bruteforce Posted June 20, 2016 Posted June 20, 2016 After my new, bigger turbo got fitted the clutch has started slipping again. Actually a good thing as this proves that I've loads more power now. But this happens despite the MTC lockup with considerable weight on and new clutchsprings. The plates are old but fibres are within spec and steels are straight and the original non-burnt colour. Do you have any tips or tricks to solve this? Options I'm thinking about are obvious: -New plates will do the trick? I'm ready to invest but need to make sure this is it -More weight on the arms, but the bolts are already stacked up with nuts? -Spacers fitted to preload the springs? -Extra steel plate, but then the lockup itself needs to be spaced outwards? Hope you can help me tame this new-found power! Quote
wombat258 Posted June 20, 2016 Posted June 20, 2016 Add more spring pressure (diaphram or coil?) with spacers . . . standard, the lockup reduces the initial pressure so that drag racers get slip off the line. Use heavy duty Barnett springs, Use new OE clutch frictions. Use only good quality motorcycle oils . . . avoid car oils with friction modifiers. 1 Quote
bruteforce Posted June 20, 2016 Author Posted June 20, 2016 It's coil spring, new Lucas springs fitted. Oil is Castrol RS. Spring spacers are easy enough to fabricate. 1 Quote
vizman Posted June 20, 2016 Posted June 20, 2016 pissing in the wind if your plates are fooked.... 2 Quote
vizman Posted June 20, 2016 Posted June 20, 2016 you shouldn't need more weight on the arms....marco do yourself a favour and talk to dave fbm 2 Quote
strima Posted June 20, 2016 Posted June 20, 2016 Have you tried a mineral oil rather than synthetic? 1 Quote
bruteforce Posted June 20, 2016 Author Posted June 20, 2016 Castrol Power RS, as always, and as advised to me a long time ago by Castrol. But I have always had some clutch problems I have to admit... Quote
Rene EFE Posted June 20, 2016 Posted June 20, 2016 Semi-synth then. I know it's not a straight comparison, but I went to full mineral during the TT in my EFE and it's nothing short of transformed it. Power is so direct and instant, it's hard to get my head around how big the difference really is. 1 Quote
bruteforce Posted June 20, 2016 Author Posted June 20, 2016 Yes Rene, but was this the result of decent plates or the oil? Quote
Rene EFE Posted June 20, 2016 Posted June 20, 2016 Oil, no question. Did the same to the 750 without changing the clutch and the outcome was the same and tbh, the clutch that I thought I had blown, didn't look to bad when I pulled it. 1 Quote
MeanBean49 Posted June 20, 2016 Posted June 20, 2016 Swap the odd size 1st plate for a standard size one and throw the silly anti judder washer spacer thing in the bin. Stopped mine slipping. Never had any problems with good standard halfords semi synth. Dont bother with fancy oil. Too many anti friction adatives that make things slippier 1 Quote
Screwriverracing Posted June 20, 2016 Posted June 20, 2016 Shot blast the plates, makes them grip the fibres better, mine has never slipped and still using original,plates with oem fibres. Cheers SRR 3 Quote
Gixer1460 Posted June 20, 2016 Posted June 20, 2016 Summat wrong with it - you haven't got massive power (I mean it ain't excessive!) so std springs with a 10mm screw and nyloc on each arm should lock it solid ........that holds 350+hp in mine. Oil issues would top my list before spending out on plates? 1 Quote
bruteforce Posted June 21, 2016 Author Posted June 21, 2016 (edited) Thanks very much for your thoughts and replies guys! The main theme I read here, and that people with high-power-bike experience keep mentioning is: Bad choice in oil. Some particularly mention Castrol Power RS as one of the oils that sooner or later caused clutch slip. Others never had problems with this oil. I went to a buddy that runs a bike-service shop close by, and he said having had the same issue with some big-twins (lots of torque). They lost all their clutch problems simply by changing the oil by a mineral type oil- or different brand semi-synthetic oil. I bought some semi-synthetic oil off him that he uses as The Problemsolver in these big-twin cases but also as-stndard in some 4-stroke race machines that he services. As it was a lot cheaper than a new clutch and I needed fresh oil & filter anyway this is a good time just to try and see what happens. In the meantime I've found a leaking oilcooler hose so had some new ones made at the local hydraulics shop. With the oilchange I will swap the hoses as well, so I can drain the cooler also to get rid of the old oil as much as possible I will report back to you with the results! PS: @Viz, FBM told me he same about the oil Edited June 21, 2016 by bruteforce 1 Quote
MeanBean49 Posted June 21, 2016 Posted June 21, 2016 Will want new plates too. Old oil will have soaked into them. Wont stop slipping. 1 Quote
bruteforce Posted June 21, 2016 Author Posted June 21, 2016 I do want new plates but some report it will improve with just an oilchange. I want to isolate if the oil fixes it or the change of plates. Quote
MeanBean49 Posted June 21, 2016 Posted June 21, 2016 I dont think you will see any improvement without changing both. No way of getting the fancy oil out of the plates once its soaked in. Quote
Screwriverracing Posted June 21, 2016 Posted June 21, 2016 Could try spraying the old plates with carb cleaner to get as much of the old oil out as possible, then soak in the new oil before installing. Cheers SRR 1 Quote
Duckndive Posted June 21, 2016 Posted June 21, 2016 15 minutes ago, Screwriverracing said: Could try spraying the old plates with carb cleaner to get as much of the old oil out as possible, then soak in the new oil before installing. Cheers SRR Yeap carb or brake cleaner works ..then dry and leave in mineral oil overnight . I have only ever used cheapest Mineral oil I can find......never had any issues ..... 1 Quote
wombat258 Posted June 21, 2016 Posted June 21, 2016 I only use Motorex or Silkolene semi's in my race engines. No slip, no wear. 1 Quote
bruteforce Posted June 28, 2016 Author Posted June 28, 2016 (edited) There's MOTUL semi-synth in it now, went on a 30 mile trip to @Rene EFE 's place to see if all three bikes fitted onto his trailer (they did). I still have some slip on boost but it certainly is a lot less. I will see if the trip to Cadwell will "rinse" the plates enough not to replace them. Edited June 28, 2016 by bruteforce 1 Quote
colinworth79 Posted June 29, 2016 Posted June 29, 2016 also worth checking the slave cylinder isn't corroded and full of gunk . Once had this where you would be going fine then pull the clutch in to change down a gear and as you opened the throttle clutch would slip as the slave cylinder would just keep a small amount of force on the push rod 1 Quote
bruteforce Posted July 19, 2016 Author Posted July 19, 2016 To report back to you, the clutch slipping problem certainly is a lot improved. Only did a couple of hundred miles on the bike so let's give it time to maybe get even better. Now I only get slip at heavy loads (boost) in 5th. Quote
Reinhoud Posted July 19, 2016 Posted July 19, 2016 (edited) Fiber plates within specs is no guarantee for not slipping! Did you also use the shims under the springs to raise the spring load? Edited July 19, 2016 by Reinhoud Quote
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