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Hey guys, great information regarding this subject. Whilst I am waiting for my PVL coils to arrive I am thinking about doing the sprag clutch. I have a 1999 Trophy 4cylinder and was wondering if I need to buy any special tools in advance like pullers etc. How about new gaskets or seals? The bike is only my Sunday knock around so I am going to go the spring replacement route. I saw from a post that National oil seal 225545 would be required. Any advice would be appreciated as I am a tad nervous about the amount of work. Cheers, Nigel
 

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Hi Nigel, Only a tad nervous about the work? Do you know how much work it is just to replace this spring you're talking about. I didn't do the spring replacement route. I replaced the whole sprag clutch for a used one I bought on eBay. It is a big job and I've done it a few times on a 900 and once on a 1200. Take the engine out of the frame, flip the engine over and take off the bottom half, good luck finding the two hidden bolts holding it together. A good schematic helps in finding the two bolts and on which gaskets and o-rings need to be replaced. You will be lifting out the transmission shafts. Good news is you can leave the head on, just take off the cam cover. So start the job with engine at top dead center with the cam arrows pointing at each other and the transmission in neutral. You do have a Haynes manual don't you? Here's the bad news. Triumph used two different sizes of sprag clutches with a little corresponding gear. 51/15 or is it 13? The other is 53/13 or is it 11. Somebody help me out here, it's been a couple of years since I did a sprag clutch. Anyway, you VIN number isn't going to give any clue to what sprag you have. If this helps any, Triumph started using the bigger sprags on the 955 engines. So if you decide to replace the whole sprag with another get the little gear also. There are a lots of 955 engine parts listed on Ebay. Usually a sprag will last a long time if you keep a good battery with a full charge. Bad batteries are sprag killers.
 

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Hi Greg, thanks for the info. Doing the work bothers me a bit but it really bothers me when you get so far into the strip down only to have to stop because you need a special tool. It’s a real dumb design but no point harping on about that as I’m sure there have been many complaints. I have stripped an engine down 30+ years ago and have built an AC Cobra from scratch so I should be able to do the work. I take your point about buying a complete sprag and am still in the contemplation stage as I don’t want to be doing this again due to a dumb design. I have a Haynes manual on its way. Do you need a puller or any special tools? I will see if I can identify what seals n gaskets I need to buy in advance.
My PVL coils arrived and I installed them with new plugs. Right now the bike fires up within 2 seconds without hearing the clack. I believe it’s only a matter of time before the sprag quits so maybe a winter project.
Cheers mate,
Nigel
 

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Hi Nigel, The early 900 engines (1991-1993) had a cover above the sprag. Now that was a good design. No special tools are really required. The clutch will have to come off to get to the bolt head securing the alternator shaft. There is a special tool to hold the clutch basket. I just shoved a big rag into the gears and it worked. The only other special tools are some torx bits. Look on 2wheelpros.com they have good schematics. Since it take a good amount of torque to get the clutch nut off, I'd take the clutch off before taking the engine out of the frame.
Greg
 

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Hi Nigel, The early 900 engines (1991-1993) had a cover above the sprag. Now that was a good design. No special tools are really required. The clutch will have to come off to get to the bolt head securing the alternator shaft. There is a special tool to hold the clutch basket. I just shoved a big rag into the gears and it worked. The only other special tools are some torx bits. Look on 2wheelpros.com they have good schematics. Since it take a good amount of torque to get the clutch nut off, I'd take the clutch off before taking the engine out of the frame.
Greg
I replaced the sprag on a 1995 Sprint, no access cover, and no special tools other than a good set of male Torx bits are required. I did not disassemble the clutch basket it came out complete still attached to the transmission shaft.
 

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There we go, not having to dismantle the clutch basket is a bonus and only a good set of Torx bits. This build is getting easier by the day! Cheers guys
 
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