Topic: cb 750 versus z1 900 any thoughts

[scottly]

   I still have my turbocharged Z1 - 1200cc's and very fast.  That is the first bike I can honestly say I feel the frame flexing under serious load in 3rd gear - and that's with some frame bracing added - but then it's making somewhere between 130 and 150 hp for a frame designed for 80 hp.

I met a guy on Skyline Drive, near Alice's Restaurant about '80, with a turbo-ed Z1. He also mentioned feeling the frame flex when the turbo spooled up. It wasn't you, was it?

[seanbarney41]

   I still have my turbocharged Z1 - 1200cc's and very fast.  That is the first bike I can honestly say I feel the frame flexing under serious load in 3rd gear - and that's with some frame bracing added - but then it's making somewhere between 130 and 150 hp for a frame designed for 80 hp.

I met a guy on Skyline Drive, near Alice's Restaurant about '80, with a turbo-ed Z1. He also mentioned feeling the frame flex when the turbo spooled up. It wasn't you, was it?

pictures please

[dave500]

the z900 is an attractive bike,bikes back then they had attractive engines,this was probably most of the selling point?heres a 900 today at a local show close to my place,not really visable here but the end of those tail pipes have been laid on the ground and scuffed badly,it looks recent,poor bugger,a bit off topic but also today this guy with a super charged and nitros harley show bike went to start it not sitting on the bike,off course it was in gear and lucky the engine didnt fire it almost fell off the side stand.

i wonder what the aussie bikie movie "stone"wouldve been like if the honda 750 had of been used instead of the 900?
heres a better angle on that tailpipe scratch,you can see it on the lower pipe,the upper also has it.

[dhall57]

Never had one, but the Kaw 900 with it's larger dohc engine was a jump up in speed and pure power back in the day. And if that's all you were after than go with the Z1. But IMO the CB750 was a much better all around bike, it just did everything well. I guess you could say the Honda CB750 was and still is the Total Package

[750K]

i wonder what the aussie bikie movie "stone"wouldve been like if the honda 750 had of been used instead of the 900?

I hate to say it but it wouldn't have been as good with Hondas instead of Kawi's, same with mad max. That's half the movie for me with both films and I love my Cb750. The norton Stone rides just doesn't compare either, love that movie.

[dave500]

yeah i think all the actors actually rode the bikes?so heres your agent,back in the day,,"hey ive got you a gig in a film playing a bikie riding new kawasaki 900s and you have to learn how to ride"?you want in?,,,#$%* yeah!

[Terry in Australia]

I think it's always going to be difficult to get honest first hand opinions when asking whether a non-SOHC4 could possibly be a better bike, so it's great to read Jeff's post, the most credible one for me, so far.

I'd already owned two CB750's by the time I bought my 1975 Kawasaki Z900 in 1985, so I was pretty well experienced with CB750's. The Kawasaki blew me away, it was wickedly fast in comparison, (I'd never popped a wheelie on a CB750 and I did one in the first week of Z900 ownership accidentally) and while I never got mine to handle as well as my best friend's Moto Guzzi, it handled as well as either CB750 I'd owned.

Regardless of what's been said here before Jeff's post, I'd never seen or heard of a CB750 beat a Z1 at a stoplight drag race, much less a real drag race. By the mid 1970's Honda had all but given up on racing the CB750, such was the impact of the Z1. Compared to the Z1, the CB750 engine is fragile in the extreme, it's not unusual to find 140 BHP Kawasaki engines with stock cranks, rods and transmissions still running reliably 20 years after they were built. The only bottom end mod needed to ensure reliability in racing situations was welding up the "built up" crankshaft, but that's (literally) a small price to pay for a bulletproof engine.

There was only one bike that was better than the Z1 or KZ1000 in the 1970's, and that was the Suzuki GS1000. Suzuki "borrowed" heavily from Kawasaki's engine design, but built a much sturdier frame, and motorcycle magazines of the era described it as the best bike of the 1970's.

From 1978, motorcycle racing was a two horse race, and unless a bike's tank badge started with a "K" or an "S", it was just an "also ran". Not a popular view of history I know, but I was there, and that's how it really was. I still love my CB750, but you can't argue with facts, and that's where Jeff's post is so refreshing, compared to some of our other "experts" views. Cheers, Terry.    

[dave500]

[Jeff.Saunders]

Ford versus Chevy, Lager versus Real Ale, Honda versus Kawasaki - you can argue all day as to which one is better.

In the evolution of the motorcycle, when you look at the family tree, the CB750 is clearly a milestone motorcycle.

