peterh

Thanks copemech - I might start with what the 2016 specs say and go from there.

Hi, I am the new owner of a 2nd hand 2015 ST125 and yes it is a 2015 model. I am looking for the standard jet specifications for a 2015 Sherco ST125 with a Keihin PWK28 carby. The Owners Manual (hardcopy and those downloaded from Sherco manufacturer and agents sites) give details for a Dellorto for that year for the 125, but the advertising brochure says it is a Keihin PWK28 and the parts book gives both dellorto and keihin parts and various jet sizes. And I am told only the 250 came with the Dellorto in that year. I can find the standard specifications for the 2016 ST125 but would like to check the current carby against the standard specifications for slow, main and clip position on the JJH needle for the 2015 model. Any help is appreciated.

To add to the theme, i use Mohican Chief Oil ATF Dexron III which has viscosity specifications at 40°C and 100°C and a Viscosity Index almost identical to very popular and well known trials transmision brands but pay AUD $30 for 4litres from Supercheap versus the same cost for 1litre for a trials specific gear oil. Makes doing regular changes very economical. And no, despite what you may be thinking on the theme name, Mohican Chief oil is not North American but is from the Netherlands. Almost opposite Downunder.

Looking at the wiring diagram in the manual that i found online, it does appear the same as in the video. You could/should check with your oset dealer if you have one close.

Have a look at this youtube video - is this the information that you are needing?

Hi - I'm from Aus (WA) and have a 2015 JGas 250. I suggest you contact Paul Arnott from TheHellTeam as he would have imported and likely sold the bike originally. I had a look at that on Gumtree (my 2014 Jotagas is up there as well). The bike you are looking at certainly looks to have the specs of a 2015 Jotagas with the Elka Shock but may have a later sticker set than mine - looks to be an S3 set. Also looks to have the thicker bash plate than the original 2014 and 2015 bikes. Also the VIN number gives it as a 300cc and looking at the 115 number is similar to my 2015 bike while my 2014 Jotagas had 114. So to me it is a 2015 JGas 300. Cheers Peter

Well at long last their website is back on-line. Nice pics of the 2017 bike.

There is some good information above - see beta-blocker. With regard Maxima 927, I too use Maxima 927 and researched it before decision to use. Yes, there is past history of sticking ring grooves etc etc but reading (yes, from the manufacturer who acknowledges that history) these issues may well be past history. I converted to Maxima 927 18 months ago after a long history of using two well known brands used in trials bikes. Why did I investigate and change - some of it was "advice" given by others that they would never use X brand because someone they knew seized their engine and then for the other brand having pulled apart my motor for another reason (one ball bearing delaminating in a well known and respected bearing manufacturer in an engine lubricated by a well respected transmission oil for trials bikes) I found the piston crown with a hard encrusted black carbon, compression dome similarly encrusted and rings and ring grooves horribly gummed up having used a common respected trials pre-mix oil at 100:1 (as recommended by the factory). After much research and some discussion with others, I converted to Maxima 927. Find attached images of my piston crown and the compression dome after 18 months of use (~100 hours of riding) since previous tear-down (pics taken through the spark plug and by a USB micro camera pointed up from the exhaust port. To be able to still see the size of the piston (see attached image) and, in other pics I have, to see the manufacturing date etc of the piston and to see the clean compression dome (see attached) gave me confidence to continue. As I had the exhaust off (I needed to get the bash plate off) I also took pics of the rings & grooves through the exhaust and they were also very clean (unfortunately I must have deleted them). I use 80:1 pre-mix, (no more than 5L mixed at a time), the plug is a coffee brown colour and I have spent time on carburation and not over-oiling air-filter and my exhaust header did not appear any blacker or encrusted than I have had in the past. The downside is that I cannot use anyone else's synthetic fuel if I run out - the upside, they cannot borrow mine. So, while there is a perhaps history for those using castor based oil including gumming up rings and grooves, that may not appear to be the current state of affairs, perhaps things have moved on - after all, I started riding trials when 25:1 or 32:1 was standard and using 50:1 was "way out there" in an aircooled engine. I have obviously moved on.

If it is just a split without too much related deterioration there are specific super glues eg. Loctite make several ones that can withstand high temp, and vibration and have flexibility for rubber. Just a thought - short term or potentially long term.

And they look good on the pics published of the 2017 model.

I have recently started to use a pair of generic orthotics in my Forma boots - https://www.homyped.com.au/shop/inserts/full-orthotic-insert/ (after removing the simple foot insert) and while initially I felt they increased my height on the pegs, I have got used to them and find them very comfortable and less achy feet at end of the day (I have fairly flat feet). Being firm they provide good support. They are leather topped and I have got them soaking wet. Took them out, put them between layers of paper in the sun warmth and they are as good as new. So, something to consider.

