Just half a year after launching the first JOTAGAS, this first evolution of the model , the improvements are noticeable.
Just a year ago, JOTAGAS presented a dirt bike with outstanding technical solutions. The frame, swingarm and rear progressive system were some of the parts that stood out in a pattern that made an early impact . However, despite this Jordi did not hesitate to continue to work hard to develop those points that could be susceptible to improvement.
Starting with the chassis, we must remember that the central spine has two symmetrical parts of forged aluminum -as if it were a dual beam-that become a single chassis thanks to the fuel tank, which is integrated into it, taking almost the appearance of a monohull. The chassis comes complete with the steering shaft and the two pieces that join the rest of the frame. In this front section, we can say that nothing has changed.
However, there have been changes in the suspension system . The swingarm and suspension progressive system was another aspect that attracted attention in the first round of the JT.
Thanks to the suspension system used, with shock absorber on the side of the chassis, you could reduce weight without losing progressiveness. The result was then considered more than satisfactory but, as Tarrés himself told us, during the season, “we continue working and doing tests until we found a more progressive system, but it required some modifications “. This was to increase the length of the anchor point for the connecting rod , and make it a little shorter. And this, in addition to improving the progressivity of the damper, has made the bike a little higher in the back.
With regard to the above suspension, it was decided to replace the old Tech fork with 39 mm Marzocchi aluminums, which lower the weight about 400 grams.
Also changed the brake calipers and pumps, with the new Braketech which replace the Formula. ” In time Formula assemble because AJP had closed and seemed the best option, but they had some problems and some pistons lost touch, for so we opted to return to renewed AJP , “says Tarrés.
The engine, which from the beginning was emphasized by its small size , is really compact, and they have worked to improve its efficiency and reliability.
Thus, in addition to modifying the stroke and compression ratio, it was decided to change the crankshaft.“In order to get more inertia, we worked with Pol, but saw that it had excessive fly weight, so we decided to take a different counterweight that gives a faster response to the engine “ , explains the seven-time world champion.
New clutch friction discs (Atler), and new steel plates, and a change of sprockets (reinforced) to avoid any problems of reliability.
Other notable changes this 2013 concerning the exhaust. The central muffler, which is manufactured differently. Tarrés explains. “Normally, the inside is done very manually, but we have developed a pressing system with a mold that causes no variation between motorcycles, and improves performance.” The header pipe is now titanium, which also weigh 300 or 400 grams less “it dissipates heat better and makes the bike work better” . Something that also helps, no doubt, is the new CDI mapping, which offers more power to all areas.
Once we are ready to test the bike, we find that the starting is easier than the previous model. I would say that the engine has surprised us because it has a lot of low down torque, is very fast and revs up well . We say that we are surprised, because the 300 we tested last year was smoother at bottom, but this is more cheerful despite being smaller displacement!
Another significant improvements we have is the gear selector, the change is much more accurate. First is rather short, but a second and third are very good.
The engine is very strong, and very easy to control. Low down it seems smooth, but when you open the gas it has so much now … I insist: although it is a 280. With the new CDI and flywheel, the 280 has more punch than the old 300, and has more torque, and more power.
The clutch , meanwhile, is fast and is perfect .
The chassis I would say is still stable, very easy to carry and rotate , and Marzocchi suspension is very good, is very docile and lighter than the last Tech forks. I also like it better, because when you change the swingarm and linkage system it has more travel and is much more progressive at first touch, and not as dry as before. I would say that the new damper helps you climb better, and that having more power above expels you. As regards the brakes and clutch, the pumps have been replaced by a AJP.
New distribution and compression cylinder
Crankshaft with new balance
- Crankshaft with new balance
- New distribution and compression cylinder
- Crankshaft with new balance
- Central exhaust New interior
- Curve Titanium Exhaust
- New clutch plates Atler
- Change sprockets new, reinforced
- Shift fork new reinforced
- Clamps and brake pumps Braketech
- Rear suspension system improved
- 40mm Aluminium Fork Marzochi
- Filter housing lighter
- Higher quality screws
- New anodized rods and tires
- Decoration with new Graphical
- By Xavi Leon
By Xavi Leon
excerpt from Solo Offroad.com