1974 KZ400 Hope!

[thovda]

Hi everyone, obviously new to the site, and am a little over my head, but was referred here by Brian from Dime City to tap into the knowledge. I found a 74 KZ400D, 5500 miles, and it hasn't been ran since 1978, it's in perfect shape though. So we got the carbs apart and they're destroyed so after talking to Dime City he thought the Mikuni VM32mm carb would fit this bike, I had totally given up hope so this is great news. Has anybody tried this carb in this bike before, sounds like the 74 and 75 kz are the same carbs. He didn't have the exact intake boots for the bike which are very hard to find, anybody have any luck with them? Take a look at the photos, bike looks pretty good, now to get it running would be great. Thanks for any help.

 

[cxman]

there are a lot of these stock carbs around even quite a few on ebay??

why not do a stock replacement if you are keeping the bike original

 

[BLSully]

Hey, I'm currently tuning VM32's on a KZ440 motor. From experience I will say "do as I say, not as I do".

The VM32's are too large for the 440, let alone the 400 motor, and if I recall correctly, the "early" (74-77) heads don't flow as well as the later (78-82) style, so that would exacerbate the issue even more.

I do have the VM32's working OK on my 440, but again, I'd really recommend going smaller.....VM30 or maybe even 28's. The VM carbs have been a real treat to work on....read my thread linked in my signature. There's a spreadsheet linked in that thread with some research I've done.

In my opinion the OEM carbs are a pain, but if you really want some, I'll sell you both of my sets for real cheap. I'll warn you ahead of time you'll spend the price of a nice new set of VM's rebuilding them though

Good luck, it's a pretty bike! Feel free to ping me if you have any more questions

 

[thovda]

Thanks for the info guys.
cxman...I'm finding out that Kawasaki doesn't make any parts for these bikes anymore, so the carbs I'm finding on ebay are all in pretty rough shape. If i switch now, at least I can get parts when needed.
Thanks for the info BLSully, checked out your bike build thread and lots of good info, I'll be keeping an eye on it and see what works for your carb jetting. Thanks!

 

[diggerdanh]

I just finished swapping to VM30 carbs on my 76 KZ400 and by that I mean I just buttoned everything up tonight. Haven't even had a chance to start it up yet. But I believe my jetting will be pretty close based on someone doing the exact same swap with a similar setup. Check this out:

http://www.dotheton.com/forum/index.php?topic=42063.msg501199#msg501199

Once I get riding and tuning I should have more info.

From everything I've read the VM32s are too big for an otherwise stock KZ400. The VM30s are a better option. You can buy them new or you can keep an eye on Ebay for a lightly used pair. I think I paid $100 for the pair I bought used, but still new in the box. Round slide VM28s might be an even better option but they are harder to find than the VM30s and probably more expensive.

While buying a pair of good used stock carbs and finding new boots might seem expensive you can't just compare it vs. the price of the VM30s. You'll also have to buy several pairs of jets, maybe another pair of slides, some kind of carb boots, a new throttle cable, and also some sort of air filter (go for K&Ns or Unis - nothing cheaper). I spent another $100 in jets/slides, around $65 for K&N filters, $40 for a 1 into 2 throttle cable with the correct Mikuni barrels, and another $60 for a custom adapter/boots. So even with getting the carbs cheap I'm still nearly $400 into the carb swap. So your best bet, given an otherwise stock setup, might be to rebuild your carbs and buy new boots or take BLSully's offer of his stock carbs or someone else from this forum for their stock setup. My stock carbs ran really well and my boots look like new but I'm not ready quite yet to get rid of them. I'll keep them as a safety net until I get my new setup dialed in.

 

[thovda]

Thanks Diggerdanh! I'mNot Worried About Putting Money Into The Bike So Im DefiniteKly Going To Go The Vms. Now To Figure Out If I Should Go With 28S Or 30s? Im Going To Go With Air Pods Too So I Can Go Without The Boots, They Dont Make Oems Or Aftermarkets Anywhere. When You Say k&N Filters Are TheY pods, I Need To Check Them Out? Super Curious How It Runs For You And What Adjustments You Do .

 

[Nebr_Rex]

If you can locate some 28s, go with them.
Better throttle response and you will not miss anything on top end.
K&N cotton gauze and wire mesh filters are about as good as it gets,second would be Uni foam filters.
Mikuni makes carb boots ( bolt on between the carb and head ) for the VM series.
And I believe the bolt spacing is the same as the 440 at 60mm.
Oh and I'd suggest getting a repair manual either PDF or real paper.

 

[thovda]

Thanks for all the info! I thought for sure that I had this deal sealed up, something has changed. The seller wants $500 for the bike. Do you guys think that's fair being the carbs need to be redone, and after I've get it started I don't know what else might happen. Everything else seems good though, both brakes work, compression good, had a battery hooked up and all electrical worked and starter motor worked. I'm a little nervous about the clutch, it doesn't seem to 100% disengage, but I'm thinking the motor might need to be running for it to engage completely, I did tighten it up thinking that'd take care of it, it disengages some but not 100%. Is $500 a good deal?

 

[CafeRacer650]

For that low mileage a bike... its a steal.

 

[BLSully]

I'd call it pretty good. I paid that for my 79 in approximately the same condition as yours, higher mileage, a few new parts (air filters, handlebar controls, some of the electrics).

