So, with warmer weather upon us, I dragged the old girl out and together we woke up sleepy Cambridgeshire... However, the old girl seems to have a small issue. When I open the throttle fully, and/ or revs rise above 6k, it revs like mad with no extra go, almost like the clutch is slipping? It has a Barnett clutch pack which had only 50 miles on it before today... The issue is apparent wether the engine is hot or cold. Any ideas on what to check first? Any advice would be great, Ben
does sound almost certainly like clutch slip - what oil have you used? If you have used fully synthetic or even semi which is listed for use in a car engine then a slipping clutch is a real possibility. Use of semi-synthetic even when intended for wet clutches on a motorcycle is controversial despite Ducati themselves specifying it from standard. There are soo many specifications/derivatives that it's partly a case of sticking your finger in the wind - I have used 'semi' on my Elefant for 2 years now with no clutch problems but i'm not hard on it's clutch being the kind of bike it is - I guess any track use would be the benchtest.
I use Silkolene Super 4 10-40 (They say it is Semi - synthetic, but I was told by a Silkolene Rep, it is as near as dammit, fully synthetic)........not had a problem............yet, touch wood. But as Chris says, I definitely suspect the clutch unless there is a serious compression issue......but then, who fitted the clutch? Was it you know who?....Better have a look and see if the spring retainer nuts haven't come loose.............that's what I would go to first if it has only done 50 miles. AL
btw - it's really nice to see a 750 'tricked-out' like that, so many people only reserve that treatment for a 900 yet the 750 is much underestimated.
Clutch was fitted by myself and dad... I believe the compression to be perfect, as on of the last times I rode the thing it was returning from a full head refresh so thankfully it shouldn't be that end of things
Thanks Chris still a work in progress , now I've the time and money again I have some nice plans for this one!
you do need to address that clutch slip immediately (if that's what it is) as the plates start to change their friction characteristics pretty quickly if allowed to continually slip even to the point where you would have to replace them. An in-depth examination will soon tell you as you will see the overheating patches/deposits and maybe even slight warping. If severe then a good dressing down of all the high spots/deposits on the steel plates with fine to medium aluminium oxide paper will give it the best chance of a fresh start. Were all the plates new btw?
I know it means work and draining the oil, but I think I would have a look at the clutch anyway....maybe the friction material has compressed or hardened through non-use.... Beat me to it Chris..... AL
The clutch was brand new, and the stack height made up to that which JHP recommended at the time. I will strip it down and do as you advised thank you both for your time and help
The dad is ok! Grumpy as ever but ok! Now souly into his enduro bikes, owning an XR 400 and DRZ400! Hope things are good your end mate
Ben - you have me thinking - has it stood unused for a while? have you got free play at the clutch lever and if so, how much? There is a very small relief port/hole in the master cylinder which allows fluid levels to equalize during use. If this gets blocked up (usually only when left unused for a long time) the system starts to 'pump up' resulting in no free play at the lever and yes you guessed, a slipping clutch. You should have an adjuster screw in the lever if standard by which means you can adjust the free play. even if the port is not blocked too little play will also result in clutch slip (much worse in the summer). You should have about 10 mm minimum play at the lever tip when 'cold' (i.e. bike not used for an hour or so)
Chris is right Ben....the adjuster is usually Araldited over from the factory and the play can vary from lever to lever. Mine are set at about 20mm.....Luckily I have four levers not altered but all the same play..... AL PS....Did he get rid of the (spit) BM?
It had a new lever fitted not so long ago, which hasn't got the screw aralduted. I will play with that first then The BM went to make way for the zx12 which went to make way for the DRZ. I don't think he will be on a road bike again as my crash put him off them
So... we thought it was solved.... But no, it is not. Ive checked the springs. changed the oil. ensured the pressure plate bolts were to right torque and loctited. I have bled the clutch and checked its height. and all is as near as damn it perfect. So. could it be something other than the clutch causing these symptoms?
My Dizzy went through revving She would come to stop and it sounded like my choke was stuck on IIIRC It was either fixed having my valve stem seals done or the carbs balancing So long ago I can't remember which
Re-check the stack height. If you've new plates and it's assembled correctly, nothing's sticking, with no master or slace cylinder issues I can't think what else it could be?
