Guzzi piston source

Discussion in 'Old's Cool' started by JonnyCash, Aug 10, 2012.

  1. JonnyCash

    JonnyCash turd polisher

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    I went and picked up a new project this week, an 850T3. I'm just totally gaga over this thing. The top end is off of the bike at this point. The seller gave me with the bike, the original chrome bore cyls, a set of nice Nikasil cylinders, and a set of iron sleeve 850 cylinders. My hope is to be able to use the original pistons, which look to be pretty nice, in either the Nikasil jugs, or in the iron ones. I'll need new rings for sure, as one of them is chipped. If I go with the iron cyls, they'll at least need to be honed heavily, maybe bored, Neither Harper's or MGCycle seem to list pistons, outside of getting the Guilardoni cyl/piston sets. Also, how can one tell the difference between chrome bore and Nikasil jugs? Thanks all!
    Mike
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  2. F_Sahms

    F_Sahms mostly paved

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    How did the PO end up with nicasil cylinders w/o pistons? Do the pistons you have fit any of the cylinders you have?

    Oversize Guzzi pistons are hard to come by. Originally they were size-matched to the chrome bores (coded A, B or C), and then aftermarket nicasil sets were size-matched as well. As neither type of cylinder could be bored, there was no market for OS pistons.

    If the pistons you have are really nice, you could have either the chrome or nicasil cylinders replated with nicasil to fit. Millenium in WI does a good job at this.

    You'll need cast-iron rings for the nicasil bores.

    Chrome bores will be a dull silver color. Nicasil will have a slightly golden color.

    Some euro references to OS piston:

    http://www.gawa-guzzi.de/engine.html#i1
    #2
  3. LonerDave

    LonerDave Been here awhile

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    Greg Bender (http://www.thisoldtractor.com/gtben...gine.htm#gtb_cylinder_material_identification) says:



    There are three different types of cylinders that are commonly found on these bikes. Here is how to identify each:
    • Chrome - The material will appear shiny and smooth. Hash marks should not be visible. Absolutely no magnetic pull. Peeling be may evident exposing the bare aluminum below.
    • Steel sleeved - A ring where the sleeve was inserted will be clearly visible from both the top and bottom. The material will appear less shiny than chrome. Hash marks may or may not be visible. Very strong magnetic pull - just like placing the magnet on anything else that is steel in your shop.
    • Nikasil/Nigusil - The material will appear shiny. Hash marks will most likely be visible. Has a slight magnetic pull; certainly not as strong as steel, but definitely a little pull. If the cylinders were made by Gilardoni (aftermarket only, I think), then the Gilardoni logo will be placed between the bottom two fins at the 6 o'clock position nearest the base gasket (visible from the outside).
    There's also this: http://www.thisoldtractor.com/guzzitech.dk/pdf/identifying-cylinder-bores-on-roundfin-guzzis.pdf Appears to be originally written by Pete Roper, but found on Greg's site.

    Hope it helps.
    #3
  4. JonnyCash

    JonnyCash turd polisher

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    Thanks guys for the info. I don't know why the other two sets of cylinders are without pistons. I have the pistons soaking in the can of Berrymans death elixir, and I'll be able to asses the situation better when they're all cleaned up. With chrome or Nikasil bores, of course you can't hone them, so when you put in new rings I guess you just hope fore the best that they will seat and bed in. In the back of my mind, I know I'll end up with a Gilardoni top end, but I'll still hope that I won't need to. Tonight I'll clean things up and take note of what size pistons and cylinders I have. This rehab I'm sure will drag into next summer. I'm tickled silly with this Guzzi though. I'll try to get some pics up here before too long. It's going to be a mongrel, but made up of a lot of my favorite bits. Can't wait to ride it !
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  5. JonnyCash

    JonnyCash turd polisher

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    So... I cleaned the pistons up, and they look pretty darned good. I also have another set of pistons from another T3 that I bought for parts. All four pistons look good, and they're all B sized. I'm pretty sure that it turns out that I have two sets of chrome bore cylinders, B sized. One cylinder, original to the bike, has a tiny bit of chrome flaking at the top of the cylinder, the others have no flaking or blistering. On the "good" set, the bore is absolutely smooth. When you look down the bore at a long angle, it looks perfect, but when you look at the surface of the bore more straight-on, mostly in the middle of the stroke, it looks as if the chrome is wearing thin. My camera would not pick this up, but I wish it would so I could show you all.

    Also, it turns out that the iron sleeve cylinders are from a 1000. Darn. Or maybe I could get the pistons to fit, and run it as a 1000.

