Jump to content
GeekSpeed

Need Help with Re-Re Bigwig

Recommended Posts

Hi everyone.

I have started my Bigwig build and have run into a problem.  The rear gearbox is extremely tight.  I can barely move the outdrives.  I am thinking it must be the mesh of the motor and the gears because when there is no motor installed, the gearbox moves fine.  Also, the motor itself moves fine.  It is just when the motor is bolted to the gearbox that the problem arises.  I have tried to set the mesh several times, but that does't seem to work.  Am I missing something?  Has anyone encountered this before?  

Thanks for any assistance.

Share this post


Link to post
Share on other sites

You don't set the mesh, you use the thin metal plates to space the motor, depending what pinion tooth count as to where the plates are placed

  • Like 1

Share this post


Link to post
Share on other sites

Sorry, I should have been more clear.  I checked the little plates and made sure they were correct for my pinion.

Share this post


Link to post
Share on other sites

It should run smoothly. 

Is it a kit supplied pinion?  If you bought a pinion, and if the pitch is wrong, it won't work.  For brushed motors, kit supplied pinion should do fine.  If you are using a brushless, steel pinion is recommended. But sometimes people buy the wrong pitch.  In simpler terms, the size of each tooth is different if you are using a different pitch.  

What Snappy1 said is the most common problem.  Even after building 30 cars, I find one metal piece (BA22) on the table after building it.  So I go back to do it again.  I just count the teeth, and double check the plate locations on the instruction.  

Are you using 15 teeth pinion?  (Unless you are using a ridiculously fast brushed motor like 9 turn, 13 teeth is kinda low)  For 15 teeth, you have used 2 plates on each side of the 30mm long bolt (BA1)?  

Is there any gap between two halves of the gearbox?  You've used the yellow pinion depth measuring thing (A13)?  Instead of trusting that method, I stuck in a ruler to measure the exact depth and used that depth.  If I remember correctly, A13 gives you 0.5mm too deep or too shallow.  That shouldn't make the gear mesh stiff, though.  

Just to test, have you tried putting 3 plates up, and 1 plate down?  It's the option when you are using a 16 teeth pinion.  You should not choose this option if you are using a 15 teeth pinion.  But if it works, you know for sure it's the pinion-spur distance problem.  Don't run it that way, I'm sure there is a solution because Bigwig is a good runner.  

QIi7TK1.jpg

 

  • Like 1

Share this post


Link to post
Share on other sites

Make sure the pinion is slid onto the motor shaft the correct amount.  If it isn't close enough to the motor, it can rub on the gearbox housing and cause your problem.  If you were to try to run it, the gearbox would melt down.

  • Like 1

Share this post


Link to post
Share on other sites

Thanks for the help.  I have checked the plates, and I do have two up and two down.  I am using the kit 15t pinion.  The gearbox halves fit together well and there are no gaps.  I used the tool for pinion spacing and triple checked it.  I am kind of at a loss.  I briefly ran the motor while attached to the gearbox and it spun.  I can also spin it easily when I use the propeller shaft.  I may just run it a bit and check to see if the motor or the gearbox heats up too much.  

Thanks again.

Share this post


Link to post
Share on other sites

Hi @GeekSpeed, I have never built a Bigwig but I had seen a Youtube video where someone else had experienced the exact same issue.

It was Tamiya Legends and at approximately 3:40. I really hope this helps.

 

  • Like 1

Share this post


Link to post
Share on other sites
15 hours ago, GeekSpeed said:

I can also spin it easily when I use the propeller shaft. 

One last thing.  Do you have the motor plate on the motor?  It's the waxy, blue-gray sheet you put between the motor and the gearbox?  It's there to prevent sticking, just in case the motor gets hot enough to melt the plastic. (Since it should Never get that hot, some people don't use this plate, which is not good)  

The motor plate has only 2 holes.  Many motors have 4 holes.  If you use the motor plate, you can use only 2 holes that are 180 degrees of each other (two blue lines).  If you don't use the motor plate, you might put one bolt in the wrong place.  They could be 190 degree and 170 degrees of each other (two red lines). That could mess things up.  

 PjeEuMF.jpg

 

But, if you can turn the wire shaft with your fingers (with the motor attached), that's smooth enough.  

Tamiya Legend's video is a mystery.  After building some 30 cars, I've never seen anything that tight unless something is wrong.  It moves as if he's got 3 plates down, 1 plate up.  Or, one of the motor-mounting bolts got in the wrong place (like the red lines above).  

 

Share this post


Link to post
Share on other sites
13 hours ago, Juggular said:

 

Tamiya Legend's video is a mystery.  After building some 30 cars, I've never seen anything that tight unless something is wrong.  It moves as if he's got 3 plates down, 1 plate up.  Or, one of the motor-mounting bolts got in the wrong place (like the red lines above).  

 

I don't want to pick on Tamiya Legends, I am a subscriber and anyone who spends so much time popularising our hobby the way he does is a legend, but he does make quite a few mistakes on builds

  • Like 1

Share this post


Link to post
Share on other sites

Thanks for the replies everyone.  I finished the build and it looks like the gearbox is not quite as tight.  I ran it a little bit and I can now turn the rear wheels with less effort.  I am going to keep genlty bedding it in and see how it goes.  Fingers crossed.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×
×
  • Create New...