Jasperthedog

Just a bit of an update for those interested.... The two faulty thermostats were binned and the german spec unit fitted with an 88C stat. The result is a bike that runs at the manufacturer's specified temerature ~86C and the fans come on later as the thermostat now opens fully. The engine immediately felt better, but far from perfect so the aid of BHP Power was saught for a remap. This is done over the net after they sent down the controller. I loaded my map into the device and emailed it to BHP who sent back a map designed for a MT09 with an after-market, less restrictive exhaust. Qal, Bossman of BHP, assured me that it may not be perfectly matched, 'but would be lightyears better' than what I had. Oh,boy! Was he right!! The difference was immediate and a huge improvement. The bike now warms up quickly, runs without any stutter and delivers proper mid-range power and full on top end. I reset the data and noted that over the 7500 miles to date the consumption had averaged out at 48mpg. As it was three owners down the line , I have no knowledge of how it has been ridden. But since it had the original tyres (2019 date) only about half used, I'm guessing that it was not ragged. I have now done 500 miles and using the full range available from the engine the average is 52mpg. I regard this as a solid result. The bike now runs as it was designed to do and is a pleasure to ride. I'm just about to take it to Croatia, a round trip, avoiding all motorways, of around 2500 miles.

Skip, The standard Niken t'stat is a sealed unit. There are no gaskets, no seals. The stat inside the housing rattles about and fails to seat thus allowing coolant to pass, irrespective of temperature. Both units, original and new had the same fault. Part number B7N-12410 is perfectly formed and perfectly sealed with zero movement of the stat. Until the correct operating temperature is reached no coolant passes the stat to the radiator. This is how they are supposed to work. To have had one faulty stat is just how it goes, to have two from the manufacturer with the same fault and, from the replies on the thread, other people reporting low running temperatures points to a faulty supply chain. It would not be the first time that a manufacturer supplied poor and faulty parts, Yamaha are not perfect. Perhaps somebody else with a low temp running bike would like to try to get Yamaha to tell them the correct running temperature for this engine and explain why, with a specified stat opening temp of 84C, their bike runs at an indicated 66C. I can confirm that with a correctly operating stat, stamped/calibrated at 82C, the bike runs at an indicated 80C on a cool (16C) day.

The schematic cooling sytem shown above would result in the engine overheating and blow out gaskets, hoses and radiator in short order. 1.)The thermostat is NEVER on the 'cold' side of the radiator, i.e., the bottom, as it would never get hot as without it opening there would be zero flow past the wax bulb, but the cylinder head and top of the rad would be boiling. And 2). the 'stat bulb is shown on the 'cold' side of the unit and again will never get any heat. BTW the little jigger in most 'stats is nothing to do with bypass flow, it's there to allow air to pass the closed stat when filling.

So, as promised, I've done a bit of research. 1.) These engines should all run ABOVE 80C. 2.) The MT09 thermostat housing from 2021 owards seems to be splittable and the t'stat can be replaced (cost £7.95 as opposed to +£50). 3.) On removal the original 'stat 'rattled'. On investigation it can clearly e seen that the 'stat is loose in the housing, allowing water to bypass the control unit. Hence the cool running, with all that entails. 4.) The new Yamaha sourced 'stat in it's Yamaha box from a main dealer cost +£50, also rattled, was loose in it's housing and was just as useless. With a German sourced MT09 'stat Part No. B7N-1241000 the bike now runs at a steady 80C and is slower to run up the temperature range as the radiator runs cool, giving a pool of cool water to blend in as the 'stat opens fully by 95C. The splittable housing will also allow those who use the bike as a daily runner in cold climates to fit a 88C 'stat. As I said in an earlier post, Yamaha have a duff supplier and have not checked the product.

Hmmm. So the reading of 104C when the fans kick-in is entirely fanciful, then. And nobody has adressed the question correctly. I have direct contact with 5 other modern lean burn motorcycles, all indicate a running temperature of between 84C and 86C. Are these fanciful as well? I believe that Yamaha have a thermostat supply problem and all those not running at an indicated ~85C are affected. If you believe that the indicated temperature is totally unconnected with the real temperature, at what indicated temperature do you begin to worry about overheating? And how do you know what the tepmperature is anyway? In other words, why have a digital read-out in the first place?

Thanks for the comments and reassurances....BUT why does the WSM give the thermostat opening temperature as:If the t'stat does not begin to open until 80c+ and not fullyy open until 95C how come the engine temp indicates a steady 66C??

Hmmmm. Thanks, guys. So it's back to the zorst as the root of all evil.

Once again I'm looking for a bit of advice! I finally got round to playing with all the buttons etc., on the bars and moved from 'Trip 1' to 'Coolant Temp'. A daring move I realize. Imagine my surprise when, touring in the Welsh borders (hilly, twisty, fun) when I notice the temp is resolutely stuck on 66C. I stop and idle and very gently the read-out advances to 70-75-80-etc to 102 when the fans come on. So the read-out is accurate. But Why so cool on the go? What does everybody else run at? It is my experience that cool running is inefficient, fuel wasting and gives poor fuelling. This is a problem with this bike, I had put it down to an aftermarket zorst that the ECU could not match. I would expect a modern FI bike to run at +/-90C. Thoughts? 2019 Niken GT

Hello, Maxim. What a pleasure to hear from somebody who knows of what they speak! This is a really great help as I can now contact SW Motec and pester them! I have another gripe, which may have been adressed by the group - Side stand. Or rather the lack of a decent prop. The supplied stand, with a full fuel load and a bit of weight in the top box, just lets the bike fall over unless it's on dead level, hard ground. As to standing on the foot-pegs to get a leg over - forget it. I have had a replacement hip so I'm slightly reduced in my legswing arc. Has anyone fitted a longer/angled stand? I've added a 'Big Foot' pad that has noticeably improved the situation, but a longer and angled stand woul be ideal. Thanks for your help, Jasper

Hi, I'm an old duffer, riding into the sunset on my newly aquired Niken GT. I've had a number of bikes before this but thought that two wheels were boring so, why not try three!! So far, so moderately good. I bought it second hand, 7500 miles, and almost sparkly clean with only a few scabs on the bracketry. It has an unnamed titanium Zorst fitted (very parpy and crackly) but I wonder if it does not suit the fuelling as I think the bike runs out of steam from 9500rpm onwards. Comments? Apart from 'get it dynoed', which may be the next job... Of more concern to me is the knotty question about the Factory fitted luggage (pannier) racks. These are quite clearly made to be quickly detatchable for servicing etc., as there is a spring-loaded catch under the top rail. There is also a three eared knurled nut at the lower forward end designed to be undone by hand. This knurled nut has a central lock (with the number 5 on it) But I have no key for it. The previous owner denies all knowledge of a key, as do the Yamaha dealers I have spoken to. They had no idea the racks were Q/D designs!! Comments? Apart from 'Drill it out'!