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Yokomo MR4 BC upgrade
Posted: Sat Feb 06, 2016 4:08 pm
by stuey
Hi guys. I have a Yokomo MR4 BC that I have run a few times outdoors at a local club. I found out that there was a long wheelbase conversion available, as the car is based on a TC chassis its a bit short. I could not locate the full kit, but managed to get hold of the plastic bits. It needs a rear hinge pin brace which I cant find, but that can be made.
The trouble I have is the hinge pins. They are 2.3mm diameter, and approx 48mm long. The conversion kit looks to come with longer ones. I have been looking around, and the nearest thing I can find is some 2.2mm drill blanks that are 54mm long, which will probably work. Also 11 AWG piano wire is a tiny bit bigger diameter, but no luck finding any. Can anyone help? Drilling the wishbones to 3mm might leave them a bit thin, 2.5mm would be ok if I can find some suitable pins or wire.
Thanks for reading
Re: Yokomo MR4 BC upgrade
Posted: Sat Feb 06, 2016 10:48 pm
by rccars4sal
Re: Yokomo MR4 BC upgrade
Posted: Sun Feb 07, 2016 2:25 am
by stuey
I have aTC version too, but I suspect the pins are the same but I will check. Thanks for the heads up

Re: Yokomo MR4 BC upgrade
Posted: Sun Feb 07, 2016 9:31 am
by jwscab
2.3mm is approximately 3/32" , should be able to get that pretty easily and ream out the parts for a smooth fit. also a number 42 drill is .092", mcmaster-carr carrys both in reasonable lengths, costs, and materials.
you don't have your location listed, but if you are in US, this would be the way to go.
Re: Yokomo MR4 BC upgrade
Posted: Sun Feb 07, 2016 10:21 am
by stuey
jwscab wrote:2.3mm is approximately 3/32" , should be able to get that pretty easily and ream out the parts for a smooth fit. also a number 42 drill is .092", mcmaster-carr carrys both in reasonable lengths, costs, and materials.
you don't have your location listed, but if you are in US, this would be the way to go.
Good call, I should be able to get the piano wire and drill easily enough in the UK. I can cut it to length with a dremel cut off wheel. I may well owe you a beer

Re: Yokomo MR4 BC upgrade
Posted: Sun Feb 07, 2016 11:11 am
by jwscab
No sweat. Glad to help.
Re: Yokomo MR4 BC upgrade
Posted: Mon Feb 15, 2016 6:09 am
by stuey
I managed to sort this out in the end. I got some Bmax2 rear inner pins which are a bit longer, drilled out the bulkhead and arms to 3mm and by luck found an old Schumacher hinge pin plate with exactly the right hole spacing! I ran the car yesterday, and all seems well

I would like to fit a slipper in the car so I can run a hotter motor setup, but I think finding the parts could be hard!
Cheers
Re: Yokomo MR4 BC upgrade
Posted: Mon Feb 15, 2016 12:08 pm
by Mr. ED
stuey wrote:...
I would like to fit a slipper in the car so I can run a hotter motor setup, but I think finding the parts could be hard!
Cheers
There are 2 versions of the slipper: single padded or double padded. One is hell to find, the other even worse
They do have a standard spur adapter for the touring car version. With that and a steel spur... maybe loosen the ball diffs a bit not to strip the belts

Re: Yokomo MR4 BC upgrade
Posted: Mon Feb 15, 2016 3:11 pm
by stuey
My Dad gave me a couple of the MR4 tc chassis, I need to see if there is anything useful on those to borrow. I will check the spur gears too. I put a 17 double in it just to get it going, I am thinking 8.5t brushless will be as far as I should go without a slipper.
Re: Yokomo MR4 BC upgrade
Posted: Mon Feb 15, 2016 9:03 pm
by rccars4sal
I was running an mx4 slipper in mine. Really great handling car, but like all Yokomo,, watch out for pebbles! They will get in there, and kill everything that turns. Its worth while to find a belt guard from the rally car, except I guess it would be short wheel base.
Re: Yokomo MR4 BC upgrade
Posted: Tue Feb 16, 2016 4:24 am
by stuey
I have the car that has the enclosed belts and no top deck as such, so I'm lucky on that front! I will post a pic when I get a minute.