IP2 Sprag clutch change

[gripper]

Or should it be sprague? anyway, It's a 50/50 if my IP 2 will start without having to push it forward in gear to find a bit of bite for the starter. The question is, whilst I took the precaution of buying a new sprag direct from the manufacturer, am I likely to find the surfaces that it runs against worn? If so is there a fix? While I'm in there I'm minded to do the cush drive rubbers. Are they going to put up a fight without the proper tool or is it something I can work around. (in gear, strap wrench, rubber lube etc) Or does anybody have the tools I can borrow to achieve this? Thanks, Dave E

[Richard Negus]

Dave,It runs against a hardened steel sleeve pressed into the clutch drum and the hardened centre boss of the starter gear and, in my experience, the problem is always with the sprag itself. The ends of the dogs wear, producing a small flat that won't engage. If the sleeve and/or starter gear is worn, you have a problem as they're not available new. I believe Graham has some used ones.Another cause may be oil/rubber sludge collecting around the sprag.If the primary oil came out clean, then the clutch hub rubbers are probably ok; if it came out black, then it's time for a hub overhaul. Black radial streaks across the face of the clutch hub are a secondary indication.

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Don't underestimate the amount of leverage required to compress the 'drive' rubbers enough to get the 'over-run' rubbers in place. The one I use is a metre long with a doubled ratchet strap to the bench - and I stand well clear when it's fully loaded up.R.

[Anthony Duffield]

Richard,My Commander starter occasionally does not engage first time but does after the second or third attempt, I can hear the starter turning but it does not engage.What in your experience would you expect to be the problem?Many thanksTony

[Richard Negus]

Hi Tony,The same thing - slipping sprag, but since it works on the second/third attempt, it's probably not so severe and may only be sludge trapped in the sprag space.Either way, to fix it means taking the primary apart and, even if it just sludge, I'd perhaps change the sprag anyway.While you're in there, give the clutch bronze plates a scrub with paraffin and a Scotchbrite pad.R.

[Anthony Duffield]

Richard,Many thanks for the advice, I wish I had looked at it during the winter, is it a long job?Many thanksTony

[Richard Negus]

Tony,.drain primary oil.remove brake pedal.remove clutch cable & lift plate.remove cover.remove chain tensioner.remove clutch spring.undo clutch nut & sprocket nut (both should be VERY tight!).pull off primary drive.remove spiral circlip from back of clutch drum.remove sprag - Seemples! One hour's work.BUT almost impossible without the appropriate tools.clutch spring compressor (same as Commando but with M8 x 1.25 thread up the end of the 1/2" UNF bolt.slimmed 19 A/F socket to get to the clutch nut.clutch locking tool (or use the rear brake in 5th to hold the mainshaft).balance weight holding tool (or flywheel restrainer tool - and that means removing the water pump to get to the flywheel).30 A/F socket and breaker bar for the eccentric shaft nutTwo hours to clean/inspect/re-assemble in reverse order, with the tools.100 ft.lbs clutch nut, 150 ecc. shaft nut, both with Loctite 270. 250 cc cheap SAE 5W-30Without the tools, how close are you to A&E?

[Anthony Duffield]

Richard,Just up the road from Aberdeen RI Seriously many thanks for your advice, I am going to try to keep it going until the winter, it does seem better when hot.I do not have a clutch compressor but most of the other tools you list.Thank again and RegardsTony

[Charles Wilson]

RN, you are a treasure...Based on my experiences with the RE-5, NOT replacing the sprag clutch is a losing proposition.The sprags on the RE-5 locked up one morning and gave the ol' starter motor the spin of its life.RIP, starter...For all of the talk about lack of compression on braking with the Nortons, I can promise you, a 500 cc rotary "single" will give all the compression you would ever want, especially when kick starting the beast. I've got the hip replacement and bad back to prove it. It would've been easier to rob a bank and a coupla' liquor stores and just bought a replacement clutch.RN, speaking of which, would it be better to just swap out the clutch?CW

[Richard Negus]

Richard,Just up the road from Aberdeen RI Tony

Aberdeen - that means you've got all sorts of engineering expertise at hand. Laser cutting, water jet, etc??You could make a balance weight tool from 6mm plate welded to a long bar. It doesn't have to fit the balance weight profile exactly, just stop it turning.You could even make several and invite offers for the surplus .........Charles,The Norton rotary clutch and starter arrangement is pretty unique, so adapting something else would be a whole new development exercise.The NRS racers used a Kawasaki slipper clutch, running dry, but had to have a specially-manufactured drum and dispensed with the starter. Running dry, I doubt it would last long on a road machine.The F1 has a larger diameter sprag and doesn't appear to suffer the same wear/slip problems. However, the average mileage of an F1 is much less than IP2's and Commanders.R.

