider · 10-10-2007, 12:43 PM

BTW, the Buell Blast is a OHV single cylinder 500cc motorcycle. From all I've read, though, it's a POS that makes our chinese bikes look like Japanese reliability by comparison.

There used to even be a web page dedicated to the Buell's lack of reliability, had a lemon on the cover page.

Some of the horror stories there were heart breaking.

A LARGE portion of those stories involved the Blast.

silverman1 · 10-10-2007, 04:39 PM

The OHC motors make more of thier power on top, higher revs, but the but the pushrod motors seem to make more torque power down low and level off at a lower rpm top redline. I know honda changed some of thier later model atvs to pushrod motors creating more torque down low and less of a need to rev the crap out of them. It does seem kinda of senseless in a passenger car to be spinning 4 cams, running cam chains or belts everywhere versus pushrods and one cam. like v-6s or eights. If things break big time cost guranteed.

Well enough of my bullshit

katoranger · 10-11-2007, 09:42 AM

My bike doesn't like to rev over 8k rpm. It does have plenty of low end grunt though.

Allen

Nate · 10-11-2007, 11:06 AM

Quote:

Originally Posted by tzrider

BTW, the Buell Blast is a OHV single cylinder 500cc motorcycle. From all I've read, though, it's a POS that makes our chinese bikes look like Japanese reliability by comparison.

There used to even be a web page dedicated to the Buell's lack of reliability, had a lemon on the cover page.

Some of the horror stories there were heart breaking.

A LARGE portion of those stories involved the Blast.

Ya the Blast would be a very kick-ass little bike if it wasn't for the Harley Motor.

Beul does some very cool things and innovative things, but being stuck with Harley engines in these things is like trying to polish a turd.

Any modern Jap motorcycle is about as reliable as any automobile.

Phil_R · 10-11-2007, 11:48 AM

2002 Buell Blast: Purchased as a "repo" with less than 25 miles... paid China Bike price. In 5 years it has needed gas, oil, filters, and tires... lots of tires. Shop bike / loaner / commuter... hope my LF200GY-5 is as dependable and inexpensive to operate. Blast is currently my son's work vehicle... everyday, year-round, rain or shine.

knothead · 10-11-2007, 07:40 PM

Quote:

Originally Posted by Nate

Ya the Blast would be a very kick-ass little bike if it wasn't for the Harley Motor.

Beul does some very cool things and innovative things, but being stuck with Harley engines in these things is like trying to polish a turd.

Any modern Jap motorcycle is about as reliable as any automobile.

You mean 1/2 of a Harley motor! I cannot belive they kept that huge honkin tranny on half an engine. I found a Blast for $2300, looked at it for about 5 minuets and decided I really didn't care for the things at all. Now if they had put some effort into the design, at least a somewhat serious attempt, it might have been an attractive bike. As it is I would take a Ninja or GS 500 over a blast any day of the week.

mrhyak · 10-11-2007, 08:32 PM

A co-worker had one. I thought it was a cool looking bike, but after I took it for a spin I decided it was one of the worse riding road bikes I had ever been on.

10-10-2007, 04:39 PM	#35
silverman1 Join Date: Jul 2007 Posts: 42	Not really sure but just speculation The OHC motors make more of thier power on top, higher revs, but the but the pushrod motors seem to make more torque power down low and level off at a lower rpm top redline. I know honda changed some of thier later model atvs to pushrod motors creating more torque down low and less of a need to rev the crap out of them. It does seem kinda of senseless in a passenger car to be spinning 4 cams, running cam chains or belts everywhere versus pushrods and one cam. like v-6s or eights. If things break big time cost guranteed. Well enough of my bullshit
	0

10-11-2007, 09:42 AM	#36
katoranger Join Date: May 2007 Location: Altamont, Kansas Posts: 15,103	My bike doesn't like to rev over 8k rpm. It does have plenty of low end grunt though. Allen __________________ You meet the nicest people on a Honda Clone.
	0

10-11-2007, 11:48 AM	#38
Phil_R Join Date: Sep 2007 Location: Live Oak, FL Posts: 43	2002 Buell Blast: Purchased as a "repo" with less than 25 miles... paid China Bike price. In 5 years it has needed gas, oil, filters, and tires... lots of tires. Shop bike / loaner / commuter... hope my LF200GY-5 is as dependable and inexpensive to operate. Blast is currently my son's work vehicle... everyday, year-round, rain or shine. __________________ Phil '18 FXBB Softail Street Bob '17 Tacoma TRD
	0

10-11-2007, 08:32 PM	#40
mrhyak Join Date: Jul 2007 Location: Hyak, WA Posts: 448	A co-worker had one. I thought it was a cool looking bike, but after I took it for a spin I decided it was one of the worse riding road bikes I had ever been on. __________________ 1985 Kawasaki Tecate-3 1997 Ural Sportsman 2WD 1980 Yamaha XS1100 2005 TANK Trail 200 2009 Lifan LY110GY-3 (2)
	0

10-09-2007, 03:15 PM	#32
Nate Join Date: Aug 2007 Posts: 24	Ya for larger engines, especially for V's and boxers pushrods make a lot of sense. With those type engines you can get away with having a single cam in the middle of the motor and having pushrods going out to rocker arms (or whatever). This makes the motors less expensive, lighter, simplier and more compact. Imagine having a V-8 with a single cam in the middle, in the valley of the 'V'. Now imagine instead with a OHC V8 motor with the complex arangement of gears, pulleys, and belts needed to power the cams at the far ends of the motor and keep the timing accurate and expensive materials needed for long-life and such things. Expensive, large, and heavy. Now with Inline fours and Inline six motors then OHC makes much more sense and with smaller engines they will work better with the high revs needed to compinsate for lack of displacement. With thumpers. though, I don't know. I think it's a wash either way. Your only dealing with a single cylinder and it's not like pushrods are that heavy. I personally don't care and I probably would lean towards the OHV : ) because it would be easier to replace the exhaust valves and such (which I would assume would be the first things to go on these air-cooled motors.)
	0

10-10-2007, 12:43 PM	#34
tzrider Join Date: Jul 2006 Location: Texas by gawd! Posts: 407	BTW, the Buell Blast is a OHV single cylinder 500cc motorcycle. From all I've read, though, it's a POS that makes our chinese bikes look like Japanese reliability by comparison. There used to even be a web page dedicated to the Buell's lack of reliability, had a lemon on the cover page. Some of the horror stories there were heart breaking. A LARGE portion of those stories involved the Blast.
	0