thall1

glad it worked!!....back brakes can be a bit of a pain because the hose is quite flat...after a day out you can always leave the bike between rides with the brake's clamped just to keep them up tight...works the same on the clutch as well....

try back bleeding ( or the other way) then once you feel its not getting any better and still spongy, fill the reservoir, leave the cap off or loose, and tie the lever back to the bar (make sure the lever actually pushes the master cylinder in all the way) or in the case of a back brake, wedge the foot pedal down and leave it for a few days.... you'll find the air makes its own way out....the longer you leave it the better it will be...if your bleeding the front, when you leave the bike make sure there aren't any 'upward' loops in the brake hose across the bars, if need be, tie wrap the hose down to flatten out any loops...

unfortunately because it was intermittent it threw us all off course! we had ruled out the ECU quite early on when it was fitted to another bike as that bike started and ran fine... I am considering going back to a two stroke...the 4rt is great when its running but I have lost faith now....maybe a little unfair but this one just seems to be pup! I appreciate all bikes have issues but when these go wrong, trouble shooting is a pain! when a 2 stroke plays up there isn't much to look at, usually a leaky or blocked carb or a dodgy plug.... Fred has had four 4RT, apparently two have had ECU issues....

hi all, just an update...fitted a new temp sensor....after 3 1/2 hours of checks and kicking it over I finally got it to start!...still running rough with black smoke...At this point I conceded defeat and gave the bike to Fred Adams at GLmotorcycletech@outlook.com. The ECU was read with the diagnostic kit and it came up with Temp sensor and Injector fault. ...As a new sensor had just been fitted that seemed strange. After 2 days of swopping looms with his own bike plus other components then one by one swopping my bits back onto the bike with varying results it turned out to be an intermittent fault on the ECU.....A replacement ECU was fitted and its all fine!!! Cheers Fred!

yes that was one of the first things I checked last year when it first started playing up!...will check again though...

just tried the bike again....started ! but only once!!...took the temp sensor out and brought indoors...resistance check was 2500ohms as per manual....put it in boiling water and resistance dropped and came back up when left in air...put it back into the bike and it started first kick! and continued to start first kick thereafter!!! hopefully it is the temp sensor so a new one fitted when it arrives may sort it at last...wont hold my breath though!!!....think I shall be returning to a gasgas soon!!

the pump always powers up ok with 12v battery and when kicking there is 12.5v at the connector....but yesterday it didnt start even with 12v on the pump...as said previously I think it the temp sensor - I checked the temp sensor plug wiring and no issues there....

Loom stripped and every connection was checked out -only issue was the capacitor wire corrosion - no air leaks...checked with wd40 when bike was running as well as visual...throttle cable is fine...lot of slack to make sure at the moment. no relay under the tank on this one. its on the plate next to the rectifier...all checked out ok, just the earth block and lighting output connector under the tank...No oil in the bypass tank so nothing getting back into the airbox....the bike started yesterday with the airbox off (but only after 2 hrs of kicking /fault finding)...airbox/tank and wiring loom put back in while it was running...it was running fine without coughing or running rich....restarted ok when hot but got more difficult as it cooled down....tried it earlier this afternoon after being sat in a cold garage all night and it wont start...my guess(hopefully) is the temp sensor...

nothing left to swap out. Loom was stripped when I found the black wire corrosion on the capacitor side of the connector then once striped out it was found corroded back up almost to the crimp points into the loom. All loom wire was replaced and a new capacitor fitted..

No it hasn't .... I'm getting 12v plus at the pump connector when it's being kicked over - it was lower than this with the old capacitor - and 14.2v when running. Rectifier has been bench tested- see earlier post... And it appears to be fine ... I guess proved by the Voltage output when running...

Currently running a hotter plug. Tried it yesterday and bike wouldn't run even with 12v on the pump. Pump was running and I had a spark .After checking various things over two hrs and kicking it in between it fired up and ran fine without coughing or running rich?.... After letting it run up it restarted fine while it was warm. However the longer I left it and the colder it got the harder it was to start...ecu, tank/pump, coil and injector assy have all been put on other bikes with no issues .... The test bike started and ran fine each time.

new capacitor fitted.... started second kick with a nice slow push on the kick start! ran lovely and smooth....all sorted!...or so I thought!! After letting it run until the fan cut in/out I stopped the bike...second time starting it was the same, 3rd time after refitting the air box it wouldn't start! I put 12v onto the fuel pump as before, bike started fine and ran fine.. cleaned the air filter, plugged the pump back into the loom..it started but it wasn't as easy as before, put 12v onto the pump again and it started fine with an easy kick, reconnected the pump into the loom and after a few kicks it started but its not very smooth, coughing and puffing black smoke on flicking the throttle open-spark plug was all sooted up. I stripped the fuel pump, some corrosion in the pump sump bowl under the filter but otherwise all seemed ok. Resistance check from the 2pin connector back through the gland and up to the connector on top of the pump are both ok. Bike wouldn't start after refitting tank!...put 12v on the tank and it started fine....put the tank back into the loom and it started but again with a stronger kick... Might put a new temp sensor in as that's the only thing I can think of that would give a signal to the ecu to run rich...??

just a note...before xmas the tank/fuel pump was fitted to another bike and it ran fine...

