Super moto power with kz550 engine (project)

[nelson8708]

I figured i would start a build thread in here since the only kawasaki part is the engine and this is the best place to get my questions answered. For starters the reason i am putting the kz in there is because it is going to cost the same to put new crank bearings in the yz engine since that is what it needs along with a whole new top end.....jug and all. So instead of going through all that just to end up with the stock 30 or so hp seemed kinda boring. Not to mention the headache it would be to split the case and do it all my self. So instead i happened to find a wrecked 1982 kz550 with nothing left but, a frame and engine more less. No electrical, carbs, exhaust...nothing. For the price it was what i was looking for with a title. I have spent the last week ordering parts for it and was a little surprised how fast the budget build seemed to suck up my checks but, if it runs then it will all be worth it. Carbs, igniter, rectifier, starter, shifter, vulcan vn1500 coils, and starter solenoid have been ordered. The engine only has 9,100 miles on her so she is still fairly young. My goal is to have all the parts by the end of this month and to have the engine mounted in the yz frame by the end of july. Then be running in august and plated with lights and all by september. I have a lot of work ahead of me but, with everyone's knowlege of vintage engines i think with your guys help i should be able to get it done. Anyway here are a couple pics of where everything is right now.


^ Got suckered in to buying it not knowing that the previous owner ran it with out an air filter......


^the head looked just as bad and what ever caused this is what trashed the crank bearings....i got owned on this purchase, so lets hope that didnt happen on the kz purchase


^just after i got her home


^a few hours after i got her home.....DO WORK


^Got the carbs


^During reassembly after a cleaning....those pilot jets were clogged....one of those suckers took for ever to clean out.

I will keep updating as i receive parts and start pulling the engine out of the yz. I plan on pulling it next weekend as some one has shown interest in buying it but, you guys know how that goes......i told him i would hold off on the project until the 28th giving him two weeks.

Opinions, objections, suggestions welcome

-Nelson

[elr658]

Handling is going to be INTERESTING to say the least.

[tark48]

Put down the crack pipe

[eslmatt]

Are you still going to be running it on dirt? How much weight are you going to add by putting the 550 engine in?

Keep us updated, sounds like it could be a cool project

[nelson8708]

Originally Posted by eslmatt

Are you still going to be running it on dirt? How much weight are you going to add by putting the 550 engine in?

Keep us updated, sounds like it could be a cool project

I dont plan on running it on dirt with the 550 engine but, i'm not going to say i wont ever do light trail riding with it. Defintally no jumps with all that weight but, a hill climb or two could be in my future. I'm not sure how much the 125 engine weights or how much the 550 weight but, i would say some where in the ball park of an extra 120lbs. I will weight the 550 some time soon to see what she comes out to and then the 125cc engine to see how much actual weight i am adding. I need to rebuild the front forks so when i do (after the 550 is in and running) i will get stiffer springs if i need them.

Originally Posted by tark48

Put down the crack pipe

These are the comments that drive me to do such things

[nelson8708]

I measured my valve clearance last night and found the exhaust side to be .004" and the intake to be .003" (measured at 80 degree temp) . Since i will only be able to ride it for a couple months before winter hits i think i'm going to leave it as is and then change it over winter.

You guys think those clearances will be ok for 2000 miles?



^clean....

[elr658]

Probably, but you already took off the valve cover. Why waste TWO gaskets.

I was thinking, you're going to have to offset that motor big time or run a jackshaft to get the chain to line up.

[nelson8708]

I already put the vc back on that night. I haven't measured it out completely but, when i used the calculated eye it didn't seem like i would have to off set it too much. Maybe a inch....i plan on spending some time in the garage tomorrow so i'll take a couple measurements and see how much offset i'm going to need.

I got my shifter and rectifier in today. Still waiting on the starter, starter solenoid, and igniter. I also, finally got my "license to carry" in the mail today. Its more for when i move out but, i wanted to get the life time now incase they do away with that deal so i'm "grandfather clause'd" in.

[nelson8708]

I just checked the offset of the front sprocket compared to the 125 engine and they are the same +- 1/8". This might work a little better than i planed. I'm going to start the process of removing the yz engine this week. Next weekend is when i will start to chop up the yz frame and that is when there is no turning back so i need to make sure this thing will phyically fit where i need it to.

[eslmatt]

At least you can shoot the bike if it tries to kill you

Is that from 1/8" off the center line or the center of mass? It is cool that it will fit well.

[nelson8708]

Measuring from the center of the yz engine to the sprocket is about 3.5" and from the center of the kz engine (in line with the timing chain) to the sprocket is about 3.6-3.7".

I tore the yz down to the bone earlier today. I was really surprised at how little the yz engine weights (40lbs maybe). I'm going to weight the yz and kz engines tomorrow on the bathroom weight scale ( ) but, i would say there is at least 100lb difference.




3 post till i can put all the kz stuff i have up for sale...

[nelson8708]

Just got done weighting the two engines.

yz125- 43lbs
kz550- 146lbs

So the bike will sit as if it had a 103lb rider on it.....

[nelson8708]

Anyone have an idea on the best way to line up the sprockets? I was thinking about using a piece of string tied to the teeth for something i could use for reference. Looks like i might have the engine in the yz this weekend.

[nelson8708]

Progress anyone??? The first cut was the hardest because after that there is no turning back.



A little bit of trimming and the tank and ex-radiator shrouds will fit.....going to keep it looking some what like a dirt bike.

[eslmatt]

I have seen those little 125s go pretty good. I am really curious to see how the bike responds to the new engine. When you post the video, please don't use youtube... it is 'inaccessible' from China right now.

How are you supporting the engine? Are you going to change the sprocket ration?

Keep us updated, I am following this.

Matt

[nelson8708]

As far as supporting the engine goes i am using part of the kz frame from where the pegs mount up to just before the header. From there on i'm going to graph it into the yz frame. I will use all the stock mounting points on the back of the engine as well. Yes i'm going to use the stock kz ratio and use the kz rear sprocket and just drill it for the yz bolt pattern.

After i get the engine mounted i will be coming to you guys for wiring help. I got my rectifier in and after i looked at it and the wiring diagram i noticed that 3 wires on it are all yellow, so i not sure which goes where. I need to build a battery box where the air box use to be also and pick up some pod filters.

The 125 engine got the thumbs down because its locked up....lol....There is a 100 lb difference between the engines but, there is also a 23hp difference.

[nelson8708]

I got it mounted in the bike but, i need to remove it to do some final welding on the areas i couldn't get to. I also ground down my thumb in the bench grinder accident. So now i have blood, sweat, and i'm sure tears will follow some time during the build. Probably when i get my credit card bill for this past month will all the part purchases i made. I'll get some pics of the bike later today.

[nelson8708]

Pictures.....

^mocking up the front tubes





^bench grinder accident

^electric tape bandaid ftw!!!!

^this is where i started today

^this is where i finished....i had to remove the engine for final welding

I still have a couple more braces i want to make before i put the engine back in for the last time. Its sucks getting it in and out but, now i need to make new gas tank mounts since the stock one wouldn't allow me to remove the engine....Its getting there

[tark48]

Wow I take it back!
Nice job!

[eslmatt]

Try not using the kleenex under the tape. The glue on the tape helps seal the wound. Let it air out as soon as it stops bleeding. Helps with the healing.

Looks cool, do you have enough room for front wheel travel? looks like it will get close on full compression.