1977 z1000 a1 - modifications

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Finally have a little time and think I have figured out the taking pics, resizing business so thought I would try post a couple of pics

This is always the easy bit

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Next was getting the frame sorted, strengthened and powder coated

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then rear end, GS1100 swing arm powder coated and fitted up with new shocks

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next job, front end with progressive springs and fork brace

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and now the wiring to play with, great therapy that is

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Yep I will still have to pull her back apart a few times to sort stuff as I go, but progress has been made.

With all the great info Gos has given me I still have to make up my mind re engine bits but figuring it all out is half the fun.

cheers all and will try and give you an update in another 12 months

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......If you want to do it with minimun fuss,fit 1015 barrells high comp pistons and smoothbore carbs then get it dyno tuned.....

I think this bike already has the 1015 barrels Mal ? Hi-comp pistons and some smooth-bore 29mm or 31mm carbs would do the business though - I would add some good cams to those.

Yep is 1015

what would you expect to pay for 29mm or 31 m carbs ?

are high lift cam shafts worth the dollars ?

sorry about all the questions, just trying to weigh up the value v hp for the next step or whether to just chuck it together

[Gosling1]

photos look great mate things coming along nicely. The current build I am doing on 'Cherry' the 1977 Z1000A1 is almost identical to this one of yours in almost every respect.....some photos going up on that thread tonight.

Will be in touch soon, things are finally starting to settle down here after a mad 4 months since Xmas, and we can look at doing a number on that motor of yours. I will be doing the 36mm CVK Keihin conversion on Cherry - if this works OK, it could be a better option than smoothbores ? Big cams are great but they need big capacity & carbs to work properly, the result will be more HP for sure, but you will have to ride the bike accordingly.......

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thanks mate, checked out Cherry, looks good, i reckon that is a great colour . nearly bought one in that colour before mine. it was in queensland and already had frame and swing arm mods, but i didnt know then what i know now otherwise it would have been in my shed instead. not too worry.

my earlier post re late model head and lower compression came from APE Race Parts as per quote below, not sure what the diff is though?

"The J model / '81-'82 GPZ1100 cylinder head has a larger combustion chamber than the early style head. When these heads are used on the early style motor, a compression ratio drop of about 2 full points can be expected"

Anyhoo, i am still researching but I now have the motor on the stand and have parked the frame in a corner of the shed for later.

My thoughts on the engine, prob a 1075cc is cheapest but also best option for road and occasional track day, with the option of maybe doing a race or two if the planets were to align

Breath In.
I am thinking Mikuni RS Flatslides 34mm or Keihin CR Special but not sure best size for 1075, maybe 31 or 33mm? need advice for this

Head
Not sure which is the right year model cylinder head to get better flow but will go for a late model head with cams. there are about 3 different size cams available from the states so need to find out what size is best for my expected use? APE does a kit with 1075 pistons and cams with .410" LIFT
266deg. Duration @ .030" which really means nothing to me at the moment

Breath Out.
Kerker with 2" baffle, not too much choice around in this department

Electrics
dyna s with 3 ohm coils.

i think that is the general direction I am going to go, let me know what you think

[Gosling1]

If you wanted to race this bike in PCRA - go with some CR Specials. Flat-slide carbs are excluded from use in Period 5. 31 or 33 both work on 1075 motors, you just jet them as required. You will get better response from the 31mm carbs though with a 1075 motor. Not much in it......

The J / B1 & B2 heads are basically identical as far as flow is concerned with an OEM head. Only the later 83/84 heads were cleaned up at the factory - every inlet port was hand-finished ! You can still do some port work on these heads if you want to. Any of the 81 & 82 heads will be fine for the conversion you have in mind. That lost 2 points on c/r will be regained with a slight machining of the head surface.

The APE kit is basically a high-lift cam, duration is about the same as a stock cam. Duration is always measured at a certain point of valve movement, to ensure consistent measurements. Normally though its at 50thou, not 30thou ? Either way its no big deal.

There should be no real difference in cost between 72mm pistons and 73mm ? 73mm gives you 1105cc..... its a good size for these motors....

[Kwakked Up]

thanks Gos,

just had the chance to sit and read over your advice, thats excellent, thanks heaps. to summarise

I can get the 1015cc barrells bored to 1105 cc no probs with the 73mm pistons similar cost. Can heat be an issue for road use? I do have an oil cooler for the old girl.
crs carbs at 31mm for both street and track - bolt straight on
83/84 heads will give me the bigger valves and clean ports - but will need conversion for a1/a2 cam chain

You lost me with the race cams though, the APE kit opens more bigger but for about the same time, this is good yes? or would you recommend alternative.

Sorry about keeping this basic I learnt this stuff as a young apprentice many moons ago and it takes a little time to dredge it back out of this shrivelled and abused brain of mine

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Gos
I would be interested in your thoughts re this comment from pitstop performance,

http://www.pitstopperformance.com/machi ... ing-c-2_17

"Some manufacturers advertise that a KZ1000 cylinder can be bored to 73mm or 1105cc.
I have had bad luck with this in the past and would not recommend it to anyone."

He doesnt really say why though? I did find another forum where they were saying that taking the barrels out to 1105 leaves the cyclinder walls too thin and they tend to crack and heat becomes an issue.

any dramas in your experience?

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I have slowly been collecting bits for the rebuild and finally got a chance to get back to the old girl.

I went for 34mm flat slides and 1075 high comp JE pistons. I have had the barrels bored and am nearly ready to throw her back together.

Gos cleaned up the stock head for me so it is right to go back together. The other head is off an '83 Z1100 so will keep that for later mods.

Polished all the cases etc so she goes faster and started to make some progress until I snapped a piston ring putting her together today Absolutely filthy on myself, oh well back to online shopping again.

[davo231481]

Nice job on the covers

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Slow but steady progress made lately but starting to get closer. Really looking forward to taking her for a run