I wear bifocals all the time as cannot tolerate the varifocal type lens. The bifocals give me the distance and the fine reading, which is what i use when riding. I also have a pair that are bifocal for mid range and reading e.g. good for work on the computer and reading but also great for working on the bike and then on the bench e.g. taking the carby out and then reading the jet sizes. Have been thinking about trying these http://www.neweyeco.net where you have a prescription insert that you can swap in and out of different frames including safety glasses.

Perhaps suggest to FIM for World Trials Championships to help with no-stop rules?

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.

I have an Elka shock on my 2015 JGas. I do not know what the factory settings were (I got my bike 2nd hand) but I initially set my rear damping at mid-range, then set static sag according to this article https://www.joomag.com/magazine/trials-enduro-news-december-2014-volume-49-issue-12/0716551001416757092?page=54 by adjusting rear pre-tension. But found that for me I liked about 42% of overall travel to suit me and our riding terrain. But I also made sure that the front and rear worked together. Also, before setting the rear, I set my front forks to what I felt suited me (~74kg body weight and I like softer springy settings than hard). I found through examination of fork oil properties that Motul 2.5W Fork Oil had same properties in viscosity as what was recommended in the Jotagas owners manual (and importantly Motul was available in one of my local bike shops). But depending on personal preference, body/riding weight, riding style and terrain that is being ridden, then suspension needs will differ but from what I understand the front and rear need to be able to work together. I have then adjusted front and rear damping according to terrain being practiced and competed. So, sorry, I have not answered your question directly, but those are my experiences.

Maybe it has sprung a leak.

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.

A clean in trials is better than a messy 3 or worse, a 5

Yes, tyre was beyond it's best, battered about on limestone ledges, steps, sand and dry conditions here in Western Australia. Not much mud, mud and slippery, slimy tree roots.

Hasn't been much activity here so thought I would offer some things I have recently done to my 2015 JGas JT250: 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. To fit the OKO, I used the JGAS accessory intake manifold part for Keihin PWK carby’s to accommodate the larger diameter needed. 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 Fitted Dual Stage Boyesen PowerReeds (model # 6TR123) 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. 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 Air screw is 1 to 1¼ turns out. I use an NGK BPMR6Y plug – a v-grooved electrode plug. Standard recommendation is the NGK BPMR6A 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: 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. 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. 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. 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.

For the new tyre, if you have a 4:00×18 tube lying around, put it in the casing of the new tyre, pump it up enough to make the tyre and bead nice and even and let it sit for a while or day in the sun, this helps make it the shape you want and makes popping out the bead much easier when you install it or use ratchet straps as many youtube videos do. I use a 20" mountain bike tube (only need about10psi in it) as my doughnut and Mr Sheen spray on furniture polish (as i was shown the first time i did this job) to make things nice and slippery at installation. Preparation is the key, and perseverance.

I have used this breather screw to replace the filler plug and a blind rivet goes into the original breather outlet. Works well. http://trialparts-shop.de/en/. Stops capillary action up the original breather tube if any transmission oil gets into the breather as it is very close to top of transmission oil level.

I did almost the same as peterb on my 2015 JGas but found a better spring washer than the original - slightly wider (did not measure it) and slightly thicker and checked and checked that it would be flat once torqued up and used mid-strength Loctite (blue) after carefully cleaning threads of both components and all has been well since then. But will take peterb advice and check endfloat again to be sure. Cheers peterH

Hi slik, Apparently, the Elka shock on my bike always clunked on landing from new (as per previous owner who did slightly dremel the connect point on the V-linkage). I have since last written wound up my spring compared with previous owner and measured sag (but always on the lower end of settings as I like a softer cushioning setting), played around with the damping setting and dremeled out some of the linkage and chamfered the edge of the shock bottom (silver bit) more than what was previous. I have got rid of the clunk and have a nice progressive softish setting that suits me. I had the advantage for a while of having my 2014 and 2015 bike together so could replicate the feel that I had liked on the 2014 bike. I am pretty sure that bearings were all okay and had replaced one of the ones on the V-linkage due to my error in inserting and tightening the bolt (pushed out one of the loose rollers against the bearing cage and made a dent in the cage. Will be interested to hear more of your solution.

Have you tried cutting back on the number of turns of wire around the spark plug lead. Too many may cause too great an inductive pickup and amplify the revs. This is the advice from another brand of tacho that uses the same approach. Try 2 tuns only - what do you get? But heck, how many turns is going to be determined by what looks to be correct - so maybe the ear is the best truth.