Kawasaki Motorcycle Forums banner

Kawasaki G4TR-E 100cc - get her going again?

29K views 241 replies 10 participants last post by  Kawasaki Nut 
#1 · (Edited)
My son and I are taking on a new project - a 1975 Kawasaki G4TR-E 100cc bike we had at the farm from new when I was a kid. It hasn't ran in 35 years approximately so its going to need a lot of work.

The engine is somewhat in pieces but I think and hope all the parts are present. I didn't dissassemble any of it, I believe my nephew took the side covers off, removed the carb and the motor off the frame. My son said he could not move the kick starter so the cylinder/piston might be seized.

Advice anyone? I'm hoping it will be a fun project that won't break the bank. I do realize nothing is free in life and will have to shell out some cash to make it happen.
 
#6 ·
For a bike this old, many parts will not be available as new. My goto source for new parts is Partzilla but there are many others and don't forget the Kawasaki dealer. Sometimes I have actually found the dealer had the best price and they typically don't charge for shipping costs.

I suspect Ebay and Google will be your friend when it comes time to track down some of the parts.
 
#8 ·
Once I can get the cylinder unseized, then I can assess the parts I need. I plan on bringing the bike from the farm into my garage here in the city to assess it more and take "before" pics. Used parts will have to do, and they will be cheaper too. I've been calling around locally to see who can rebuild the engine or at least bore out or hone the cylinder for me. I hope the bottom end of the engine is ok and doesn't have any water in it. I hope I have most of the original parts since it is somewhat in pieces when my nephew dissassembled some of it.

Thanks for the great advice!
 
#9 ·
Agree ^^^^^ and this manual is probably the best for your needs (y)
I found that my local library can get the manual you refer to through the provincial library system and I just placed a hold on it.

I can buy it on eBay for about $31 used, which isn't bad - maybe I'll go that route.

Is this manual pretty generic (since it ranges from 80cc to 350cc from 1966-2001)? Too bad I couldn't find a more model and year specific manual.
 
#11 ·
Congratulations on a fine old motorcycle, These are very simple machines. My advice would be to take your time and do the work yourself. The cost to have a competent, experienced mechanic do the work will more than the machine is worth. You will almost certainly be able to find someone who will give you a low estimate, but almost without exception that will lead to disappointment. Take the project one step at a time and treat each step as a learning experience, enjoy the satisfaction of a learned new skill.
 
#13 ·
Also, these bikes are getting hard to find and thus are rare and valuable. I wish I could find one to restore but they just don't come up for sale often. I have been looking for years without success. You have yourself a rare gem and I would do exactly as 1981GPz550 has suggested; Take your time, learn new skills and enjoy the process. We are here to help you through it.
 
#16 ·
My preference is Partzilla mostly because I am used to it but it does have a useful feature in that it will show you all the different models that used the same part. After you find the part you are looking for an click on it, it will show you a list of what other models used that part. I have no affiliation with Partzilla.

 
#18 · (Edited)
I popped the head off to see that the piston was about 1/2" to TDC...

We put the head back on, snugged down the nuts and filled the chamber with diesel fuel. There is no movement so it's either a seized piston or seized crankshaft.

Advice anyone?

Hey WFO-KZ,

Why doesn't Partzilla list the G4TR-D for 1975? It lists a G4TR-E for 1975 but no G4TR-D... ??

What is the difference between the two bikes? I'm assuming not much...
 
#19 ·
I would not use the kick starter to free the engine. Remove the head and using a block of wood tap on the piston until you get some movement. A Kawasaki mechanic I used to work with bent a rod on an H2 trying to turn over a hydro locked engine with the kick start. Also puts a lot of stress on the kick start components. A handy way to keep bolts and screws from getting lost and to ensure the proper length bolt is used is to draw a simple outline of the part on cardboard, mark each bolt hole and punch a small hole at each fastener location. Push fastener thru the proper hole and the cardboard will hold it securely.
 
#20 ·
The alpha characters at the end of the model, indicate versions, which in your case follow the model years exactly.

So the G4TR-A was for 1971
G4TR-B was for 1972
G4TR-C was for 1973
G4TR-D (your bike) is a 1974.
Not sure why you think yours is a 1975 but possibly the bike was sold in 1975 and mistakenly registered as a 1975 model. So if you go back one model year to 1974 on Partzilla you will find the G4TR-D.
 
#21 ·
It's good advice not to use the kickstarter to free a seized engine. I have also seen con rods made into a pretzel by someone using the kickstarter.

You can also fill the crankcase with diesel if you expect rusty crank bearings. Just make sure that the fluid has some place to go when you start tapping on the piston with a block of wood. Removing the filler plug will accomplish this.

You should also spray the side of the piston through the exhaust port with a penetrating oil. My favourite penetrating oil is Deep Creep by Seafoam. With patience you can get it freed up.
 
