kenward

hey there copemech , after ordering a new thermo switch yesterday , i have stripped down the gearcase side again today. the washer you talk about on the water pump assembly is there (more luck than anything admittedly! ) but i have found found the clutch basket to be loose ! after checking the retaining nut and making sure that i had secured all the clutch basket rivets tightly i realised that its actually the clutch needle bearing which sits within the basket, that has excessive play ! so ordered a new one today, together with the top hat washer. any ideas why the top hat washer is £55 !! and the needle bearing is just £16 ??? anyways , malcolm rathmell have said they doubt very much that i will need the top hat washer and if so , i can return it thanks very much for your thoughts on this thread it is appreciated ! hopefully i will be able to put it down to a faulty thermo switch and a clutch needle bearing. again many thanks copemech , will report back tomorro with hopefully a sweet sounding bike with a fan that cuts both in and out regularly !!

hi there cope , right after looking at the impeller as you said , the impeller has the slightest bit of movement ever ( maybe 1-2mm ) after re-filling the rad ( and squeezing the pipes to check for air , although i doubt very much if it possible to get an airlock within the system ! started the bike, but unusually took two or three kicks to start ? on the first and second there was HORRIBLE grinding / rattley noise like ends were shot ! started it anyway and the knock / rattle was not there, the fan cut in after just 2 mins and stayed on !!! let the bike run regardless , ( because it was not actually hot ! ) after 7-8 mins the bike was still not "hot" to touch . . . .the head was warm but not "hot" as you would expect . . . . . .took the thermostat out of a mates gasser that i'd been riding today and knew worked 110% put it in my bike and guess what . . . . the fan was not on when first started the , after around 5-6 minutes the the fan cut in and then cut after a few seconds !!! just how it always used to !! sweet as !! new thermostat on order , 9am tomorrow ! couldnt find any posts on here where the thermostat stays on permanently when its given up ? now to sort the funny knocking / rattle noise that is most prominent when u kick it without HT cap on . . . . .. ??? any ideas as always any suggestions greatly appreciated many thanks, kenward

hi there cope , thanks very much your help . . . . . its much appreciated ! i am about to go and check ur diagnosis,it does sound like the only logical explanation as far as the impeller moving in and out what is "too much" movement ?? would you recommend replacing the gearcase gasket again if i do have to re-build the water pump assembly, even though the current gasket has only been in the bike for two hours will report back to you later on with hopefully a fixed bike many thanks again , kenward

hi mate , was goin on the theory that that the knocking was due to the bike becoming hot ?? i am new to trials and 2 stroke engines and cant really understand why the bike would get hot when it has fresh coolant, the impeller is turning and the fan, once started doesnt seem to stop running ??? and then in turn, the bike develop's a slight knock / rattle ?? strange ??? ? ? or am i missing something ??

i've just replaced both crank seals on my o8 sherco 290 because the gearcase seal was leaking and causing vast amounts of smoke whilst doing i also replaced the clutch and clutch basket . . . . . . . after putting it all back together today went out to check all was ok after riding for a couple hours i noticed it sounding diffrent (knocking) at the same time noticed the fan running constantly ???? let the bike cool down a bit and when restarted it sounded good again ( no knocking ) BUT . . . . the fan was still running ??? thought there might of been an air blockage, so went back to the van and checked the coolant level - all good was concerned that i had'nt connected the water pump properly, so took thee water pump housing off , as i did also noticed the coolant wasnt that hot ( i could let the coolant run over my hands no problem ) moved the kickstart with my hands to check the impeller was workingand yep the impeller is all working fine. refilled the rad with new coolant , started the bike , the fan wasnt on initially but after 2 mins or so it came on and stayed on, tried repeatedly squeezing the rad hoses whilst the bike was running but still the fan did not cut nor did seem to get any air out of the system , and then, the knock starts again !!! wtf ! was meant to be riding a trial tomorro - thats gone out the window now !! loaded the bike up and went home to check if there was anything on here . . . but there doesnt seem to be any ideas help on this problem would be greatly appreciated,