MR4 BC?

[rccars4sal]

Anybody have experience with, information regarding the somewhat rare and forgotten yokomo mr4 buggy?

[DennisM]

I´ve got a nib and a resto project.
Just by the looks of it, I´d rate it to be a downgrade from the Hot Dog

[rccars4sal]

SSSoooo,,, does it have a slipper clutch and ball diffs?

[littleVETTE]

it's not rare, and wasn't a favorite with some. but there are some that wished it was forgotten. nearly every person i've talked to had something bad to say about it. "lively" "mothertrucking belt skipper" etc.. that could be why they go for so cheap at auction.

it does have ball diffs (plastic outdrives) and there was an optional slipper clutch. with a little work you could make the buggy work right. replacement parts could still be found at reasonable prices. you could interchange parts from other cars and buggies onto it.

some have taken the bc buggy to other levels by making it into a hybrid. there's a lot of nice ones on this forum.

[rccars4sal]

I did a search and found not much. No worries. Ive got one on the way, and going to add it to the pile of yokomo that is accumulating in my shop to do another mega build project. Im hoping to realize the genetic relationship to other yok buggies by having it in hand along with a pile of yz10-870Cs. From what I understand, it is already a hybrid of sorts, relating in some ways to the mx4...

[rccars4sal]

Ahh its arrived. Im going to gut it and see what parts will fit yz10870c and tomy intruder.

[rccars4sal]

Oh boy, UJ axles too long for any yz10870c application, hubs, arms all non compatible as well. Im hoping the ball diffs and main shaft set up might be workable into older cars, not there yet though. Im pretty impressed with the design. Its a solid, well thought out buggy. No idea how it handles. Its ready for brushless and lipo though, no mods needed.

[rccars4sal]

Spacing between belts is narrower than in yz10870c models, and as such, the diffs have a different offset than older cars. Im thinking they will fit in the older cars bulkheads, but the side to side offset might be wrong. Crooked belts are bad. Looks like this buggy is going to get cleaned up, mildly restored, and made a runner.

So, if anybody is thinking as I did,, that possibly some parts from the newer mr4 buggy might work in an older yz,, then heres the answer: It appears that no parts worth considering will translate without some kind of comprimize. Sure, a guy might be able to use shims to make the arms fit older bulkheads, but then the UJ axles might still be wrong length...Belt drive pullies might work on some models of 870c.. Shocks, threaded, and nice! should work on any buggy. Really not enough similarities to persue as a source of parts for older.

[pumpkinfish]

I have a MR4-BC Super Dogfighter 2 Special. I have had it since it came out and just raced it a few weeks ago. It is a tough car and needs little maintenance but the two biggest pain in the butt things is new wheels and especially diff rings. I recently broke a rear arm and used my last one in stock. If you are looking for parts, you need to look for MX4 parts in addition to MR4 parts. The rear arms are the same as a well as a few other bits and pieces. You can also use MR4 touring car hubs and back in a day we all converted over to them. You really want to look for the 7 degree front c blacks and the 1 degree MR4 touring car rear carriers. They will make the buggy feel less skittish.

[rccars4sal]

Yeah. Im looking to get a few spares in hand. I just finished rebuilding the whole thing, nice and clean, and finally got the diffs pretty good. Its a stout buggy for sure, very stiff build. I had originally got this one to see if there was any relation to older cars, but its ended up as another runner. I dont think I would want a shelfer in this model, but its begging to be flogged hard. As for wheels, I did notice the proprietary hub system,, but it can be changed to mx4 hubs,, but those wheels are just as rare as mr4 wheels.. So,, wheels are a bit of a problem. There is a ton of toe in in the stock rear hubs for sure. More than other buggies it seems. So, while shopping for spares, Ill keep that in mind.

[pumpkinfish]

The most important thing to check for is the two small screws that go in the sides of the front shock tower. You may think they are unnecessary, but they are critical to keeping the front bulkhead from breaking. Back in a day I bought a carbon fiber front and rear shock tower and promptly broke the front bulk head because there was no provision for these screws.

Also, you can fit a 5000 lipo in there but it is very tight. I ended up using a velcro strap to keep it in place.