Jump to content

Recent Things I Have Tweaked On My Jotagas


peterh
 Share

Recommended Posts

Hasn't been much activity here so thought I would offer some things I have recently done to my 2015 JGas JT250:

  1. Fitted an OKO 26mm carb – model K103BT - http://oko-australia.com.au/trials in replace of the standard Dellorto PHBL26. Stayed with the 26mm OKO rather than a 28mm due to the type of riding I do (i.e. no splat walls) and apparently easier to tune, jetting and air-screw wise.
  2. To fit the OKO, I used the JGAS accessory intake manifold part for Keihin PWK carby’s to accommodate the larger diameter needed.
  3. Fitted a 5mm intake manifold spacer – http://trialparts-shop.de/en/shop/jotagas/vergaserflansch-jotagas/ which accommodates the slightly shorter length of the OKO compared with the Dellorto
  4. Fitted Dual Stage Boyesen PowerReeds (model # 6TR123)
  5. Removed the angled cable guide from the Dellorto and used it in the OKO – uses the same thread (used some threadseal for peace of mind) as this allowed my original cable to be used.
  6. Set up the OKO with needle in the middle position (3 from top or bottom) and fitted a 48 pilot (standard issue was 45) and kept the main at 115
  7. Air screw is 1 to 1¼ turns out.
  8. I use an NGK BPMR6Y plug – a v-grooved electrode plug. Standard recommendation is the NGK BPMR6A
  9. I use Maxima 927 at 80:1 – love the smell and also having used a usb micro camera into the bore, the top of the piston is lovely and clean and very light tan shiny colour. This is different than what I had seen before with my previous Jotagas on a different synthetic oil.

My impressions are:

  1. Carburation is improved compared with the setting up of the Dellorto that I had done previously. There is smooth transition throughout the range from idle to WOT.
  2. There is no hesitation (fluffiness) in transition from ¼ throttle to mid-range as there had been, despite my attempts to tweak this in the Dellorto.
  3. Improved low end torque – I am using 2nd gear now much more commonly and being able to pull off the bottom at low idle without hesitation (albeit hopefully with my good throttle control). The improved low end torque is characteristic of Boyesen Reeds from my experience in other bikes and to me has made the JGas even better in that area that it is already.
  4. I could tweak the set up a little further but prefer a slightly richer setting than being too lean, particularly for transitions between sections. And currently the bike pulls easily and consistently throughout the range of throttle response.

As in a previous post with my 2014 Jotagas 250, I have also “dremelled” the frame to increase turning circle (3.5mm into the frame on each side) and that greatly improves turning – saves me having to think about perfecting hopping to turn. I recently had my Elka shock serviced and apparently some re-valving that seems to have reduced bottoming out.

 

If you are interested in spending time in the shed in tweaking your bike – just because you can – then give the above some thought. I am very happy with the outcome – and yes, of course I have to say it has helped my riding (got to justify it), giving confidence particularly in those low speed, 1st or 2nd gear tight turn climbs and double-blips and letting the bike just work smoothly from low down right through the range.

post-11668-0-93533700-1474598703_thumb.jpg

post-11668-0-79830100-1474598710_thumb.jpg

  • Like 2
Link to comment
Share on other sites

 

 
 
 
 
 
 
 

Pics as requested. Taken today before off to a practice session up at our Club's Trial Park. Rocks, rocks and more rocks. Bike has about 100hrs on it. A few other tweaks was to replace the standard bash plate with the thicker version that also extends further back - replaced the standard countersunk bolts with longer countersunk ones and put a nyloc nut on the ends - keeps things much more secure. Also replaced the standard oil breather with an accessory part that breathes through the filler - obtained from the same place as the intake spacer on the carby manifold.

post-11668-0-41394600-1474876492_thumb.jpg

post-11668-0-57621400-1474876496_thumb.jpg

  • Like 1
Link to comment
Share on other sites

 
 
  • 5 weeks later...
 

Hi Fabio,

 

The fuel tank cap was from here: http://trialparts-shop.de/en/produktkategorie/jotagas/ - same place as the oil filler breather and the flange for the carburettor.

The carbon-look (not real carbon fibre) are Jitsie frame protectors. I also have fork protectors and the exhaust protector. I got these from The Hellteam here in Australia - http://www.thehellteam.com/products/protectors/frame.html but should be available from Jitsie stockists.

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.

Loading...
 Share

×
  • Create New...