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So I just get done an 800 km ride from alberta into bc. The bike is running good but not great...it feels a bit low in power. Yesterday I decide to take off the aircleaner and have a look at how things are working. It turns out, one of the slides isn't moving. I take the diaphragms out and one has come completely apart.

 

This is the second carbon this has happened on so I take all the diaphragms out and a third inevitable is loose as well. It is an easy fix to glue them back together. Now, it runs like it should.

 

Check those darned slides, folks.

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I have "fished" pieces of slider assemblies out of intakes and even had a few bikes with a piece of the slider stuck to the valve face! Not a pretty sight. This is not an area of a motorcycle where I like to use a "Band-Aid" because the next stop for anything that brakes loose is into the engine or valve train. The way I see it, with a bike that red lines at 7500 RPM's it would be better to park it and repair it properly than risk engine damage.:doh:

Earl

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Parking isn't an option since I am on the road. As it turns out, I did use job weld. The first slider I fixed is still working perfectly. I do have a hairline crack in one near the diaphragm but that is covered by the slider reassembly.

 

I will be replacing the sliders but I am confident my repairs will hold long enough.

 

Bob...a basic check of the sliders is easy. Take off the air filter and you can look down the carbon throats and see the sliders. Start the bike and you can see the sliders move when you blip the throttle. All 4 should move and be most noticeable at low rpm. Be warned that your bike will probably run like scrap with the filter out.

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The way the keeper is press fitted into the plastic slide is a real problem on these old Mikuni carbs. My thought is that in Northern climates after 20 years of riding in summer (heat) and storage in winter (cold) creates multiple expansion cycles, leading to these slides coming apart. Either the plastic gives or the metal looses elasticity - or both.

 

These slides are hard to come by and they are very expensive these days. It just seems wrong that a new slide is well over the $100 mark - each. I wonder if we could organize a group buy and get the cost down.

 

I must admit that I have glued a few of these together but also have replaced others with new &/or used slide units. The glued ones seem to hold up but I don't know if they will hold for 20 years or not. On these forums, a lot of people mention using superglue to do the deed. I wouldn't use superglue or JB Weld - I don't think it will hold.

 

What I have used is the Versachem Plastic Welding System which I bought at the local NAPA store. This is a two part methacrylate system that hardens in a few minutes. (It is the same stuff I use to glue broken Venture plastic parts everywhere else on the bike). I checked with Versachem and they said it should be gasoline resistant and the temp properties should work for this application.

 

No sanding, I just used the smallest amount of Plastic Welder spread evenly where the metal keeper meets the inner barrel of the slide. The three times that I've done this, I made sure all the slide parts were assembled at the time of gluing (i.e. plastic spacers, diaphragm, metal keeper). I made sure that the keeper and the other parts were seated all the way down and all the excess was removed. The operative word here is use only a little amount of the plastic welder and wipe the excess off quickly. The rationale is to minimize the weight of material added to the slide in addition to getting a tight fit.

 

http://www.itwconsumer.com/catalog.aspx?prodID=49

 

 

If the slide came apart on you and you have no clue how to get the pieces back together, I offer this old post --

 

http://www.venturerider.org/forum/showthread.php?t=37273

 

Final word, use my repair technique at your own risk - it is experimental at this point. Yes, it is probably better to get new slides if you can but this may get you back on the road in a pinch.

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