It brought a reliable larger cc motorcycle to the masses - a bike happy on the open road, comfortable for 2 people.  No longer did you need to be a mechanic to own a motorcycle.  No puddles of oil in the driveway anymore.  Smooth running, very reliable and nice looking.  It was not particularly fast for its day - but fast enough to appeal to many people.  Honda set a benchmark which lasted for 3-4 years.  Then came the Z1.

The Z1 is also a milestone motorcycle.   You can easily argue the Z1 is the grandfather of all the sport bikes today.  When it came out it obliterated performance records - 160mph average speed around Daytona on a tweaked Z1 (Yvon Duhamel), 24 hour performance records - many stood for decades.  The DOHC formula is prevalent on all performance bikes now.  So much about the Z1 engine set the yardstick for all the following engines.  Suzuki blatantly copied it to create the GS1000 - the cylinder spacing is exact (you can drop a GS head on a Z1 cylinder block and everything lines up!).

Each generation of motorcycle brings something new to the market.  It's not always about which is best, but appreciating what each brought to the market.

[Dave K]

In 1970 when I bought my '70 500 H1, I bought it because of performance at a low price. I was also kind of a 2 stroke fan as well. But I couldn't deny the CB 750 when I first heard one in the middle of the night. The sound and polish was awe inspiring to me. I waited until June '73 to buy my new K3 750. I had thought of a Z1, but the experience of the H1 told me to NEVER, EVER put another dollar in Kawasaki hands. Of which I never wavered. The H1 500 was just such a horrible experience, I almost went away from motorcycles. I was actually kind of crushed when the Z1 came out and left me with a "2nd rate" bike like the 750 K3, compared to then new Z1. Now don't get me wrong, the K3, that I bought new, is still very much alive, in my garage.  I had it for a 25 mile ride just yesterday. It will probably roll over to 48,000 miles this week and has NEVER EVER gave me grief. It has done everything for me, from spirited ridding, to long trips behind the Vetter fairing it used to carry. So far, maintenance and reliably, it has been the very best bike I have ever owned and that means so far comparing to my 'Wing. If there is a weakness in ownership to me for the 750, it has to be the attractive, but horrible rusty exhaust system. My first set of pipes lasted less than a year and were getting holes in them in that year, by the time they had 7000 miles. But, Honda warranted new ones to me. The other problem taken care of by warranty was the Tach went bad within the first 2 weeks and a new one was quickly put on. Only an opinion. but it seems to me that even though the other motorcycle companies my have had their inlines on the drawing board, Honda without question set a pretty tall order for them to follow. Like many "good" companies, the other manufactures had a good view of what it took to make a 4cyl.  even better and so they did. When I took the K3 out the other night, it is no wonder I have owned that bike 39yrs. It is just so smooth to me, the power is adequate,even by todays standard. I can handle it easily. Funny, how times change. When I bought this bike I was 20yrs. old. Rolling her off of the showroom floor that day, I thought to myself, what did I buy. It was BIG, it was top heavy, it seemed huge! Now it seems small. I bought the bike 512 miles from home. Drove it straight through to get home with it. Arriving home at 1AM the next day, it was one heck of a day, to ride a brand new bike all that way, I still love it today. I can still recall the glow of those gauges that night in June of 1973 on that first 500+mile ride and the prrr of those pipes.

[PeWe]

Kawawsaki Z1-900 has a really beautiful design. Look much better than CB750
It's strange that the 1977 Z1-1000 which has the same design and rear disc brake has not the same WOW factor as the older Z1-900. Maybe 900 was programmed in my brain in young years...
I saw an OEM Z1-900 74-75 on internet sale earlier this year here, went for about $8500US.

A Z1-1000 with clip-ons or clubman or dragbar and nice sounding 4-1 (yoshi or devil) would be nice.
I had a friend 30 years ago that had a Z1-1000 -77 with ported head, RC cams, RC pistons (1000-1100cc), Dellorto carbs, trap-door for oilpump,  RC 4-1. It ran very well and with the correct sound! 

[754]

 Terry I think that the bearing cap girdle is a wise mod as well...

[Bailgang]

Regardless of what's been said here before Jeff's post, I'd never seen or heard of a CB750 beat a Z1 at a stoplight drag race, much less a real drag race. .

I'm not arguing which bike is faster/better but I swear I wish I had a $ for every time somebody made a comment like that because I'd be rich now. Hondaman saying he never lost to a 900, my older brother saying his H2 never got beat, Terry saying he never saw a cb750 beat a Z1, I mean come on somebody had to have gotten their butt whooped and isn't admitting it.

