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1stepcloser

Funny how life is....

5 posts in this topic

So last week during a routine valve adjustment I discovered a broken intake spring.

No real drama, the valve didn't drop so I'll just order a set of springs, lap the valves and be ready to go on Sunday.

Funny how life is.

For years I wanted an XR650R... I finally got it November 2002, a well maintained 2000 XR650R.

I should say that the previous owner had the engine as well as the rest of the bike professionally built and I was given all the receipts and build sheet for the engine, suspension, etc. Lots of nice parts and preparation went into this bike, including, but not limited to, the cylinder head.

According to the build sheet, it received new guides, stainless oversized valves, a full port and polish, Kibblewhite valve spring kit and a HRC power up cam topped it off. Pretty cool. The bike is awesome to ride, buckets of power are available at the mere flick of a wrist.

Back to the story.... I called XR's Only for a new set of KB springs and they arrived on my doorstep the next day. Heres where things begin to go a little strange, the new springs are physically larger than the ones that came out... by a large margin. The retainers are so much larger than the valve stem that the cotters simply fall through. I think, hell, KB must have mispackaged them, so I run off the my local dealer, order a full set of OEM springs, seats and retainers... wait the appropriate three days, go back to the dealer to pick them up, and discover (much to my dismay) that they are about the same damn size as the Kibblewhite springs sitting on my bench.

What the hell is going on here, I ask myself.

Another call to XR's Only gets me the same I dunno answers that I have.

So..... this morning I pack the head and all the hardware in the truck and off I go to XR's shop, where I encounter more quizzical looks at my dilemma, I leave the head and tell them "go ahead and grind the valves, and put it all together." I need this done by tomorrow.

"no problem"

I got a call a little while ago..... It seems that during the original build the guides, valves and spring kit installed were for an XR400.

:thumbsup:

My options are somewhat obvious, replacing the guides and valves with 650 parts, or replace the springs with 400 springs.

I told the guys to install 400 springs.... and I'll pick it up tomorrow.

"no problem"

A quick estimate reveals that rebuilding this head, including replacing the over sized seats with stock is gonna set me back about $650.00 or so, not including the new springs. :bonk:

A new head from Service Honda with the same stainless valves is about $525.00 not including the springs... or the port/polish which, for the record, lists at $300.00.

Has anyone heard of this type of modification being done before?

I can see no benefit to it... other than possibly to increase airflow by having a reduced stem diameter within the port? Lighter valve form the 400?

Anyone have an extra 650R head they would like to sell?

Funny how life is.....

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See, I've been wondering about that...

For some time, my BRP has been making this funky top-end noise. Whats weird, is that when its cold, the noise doen't seem to be as pronounced as when its hot. When its hot, there is a definate sound coming from the top-end. When you sit on it, it sounds like a ticking, but when you get up close to the motor, it sounds more like a knocking.

I have the service manual, and one of the things that says might be the problem, is a possible cracked or broken valve spring, or worn rocker arms. Those are the only items I haven't replaced in the top-end, but when I did the rebuild, the springs spec'ed out fine.

So, I'm wondering, is it possible that this valve spring thing could be more then me; is it a BRP thing, and should I replace the springs too? I know 1stepcloser had smaller springs, but would this still be something to look at?

Also, how can you fit 400 hardware into a 650 top-end? The heads are almost completely different; the only similarity is that they're a single cam, and four valves, and have rockers. Other then that, it wouldn't make a whole lot of sence...

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See, I've been wondering about that...

For some time, my BRP has been making this funky top-end noise. Whats weird, is that when its cold, the noise doen't seem to be as pronounced as when its hot. When its hot, there is a definate sound coming from the top-end. When you sit on it, it sounds like a ticking, but when you get up close to the motor, it sounds more like a knocking.

Mine does the same thing. I chaulked it up to being a noisy oil pump.

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I want to know if a guage can be installed to check oil pressure, & to see if bearings are worn or tired pump. I think my XT500 yam had a port on top of filter by cover. Just for diagnostic purposes, not permanant thing.

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