If it hasn't run in a long time, the clutch is probably just frozen. Easy to fix yourself, but maybe a good negotiation point.

 

[Bozz]

$300-500 with title is good deal territory.


Figure the cost of all new rubber, bearings & brakes to be $300-400 plus carbs ($200ish?).


Back on the road and running decent will take another $600 plus quite a bit of time and learning.


So $1100 for that bike rolling around on a Friday night? decent.


I'd try to talk him down at least $50 though on principle...

 

[thovda]

Thanks for all the suggestions! I'm going to pull the trigger today and get it. I just can't get this bike out of my head. I'm pretty green so I'll probably be hanging out here quite a bit while doing the carb swap and getting ideas from all. I've been reading alot of posts lately and have already learned alot.
Hopefully she'll be running soon...

 

[thovda]

I ended up buying the bike ;D ...I have mikuni vm30's, k&n air pods, carb intake boots(mike @ power barn has some that are made for the kz400 to mikuni carbs-awesome news), and a new throttle cable on it's way. In the mean time I thought I'd get the old intake boots off, but man are the screws ever stuck! Any ideas to get them off, I think the first thing to try is heat it up...any problems with that idea? Any other ideas?

 

[diggerdanh]

Lots and lots and lots of good penetrating oil like PB Blaster. You want to make sure those things turn out and not break off or you'll be in a lot worse shape. Then an impact driver or you may be able to get vice grips on them to get them to break loose.

 

[Bozz]

Penetrating oil, then cycle the heat. Try to focus the heat more on the head than the bolt if possible.
Get it good and hot, then careful P oiling. then let it cool. The next day (or 12 hours later) do it again.
Impact driver (manual hit it with a hammer type) is a big help.
Don't just try to loosen the bolt either, feel free to smack it the other way a few time as well.
Once it starts to move, don't get hasty. Keep working it both ways, keep heating and oiling.


THe reason for this is that you have a steel bolt in an aluminum head. The fact that there are different metals is what has caused this corrosion.
A big problem can happen when it is just starting to break loose and it only loosens up on SOME of the threads. If you use too much brute force the bolt will come out with the aluminum threads still attached, thereby stripping your head and making things a lot more complicated when you want to reassemble and the bolt will no longer tighten correctly.


Patience is the key!
That corrosion took years to form, so take some time to get it out with the least amount of damage possible.


Best of luck! That KZ will be a nice bike if you treat it right!

 

[thovda]

No luck. Heat, lots of pb blaster, an impact wrench...the only thing i was able to accomplish was spin one of the screw heads not the threads. I was thinking awesome, they're coming out, nope. I spun the head off center but it's still secured. So if I take the head of the motor off, get it to a machine shop to see if they can get them out, when I put the head back on, is it simply to put it back on and tighten the bolts. Does anything go out of timing or anything if I take it off?
I'm tempted to just keep the current intakes on and see how they work out with the new carbs, but it would be nice to get the new ones on so I know it isn't leaking.
Thanks for the help!

 

[Bozz]

removing the head is non-trivial.

Purchase/download a shop manual for it before you go much further into the motor.
With stripped head you can now remove intake and get a hold of the remaining bolt with vice grips.
Patience is key.
A shop is certainly an option if you have the dough, but removal of the head takes some doing...
Good luck!

 

[thovda]

Thanks for the help Bozz.
I have the workshop manual.
I think I'm going to see how the bike runs with the current boots, and keep working oil into the screws throughout the summer, I'm thinking that the heating and cooling of the motor, and keep attacking the screws with oil throughout the summer, will hopefully allow me to get them out after the seaon is over. Then this fall I can replace the boots, clean her up, and start building some mods, new mufflers, seat, and handlebars for sure. Hopefully the current boots will workout for now.

 

[Nebr_Rex]

The easiest and fastest way is use a needle nose a Vise Grip® .
Clamp down with the ends of the jaws just over halfway the head of the machine screw.
That way you can work it back and forth.
Do the top ones first then spin the carb boots to put the bottom screws on he top side of the boots for easy access.
A little info about vice gripes.
Years ago a farmer here in Nebraska designed and with his brothers started making Vise Grips®.
Their name is. Peterson, it's stamped on the handle.
So if you can find a pair they are the ones to use,they will not pinch your hands like most of the copy cat versions will.
Peterson no longer manufacturers them,Irwin bought them out about 15 years ago and shipped all the machinery overseas.
If you have a pair keep 'em, they'll last a long time,the Peterson boys knew what they were doing.
All others can't hold a candle to them.


.
.

 

[thovda]

Progress! I got the carb intake screws out. Had to drill them out and put in Helicoils but she's ready for the mikuni's. I'm just shi!!ing on myself to get this girl running, come on parts! It's been a while since I've been riding. I grew up riding a Magna, I can't get over how much lighter this bike is. Anybody know if this bike will do the ton by chance. I don't have any experiences with a 400cc so it's going to be fun to see what she'll do. Since the tires are from 1974 I better see if they're going to hold up until I can see what she does. Good news too, the clutch loosened up since I've had fresh oil in it.
Anybody interested in a seat like she has...I'm just going to enjoy driving it this summer but this winter I'm going to brat seat it, so in the future I'll sell it. It's in awesome condition.