[754]

 I have seen a 750 beat a Z1 the first 200 feet smoked him bad....  I ended up buying those Webers,  and the gearing ..

[dhall57]

Time and technology march on. When the Honda CB750 came out in 69 like we all know it changed motorcycling. It was fast, but it was so much more than just that. It was reliable, had frt. disc brake, electric start, handle good, and didn't vibrate your teeth out and no matter what angle you looked at it the bike looked great. As the years went by Honda concentrated more on refinning the 750 not so much in the performance end but in making it a all around great motorcycle that anyone could ride and enjoy. Of course a stock Z1 900 dohc with 903cc at 82hp is going to be faster than a stock 750 sohc with 736cc at 67hp. Both these bikes broke new ground when they were introduced. The CB750 in 1969 and the Z1900 in 1973.

[MRieck]

Kawawsaki Z1-900 has a really beautiful design. Look much better than CB750
It's strange that the 1977 Z1-1000 which has the same design and rear disc brake has not the same WOW factor as the older Z1-900. Maybe 900 was programmed in my brain in young years...
I saw an OEM Z1-900 74-75 on internet sale earlier this year here, went for about $8500US.

A Z1-1000 with clip-ons or clubman or dragbar and nice sounding 4-1 (yoshi or devil) would be nice.
I had a friend 30 years ago that had a Z1-1000 -77 with ported head, RC cams, RC pistons (1000-1100cc), Dellorto carbs, trap-door for oilpump,  RC 4-1. It ran very well and with the correct sound!

I hate to say it but that is very true.

[754]

 There will alway be bikes that are quick out of the hole.. Some riders are just not good at it.
 I know my buddies sohc gets 60 foot times, that are better than stock Busa's..
 but I am thinking that in the higher hp bikes getting of the line would be trickier..

[Jeff.Saunders]

There will alway be bikes that are quick out of the hole.. Some riders are just not good at it.
 I know my buddies sohc gets 60 foot times, that are better than stock Busa's..
 but I am thinking that in the higher hp bikes getting of the line would be trickier..

Getting the most out of a bike isn't easy.  I raced for two years competing 15+ weekends a year.  The first year was a massive learning experience.  It isn't easy to come off the line consistently every run.  Many times I would spin the tire or have the front wheel climbing for the sky.  Between learning to launch, the next issue was gearing the bike to get the most out of it.  I probably tried every possible permutation of front and rear sprocket.  I also experimented with different tires and tire pressure.  While I had a fairly fast bike, the first year I was beaten a few times when I should have won those rounds.  The second year was much easier.  I had the bike performing better, and I was very consistent.  I was much better at getting the balance perfect with the back wheel spinning a little and the front wheel just bounding in the air..  Out of 15+ events, I ended up with 3 x 1st places and 5 x 2nd places - this was heads up racing with a field of 16 riders - all with totally street legal bikes - no wheelie bars, no slicks and you had to run working suspension.  The bigger GS and KZ engines were tough to beat - my bike was only 1015cc - and I was going against 1200cc KZ's and GS's.  I won a few rounds with holeshots.

[Stev-o]

There is no doubt that both are great bikes and hold a place in motorcycle history. I believe the Honda was built more for the everyday rider and for reliability and the Kaw for high performance to beat the CB750.

Thanks to Jeff for his good posts. His Kaw is truly a beautiful bike.

[754]

 Denco pipe on that Kawi? ..looks like

[Jeff.Saunders]

Denco pipe usually exit on the LH side.

That pipe is from an English company S&S - not the same one that sells pipes in the USA.  They exusted in the 70's and seemed to have faded away by the early 80's.  Noisy as can be - I did receive a ticket for that pipe making too much noise.

[PeWe]

+++ for CB750 today is plenty of parts, tuning as well as parts for repair, restore. Plenty of new parts, not only old found in old stock somewhere now found on eBay.
For Z1-900 it might be trickier to find parts, right?

I compared my CB750 tuned with 836cc etc with a later not modified Kawasaki Z-1000R-1983. My bike ran much smoother and no irritating vibrations around +120km/hour on 5:th gear. The vibrations felt very bad from the pegs, thru the boots....
Kawasakis had generally harder engine characteristics than a CB750... right?

[Jeff.Saunders]

+++ for CB750 today is plenty of parts, tuning as well as parts for repair, restore. Plenty of new parts, not only old found in old stock somewhere now found on eBay.
For Z1-900 it might be trickier to find parts, right?