#22 ·
If you continue to have trouble freeing the engine you could try the following. Remove the right side engine cover, remove the rotary valve cover and disc. Lay the engine on its left side and fill the crank case with a solvent of your choice. This will flood the left crank bearing, lower con rod bearing, wrist pin and lower cylinder.
 
#24 ·
Not really your bad. I must be brutally honest, I can not remember with the small Kawasaki 2 stroke rotary valve engines which side the right crank seal is on, Crank side trans oil would lubricate, Rotary valve side fuel/mixture would lubricate, I just can not remember. Old age and hundreds of motorcycles in the past, do the best that I can, sure you do the same.
 
#29 ·
Technically you are searching for the frame number since VIN's did not become a thing until around 1980 (I think).
Anyway, this posting will help you locate the frame number. There is an excellent photo of the sticker in this post and below the sticker you can even see where the number is stamped into the metal.

 
#30 ·
Good news and bad news...

Good news... my son and I have gotten the piston and cylinder unseized:
42605


42604


42606


42607


Bad news is the crank bearings seemed to be solidly seized... not sure why. Time to split the crankcase.

I also bust a cooling fin off the cylinder... #%@%$&!!!! Hopefully not a big deal:
42608


Any advice on splitting the crankcase? Off to YouTube...
 
#33 ·
Good news and bad news...

Good news... my son and I have gotten the piston and cylinder unseized:
View attachment 42605

View attachment 42604

View attachment 42606

View attachment 42607

Bad news is the crank bearings seemed to be solidly seized... not sure why. Time to split the crankcase.

I also bust a cooling fin off the cylinder... #%@%$&!!!! Hopefully not a big deal:
View attachment 42608

Any advice on splitting the crankcase? Off to YouTube...
Youtube saved my bacon many times.
 
#31 ·
My son and I are taking on a new project - a 1975 Kawasaki G4TR-D 100cc bike we had at the farm from new when I was a kid. It hasn't ran in 35 years approximately so its going to need a lot of work.

The engine is somewhat in pieces but I think and hope all the parts are present. I didn't dissassemble any of it, I believe my nephew took the side covers off, removed the carb and the motor off the frame. My son said he could not move the kick starter so the cylinder/piston might be seized.

Advice anyone? I'm hoping it will be a fun project that won't break the bank. I do realize nothing is free in life and will have to shell out some cash to make it happen.
I'm located across the bridge in Michigan, I hope that it works out, but if not, I am interested in buying it. I have a 74 G4TR-D and want another (74 or 75) for my wife. BTW, a 75 is a G4TR-E. Mine was running when parked in the 90s, but wasn't "stuck". I got it running after a few months, but it did cost more than buying one that was already running, without even factoring in time spent.
 
#34 ·
I'm a long ways from Michigan, so shipping my bike to you might be cost prohibitive. I hope I can get the crankshaft and connecting rod bearing unseized, as this is what appears to be the problem. The locked up condition might be because of a blockage in the clutch/gear box area, I don't know.

Splitting the crankcase tonight to see what the cause of the lockup is. Any advice anyone on splitting the case?
 
#32 ·
My son and I are taking on a new project - a 1975 Kawasaki G4TR-D 100cc bike we had at the farm from new when I was a kid. It hasn't ran in 35 years approximately so its going to need a lot of work.

The engine is somewhat in pieces but I think and hope all the parts are present. I didn't dissassemble any of it, I believe my nephew took the side covers off, removed the carb and the motor off the frame. My son said he could not move the kick starter so the cylinder/piston might be seized.

Advice anyone? I'm hoping it will be a fun project that won't break the bank. I do realize nothing is free in life and will have to shell out some cash to make it happen.
My son and I are taking on a new project - a 1975 Kawasaki G4TR-D 100cc bike we had at the farm from new when I was a kid. It hasn't ran in 35 years approximately so its going to need a lot of work.

The engine is somewhat in pieces but I think and hope all the parts are present. I didn't dissassemble any of it, I believe my nephew took the side covers off, removed the carb and the motor off the frame. My son said he could not move the kick starter so the cylinder/piston might be seized.

Advice anyone? I'm hoping it will be a fun project that won't break the bank. I do realize nothing is free in life and will have to shell out some cash to make it happen.
I am in the home stretch on my 74 Kawasaki F9 350. The Clymer manual is very handy. Check out CMS for new parts. They're in Canada. They have exploded views of the entire bikes. Ebay has been the only source for many of the NOS parts. The Suzuki shop near me bored the cylinder for me. Oversized piston and rings, bearings and connecting rod all from eBay. Have fun. Those are fun bikes. Does yours have the dual range transmission?
42611
 
#36 ·
Wow it has been a very, very long time since I split the cases on a Kawi dirt bike. Advice? Be gentle. It will take some tapping with a plastic tipped hammer to separate the halves. Resist the temptation to pry it open with a screwdriver. You can try tapping on the heads of the case screws by backing them off by a few threads and then tap each one gently and go around to all of them but don't hit too hard as the steel screws are bearing on aluminum threads.

You can also try tapping on the end of the crankshaft, or transmission shafts but always gently.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top