Sprag Clutch & UK info

[shaggy]

Hi all,

I've just bought a non working XT600 (1986, imported, 1VJ - methinks) from a mate. The starter seems permanently engaged, and I suspect a dodgy sprag clutch.

I've done lots of digging (including finding out how a sprag clutch works), but I've not been able to find any UK reference sites, all roads lead to xt600.de, and my German simply ain't up to it. I'm not getting my hands dirty until I move house and get a garage, but I'd like to know as much as possible about it before servicing the beast. I'm getting very attached.

I've kind of figured out that an 86 bike wouldn't have had an electric start, and I'm keen to find out more about them generally (how does the decompression lever work, I know what it's supposed to do, but I couldn't fix it).

Any specific help on the starter motor/conversion story, or good Engish sites would be much appreciated. I can offer hovercraft advice in exchange.

thanks,

jim

[shaggy]

I tried google translate on xt600.de, poetically unhelpful,

"Here thus only the course helps into the framework place (mechanical engineering or engine repair enterprises, yellow sides!)."

http://translate.google.com/translat...s%2Bin%2Bdie%2 BXT%2B600%2BE%26hl%3Den%26lr%3D%26ie%3DUTF-8%26safe%3Doff

[Steve Pickford]

Most, if not all, de-compressors work by slightly opening/lifting one of the exhaust valves via a small cable operated cam or lifter within the cylinder head.

My 86' DR600 had two, one for each exhaust valve. One was automatically operated via the kickstart, the other was operated by a handlebar mounted lever. I ditched the second one because it was not needed.

As with everything else, the cables that operate the de-compressors need to be kept in adjustment. I do mine when I do the valve clearances as the valves & piston need to in the same position to adjust both anyway. I could always tell when mine needed adjusting as it was that little harder getting the piston past TDC.

Defintely worth having, a big single without a de-compressor can be a nightmare of shin shredding kickbacks - I still feel the pain when this happened on my XL500, my foot slipped off when the bike kicked back & the serrated footpeg tore through my jeans & ripped my shin.

Steve

[shaggy]

thanks dude, that helps.

I should have my garage by wednesday of next week (there is a house as well), I look forward to tinkering.

jim

[Mark]

The starter motor is permanently engaged to its reduction gears which engage with a one way “ratchet” connected to the crank directly behind the alternator ( on the right hand side ). The one way “ratchet” function is achieved by a large number of comma shaped rollers held in a cage which lock up if they are trying to move over the surface connected to the crank, so allowing the starter motor to turn the engine over. But when the crank starts turning faster than these rollers they flip and lrt it pass without resistance.


To check if these rollers are releasing I think you can remove the starter motor reduction gears by removing the small cover high up on the side of the left hand side engine case, which will expose the outer gear ring that these rollers live in . With the engine in gear you should be able to turn this ring quite freely in one direction, but only a small amount in the other (while the rollers flip). No need to remove the starter motor, but be careful of the gears falling out as you remove this cover.

Hope tat is a little clearer than the Google translation !

The design of this starter clutch has changed over the years, being quite different between my 3AJ Tenere and my girlfriends 3TB XT600E, presumably because the earlier type wore out and started slipping prematurely.

The electric starter does not need help from a decompressor, there is not one fitted to the XT600E or my (originally) electric start only Tenere. I have retro-fitted kick starts to both our bikes and feel no need for a decompressor when kick starting them either.

[aukeboss]

I think the 1VJ is the only one that was supplied with both kickstart and e-start.

For exploded views, check for instance www.hlsm.com, this will do some of the explaining by picture.

What exactly are the symptoms leading you to think that the starter is continuusly engaged?

Auke

[shaggy]

evenin,

I've already done the procedure mark suggested, I am fairly familiar with this layout, given the evil things I have done to an NTV600 flywheel (http://www.foodfight.org.uk/images/oilsealcomposite.jpg) The ring gear on my bike doesn't move, it is definitely stuck - whether fixing this makes it start or not is another matter.

So the layout is what I hoped for, that's good. My real worry was because I didn't know which bits of the starter were OE - kick or motor? If the 1VJ had both, that's great, I thought that it'd be some crazed botch job and I wouldn't be able to get parts.

I do hope it's just gunked up and been left stood and can be cleaned and fixed.

Thanks to you all

jim