I compared my CB750 tuned with 836cc etc with a later not modified Kawasaki Z-1000R-1983. My bike ran much smoother and no irritating vibrations around +120km/hour on 5:th gear. The vibrations felt very bad from the pegs, thru the boots....
Kawasakis had generally harder engine characteristics than a CB750... right?

In terms of what is available from the OEM, Honda is far better than Kawasaki for parts.  Aftermarket, there are a massive number more Z1 parts being made than for the SOHC CB750.  There's not much you can't get now.  We stock most of the common parts - both replica and performance - hundreds and hundreds of them.

Vibration - it's down to how the engine is built.  While the Z1/KZ engines do vibrate a little, usually a carefully built engine isn't bad.  I don't think my 1200cc Z1 engine vibrates very much - although I don't tend to cruise around on that bike.

On most Z1's/KZ's, there's a vibration spot around 5,000rpm that's always good for blurring mirrors...

There are 4 main variants of Z1/KZ crank - and they all have different characteristics.  The Z1 crank is the lightest - it spins up quick, but not as much bottom end grunt.  The 77-78 cranks are very heavy - good cruising cranks.  The 79/80 cranks are the performance cranks - the best of all of them from a performance perspective - beefier and a good compromise between the light and heavy cranks.  The 81 and up cranks are similar to the 79-80 cranks, but a slightly shorter rod length.

BTW, there are some wonderful design features that come with the Z1 engines...

- You can take the head off the engine with the engine in the frame. 
- The crankcases have three special jack bolt holes in the cases.  Once you remove the crank case bolts, you thread three bolts into these jack bolt holes and evenly tighten - the cases are pushed apart by the bolts...  nice huh!

[Retro Rocket]

Aftermarket, there are a massive number more Z1 parts being made than for the SOHC CB750

I would have to disagree with that Jeff, there is nothing you can't get for the 750 Honda as far as after market stuff goes, i have literally hundreds of links to people and companies making parts for the Honda....   I started collecting Honda stuff again in the late 90's, there wasn't a lot of stuff around then, now is a totally different story, there's nothing you can't get...

[Terry in Australia]

+++ for CB750 today is plenty of parts, tuning as well as parts for repair, restore. Plenty of new parts, not only old found in old stock somewhere now found on eBay.
For Z1-900 it might be trickier to find parts, right?

I compared my CB750 tuned with 836cc etc with a later not modified Kawasaki Z-1000R-1983. My bike ran much smoother and no irritating vibrations around +120km/hour on 5:th gear. The vibrations felt very bad from the pegs, thru the boots....
Kawasakis had generally harder engine characteristics than a CB750... right?

In terms of what is available from the OEM, Honda is far better than Kawasaki for parts.  Aftermarket, there are a massive number more Z1 parts being made than for the SOHC CB750.  There's not much you can't get now.  We stock most of the common parts - both replica and performance - hundreds and hundreds of them.

Vibration - it's down to how the engine is built.  While the Z1/KZ engines do vibrate a little, usually a carefully built engine isn't bad.  I don't think my 1200cc Z1 engine vibrates very much - although I don't tend to cruise around on that bike.

On most Z1's/KZ's, there's a vibration spot around 5,000rpm that's always good for blurring mirrors...

There are 4 main variants of Z1/KZ crank - and they all have different characteristics.  The Z1 crank is the lightest - it spins up quick, but not as much bottom end grunt.  The 77-78 cranks are very heavy - good cruising cranks.  The 79/80 cranks are the performance cranks - the best of all of them from a performance perspective - beefier and a good compromise between the light and heavy cranks.  The 81 and up cranks are similar to the 79-80 cranks, but a slightly shorter rod length.

BTW, there are some wonderful design features that come with the Z1 engines...

- You can take the head off the engine with the engine in the frame. 
- The crankcases have three special jack bolt holes in the cases.  Once you remove the crank case bolts, you thread three bolts into these jack bolt holes and evenly tighten - the cases are pushed apart by the bolts...  nice huh!

G'Day Jeff, considering that the Suzuki GS1000 is such a great bike, why is there such a small aftermarket for performance parts? I've got a discontinued NOS Wiseco 1170cc 15:1 compression ratio big bore kit here for mine, but I'd really like an MTC (or similar) big block of around 1200cc (or more) with more streetable pistons? I've looked around, but haven't found much? Was it because of the relatively short model run of the 8 valve head variants, or was it because they were eclipsed by the all conquering 16 valve Suzy's? Cheers, Terry.