Yokomo MR4-BC and MR4-BC special builds

[Alex B]

Having been a way from any Yokomo builds since my WCS build I thought I'd jump back in with a couple of Yokomo MR4-BC builds.

The first is a standard MR4-BC which I snagged of ebay for okay money, I managed to get a donner MR4-TC for a the special chassis and top brace, one way adaptor and one way front diff and a few other bits. I plan to fit MR4 - bx shocks, MX-4 slipper and LWB kit to this one. I'm still waiting for some parts to arrive so I will update the thread when I start the build.

N.B pictures taken from ebay listing.

[Alex B]

The second build is a MR4-BC special which I got from Japan Yahoo auctions for an excellent price, it has the special shocks, special chassis and top brace one way adaptor (no special slipper unfortunately), special wheels and adaptors, the LWB conversion and I think a one way front diff which I will know for sure when I strip her down.

This one doesn't need much work just a really good clean up and some TI turnbuckles which I have already got.

[Alex B]

Just for comparison here is a picture of the difference between the special shock and the later MR4-bx shock. As you can see although similar there are a few differences namely the bore seems smaller on the special and the bottom shock seal part is different. On the later shock the seal consists of three plastic spacers and two o-rings on the special shock there is only one spacer and two o-rings. The caps and the spring retainers are the same.

[Alex B]

I thought I had managed to find a LWB kit but the shop I had purchased from thought they had it in stock but it transpired that this was not the case so I'm going to modify the parts myself to do the conversion.

Taking measurements from the special I need to modify the rear bulkhead and get the part down to around 24mm.

Not quite worked out the best way to do this yet.

The second modification is removing part of the rear suspension block, I did this by taking measurements from the special and using a jr hacksaw and a file. For this modification to work you will still need the rear alloy suspension bracket and the spacer to push the rear shock mount outwards, the spacer as it happens is the same spacer as the one used when fitting the anti roll bar kit in a MR4 TC, luckily I have.

[Alex B]

The parts needed for the conversion.

[Alex B]

Making slow progress on these builds after I contracted the 'human malware' but I'm on the mend.

First up got all the bits for a MX-4 slipper. Not sure if this is going in the official special or the modified standard car.

I managed to modify the rear gearbox parts of the LWB conversion using my trusty Dremel, not as neat as factory but more than functional. As it turns out I needed have bothered as the LWB bulkhead arrived after I was told no stock was available.

First picture shows the modified parts:

DSC_1801.JPG (28.58 KiB) Viewed 3491 times

DSC_1801.JPG (28.58 KiB) Viewed 3491 times

Second picture shows the factory modified parts.

I also modified the chassis to accept the LWD conversion.

[Alex B]

I came across a bit of an issue with this one. I had planned on using a chassis from the MR4-TC but is transpires that the chassis will not work if you use the standard MX-4 spur gear as it does not have the necessary molding in the bottom of the chassis (Picture below) which causes clearance issues.

The correct chassis is Yokomo ZS-002GB Graphite Main Chassis. I managed to get one in the UK from DMS so I decided to use that one for the restoration of the Special.

Just a few things to finish and this one will be done.

[Alex B]

Got a little bit done last night on the rear of the MR4-BC, the pictures below show the parts needed for the LWB conversion. I found the right plastic spacers in my parts bin and the rear inner hinger pins are the standard items. You will need to put a hinge pin retaining screw on the front side of the rear arms to stop the hinge pin migrating forwards.

The small spacer are used towards the rear and take up the place of the original molded plastic piece used on the standard car to retain the rear arms which has been removed in the LWB conversion. The blue alloy piece is used to retain the rear hinge pins.

How it looks when it is all fitted and complete.

[Toaster]

Great work, always wanted to find a way of modifying a ‘BC’ as they always seem to pop up every once in awhile at a decent price (at least right now given how crazy prices are getting).

Will be following with great interest! Keep it up.

[iiokurud]

Great post! I have a NIB MR4BC on the way and a used one, not sure my plans yet but following and thanks!

[Alex B]

I thought I'd update this project.

The second build is going to be a bit of an MX-4, MR4-BC, MR4-TC MR4-BX mix up build. I'm I'm using a front bulkhead cap from the MX4 and the slipper assembly the front and rear shock towers and camber link, a MR4-TC front one way, MR4-BX shocks, JC racing wheels and all new Lunsford Ti turnbuckles. The Chassis and top deck are from the MR4_BC special with the LWB conversion.

[Alex B]

A couple of shots of the chassis build.

[Alex B]

Front and rear shock towers.

[Alex B]

Completed chassis.

[Alex B]

Finished other than the electrics.