xr 600 problem(s), 628 kit, and exhaust

97 xr 600, has the "pop and die" problem as well. oh well... I'm not a racer or anything, but would love some more power; does the 628 kit provide noticeable power gains?

also, need a new exhaust; what's the best on the market for performance? price? note: I love to hear my thumper, particularly on closed throttle...

also, my chain picked up a rag and thrw itself off front sprocket, shattering engine case in front. temporarily repaired w/ "paste" and holding up well, but looking to replace. any ideas where to get cheap replacement and amount of labour involved?

thanks guys.

I got the bare bones 628 kit from XROnly but it lasted only about 1000 miles. Burned it up in Baja running on low octane gas. When I got it I loved the arm-pulling power. I was also running a 41mm Mukuni flat-slide, and the XRonly header and exhaust. If you go for the 628 kit, get the cylinder fitted with oversized sleeve, don't bore the original sleeve all the way out like I did. The thin sleeve couldn't dissipate the heat very well and I had a partial seizure when I got it stuck in a sand wash and had to paddle along with my feet. It still ran for another day until a piece of piston got lodged under my exhaust valve. Also consider the 10.5 piston, which will work on pump gas. You'll also need stiffer clutch springs, I fried that too. Any way you look at it, it's big $$$. Getting big power gains is 3 piece puzzle: carb, cylinder, and exhaust. The best upgrade I ever spent money on was getting new springs and having my forks and shock tuned by a professional suspension shop.

If you want power, I recommend selling the 600 and buy a used 650R, and just uncork it. In the end it will probably cost you the same. The BRP rips and chicks dig red.

Good to know, thanks. maybe 650R in a couple of years ($$$). keep hearing about liquid cooling hassles, though.

when i was a little kid, my father would get so peeved when we added some hop up item to the engine. Always drilling us on benefit of keeping the engine stock. Now that i'm older and ride 100+ miles in the desert each weekend, i see where he is coming from.

Can I get an Amen for brother slowpoke!!

I remember rolling my XR628 off the trailer in San Felipe, so proud that I blew nearly $500 on motor hop ups. The wise old ones just shook their heads and told me to watch out, she might not last the 5 days and 800 miles we were planning to ride. They were right! It blew on the last day and 50 miles south of San Felipe. Those last 50 miles sucked the big as I sat in the back of Mexican's truck holding my bike and watching the 50 some other riders blow by waving. And don't forget I had to pay the Mexican $50 to haul me back.

The moral of the story: Engine hop-ups are better left for those who can afford them, repeatedly.

You don't need to fit a big-bore kit in your XR600 to get serious power!! My XR600RJ is rolling proof! The piston, cam & carb is stock and it can outrun my '99 WR400!! The secret to this success is-

*Head shaved 20 thou to gain more compression without resorting to a heavier and reliability robbing aftermarket piston.

*The ports in the head are tidied but not altered to any significant degree.

*An aftermarket Staintune muffler is fitted

*The jetting has been changed from-165MJ, 60PJ, needle 3rd clip-to-168MJ,62PJ, needle 3rd clip.

*Bike is running a twin-air airfilter.

With these mods. the bike runs and starts as well as a stocker, with no reliability problems and will run on the same fuel as a stocker! :)

thanks guys

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