1428cc for street use

Hello again

Finally back after a very busy year with surgery's and bike building

LAst i was here i was building a 1200cc engine in which came out okay, bit over 120WHP - won races but defiantly not made for the small roads of Copenhagen - So now a bought a stock MKII to for that...

I wanna do a 1428cc engine and still use my PSP stage1 Z1 head and right know im runing the K410 cams (might have some Andrews stage3 cams on hand) and some Mikuni WM33 - would this still be rideable for 50/50 street and strip
Would you recommend to lower the compression from 10.5 till ?? when its for street use??
I

It have welded crank, lock-up cluch and plenty of oilcooling

Dale Walker build one only it was 1394cc and was in a 82 Hot Bike magazine...... you should be able to find a few things on it by googling it.

It was his first project bike for his Hole shot business and he ran it on the street. It ran 10.5 to 1 and 33mm smooth bores and I guess was a real beast.

That big of an engine would be ok for the street but you don't want to sit in traffic a lot during the heat of the summer. At best it will run hot. With any head that is using stock size valves, the head will be the choke point. Those valves in a small port head will give good velocity but not much top end. The motor will be a beast on bottom end and mid range but will run out of breath up top. Lots of torque. Cams will help the top end HP but the small ports and valves will still hold back a motor that big. It will still be a stronger motor but just not up to its potential. Be ready to hang on tight when grabbing a handful of throttle.....it'll be super strong especially down low.....Don't think reducing the compression would be a big help here.....motor size will be the main factor. That big motor will build heat but as long as you keep air flowing over it it would be manageable.

Cheers Lars! I remember your build. This build is the epitome of a cafe racer! Worthy of a cable TV show like" Cafe Racer" on the Velocity channel! How is Denmark? That big of a engine why? unless you have the parts. I would go 1327cc old school build big. Makes it quite thin down at the engine block.
But keep up the good work. I have had 2 surgeries on my spine, 2 on my shoulders and 2 on my wrists! I can't stand it anymore!
But I can wake and get out of bed in a reasonable amount of time! It is a good day!

with a Z1 style head you will be out of air best bet stay with 1200 and do more work with head, cams and compression. unless you want to step up to a "J" head min or the 83/84 GPZ1100 head.

You could do it with a Z1 head but you'd have to port the snot out of it. Man, speed is relative. I like a good 1075 setup with those cams you have and good carbs set up just right cause no matter how fast you go, you'll always get used to the speed. And on the street in traffic you will be going through rings and bike will not make you happy with the extra heat it will make. There are lots of guys who run big blocks on the street but they aren't practical at all. Once you start beating on it you'll probably overheat. I'm sure there are several guys who don't care and do it anyway but I like to ride mine and put a lot of miles in summer. I think a good 1075 setup is better than a big block bike on the street.
Good Luck

You really need a ported 'J' or GPZ head to get the full benefit of the 1428 block.
Even with a maxed out early 900/1000 head it will be short of breath when going on song .
You won't really be any better than having a 1200 in there but will have all the downsides of the extra heat the 1428 produces .
Twin plugging the head is also the proven way to go with the big block to get the most out of the burn and make the best power.

How in the world do you stop that thing? Theres a lot of heat coming off that motor that blows through area where that oil cooler sits when youre rolling down the road.

bike turned out awesome !
looks like a fun lil beast! :evil:
i bet that tls front brake works better than you may think plummen.
i'm no help on the big motor,
sorry.

leon

I understand they run real hot. The Old Kaw Man has videos and information on these.
Steve

Thanks for all the feet back - been reading a lot about the 1428 in here and also know it need a bigger head to get the full out of it all tough im actually looking for Torque and not high-end HP so for me the 1428 was more for the fun
I also know it needs a better breathing system for the crankcase etc etc
The bike as it is now is to powerfull for copenhagen meaning it gets boring to drive on it due to you can really rev it anywhere thats why i was thinking of the 1428 (to make it completly non rideable but still fun to say byebye to the new plastic bikes
Im gonna use it for events around Copenhagen and going (by truck) around europe to do 200m sprint races...
Everyone around Europe puts on NOS but i want to go bigger but still keep the estetik look of the old Z1 engine/bike

Im gonna upgrade the rear end with a 17" tire and a GSXR750 swingarm - gonna be 4cm longer and hopefully some more grip......
Also thinking about tuning on the ignition - im only using the DynaS... would people recomend the Dyna2000???

The bike brakes better than you thing Plummen - its 4LS system from an old Suzuki GT so in daily its the same as stock brakes and im not in it for the speed so suits me right




This was one of the last runs - we only adjusted the right side 3-4 on the engine and the guy doing it 'found' 11hp from my first set-up on the carbs - he is a Guru in motorcycle tuning, making cams and porting heads etc...



this was the A/F mixture at 1/4 - 1/2 and full throttle - learned so much about engine tuning the 4 hours we where adjusting mine



the day after my surgery - the rotated my foot 20 degrees - old bike injury they put wrongly together the first time

Ouch. I had 5 screws on my right rotator and still have one in my left ankle. That was one Fk'ed up day. 06/13/86 a Friday. :dry:
Steve