I can measure the current -will have a go in the morning but previously I have kicked the bike with the fuel line disconnected and fuel is 'pumped' out... I can only assume that during kicking there isn't enough current to power up all the bike... By putting a battery on the pump the overall load on the bikes system is reduced.. Capacitor is on order but won't be here till next week...

I have some progress.....if I kick the bike I get voltage at the fuel pump loom side connection of up to 12.5v...its not a constant, repeatable reading, sometimes its less at around 9v but as you continue to kick it increases to 12.5v. If I leave the meter to continue to read after I get 12.5v the voltage slowly drops away which I guess is the capacitor discharging? I put a separate 12v supply to the fuel pump - you can hear the pump running & bike starts first/second kick....if I take a voltage reading at the loom side of the fuel pump connector when the bike is at idle I have 14.17v dropping to 13.57v when the fan cuts in so the bike when running produces plenty of voltage but not when initially kicked over...I have cut back the insulation on all the earths and positive feeds to check for any signs of wire corrosion as I found on the capacitor but none present. with the fuel pump reconnected into the loom the connections via the 2pin connector appear fine either side with continuity and no high resistance.. as I said in an earlier post, the rectifier diodes check out ok using the check listed below found on a Yamaha forum.... 1. Attach red lead to the Bat+ pin, touch black lead to each stator pin on the RR. Each pin should read "OL" (open circuit) on the meter. 2. Attach Black Lead to Bat+ pin, touch red lead to each stator pin. Each pin should read about .5 volt. 3. Attach red lead to Gnd- pin, touch black lead to each stator pin. Each pin should read about .5 volt. 4. Attach black lead to Gnd- pin, touch red lead to each stator pin. Each pin should read OL on the meter. could it be that the capacitor/condenser is taking too much voltage from the system? any thoughts would be appreciated - as always!

just had a thought....if I connect the fuel pump to a separate 12v supply and try starting the bike would I need to do something to the fuel pump supply connector to fool the ECU into thinking its connected or is it not that clever? I could I suppose connect the pump supply connector to a 12v bulb in order to give it a small load?

Hi Honda_Freak....I found another test procedure on a Yamaha forum....mine test's out ok...so I'm thinking its back to the capacitor now?... I kicked the bike over before I took off the rectifier and did get it to fire a few times but again it was only with the fuel line off the injector and the fuel pump disconnected...

Honda_Freak....unfortunately the link didn't work!

many thanks Honda_Freak.......I give a go later!...thanks again

anyone know of how to fully check out the regulator? There is a resistance check in the manual and that checks out ok but just wondering if there is more that can be done?...Honda Freak - did I read somewhere on this site that you had a problem bike that you fixed by changing the regulator? I have gone back through the site but cant find it....

couldn't find anything wrong with the loom when I stripped it other than black corrosion on the wires leading to and on the capacitor... the corroded wire was replaced and the old capacitor was reused but once it had been striped of its wires back to the capacitor spades... my thought at the moment is the capacitor has been damaged internally by the corrosion. Before the bike packed in the first time it did exactly the same, ran for a few times then stopped....I can only think that by playing with the capacitor, discharging and recharging while being tested re-lifed it for a while?...As I said in earlier posts, the engine was stripped to rule out mechanical issues, this was done after the Fuel pump, ecu/throttle body and injector was fitted another bike to try out. This second bike started first time with my bits fitted....my bike is sparking so the stator/pickup and coil are all working.....i'll try a new capacitor and go from there....

spoke to soon....its dead again!! same as before....will try a new capacitor first then a regulator

curves formed over a 1 1/2" steel bar. Not sure on the material - it was nothing special and not as hard asT6. Once it's formed its pretty tough. I don't land the sump on rocks just rock over a few logs now and again. I made it wider at the front to cover the bottom of the clutch and flywheel casing and longer to cover the rear linkage. Didn't bother with most of the 'lightening holes'...certainly not the ones at the front and underneath, it stops the muck getting up under between the engine and sump.

just a quick update.....bike still starts and now it starts with the 4RT push rather than a 2-stroke kick. Also, the bike used to 'cough' every now and again but as yet it hasn't done it, also the revs stay steady when the fan cuts in, it used to drop revs then recover, but no more!

Hi all....it now runs!!...as I said earlier, I replaced the wires from the capacitor(condenser as Honda call it) until I found clean copper. The wires from the capacitor to the connector were also corroded - both positive & negative were black, so I was looking to get a new 'light weight' capacitor from H&D racing but they were out of stock. So I stripped the rubberised coating off the original to see if I could find a voltage rating & then get something suitable from RSonline - (a 16v 10000uF one is only £7!) but nothing found. Once it was back to a bare Ali can capacitor (and half the size & weight of it before I stripped it) I unsoldered the wires from the spade connectors and tested it again...all test repeated ok so I soldered it directly into the bike loom....just finished building the bike back up and after a few kicks it burst into life!!......left it running for the fan to cut in and it started first kick again after !!!...i'll try it again tomorrow but hopefully its now all sorted...thanks to all for you input!