MR4-BC.

Dingbat · #1 16-10-2010

Almost ready for some club bashing.
It's not quite vintage but It Is definitely old.

Not sure what motor to use at the moment.
I have a stack of good brushed motors and a stack of good
NimH stick packs.
One GM brushless pro 97290 10.5
but I think It's for touring cars.
Any advice Is most welcome.

Cheers.
Db.

chris brown · #2 16-10-2010

Its a great car. What surface are you racing on?
You can still get spares on ebay and there are a load of set ups about if you google for them.
It looks like you have got the mr4bcspecial there too with a lot of the option parts on.

Dingbat · #3 18-10-2010

Cheers Chris,
Yes It does have quite a few upgrade parts including a one way front
differential.
I'm not to sure about using the one way front because when you come off the throttle whilst turning,the rear end slides out when the motor slows the rear wheels down.(like lifting the hand brake in a real car)
It wouldn't be to bad if I could adjust the amount of front freewheel,
to make the rear just slide slightly rather than handbrake on and handbrake off.

Anyhow It's quite an old buggy and I shouldn't get too technical,
I do have a few spares including four chassis,four of each drive belts,
a dozen wheels including some alloy wheel adaptors,
suspension arms and steering knuckles.

I'll be using it outdoors on astro
and i have never raced on astro before,
I've currently got the brushless motor installed and I'm using
NimH battery packs between 3800 mAh and 4300 mAh.
these seem to last about 10 ish minutes giving it lots of full throttle.

Any motor help much appreciated.

Db.

chris brown · #4 30-10-2010

Hello.Not sure what you mean by motor help. If your track is tight and technical then your 13.5 will be really good and you will probably beat higher powered cars in the corners but will really suffer in the straights. Also the car doesnt have a slipper clutch so I wouldnt go overboard on the motor you use. 7.5 tops I would say. You could use a more powerfull one but you take the risk too of the drive train not being able to cope with the torque of a brushless motor. The front one way should be really good to use on astro turf as the rear wont slide on astro, correct tires needed of course.

Dingbat · #5 30-10-2010

Thanks Chris,
just the sort of advice I needed.

Bikerbob · #6 03-02-2011

Still running mine, keep breaking servo arms.. hate that outboard steering.

We are indoor on a hook and loop low pile carpet.. but reducing the grip of the buggy is the problem right now.

otherwise I still love it.. I have lots of spares.. so I keep running.

james

Dingbat · #7 03-02-2011

Quote:

Originally Posted by Bikerbob

Still running mine, keep breaking servo arms.. hate that outboard steering.

We are indoor on a hook and loop low pile carpet.. but reducing the grip of the buggy is the problem right now.

otherwise I still love it.. I have lots of spares.. so I keep running.

james

Hi james,
I've just put a post in the "I made this section"
I was having trouble finding spur gears for the slipper clutch
so I modified a B-max one to fit.
Quite a simple mod.
As for the servo arms,I use an alloy Ansman one shortened with a dremel to fit under the body.

Db.

Bikerbob · #8 28-02-2011

So are you saying you made a Bmax slipper fit in the BC? or Bmax spur gears?

I heard the B44 spur fit right in.. is that not true?

What about different springs for this car? I cant get rid of my traction roll??

James

Bikerbob · #9 28-02-2011

Also has anyone who does or used to run this buggy done the mr4tc steering mod?

Rotate the servo 90deg and reverse the bellcranks so the servo is across the centre of the chassis?

I think I am going to do it.. was wondering if anyone knew a negative to doing it?

Bikerbob · #10 11-03-2011

I got screwed on my local deal for a slipper..

ANYONE help me with this??

Any ideas for this car??

IF you have and old roller with a slipper? or just a slipper unit??

I need one please.

I am running this indoor on industrial carpet.. I am not buying a new 4wd, I am going to run this till dead. SO would love to have it live a little longer with a slipper.

James

Dingbat · #11 11-03-2011

James.
I use the genuine Yokomo slipper clutch.
Part ZS-670
It did take a while to find one,I got mine from 'End of line RC'

I now use a modified Bmax spur gear to fit the MR-4BC slipper clutch.

superdez · #12 11-03-2011

Quote:

Originally Posted by Bikerbob

I got screwed on my local deal for a slipper..

ANYONE help me with this??

Any ideas for this car??

IF you have and old roller with a slipper? or just a slipper unit??

I need one please.

I am running this indoor on industrial carpet.. I am not buying a new 4wd, I am going to run this till dead. SO would love to have it live a little longer with a slipper.

James

DMS racing have the slipper listed in Yokomo upgrade parts at £50. Drop them an Email.

http://www.dms-racing.com/

Bikerbob · #13 12-03-2011

have done, thanks for the link.

Fingers are crossed.. if so.. thats the last major part I will spend on this 4wd.

I love YOKs .. and soo wish they were available here.

There has not been good YOK support in Canada since the 90s.

In North America since early 2000s

There is NO WHERE to buy a MAX-4 here.. so a max-4 II is out of the question.

James

Bikerbob · #14 21-03-2011

Apparently they dont keep their inventory up to date.

They did not have a slipper.

SO I am still asking.. If anyone has a slipper or roller with slipper (only) I am interested.

Parts??? belts??

Anyone use any different shock springs on the yoke shocks?? Very nice shocks but the while only springs I find difficult to tune.

James

chris brown · #15 27-03-2011

Think you can use the associated springs. You can buy them in full sets. RC boyz in the states should have them. I dont know any shops in Canada you see.
Try ebay uk for spares. There usually seems to be a lot on there from week to week.

mr. ed · #16 28-03-2011

oops double post

mr. ed · #17 28-03-2011

I think kyosho springs would be a better fit. Got to check but I think the diameter is metric on the yokomo.

Here 's a little pic of what I did with my MR4-BC:

To fit the shorter wheelbase body I reversed the front arms, moved the shocks to the back of the tower and moved the steering posts back too.

chokoboy · #18 29-03-2011

AE springs are a direct fit, kyosho's are larger in diameter

CODMAN · #19 29-03-2011

A Yokomo converted into a Beetle...

That is just wrong....

Quote:

Originally Posted by mr. ed

I think kyosho springs would be a better fit. Got to check but I think the diameter is metric on the yokomo.

Here 's a little pic of what I did with my MR4-BC:

To fit the shorter wheelbase body I reversed the front arms, moved the shocks to the back of the tower and moved the steering posts back too.

Bikerbob · #20 30-03-2011

Oh I read somewhere that the Associated springs dont fit the bottom cups??

I have some.. so I will give it a try.

Broke my front shock tower trying to race last weekend... I have 1 left.. then I am done anyway. This buggy is not working with 4300kv power.. the belt is pulling right over the pulley.

So I have to baby the throttle, and that is not even B-main competitive.

Hmmmmm this sucks.

James