[gripper]

Thanks for the advice on the sprag Richard. I Loctited my nuts (as you do) when I rebuilt the motor a couple of years ago. I'm tempted to use a bit of (very) local heat to persuade the nuts off without too much of a fight. Your thoughts on this Richard?

[Richard Negus]

Dave,Heat with a hot air gun is kinder than a flame, and less hazardous. No need to get things blue though.You've still got to break the tightening torque, but after that removal should be easy. You've got a simpler job than Tony as the flywheel restrainer holes aren't as difficult to get at.R.

[Wayne]

Hi allI think graham is running very low on decent second hand commander/interpol spiders (thats what i call them) but is always worth checking. I borrowed a ex norton tool to do my clutch cush drive rubbers, and thought B"""""s to that idea i made a tool that fits in the vice and i can accuratly apply the pressure with very minor adustments. I obtaind a old main shaft to make the tool oneside F1 the other interplodI lubricated the rubbers with victalic slip a proper ruber slip when compressing rubber. I found the flat tip of a snap op pray bar worked 10 times better than a screwdriver to ease the last rubber in. all in all a very easy job to doRemoving the counersunck allen bolts i followed richard advice i heated the head of the screws but used a hand impact wench and all of them came out no problem.The Race clutch has the best idea yet, the rubber cover metal ring has a grove cut on a lathe through the centerline of the counter sunk screw holes, if the allen key in the screw rounds is a simple mater of grindin a wide slot in the screwd head, you run off in to the grove in the ring then use a substansial flat blade in a hand impact wrench and out they pop. Note on the race clutch they center punched the screw heads as well as locktight.Its also worth mentioning that the hand impact wrench i mention is not the cheap items from halford but the very heavy duty Sikes Pickervant version. Do not try an air or electric powerd impact wrench they are too fearceRegards Wayne

[Anthony Duffield]

Richard,Since changing to ATF in the primary drive the starter has worked without problem, I still intend giving it a once over in the winter though.My main clutch was binding so having purchased a compressor from Andover, who are excellent by the way, last night I overhauled the clutch, which was gummed up with a lot of sludge type crap. I will see how it goes this weekend.I noticed that the clutch drum teeth and the teeth on the engine drive sprocket are quite sharp.I would guess that the clutch drum is available as I think it is from a Commando, are engine drive sprockets still available?Tony

[Richard Negus]

Richard,I would guess that the clutch drum is available as I think it is from a Commando, are engine drive sprockets still available? Tony

Tony,Sorry to disappoint, but the clutch drum is unique to the rotary. ANIL have new in stock at an eye-watering price (and slightly cheaper than a Commando one), but I don't think they include the bearing or sprag sleeve. Graham probably has some usable ones.I think ANIL have new engine sprockets for a moderate amount of money.These sprocket teeth are usually quite sharp when new, so unless there's evidence of running with a very worn chain (such as wear marks on the casing or damaged teeth) I would continue to use them. I don't think I've ever had to change a clutch drum, even on mine when the axial bearing broke up, allowing the eccentric shaft to float about. Wrecked the engine sprocket though!R.

[Wayne]

Hi RichardMy brand new commander clutch drum £50 and F1 clutch drum £150 from Graham, these items were new and looked new as well. Reasnoble cost.Regards Wayne

[Anthony Duffield]

Richard,I would guess that the clutch drum is available as I think it is from a Commando, are engine drive sprockets still available? Tony

Tony,Sorry to disappoint, but the clutch drum is unique to the rotary. ANIL have new in stock at an eye-watering price (and slightly cheaper than a Commando one), but I don't think they include the bearing or sprag sleeve. Graham probably has some usable ones.I think ANIL have new engine sprockets for a moderate amount of money.These sprocket teeth are usually quite sharp when new, so unless there's evidence of running with a very worn chain (such as wear marks on the casing or damaged teeth) I would continue to use them. I don't think I've ever had to change a clutch drum, even on mine when the axial bearing broke up, allowing the eccentric shaft to float about. Wrecked the engine sprocket though!R.

Richard,Many thanks for the infoTony