1 [solved]k75 Strange starting problem Sat Oct 30, 2021 7:37 pm
costellon
active member
I recently purchased a 1993 K75 non runner (non abs) with a sprag clutch problem. On investigation it turns out that the PO had refitted the male alternator flange without the bolt and damaged the sprag/ idler gear mechanism. I stripped off the bell housing and found the countershaft spring broken, teeth on the back of the countershaft ground off in one spot (all sitting neatly below the shaft) and the splines on the intermediate shaft completely destroyed. I replaced the offending items along with bearings and seals and rebuilt everything. Splines lubed etc ....
When I hooked everything up and pressed the starter button the motor just whirred - seemed like the sprag was not catching. Stripped everything off again right down to the sprag - all good, I checked and double checked and rebuilt everything again. I pressed the starter button ..... same result - whirrrrr - but no rotation of the engine !
Pulled off the crankshaft cover and starter motor and rotated the countershaft with my fingers ..... perfect ! Sprag engaging and engine turning. It could only have been that the starter was rotating in the wrong direction. Contacted a helpful and knowledgable friend who explained that once by chance he had rebuilt his starter motor with the centre housing the wrong way around (thanks Will) and his starter ran in the opposite direction.
I stripped the starter motor, flipped the centre housing, rebuilt it and refitted it to the bike. Took a deep breath and pushed the starter button - rotation !!!!! Woohoo !!!!
Fuel pump was whirring happily and I had a healthy spark - so I thought i'd address the other issues. Dropped the sump and desludged it, cleaned the primary oil strainer, changed oil filter, refitted sump, fresh oil in bevel drive, gearbox and motor, fresh coolant, changed fork oil, greased and adjusted steering head bearings, fitted 2nd hand rear shock, changed fuel filter in tank, stripped instrument cluster and replaced bad bulbs, fitted manual over ride switch to radiator fan (just like I always do), fitted fresh heavy guage wire from starter relay to starter motor, fitted new starter relay, gapped and fitted new spark plugs (7mm), charged the battery and put fresh fuel in the tank.
HERES WHERE MY PROBLEM CURRENTLY LIES .... Hit the starter button and the engine turned over nice and healthily but didn't fire. Pulled the plugs - getting loads of fuel, checked the spark - good healthy spark. Bypassed the clutch switch - still the same.
Took it out onto my street, put it in 3rd gear and gave it a push - fired up straight away. Drove back into my garden, stopped it and tried it on the button again - it did start but after cranking for far too long than is necessary or good for the starter motor and only with the throttle wide open.
I bump started it again (fired up straight away) and went for a 10 mile spin. Drove fine, smooth, good power, no farting etc ... Got back, stopped the engine again and tried to restart it on the battery - nothing. Checked again, on the button, healthy spark, wet plugs. Gave it a short push - fired straight up. I stripped off the HES cover in case the pickups might have been dirty - but no, nice and clean and timing plate in the correct position. I pulled and cleaned all of the electrical connectors from all the switchgear, checked all of the fuses, gave the relays a tap and even checked to see that the headlight goes out whan I press the starter - yep, no problem there with the load shed relay.
To recap: It'll start fine on a push - but takes far too long for it to "catch" on the starter - far too long and the throttle has to be wide open ....... any suggestions would be greatly appreciated ?????
N.B.
One thing I did notice when I was changing the fuel filter - with the fuel tank lid open and the starter button pressed (fuel pump whirring) there seems to be a substantial flow of fuel on the right hand side at the front part of the tank - never noticed that before on a K- like a little waterfall of fuel falling from just in front of the filler cap back down into the tank. The fuel filter is the correct way around
Cheers
Last edited by costellon on Sun Oct 31, 2021 10:46 am; edited 1 time in total