TOPIC:

I just bought a 1979 KZ 1000 LTD the following list are the mods that the seller told me the bike had.
De-tuned drag race motor-closer to stock clearance for dependability.Race motors have open clearances for the least mechanical resistance to be able to compete. Rebuilt every few run’s
* Motor dyno’s @ 170 h.p. Stock motor was 85 h.p.Stock LTD’s turned consistent 12.5’s with stock carbs (26 mm).I figure this bike to turn mid to high 9’s with right rider and tune.These bikes weighted 525 lbs.stock.
* Motor - 1398 cc. MTC Big Block kit built by CW cycles-some of the best in the country.Rev limited @ 13,500 rpm.
* Crane electronic ignition - performanced.
* 10.5 to 1 compression.There race motors were 13.5 to 1 and rated @ 240 hp.
* Oversized Manley Stainless Steel valves- high performance springs-Titanium retainers.
* Head work by Jeff Reel (one of the top guys in the country at the time.)
* Performance Cam,Chain and gears-MTC used the highest quality pistons/pins and bearings in there kits for compatition.
* Weled Cranckshaft/Pins
* 29 mm Mikuni Smooth bore carborator’s (bored out) K&N Filters pods.
* Kerker Headers,Rosch rear-sets, Yoshimura suspension, Michelin Pilot tires.
* Aluminum Box Swing arm with needle bearings-2” longer than stock.
* Transmission built by CW cycles,undercut gears heavy duty bearings.APE clutch plates and springs.
* Tapered Bearings in the steering head/ 630 o-ring chain
* Carbs are just rebuilt by Rick West from Oldschoolcarbs, I’m told he is the best in the country
The bike is running rick it is a rocket on timid to top revs but it does not clear really up to 4500 RPM, bellow that the bike engine is not feeling stable if it is the right word for it. it gives me the feeling that i had when the points were not right on an old gs.
I am putting new sparks but I guess I have to start by opening the carbs to check what jets have installed.

Couple of points to note.
You are probably never going to get that ex race motor to run clean all the way from idle depending on what spec the current cams are and other factors.
That 13.500 rpm rev limit is way too high and you will kill the crank very soon if you hit that often.
11.000rpm is the point where the crank rollers start to skid on their races so that should be the max for the limiter.
29 smoothies, even bored out to their 30mm max seem too small for the power figures quoted so i suspect that they have been fitted in place of Lectrons or some other make of drag race only carbs.
All the specs you quote sound like the sales pitch BS from the seller and I would ignore all the high numbers.
Was this a nitro motor as even with my turbo funny i'm only getting 240hp at 30psi.
Are you going to race this or put it on the street.

zed1015 wrote: Couple of points to note.
You are probably never going to get that ex race motor to run clean all the way from idle depending on what spec the current cams are and other factors.........

Exactly. Years ago I owned BSA factory competition engine I bought from Gary Nixon. At low rpm that engine would try to shake the fillings out of my teeth, but as the revs rose and approached redline it would smooth out beautifully. It was a great engine, but not nice at all to use at low speeds or in traffic. Ed

OP:
You left out lift, timing & duration of the cams. Without those specs much of the other info is of little use.

A motor running cams tuned for top end horsepower will not make a good street motor where low end torque is most useful. That motor probably " idles" at 2,500 ~ 3,500 RPM. Maybe more. It's gonna overheat quick in traffic. Big lift, long-duration cams with lots of overlap are fine & needed for a life lived WFO at redline for 10 seconds and 1/4 mile at a time. They're a very poor choice for street use where run time is measured in hours and tens & hundreds of miles.

A ported head, big valves & big carbs = slow intake velocity at street RPM & small throttle openings. Add that to big, long cams and the motor will exhibit poor tractability for everyday street use. No amount of jetting will fix any of it.

Good luck.


Good Ridin'
slmjim & Z1BEBE

First of all I really appreciate and I am grateful of you guys taking the time to repply.
I think you are right all those specs are the pitch of the seller and where given to the guy that owned the bike so this is the story, the owner was an american guy that wanted to make ansleeper bike.
So he did all that work on the bike and had it for few years and became a bit to much for him going out on weekend only it was never a track bike and he did not take it to the track it was just build like that for him.
I don't know whats sort of cams lift timing and duration has on it, and I am guessing that to figure that out will have to open th engine
I am not going to take it to the track, because I don't have one near me is mostly for street use and I don't go over 9000 rpm trust me when it gets there is going fast and pulling like a train. today i did a burn out with the brake and let it go and made like a 50 yard burn out . surprisingly it riddles about a 1000 by itself.
it is just between start up and 4500 rpm that stop been kind of sloppy if I ride it like a normal person.
The guy that sold it to me took the filters off and said he did as by been rich without the filters gets more air, when I accelerate it standing I see gas coming out the back of the carbs,
I was thinking maybe needs bigger carbs for that size of engine but then with ones, are there modern versions of carbs that can withstand today gas mixture and don't get bad a vintage carbs, mine where put in keeping in some king of quemical that creates a film that the petrol don't get bad every three months.
If I have to change carbs i could get them but then i need the best ones to fit the purpose. brand and size Mikunis for keihin I heard are good but with ones?
Thanks once again for giving me light on this.
I

