Mugen Bulldog resto project

[Smeagol]

Hey all, I'm new here on the forum.. but not R/C. I was big into it in the mid 80's/early 90's and now after 20 years have got the bug again you could say. I had no idea there was a vintage R/C following until recently, so I dusted off the old collection and started going through everything. As my first project I'm going through the old Mugen Bulldog I got from a friend 20+ years ago. The car had hardly been ran, probably because there were a few errors made in the assembly process, so many things (like all of the diffs) didn't work at all. I guess the manual isn't really the greatest. Anyway, I have fully torn the car down, cleaned everything up, and am now starting the reassembly process.

I have a question on the manual speed control resistor. One of the black wires on the resistors has come loose over the years and I just want to verify the correct placement before I resolder it. See attached photos.

Is is just the one white wire in the back and 2 black wires on the front one on each side? The resistors are twisted together and soldered where the white wire is, but I'm not sure that's how it was originally. I'm probably going to replace that wiring too as it appears to have got a little hot at some point in the past. There's even a scar on the center housing to prove it. My friend did some weird things on this car that I'm having to undo to make completely original, like wiring the servo/receiver power directly to the main battery under the SC. I'm pretty sure that's not mentioned in the manual. I'm thinking that's why the resistors got a little too hot perhaps.

Any tips/advice would be appreciated, thanks!

I've added a few more before/after pics to show the progress.

thanks,
Mike

[Smeagol]

Anyone know if the acetone method to remove glued tires from wheels will work w/the Bulldog wheels/tires? Wouldn't want to ruin them as they've hardly been used, just want to clean up some of the excess CA mainly.

thanks,
Mike

[madweazl]

Anyone know if the acetone method to remove glued tires from wheels will work w/the Bulldog wheels/tires? Wouldn't want to ruin them as they've hardly been used, just want to clean up some of the excess CA mainly.

thanks,
Mike

It looks like the wheels have a natural finish (no paint or plating). The acetone trick would work on them. Clean the tires well before putting them in acetone. I didnt saturate the last set I did (couple days ago). I just dropped them in a small bucket (~1 gallon) with a lid and a couple mm of acetone at the bottom. Just the vapors of the acetone will soften up the glue. Took about 26 hours before they came off easy.

[Coelacanth]

Anyone know if the acetone method to remove glued tires from wheels will work w/the Bulldog wheels/tires? Wouldn't want to ruin them as they've hardly been used, just want to clean up some of the excess CA mainly.

thanks,
Mike

Mike, make sure you know whether the Bulldog's wheels are plastic or nylon before subjecting them to acetone. Acetone will melt plastic, but shouldn't harm nylon. I tried some acetone to remove some silver paint from a Marui Galaxy wheel (plastic) and it damaged the wheel. Keeping the wheels out of the acetone and letting the fumes do the job might work, but I'd still want to make sure those wheels are nylon first.

[RJK33]

Boy, does that ever bring back memories! Had one of these back in the day! Fastest thing on our track! Couldn't beat 4wd & 4ws. Very COOL project!
Thanks for sharing.

As for the wheels, I use to bake them. Just make sure you let them cool before breaking the tire off the wheel. I found out the hard way and lost all my finger prints for a couple of weeks!

[Smeagol]

Thanks! I has been fun so far, bringing back the good ol' days.

I've tested a small section on one of the wheels with acetone and haven't seen any adverse effects, I'm thinking they're nylon.

Hmm, I hadn't thought of baking them. Any set time/temp for this recipe?

thanks,
Mike

[highwayracer]

The bulldog was THE car that I wanted back in the day. I remember looking at a catalog from 85...but I couldn't afford it. In the mid 90s, I was fianlly able to one. Unfortunately, it was a real basket case that was covered in red dirt and rust. I was so disapointed at the condition (since the seller told me that it was in mint condition) that I threw it on a shelf and didn't touch it for a good 10 years.

I restored it and was really happy with the outcome.

Back to your question. One ide of the resistors connect to the single white wire. The other side of the resistors each connect to a black wire. So if you were to streatch the whole thing out you'll have: a black wire, resistor 1, white wire, resistor 2, black wire.

As for the wheels, they are nylon, but there are different grades of nylon. My wheels were very thin and weak/brittle in some spots. I wound up using an exacto to carefully separate the rubber from the plastic. But this was before I knew the true benefits of acetone.

Good luck with the project.

Regards,
Roger

[Smeagol]

Thx for the info highway, last weekend I quickly soldered everything together (2 black wires front, 1 white wire back) to test run the motor and it was fine. Nothing smoked or exploded, so I figured it was right.

Now onto the wheels. I'm about to try the acetone trick.. just hoping it doesn't mess with the tires at all.

-Mike

[RC10resto]

Tires should be fine, the wheels are what you have to watch out for.

[ROH73]

Acetone can destroy the tires as well! I would highly recommend not using acetone to remove the tires if you want to save them. At least do a test first. The only common rubbers compatible with acetone are natural rubber and EPDM. I have no idea what the Bulldog's tires are made from, but I believe that natural rubber was not common until Losi brought them out in the late 80s.

I have used acetone to remove tires from many rims and in almost all cases, the tires were destroyed (they were all worn out, so now problem as I wanted the rims not the tires).

[Smeagol]

I do want to save the tires as they've hardly been used and have 90% tread remaining at least. I may just try using a nylon brush to clean up the excess glue and make them look nice. They were originally glued on a bit sloppy, almost seems like they were glued on covered with dirt, heh.

Longshot, but does anyone make Bulldog reproduction tires? wheels?

I tried boiling them to clean off excess glue but it just made it turn a white/grey color and inflated the tires a bit. I suspect baking them would probably do the same.

Slowly making progress...

thanks,
Mike

[Coelacanth]

That's looking really good so far! I was never sold on 4-wheel steering, air shocks or mono-shocks but the Bulldog was certainly a unique, great-looking car.

[highwayracer]

The tires on the bulldog feel like the same type of material used on the tamiya blackfoot. It's not the same type of rubber that's used on the modern or even vintage losi tires.

You can use fine sandpaper to remove the white residue....but it will expose the natural rubber finish...vs the shiney surface currently on the tire. I would experiment on the inside of the tire.

[Smeagol]

Hey all,

Wow.. haven't been on in quite some time. I've slowly been making progress on the Bulldog. It's almost there. Recently picked up a couple more vintage R/C's so I've been slightly distracted lately.

thanks,
Mike

[Smeagol]

Finally finished! She came out pretty good I think. Found it's way to eBay as I have too many other projects on the back burner that need to be funded.

-Mike