Happy with the performance of my 400 C, but not so much the brakes.

I did fit new brake shoes front and rear so they will have to bed in, but given that they are new I would have expected them to be a bit better than they are.

Can I expect them to markedly improve as they bed in, or are the brakes pretty poor ?

It does have the original front brake cable so wondering if I should replace it with a new heavy duty one.

Only based on my personal experience with my DT1 . I replaced the brake shoes with
aftermarket items . The front was useless until the linings wore in .
Later I replaced the fronts again with OEM Yamaha shoes , and there was a marked improvement ,
even over the worn in aftermarket shoes .

Hello Andy_C.  There have been many posts about brakes and brake performance on this forum so I'm sure if you do a search you will get many 'hits' with useful advice.  The two standout comments and consensus from members was that YAMAHA OEM shoes are the best and always buy good quality cable replacements (again OEM is probably best). Definitely do not buy cheap cables. They stretch too easily. Best regards Andy L.

Andy, I've replaced the shoes on every bike that I own and my experience has been that the bedding in takes hundreds of miles before the brake performance reaches the level I would expect.
Of course, how you ride and how much braking you do will affect how long it takes.
Most of my replacements have been EBC, although M&P did substitute a set with another brand, I didn't notice any difference in performance.
The one exception to this was my RT1, they seemed to bed in a lot faster and were surprisingly good brakes.
 

Pretty much as expected needing to bed in, so I will just have to be patient.

Shoes at both ends are EBC so I expect them to be reasonable once bedded in.

It still has the OE 40+year old cable which I am replacing with a new heavy duty one.

Once I have the cable I cen get some serious miles on it........

I always hold the brake on hard while tightening the axle. Sort of help centralise things a bit if there's any slight play in things--brake plate fit on the axle etc. Don't start doing that from 'way out' but if nut is tight just back it of a turn or enough for movement then tighten again while holding brake hard on. Also i give the hub a good scratch with coarse emery.

RT325 - Sound advice, I did the rear brake in exactly the way you describe, but not the front !

Hope to have the new HD cable for the front soon, so I can take the front brake apart and give the drum the emery cloth treatment while I am waiting,

Thanks.

There's been a lot of posts on brakes...  I've personally found some of the EBC shoes to be undersize (175 models, not sure about the 250...  I use Yamaha shoes as they seem best IMHO).

Here's a link to a post from Scott on his simple method to arc the shoes to match the drum.  Racetech in the US offers arcing service but quite expensive.  (Shoe arcing service used to be very common, now it's almost impossible to find anyone that does it.)

yamaha-enduros.com/index.php/forums/gene...rakes?start=10#85816
 

Another thing to consider on brake feel. Some cables have a sheath that compresses more than others. This will give a spongy feel with poor stopping power even when the shoes are good quality and bedded in.

I've been using newly manufactured Yamaha shoes and cables from KDI or Beck Arnley. Good feel and stopping power even without breaking them in. But I ride like the old man that I am.

Very true what you say about cables - I am getting a company called Venhill in the UK to make me a Heavy Duty cable.

Their cables are really good - much better that OE ones, I have used them many times before, and they really are good cables.