I'd take the valve cover off and identify the cams. You May be able to "Detune" the motor with milder cams and smaller carbs for the street. Nice to have all those "Goodies" but useless if you can't ride it.
Pics?
Steve

www.oldkawman.com/

Here is the pick of the bike.
I went to see a friend and he said to put the pods back as it was jetted with them and should improve performance, we noted that the joshimura exhaust is getting yellow in the union with the baffle so he we think that the exhaust is to narrow for the engine and also that the carbs might need to be 33 or 36 mm.
Wich carbs are the best option to go for carbs and header keeping in mind budget and street ride.
He said that the Keihin are more for racing and it will not make me happy for street use

Ahhh.. the neato parts blues again. :-/

In reading through the replies in this thread, almost every one of them are spot on. A motor that thrives at say 6K is a pig on the streets. Zed, Ed, Steve and Slimjim are all correct.. How do I know this? lol

Well, many moons ago, I bought a Honda CB900F Super Sport. It had the 1100cc big bore kit, 4-1 header 10.5 wiseco's, etc, etc.. This bike ran great when the bars closed and the cool heavy air was surrounding it, but during the day in 90 degree heat, it would sputter and pop and in general run like crap. I couldn't keep the front wheel on the ground when it was running right. In other words, it ran great after it sat overnight, but with pump gas it would ping and sputter and pop while street riding. ((all the neato parts are useless then) After many attempts to make it act right, and the legal problems it induced when it DID run right, I got rid of it. I swore after that to not get trapped up into the "upgrades are good" mindset again.

The decals on the tank were almost worn off from squeezing it when the front wheel came up.

Sayonara wrote: Here is the pick of the bike.
I went to see a friend and he said to put the pods back as it was jetted with them and should improve performance, we noted that the joshimura exhaust is getting yellow in the union with the baffle so he we think that the exhaust is to narrow for the engine and also that the carbs might need to be 33 or 36 mm.
Wich carbs are the best option to go for carbs and header keeping in mind budget and street ride.
He said that the Keihin are more for racing and it will not make me happy for street use

Absolutely gorgeous bike! You should insert the attachments into your post so they show as you scroll through the thread.

Well one of the more experienced tuners probably can recommend carbs, if you are looking to toss more money at this bike. If you want this bike to be more streetable, more and bigger may not be a good thing, and possibly could turn into another thing to deal with. In adding almost 400cc's to a 1000 cc motor, the cylinder sleves are also paper thin at this point. (100cc per hole?) This bike will also have dependability issues, besides frequently running poorly in normal riding. My 900cc Honda had thin sleeves with only a 200cc overall increase in engine displacement. it will be fun to ride in between those frequent repairs, though.

Maybe instead of looking for bigger carbs, a more streetable top end / cams might be a better thing to look into.

Also, why does it run like it does? It is probably his reasoning for selling it. Just my uneducated guessing here. Bone stock works best. Those bikes were fast and dependable completely stock. One thing people don't seem to notice, or remember, that racers also overhaul their motors after either one or a few races. High performance = enjoy it while it lasts.

The 2 rings next to the cam gears are the "cam identifiers" on my stock 81 Kz1000 cams, as an example.

Do you have closer pics of the engine.
It's hard to tell but it doesn't look like a big block from the images ?
Maybe it's the paint finish.
The stock block will only accept 1260 liners at the max and 1395 would need a big block and they usually have a cast identifier of the maker on the ends, APE, Wiseco, Orient Express etc.
Maybe i'm wrong but the PO may have "detuned" the engine dropping on a stock block with a mix of the ex race parts that don't want to work together.
If you have drag spec cams fitted they will probably be too long a duration for the street, hence the fuel blow back at low speeds and you would be better either fitting a good set of stock cams dialled in or something like the PSP3's from Pitstop performance..
You need to get the bike to someone who can really tell you what you have and let them sort out the good from the bad.
It will save a lot of costly mistakes in the long run if you don't really understand which parts are actually suitable for your requirements.

^+1^

Good Ridin'
slmjim & Z1BEBE