    Opinions on 1000 vs 850? I don't know if the heads will swap over. So much to figure out, good thing I like this stuff!
    #5
  6. F_Sahms

    F_Sahms mostly paved

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    The 949 cylinders (if OEM, which came in iron for the early Converts, G5s, SP1000s and CX100s) won't fit in your T3 block without either opening up the holes in the block or turning down the spigots on the cylinders. You'd still need 88mm pistons to fit them, I assume?

    Personally, I would not go through the trouble of building a motor with used chrome bores, even if they look fine. Other people might.

    I would take the best set of 83mm pistons and the peeled chrome cylinders and send them off to have the cylinders plated with nicasil to match. It's about $200 per hole, little more than half of a new Gilardoni kit. But you'll still need nicasil-friendly rings.
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  7. JonnyCash

    JonnyCash turd polisher

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    Heck with that! Anybody want to buy a set of iron sleeve jugs? Thanks for the info.
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  8. F_Sahms

    F_Sahms mostly paved

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    One thought. Are you sure your block is T3? What's the prefix?
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  9. JonnyCash

    JonnyCash turd polisher

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    The prefix before the VIN is VD. I'm pretty sure it is a T3, as the numbers are the same on the frame and the engine block. Why do you ask?
    #9
  10. F_Sahms

    F_Sahms mostly paved

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    Just on the off chance you had a 949 block already.
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  11. manxkipper

    manxkipper Fishpistel

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    Would it not be possible to resleeve the bad set of chrome bores with an iron sleeve bored to the spec of your pistons? I have had that done to numerous bikes in the past. You would need to check on the existing wall thickness so see if there is enough material available to bore it out to take the sleeve. Iron sleeves minimum wall thickness you can get away with is 2mm.
    #11
  12. HRS

    HRS n00b

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    Hey Cash- where did you see or hear that quote - "I wouldn't bring her home to Mama, but Mama ain't home tonight"?

    It seems like I've heard that in a song, but can't ever find it, even on google. A google search this time, though, did take me to this thread.

    I know this is a strange first post, and I should introduce myself. I've been on motorcycles since I was about 10 yrs old. I've been on Harleys since I was about 20, and currently ride an 01 Heritage and 04 Ultra. For the record, I'm not real fond of The Brave New Harley World, and all its trappings, but to each his own.

    Though I just joined today, I have browsed this forum for yrs now. In fact, I have had this thread bookmarked for a long long time, and have posted it on many message boards. It's always a huge hit.............
    http://www.advrider.com/forums/showthread.php?t=29723&highlight=original

    Ok. So Cash- how about that quote. Where did you see or hear that. Is it a song? If so, what's the name and band/musician. I would assume it's one that Cash covered. Yes, no, maybe?

    Oh, and you guys have a very cool forum here. Thanks for having me.
    #12
  13. peter650

    peter650 Been here awhile

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    Some VW Beetle pistons will fit. You can get 4 of them, for about $120.
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  14. JonnyCash

    JonnyCash turd polisher

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    That's some good info there! I know a local AC VW guru who can probably put one in my hands to check out. Even if one has cut the skirts down or whatever, that seems like a good option. Thanks.

    HRC, the signature I have is from a song that was covered by Hayseed Dixie, called "The Perfect Woman". I don't know who wrote it/ first recorded it. I think I had the song playing when I was setting up my profile on here, and the line made me chuckle. Welcome to the forum!
    #14
  15. Nick in PRC.

    Nick in PRC. Been here awhile

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    Used pistons ?.............call Moto Guzzi Classics. 562-986-0070. Call don't email, Closed Sun and Mon. Pacific timezone.

    Millions of used Guzzi parts.
    #15
  16. mtiberio

    mtiberio Adventurer

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    you most certainly can hone a nikasil cylinder. I used to do it every year back when I raced. The trick is to use a "used" dingleberry hone, Get a bucket filled with soapy water, put the cylinder in it, and put the hone in a drill. You only want to make one or two passes, just enough to clean up the cylinder, and put crude cross hatching back on the surface.

    You can also use chrome top rings on nikasil, but cast iron is the recommended material.

    Wiseco makes some 94mm stroker volkswagon pistons that I have used in an SP once. I believe they gave 1083cc. They have the right compression height (distance from wrist pin to deck), wirstpin diameter (22mm), and are flat topped. they are about $100 each:
    http://www.nolimitmotorsport.com/prod/K001ESV
    #16
  17. mtiberio

    mtiberio Adventurer

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  18. woodly1069

    woodly1069 Long timer

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    Hey JonnyCash, you still have those old iron sleeved jugs lying about? I just found out my chrome is flaking...I'll try a PM too!
    #18