Yokomo Bmax2 M

[OneKiwi]

Tyres and inserts would be the first to check. Also if one side is spinning up faster then thicker diff oil and or a softer TH curve

[big_boss]

Hi Brett
First thing that comes to mind is: why mid motor?
Surely it works but only on high traction tracks. anyway that's my take on it.
First thing I would check is the front wheels, If one wheel is not pointing ahead (toe in or toe out) and the other isn't you can get the problem you mentioned. Second thing to check: are the shocks the same length (rear shocks as a pair & front shocks as a pair should be the same length).
Third thing to check: if you turn the car on the it's roof and press on the suspension arms or tires, do the rears feel the same? do the fronts feel the same? do you feel there if oil missing from one of them more than the other?
I run on a medium grip when wet track & low grip when dry rear motor with the battery all the way back, a 8.5t motor, box setup. The car is very well behaved.
hope this helps.

[Brett.w]

Thanks for the reply Big Boss, I have tried both ways and preferred mid motor especially on the jumps.

I will look into your suggestions, thanks again for your help

Brett

[DrPaul]

Hi Brett,
Is your slipper set correctly. I also run on a low grip track but I find setting the slipper correctly is very important. Also try putting the rear link in the middle hole on the hub & the inner hole without a spacer on the gear box end.
Good luck.

[neallewis]

Mid/rear motor isn't the issue. Mid motor works very well in the lowest of traction tracks. The issue is the unloaded wheel is spinning up. If your tyres are ballooning, then I'd say the driver is giving it too much throttle when the car isn't straightened up. Are you running the right tyres for the track? Same as the local top guys. Suspension setup, what do you have set. Fill out a setup sheet so we can see. Check your rear shocks are not pressurising. I noticed this with the plastic shock tops. When this happened, the car became undrivable. Bleed.
Diff. I run a ball diff and would on low traction, as I've experience in setting it right. I've not yet messed with the gear diff, but again the oil may be wrong.
Slipper. Is it too tight and not slipping?
ESC. Is the initial acceleration or punch to harsh?
Give us a bit more info on your setup and we'll suggest some changes to try.

[skyaflake]

I'll be getting some Team Azarashi bodies soon (For UK people, check out X-Factory UK dealers!). Looking forward to try one out. Need to figure out a cool paintscheme and I'm good to go.

Last Saturday I did some testing with a little bit more weight in the front (i removed all the weight when I switched to the carbon chassis) and it was better. Especially with less droop up front. I need more pressure on the front wheels to have that little bit extra steering. I will need to try that next time. First I need to build up the B-Max4 this Sunday

[StwBald]

Just got a bmax 2, coming from 1/8th nitro and not doing 2wd for a good few years I was wondering how I'd cope, it went well.

Now I'm thinking of changing the diff for a geared version, couple of questions:

what's the advantage over the standard ball diff, handling wise??

is the geared diff supplied with plastic internal gears, if so am I correct in thinking it would be cheaper just buying the diff components separate but getting the steel gears from the start..??

Cheers

[skyaflake]

I'd recommend the steel gears.

Gear diff should be better on medium/high grip tracks. Personally I drive a ball-diff because I just like it. I tried the gear diff and it's good. I use it as a spare diff now.

On what kind of track are you driving?

[Juddy]

I've spent a lot of time playing with role centres, weight and drop suffering from the same kind of issues. Then I put the 116t six hole pistons in and things are much better.

Rear grip and side bite were much improved, and the car got through the corners much quicker, when grip is low. Before with the kit setup the rear was so stiff even with 27.5 oil, it wanted to breakaway in corners and never settled on landing. Having always run a B4 using 2 in front 1 in back, I've never had to think about piston setup, because it was never a issue.

So I'm no expert but I think maybe putting the kit 1 pistons in the rear might help due to the holes being larger? or getting some six hole pistons might be worth a go?

I'm sure those who really understand all this can give clearer advise, but opening up the holes in the rear pistons certainly worked for me.

As for the tire thing I'm not sure.

[StwBald]

Originally Posted by skyaflake

On what kind of track are you driving?

Indoor - Carpet, wood and polished floor.

Was thinking the geared diff would be more tuneable with changing oils and better for maintenance.

[dikke hond]

Originally Posted by skyaflake

First I need to build up the B-Max4 this Sunday

TBB!

[skyaflake]

Originally Posted by dikke hond

TBB!

QFT

Originally Posted by StwBald

Indoor - Carpet, wood and polished floor.

Was thinking the geared diff would be more tuneable with changing oils and better for maintenance.

You have a wider tuning range, that's true. IMO the ball-diff is better on low-medium grip tracks.

[dpackster1980]

Originally Posted by Brett.w

Hi Guys

I have a BMax-2 MR running in mid motor (8.5t) configuration and stock set up apart from adding 3000wt oil to the rear diff.

The issue I have is that it is impossible to put the power down with out it the car veering to the left or the right, coming out of a slow corner and accelerating is very difficult. One of the marshals said that it was because one of the rear tyres is ballooning before the other?

I have tried the rear motor configuration and it still does the same thing.

The track we run on is low traction, loamy dirt.

Any suggestions would be great thanks.

Cheers

Brett

Sounds like the oil is too heavy making the diff action too slow so it's not squaring up quick enough before you accelerate. Try 2k or if it's really slippy try 1k.

[450kid]

I would of thought the oil was too light and diffing out when the inside tyre becomes light. Then loosing traction?

[Danosborne6661]

1000-2000k is far too light for a geared diff. Been there done that and all Oy get a car that diffs out. 5000 weight makes a geared diff feel like it has the same action as a ball diff so you can then start comparing their characteristics.

[Brett.w]

Hi guys, thank you very much for all you suggestions. I will hit the track this weekend and do some changes and come back and let you know what happened.

Thanks again Brett

[sheddy]

Having trouble with the shocks on my bmax2mr. Have replaced the plastic caps with the alloy ones which has stopped the leaking from the bleed screws but still having trouble with the shocks filling with air.

Bleed the rear shocks yesterday and lost nearly half the oil through the bleed hole just from the air in it.

Could this be down to the orings?

[neallewis]

Originally Posted by sheddy

Could this be down to the orings?

I put the yokomo blue ones in, at the same time as putting the Ali shocktops on. I don't have the problem of a rear shock pressurising now.

I think you can also use the red kyosho o-rings.

[mes]

Did you use the upper o-rings supplied with the aluminum caps? The manual says they are different. My shocks were already brilliant with the plastic caps (which I replaced with new ones as soon as I stripped the bleeding screw hole), but they became even better with the aluminum caps.

[neallewis]

Yes Mes, I've no problems now I'm using the Ali shocktops. But I also rebuilt at the same time with the blue shaft o-rings, so unsure which was the cause of the air leak causing one shock to pressurise.