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Question About Starter Valves (5Th Gen)


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Do the starter valves have seals on them to keep air from leaking past them?(vacuum leaks) I think I'm hearing air being sucked past them when I manually open them. (into the bores they slide in) If that makes sense.

Jeffrey

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I've never pulled them apart, but I would expect that the valve would include some form of o-ring seal around the shaft of the valve core that gets moved for cold starts. A starter valve is effectively a controlled vacuum leak as it allows a controlled amount of air to bypass around the throttle valve. If it was leaking around a seal I don't think that wouldn't make a lot of difference except the air wouldn't be filtered.

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"manually open them"? Are you sure you're talking about the starter valves? They're down on the right side behind the frame and I don't see how you can open them other than screwing them open a little.

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Yes, you can manually open/close them by pushing/pulling on the lever where the wax unit push rod connects to it.

post-26694-14304108869168.jpg

Sent from somewhere in middle Tennessee.

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I've never pulled them apart, but I would expect that the valve would include some form of o-ring seal around the shaft of the valve core that gets moved for cold starts. A starter valve is effectively a controlled vacuum leak as it allows a controlled amount of air to bypass around the throttle valve. If it was leaking around a seal I don't think that wouldn't make a lot of difference except the air wouldn't be filtered.

Well the way I understand it is when the engine is cold, starter valves are fully open to allow more air to pass through the intake ports to mix with the added fuel (enriched) because the ECU is programmed to do when the engine is cold. At some point when the engine is warming up, the starter valves start to close.

If the starter valves are leaking air passed them, this extra amount of air will make the engine rpm's go up. Will it not? This is the problem I'm having during engine warm up. While riding, I've noticed the engine idle speed is not consistent when I'm stopped. One moment engine idle speed is a tad high and then later the idle speed could be a tad lower. Could this also be do to leaky starter valves?

Sent from somewhere in middle Tennessee.

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I just had mine totally apart about 2 weeks ago. There are no seals within the starter valve assembly. The only seal is a rubber ring just above the hex nut that holds the starter valve in the casting. Inside are just keyed "pistons" that the adjusters thread into - turning the adjuster threads into or out of a movable piston which opens and closes the "leak" orifice.

As was noted earlier, the choke lever or the wax unit actually pulls on a comb that opens the starter valves.

Spray the area with some starting fluid and see if the rpms rise.

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The seals you are describing is where I hear the leaks. Are these seals replaceable? Are they available for individual purchase from Honda?

Sent from somewhere in middle Tennessee.

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Unfortunately, no the seals are not available individually. You can order sets of the parts that go inside the throttle body assembly which includes the seals, but not cheap.

http://www.ronayersmotorcycles.com/fiche_section_detail.asp?section=4747571&category=Motorcycles&make=Honda&year=1998&fveh=204642

Reference part #6 and #7 - part number 6 includes all three adjustable valves and part 7 is just the one fixed valve. Grand total of about $60 for the set.

I would very carefully go over the entire vacuum system, looking for leaks, cracks, poor connections, etc before I ponied up that much cash. You might also try reviving the seals by soaking them for a while in power steering fluid. I've never done it, but I've heard that the seal conditioners can squeeze a bit more life out of old rubber components. Again, I've never done it so I don't know how long that treatment lasts. If the seals are cracked and dry-rotted, I don't think anything can be done to save them.

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For a moment I thought #6 was $45 each. YOWZA!! I have replaced the vacuum lines for the valves to the ports about 6 months ago. May have to live with it until winter. (Sigh)

Thanks for the link.

Jeffrey

Sent from somewhere in middle Tennessee.

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The idea of spraying some starter fluid in the area is a good one, that will tell you in an instant whether the valves are pulling outside air in. Just a brief shot and if the revs rise you know you have a leak.

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Jeff, you might also have an issue with the hot wax unit. It is coolant activated and can act real hinky if it gets an air bubble or obstruction of any type. If you have replaced your coolant recently you might need to "burp" it.

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Yes, that wax unit has been a thorn in my side. Changed the coolant in it last summer and it quit working. Replaced the guts in it and still had problems with it. Took it apart AGAIN thinking I maybe assembled it wrong. (Which you can't) looked clean but cleaned it anyway and then it started working. Had to replace the water pump a few weeks ago and it quit working again!! ARRGH!! I said "I am not taking that (insert your favorite metaphor here) little jewel apart again." So I just rode and it is working again. At 100% I don't know. It's way better than it was. The idle speed will still jump up a little while its warming up but it will idle down now. This why I posted this thread about the starter valves leaking.

SOOO, how do you burp it without involving the task of removing the air box?

Sent from somewhere in middle Tennessee.

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Place bike on side stand while engine is cold. Remove right fairing (or just loosen enough to access the coolant cap). Remove cap & start engine, allowing it to reach full operating temp. Top off coolant, blip the throttle a few times, then top off again if necessary. Repeat until coolant level is at maximum.

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