A Little Project I've Been Working On...

[TGP Nick]

This is a little project I've been working on for a while now. 
It started out as a 1989 Yamaha Razz I bought locally for $500.  It was owned by an older woman and it just sat in her shed all the time.  She rode it for the first year or so, put 600 miles on it, and parked it in the shed and thats where it sat since about 1990.  When I bought it, it was in decent shape, some of the bodywork was scratched and cracked in places, but not horrible.  The carburetor leaked gas when you ran it, and it topped out at 16 MPH, choking and sputtering, and if I turned on the choke, I could get to 18 MPH.  After I bought it, I cleaned it up nice and tore into it.  That was the nastiest carb I've ever cleaned out.. it had a good 1/8th inch of solid varnish coating everything inside the carb.  I cleaned out the carb good, cleaned the fuel pump and sender, and gutted the exhaust on it and she ran great, topping out at 30 MPH.  I rode the scoot like this all summer, putting on a total of about 1500 miles on it.  It was really fun to ride around, some of my friends got mopeds too and we just rode around everywhere in our scooter gang. :laugh:  It was funny, because most of the mopeds were really beat up and didn't want to run half the time, but that was all part of the fun.  My Razz was the only scoot that never broke down or refused to start.  At some point in time, I have had to pull each of the 5 other mopeds behind my Razz with a bungee cord, to wherever we were going.  It was all fun and everything, then they started modding their mopeds, making them go faster, so I thought I'd one-up them and do an engine swap with a motor that had a lot of aftermarket parts available.  Here is my project:

This is what the Razz looked like this summer.



I tore it down In October and started my build.

Alright I finally have all the pics uploaded.

Here is the stock original motor, out of the Razz


My new 1996 Yamaha Jog motor when I got it; filthy and blown up.


First, I stripped the Razz down to its bare bones and sandblasted the frame, next I sandblasted the engine and transmission, sandblasted the newer cylinder, and sandblasted the head.  Then, I ported and polished the cylinder for more powah!  I polished the head dome and decked the head surface where the headgasket sits, and did the same to the cylinder.  Yesterday I taped off the cylinder and painted it up (its cast, so it will rust if not painted).
Now, its all ready to go back together.

How the Jog motor looks now


My new finished cylinder, I ported and polished the exhaust port


Couple pics of the cylinder... I didn't do anything to the transfer ports, other than clean them out



Comparing the old blown up cylinder on the right to my finished, ported cylinder on the left.. notice how much bigger the exhaust port is now!




My finished head on the left, polished and decked


New VS. Old



The cleaned up engine



Lets see whats in the bag of goodies

New fan scoop


New Cylinder Cooling Duct


New Reeds and Reed Cage


New Headgasket on the Right, New Basegasket on the Left


New Top-End bearing on top, wrist pin on bottom, rings on left, circlips on the right


New Piston




New Intake Manifold


New Crankcase Gasket


Everything


Sandblasted Tranny Cover- I'm trying to decide what I want to do with this.. I'm thinkin of painting it black, like the cylinder.


Cleaned up new shock on top, old one on bottom


Bigger rear rim vs. skinny old one



I sandblasted all the welds on the frame, made sure there are no cracks or anything anywhere, and blasted the surface rust off my frame.  My battery exploded this last summer (previous owner put wrong battery in it) and all the acid ate away the paint on the frame, which started to rust.  I caught it right away and sandblasted that crap off.  All clean now, ready for new motor mounts to be welded up and repaint.


Mileage Before Engine Swap


My new motor will still be 50cc like the original Razz motor, but the new motor is more performance oriented and uses a CVT transmission, instead of the original Razz tranny, which is a fully auto clutch in an oil chaincase.
The new motor is a Jog motor, which usually goes in a chassis that weighs 165-190 lbs and manages to top out in the mid 40 MPH range, but my Razz chassis is just a hair over 100 pounds, so the power to weight ratio should be great.  I am 6' 125 lbs, so I shouldn't weigh it down too bad either.  I expect this setup to rip and be up in at least the 50 mph range, if not pushing into the 60's.  We'll have to wait and see!
Thats a complete rundown of what I have done so far.  More to come when the engine is together!

[jimmy]

          Nice job on everything :thumb:

[TurboGTU]

Dam thats a tinny little piston. Looks like one of them Autozone Piston shifter knobs  :icon_rolleyes: . Cool little project. You got me thinking of doing something with a scotter I have at home. It had a electrical problem after a wreck. Its missing lots of body penels so I don't even know what kind it is. It runs though.

[mfewtrail]

Cool project. Have you ever ported any small engines like that before? I'm curious to see whether low end power suffers with that exhaust port opened up that large in comparison to what it was stock.

[TGP Nick]

Yeah I have.  I do all the custom porting on almost all the dirtbikes I've owned.  To give ya an idea how long I've been into bikes- I started racing em when I was 6 and still do today.  I'm looking for top-end power more than anything, since I will be doing 90% of my riding at full throttle for miles on end at around 9-10k RPM. 

[TGP Nick]

nvm

[TGP Nick]

Update
I assembled my new top end yesterday- all new headgasket, basegasket, piston, rings, etc.  Top end is finished:




Today I worked some more on it...

I put the new air-cooling ducts on the cylinder and installed the cooling fan, along with new oil injection lines:


Then I put the rest of the cooling ducts on, along with my new exhaust system and rear wheel.  I need to paint the header portion of the exhaust so it doesn't rust, and refinish the rear wheel.  I just wanted to see how it would look together.



Tranny isn't together yet, my next project




Motor flipped upside-down, kickstand needs to be removed and repainted before finish


So thats an update on my little motor, more to come! :icon_twisted:

[GPChief]

Nice.......

You should check out some Italion sites (if possible) there were 1000's of those in Italy when I lived there, 80% of them having the annoying loud exhausts, many were modded.

[TGP Nick]

Yeah scooters rule in Europe, there are TONS there.  When mine was stock, I think it was about 80 DBA, with my aftermarket exhaust, it should be about 90 DBA or less, which is still very quiet.  Less noise means less trouble from people that dont like motorcycles and motorcyclists.

[GPChief]

The Italion parents would put the loud exhaust on their kids scooters so they could keep track of them also.........some of those scooters were wicked fast.

[TGP Nick]

New update

I've been working a lot during the last couple months, so this project was put on the back burner until I had time to work on it again..  As of the last couple weeks, I haven't had much work and finally got a chance to work on it again. 

I finished assembling the motor, along with replacing the clutch and CVT pullies, new roller weights, finishing painting the wheels and sidecover, and putting on new tires. 

I attached some pictures of the freshly built engine and transmission below..

All that is left now is to get the motor mounts welded up on the frame and final assembly.

[meltboy11]

dude, where did you get that piston, I want one for my keychain!!!

[TGP Nick]

I got it from my local Yamaha dealership. :laugh:  It is real.