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Discussion Starter #362 (Edited)
The air filters have been restored with foam and the chain and chain guard are now in place as well.

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So today I've disassemble the carbs which are the last parts that needs to be restored. I've realized that one cable bracket is missing, one thread at the end of a valve axis is damaged and one of the tiny springs at the choke valve inlets is damaged. Not bad, considering how they've looked when I bought the bike.
Although I have carb rebuild kits already I'm not sure if it's the best to replace all jets or if it's perhaps better to keep some of the old jets. IIRC I've read that some of the more experienced members have said somewhere that some replacement jets are not as good as the original jets.

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After a first scrub in hot water.
 

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The replacement jets might be fine as far as the brass quality is concerned, but they are often incorrectly sized. This is primarily why it's recommended to keep and clean your originals (and hopefully they still are original)
 

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Discussion Starter #364 (Edited)
I've had a look at the carbs brass pieces meanwhile but I'm not sure what to think about it. Most of the old jets have a little Keihin-like star next to the size number, so I would assume that they are the original ones but they have different sizes. I have the later style carburators with the large drain screw. Here's what I've found:

Slow jet was 45 >> 38 is standard according to my FSM >> replacement part is 38

Slow jet pilot was 42 >> 38 is standard according to my FSM >> replacement part is 38

Holder needle jet has no FSM spec but I measured that the "flute holes" are different >> I had .55 whereas the holes in the new brass piece are .45mm

Main jet was 145 >> 130 is standard according to my FSM >> replacement part is 145

I tend to replace all of the jets because I think standard sizes would be the best point to start with, but I'm not sure about the holder needle jet. What do you guys think? I'm looking for a reliable and durable set up rather than performance. Any recommendation would be highly apprechiated. I can also imagine that some combinations might not work well.

The carbs itself have cleaned up very nicely. I used boiling hot water, soap, wire and paint brushes for the carbs and some good music and beer for me. Works pretty well and you forget about your fingers. The hot water gives the aluminum body a very nice and even satin finish that looks almost as good as bead blasting. I'm by no means a metal specialist but after what I've read it's probably a fine oxydation.

I also decided to take the butterfly valves out, fixed the tiny spring at the right choke butterfly inlet valve and re-plated the choke lever. ( As a side note I've actually never used the choke on my other 450.) I will probably not take this apart again in the near future because the threads at the ends of the axes are quite soft and therefore easy to ruin. Heat helped to get the nuts loose but also made the whole thing bend a tiny bit. I think it's still ok somehow.
I'm also wondering how air tight the axes have to be...

Another thing I have to deal with is the quality of the rebuild kit itself. (4into1 again !) The big round vacuum gasket for the top cap is waaay to large to fit in. I think I have to clean and reuse the old one. Dow Corning High Vacuum Grease might help. I love that stuff.

Also a spare 150 main jet is actually a 145 despite being stamped as 150 .

Edit: I can not measure unter .45mm but everything 38 and 42 is definitely smaller than 45...

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Discussion Starter #365
Meanwhile I've found a solution to my concerns of possible air leaks through the butterfly valve axles on eBay. The felt seals are coming from the US, so I have at least 2 - 3 weeks to clean up the carbs and make up my mind about the jets... sigh... :rolleyes: I really wonder why they are not included in the rebuild kits. At least I've never seen them included anywhere.
Because I've got to wait again anyway, I've also ordered the missing throttle cable stay for the right carb and can make a checkmark on all of the obvious carb issues now.

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The jet sizes are sized by diameter in 1/10 mm. So a jet size of 50 for instance, is .5mm diameter actually. A 150 is 1.5mm. There are a couple of other dimensions affecting flow but it’s mainly the diameter. If the kit and OEM diameters match, is a good indication the calibration issue has been addressed. The other dims are orifice edge condition (sharp or radius) as well as length of flow passage (L/D ratio).

FYI, the exception is hex Mikuni jets for the VM series carbs, they’re based on a flow standard. The BS series round jets are a diameter standard. Go figure.

hope this helps.
J
 

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Discussion Starter #367
Thanks, I'm glad about any advice. I think to focus on the nozzle diameters is enough because the manufacturer didn't even bothered about a proper deburring of the jet holes. I will try the new jets though because they have standard sizes.
 

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Discussion Starter #368 (Edited)
While I'm waiting for new carburator gaskets (this time Honda parts) I had some time to work on the exhaust. The downpipes came with the bike and had some notable rust but fortunately the worst area was underneath the right side crank case cover, while the rest of the corrosion was the typical small rust stains here and there. The mufflers are used ones from eBay (while I was living in the US) and in remarkably good shape. The only downside is a welded area at the left underside seam but again, you can't see it.
Trying to make the best out of it, I removed the rust and zinc plated the worst areas. It was also a great opportunity to test zincing with a pad which worked great considering that I did it the first time this way. Of course I know that I'm only buying me some more time before it will rust again but it's a nice experiment. I also cleaned and zinc plated the weld seam, masked the seam and sprayed some caliper paint on it (another experiment). I've read that zinc plating and paint has a much higher rust preventing factor than the factors of both single precautions added together but I doubt that the paint will hold up for long...

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I like the result. The zinc doesn't stick to good chromed parts, so only the damaged areas have a thin zinc layer. It looks all much better after the plated areas have been brushed.
Although the bike looks quite finished to the untrained eye there's still a LOT of work left to be done. Thank God spring hasn't arrived here yet.
 

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Discussion Starter #369
Today I've cleaned the tank emblems. They have some scratches but the color is still pretty good. I've got new clips so they will go back on the tank soon. The side cover badges are in not so good shape. I'm really asking myself why they made them in plastic. There are almost no plastic parts on this bike and of all tings they made a not essential part that is decorative only out of plastic? I'm always afraid to crack them when I've got to put the side covers back on.
I'm planning to repaint the badges but the fitting will perhaps be a little challenging. All of the tiny locators on the back of the badges are gone. I have aftermarket chrome screws but how to fix the badges? Has anybody tried double tape? I don't think it would hold up for long though. Or has someone a real idea?
 

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Discussion Starter #370 (Edited)
Hmm, my new rear shocks are almost 2 cm (0,78") longer than the original ones. It's my fault. I forgot to check the length because they were listed in the 450 section of the seller. Not good but they are touching the muffler just very slightly when the bike is on the center stand. I think I can live with it.

 
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