Jump to content

Orange yokes are orange!


wazrs257
 Share

Recommended Posts

. . . Which is a slightly weird title for a post about mini-bike racing!

After realising that my lap times weren't coming down as quick as I'd like on my Derbi 50 race bike, I decided that the problem was down to lack of track time. My local kart track, Whilton mill, does bike nights on a Tuesday evening, where you can use a 'mini bike' on track from 5.00 to 8.30 for £25. Unfortunately their definition of 'mini bike' meant 12" wheels, so that ruled out my Derbi. I toyed with the idea of a Chinese pitbike, which can be bought brand new for about a grand, but that was quickly dismissed when I realised that 85cc two-strokes are allowed in the open class. Which in a complicated 'man maths' equation led to me buying this:

46263247635_6c9f10ce91_z.jpg

And these:

46263244015_21ae13356d_k.jpg

Everyone goes on about GSXRs being king of anodised bling, but I think KTMs have taken over in the modern age! :) 

  • Like 9
  • Thanks 1
Link to comment
Share on other sites

Whilton Mill, that brings back some memories,  went there a few times in the mid 90's when I was running the junior road race association for a few practice days, ( which is where toseland, Ellison, camier, ben Wilson and many others started their road race careers on ar80's cagiva prima 80's and even honda h100's ), certainly looks to have changed since then. Good luck with the KTM.

  • Like 1
Link to comment
Share on other sites

They seem to be sprung for some kind of weird pigmy human thing, with a 3.4 front and a 35 rear spring. So I went for 60 rear, which is the stiffest Ktech do in this diameter, supplied by Revs in the correct colour for this shock. The stiffest fronts that Ktech do are 4.0, so 4.4s are being custom wound by Springcoil in Shefield.

47342826402_fe9d87a600_k.jpg

  • Like 3
Link to comment
Share on other sites

Built a kx65 on 12" for my mates lad.

After being given the run around by various suspension specialists about springs and spring rates, my mate phoned Harris. 5min conversation with a guy there and he had the exact springs in his hands 2 days later. 

They were supprisingly clued up on this type of application 

  • Like 1
Link to comment
Share on other sites

21 minutes ago, Superdunc said:

Built a kx65 on 12" for my mates lad.

After being given the run around by various suspension specialists about springs and spring rates, my mate phoned Harris. 5min conversation with a guy there and he had the exact springs in his hands 2 days later. 

They were supprisingly clued up on this type of application 

Off the shelf springs are available for the WP43s, but only if you're 50 kg, I had the same issue when looking for springs for my Gasgas EC300. I also wanted to take some travel out of the forks, so have gone for a non standard length too. The custom wound ones work out only slightly more expensive.

Edited by wazrs257
  • Like 1
Link to comment
Share on other sites

Whilst attempting to pull the forks out I realised that the yoke pinch bolts had been WAY over tightened, meaning that I had to take a nylon hammer to them to get the forks out. The holes in the yokes that the forks are supposed to go through aren't round any more, so a new set of yokes were needed. I could have made a set, but I couldn't be bothered. Off the shelf yokes are available for these in KTM orange, or Husky blue, both of which look a bit shit. So here we come to the subject title of this thread (sunglasses may be needed!):

33563474708_cdd118fd41_k.jpg

These will be stripped and powder coated black at the same time as the frame, at the end of the season. But suffice to say, the forks now slide through nicely, and fork position adjustments should be easier. :) 

Edited by wazrs257
  • Like 2
Link to comment
Share on other sites

19 minutes ago, Tom Mac said:

Can I tempt sir with a Vforce 3 reed block for it?

boxed, with stickers, gaskets and much newness

Sir(?) already has one of those, but thanks anyway :) 

Link to comment
Share on other sites

  • 2 weeks later...

As there's been no progress on this for a couple of weeks, I thought I'd fire it up, mainly because I'd stripped it within 5 minutes of getting it home, so haven't really heard it running much.

After kicking it 3 or 4 times I gave up. Half an hour later I let out a chuckle, the cdi's still upstairs in the spares bedroom!

  • Haha 7
Link to comment
Share on other sites

I think we're pretty much ready for some track action. Over the last couple of days I've finished rebuilding the forks, fitted crash bungs and hand guards (as per regulations) and fitted an earlier swinging arm.

47597650152_ea0c3d5f5e_k.jpg

The swinging arm was fitted because I needed to cut off a couple of brackets, and couldn't bring myself to cut up my 2016 arm! The 2007 one fits, and uses the same bearing kit, but every other bolt is different, so some new chain adjusters and a bottom shock bolt should be on the way soon. I've also ordered the rubber bung that's missing from the side, allowing it to be completely rammed full of sand when it was delivered to me! The ebay breaker honestly described it as 'may need new bearings'! Bit of an under statement me thinks, although there were actually a couple of rollers still left in place.

40683873043_1ade4947e6_k.jpg 

  • Like 2
Link to comment
Share on other sites

  • 3 weeks later...

A few more bolt-ons today. Oversize rads, new rad guards, and a 65 front mudguard. The mudguard doesn't look as good as I'd hoped, but it's better than the 85 one. Hopefully be on track on Tuesday :) 

33931691048_c30fab54e7_k.jpg

The coolant I drained out of the rads is a bright fluorescent green, any idea what this is, and can I re-use it and just top up any extra with water? :unsure:

  • Like 4
Link to comment
Share on other sites

This is where the bastard thing spent most of its time at Whilton Mill yesterday,

47805480122_f18ccdd23d_k.jpg

I went out in 3 sessions, twice the back brake locked solid on within a lap, so I ended up taking the pads out, 3rd session it seized! :( 

 

Edited by wazrs257
  • Sad 1
Link to comment
Share on other sites

Turns out the big-end's shat itself. Options include rebuilding the original crank with a new rod kit, to a complete new crank. The new crank option is looking good because I can just strip and rebuild same day, rather than messing around sending it off to be rebuilt. Prices vary wildly for a complete crank, from £130 for a bare Mitaka one, to £250 for a Wiseco kit (including mains and gasket/seal kit). Any recommendations?

Just come across this nugget 'The SX 85 as we all know suffer from bigend bearing seizures due to the bigend bearing not being large/strong enough. This crankshaft has been purposely designed to over come this design fault and has a 20mm crankpin instead of the standard 22mm this allows the use of a bigger roller bearing which can withstand the loading put on the crankshaft bigend.'

Link to comment
Share on other sites

10 hours ago, wazrs257 said:

This is where the bastard thing spent most of its time at Whilton Mill yesterday,

47805480122_f18ccdd23d_k.jpg

I went out in 3 sessions, twice the back brake locked solid on within a lap, so I ended up taking the pads out, 3rd session it seized! :( 

 

Looks cool though. So partial win at least.

  • Like 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...