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Z1a BHP
Moderators: paul doran, Taffus, KeithZ1R, chrisu
Z1a BHP
Does anyone know what the BHP should be at the rear wheel for a 1974 Z1a. (rebuilt engine).
Thanks
Thanks
Past 5 Years
1974 UK Z1a, Candy Tone Brown/Orange
1976 KZ900a4, Diamond Dark Green
1978 KZ1000a2, Luminous Green
1976 KZ1000a1, Red
1972 GT750J, Candy Lavender
1974 UK Z1a, Candy Tone Brown/Orange
1976 KZ900a4, Diamond Dark Green
1978 KZ1000a2, Luminous Green
1976 KZ1000a1, Red
1972 GT750J, Candy Lavender
Re: Z1a BHP
Anybody's guess? I'd have thought 80bhp at the back wheel would have been good for a standard motor, a bit less not neccessarily a problem, a bit more very good. 50 or 60 not so good. Be interested to know are you taking one to a Dyno?
Re: Z1a BHP
Manual says maximum 82 @ 8,500 RPM. It does not mention where from, I would assume it is at the crank?
Re: Z1a BHP
Around 80 to 83hp at the CRANK for a stock 900 depending on year and what manual you read.
A little bit less at the wheel due to losses through the drive train and knock about 20 hp and 40 mph off the top end if fitted with one of those iffy restrictive pattern 4x4 pipes that were produced a while back..
A little bit less at the wheel due to losses through the drive train and knock about 20 hp and 40 mph off the top end if fitted with one of those iffy restrictive pattern 4x4 pipes that were produced a while back..
Re: Z1a BHP
I took BunnysZ1a to the local dyno.
It made 78 rwhp which I thought was very good.
It made 78 rwhp which I thought was very good.
Asphalt Cowboy Z1100R, 1981 Z1000J
Re: Z1a BHP
tlc wrote:I took BunnysZ1a to the local dyno.
It made 78 rwhp which I thought was very good.
I would live with that. What pipes does it have Chris?
Re: Z1a BHP
Looking at the readout I think the low HP (under 60), was due to the low RPM @ under 7000
Past 5 Years
1974 UK Z1a, Candy Tone Brown/Orange
1976 KZ900a4, Diamond Dark Green
1978 KZ1000a2, Luminous Green
1976 KZ1000a1, Red
1972 GT750J, Candy Lavender
1974 UK Z1a, Candy Tone Brown/Orange
1976 KZ900a4, Diamond Dark Green
1978 KZ1000a2, Luminous Green
1976 KZ1000a1, Red
1972 GT750J, Candy Lavender
Re: Z1a BHP
Guy that dynoed my 650/810 told me to get at least a 1000 miles on the engine before giving it a hard time. He did some basic jetting to get it running ok to run engine in. Did your guy deliberately keep the revs down because it's been rebuilt or did it not want to go over 7000.
Re: Z1a BHP
Rev's delibereatly kept low due to being a classic bike.
It was dyno'd to set up engine and carbs as they were only bench set previously, my bike has covered only 250 miles since full restoration.
It was dyno'd to set up engine and carbs as they were only bench set previously, my bike has covered only 250 miles since full restoration.
Past 5 Years
1974 UK Z1a, Candy Tone Brown/Orange
1976 KZ900a4, Diamond Dark Green
1978 KZ1000a2, Luminous Green
1976 KZ1000a1, Red
1972 GT750J, Candy Lavender
1974 UK Z1a, Candy Tone Brown/Orange
1976 KZ900a4, Diamond Dark Green
1978 KZ1000a2, Luminous Green
1976 KZ1000a1, Red
1972 GT750J, Candy Lavender
Re: Z1a BHP
I have a dyno printout of my ST somewhere. 59HP...
http://www.airevalleyclassics.co.uk
10% discount code Z1OCTEN
Keyster rebuild kits & carburettor spares - airscrews, jets, needles, starter plungers & gaskets.
Also petrol/ethanol proof float bowl gaskets. IMD pistons preferred seller.
10% discount code Z1OCTEN
Keyster rebuild kits & carburettor spares - airscrews, jets, needles, starter plungers & gaskets.
Also petrol/ethanol proof float bowl gaskets. IMD pistons preferred seller.
Re: Z1a BHP
I'm sure there must be plenty of dyno charts out there that folk can pitch in with.
I recall (back in the day) seeing in an American mag a dyno chart of a freshly run-in J which gave 79bhp at the wheel (Kawasaki claimed 102). They were speculating at the time whether this was reasonable transmission loss or maybe just a weak motor?
It would be interesting to get some more expert opinions here.
I recall (back in the day) seeing in an American mag a dyno chart of a freshly run-in J which gave 79bhp at the wheel (Kawasaki claimed 102). They were speculating at the time whether this was reasonable transmission loss or maybe just a weak motor?
It would be interesting to get some more expert opinions here.
H2B GPZ900R
Re: Z1a BHP
BigZCas wrote:Rev's delibereatly kept low due to being a classic bike.
It was dyno'd to set up engine and carbs as they were only bench set previously, my bike has covered only 250 miles since full restoration.
Still running in at 250 miles
Re: Z1a BHP
This is an interesting site, with dyno charts on some of the tests:
https://www.yeoldecycleshoppe.com/?offset=1489078859052
http://www.yeoldecycleshoppe.com/roadte ... -road-test
https://www.yeoldecycleshoppe.com/?offset=1489078859052
http://www.yeoldecycleshoppe.com/roadte ... -road-test
H2B GPZ900R
- wheelysteve
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Re: Z1a BHP
BigZCas wrote:Rev's delibereatly kept low due to being a classic bike.
It was dyno'd to set up engine and carbs as they were only bench set previously, my bike has covered only 250 miles since full restoration.
Hi Steve, I trust you will be riding it down to the Ace Cafe .......that should run it in nicely and gain another 10 bhp !!
Steve
1975 Z1B Candy Red/Blue
1975 Dogs Z1B
1976 Z900 A4
1977 Z650B1
1978 Z650B2
1978 KZ1000D Z1R
Yam Tracer 900GT
PUM 710
1975 Dogs Z1B
1976 Z900 A4
1977 Z650B1
1978 Z650B2
1978 KZ1000D Z1R
Yam Tracer 900GT
PUM 710
Re: Z1a BHP
I certainly will be Steve
We are planning for an early start, will be at the Ace for 9am ish.....
We are planning for an early start, will be at the Ace for 9am ish.....
Past 5 Years
1974 UK Z1a, Candy Tone Brown/Orange
1976 KZ900a4, Diamond Dark Green
1978 KZ1000a2, Luminous Green
1976 KZ1000a1, Red
1972 GT750J, Candy Lavender
1974 UK Z1a, Candy Tone Brown/Orange
1976 KZ900a4, Diamond Dark Green
1978 KZ1000a2, Luminous Green
1976 KZ1000a1, Red
1972 GT750J, Candy Lavender
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