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Thread: MTC 74mm GS1000 pistons?

  1. #1
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    Default MTC 74mm GS1000 pistons?

    So just by chance, I keep ending up with good deals New Old Stock out of production MTC Engineering pistons for all my big bore bikes...

    Now...
    As luck would have it, I've stumbled into TWENTY sets available of New Old Stock MTC Engineering GS1000 74mm pistons for $250/set...

    So I'm debating buying one or two sets of these MTC 74mm pistons. The price is right, they are a nice vintage high performance item, but probably not quite as good as a Wiseco. A $$ JE Pistons' set or $$$ Carillo/CP set would be lighter and run tighter bore clearances, but are both more $$$.

    I have a GS1000 bottom, and several GS1100GK D-port head and 1074cc cylinders (head will get ported by Rapid Ray). Custom 1100E/G hybrid welded stroker crank built for a 1000 bottom, and a spare 1000 welded crank., an old MTC 1100E clutch basket, with CR31 (I have 2 sets) or CR33 (need to trade for some 33's?) carbs. Same Yoshi 265 duration .374"/.354" lift cams as my 750-920cc is getting.

    This would put me at 1135cc and 10.65:1 (estimated, could mill domes slightly to lower CR for pump gas or retard timing when on pump gas).

    Option #2 Wiseco 73.5mm K1100 kit (1120cc on my stroker crank) for $470
    I have heard Ray talk about how Wiseco in his opinion are definitely better than MTC, and MTC use Old School Technology. I'm guessing the Metallurgy is better as far as expansion rates when heated, and the pistons are lighter. I am assuming.

    Option #3 Custom Dynoman (JE Pistons?) 73.5mm gs1000 kit (1120cc for mine) $700
    Definitely a higher quality piston than either of the other options. And higher price. Substantially.

    Option #4 Dynoman (JE?) custom GS1100G 10.25:1 74mm 1135cc kit $675
    This is a very sensible way to go because it brings the compression ratio down because it is made for the 1100 stroke which I will be running. The price of course is very high! Slightly less than the 1000 73.5mm pistons though for some reason.


    Option #5 Wiseco K1085 73mm (1105cc for my crank) kit $470
    This would leave the most metal in the 1100 block, heavier engine, but lighter rotating assembly , but it is only a 1 mm overbore into the 1074cc 1100 block!


    I have been told by road-racers that the 73 mm pistons will spin up faster due to being lighter weight and less friction versus the 74mm pistons. I am not a drag racer, I may just for kicks do some land speed record type 1 mile airstrip drag races that the East Coast Timing Association, ECTA, puts on, but primarily I build all bikes for canyon carver or road racer type performance, and prefer tight tracks and roads. Lots of up & down accel/decel.


    To be honest, this engine is probably going into a Rickman CR 900 chassis, which is quite a rare 1970s performance chassis kit, and will probably never see any really serious racing, but may, who knows. More exhiition/nostalgia build, bit I really do want it to seriously perform on all facets of its nature. It is not a bike that I would want to crash due to its rarity and cost to build. However, if I do end up getting heavily into vintahe heavyweight WERA Superbike racing, the engine might end up in a gs750 frame, or as I do have two welded cranks, might build two GS1000 74mm piston D-port head engines even! A GS750 based racer might get ridden and pushed very seriously... or better yet a Harris Magnum/F1 etc frame with this engine, I would be less hesitant to really really rip into it once my track experience had earned the right of passage to step up to the big liter+ bikes. Vs the classic and somewhat rare Rickman chassis...






    Anyhow, I'm just looking for opinions on 73 vs 73.5 vs 74mm, and MTC vs the better choices. MTC certainly seems like the best choice as far as my budget is concerned.

    74 MTC's & 74mm in general will be the heaviest piston. 73mm will leave me with lightest rotating assembly but more cast iron in the cylinders, so heavier bike overall (trimming weight everywhere possible on it).
    73.5 sounds like a good compromise and leaves me with 1 semi-off-the-shelf overbore size if I were to ever put mega-miles on this engine (not likely in the Rickman frame).



    Does anyone care to persuade me to sell some stuff off or work some more overtime out of dire necessity to get the better pistons?


    Thanks GSR,

    Chuck
    Last edited by Chuck78; 12-05-2017 at 12:39 AM.

    '77 GS750
    920cc, 4-1, GS1100E swinger, 18"rims, Fox Factory Shox, twinpot dual disc, VM29's, Yoshi cams
    '99 Kawasaki KDX220 rugged terrain ripper
    '74 Rickman VR250MX
    PROJECTS:
    '77 Suzuki PE250 Pure Enduro trail beast, ported, Wiseco, TüBliss, Fox Factory Shox/RaceTech
    '76 Rickman CR GS1000-1120cc roadracer, Yoshi cams&4-1, RF900R fork, Works ProRacers
    '79 GS425 489cc, GR650 cams, GS650 fork, twinpot discs, DID rims, GS1100E swinger, Fox Factory Shox
    '77 GS550 650-740cc susp/brake mods

  2. #2
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    Default

    FYI they also have 10.5:1 71mm GS1000 piston kits left. This makes these pistons sound very old, as the displacement limit of racing classes in the early 80s I think was a 1 mm overbore of 1000 cc's... so yes, this is probably some pretty old piston technology here, but still quite a deal on a forged piston set to get me to 1135cc. This will be the biggest engine I have ever built or owned. Ported head, hot street "Road & Track" cams,CR31 smoothbores, stroker crank, Yoshimura Series 1 4 into 1...


    Just by chance this would have me ending up with 3 of my 4 big bore bike builds all running old MTC pistons! 920cc GS750 2nd incarnation, and 2 of the 3 remaining used 1st incarnation 920cc pistons going into a GS425 2 cylinder for 489cc! I fried one piston after over revving and bending two intake valves... and kept riding on it, as it still ran as strong as a fine racing steed...
    Last edited by Chuck78; 12-05-2017 at 11:31 AM.

    '77 GS750
    920cc, 4-1, GS1100E swinger, 18"rims, Fox Factory Shox, twinpot dual disc, VM29's, Yoshi cams
    '99 Kawasaki KDX220 rugged terrain ripper
    '74 Rickman VR250MX
    PROJECTS:
    '77 Suzuki PE250 Pure Enduro trail beast, ported, Wiseco, TüBliss, Fox Factory Shox/RaceTech
    '76 Rickman CR GS1000-1120cc roadracer, Yoshi cams&4-1, RF900R fork, Works ProRacers
    '79 GS425 489cc, GR650 cams, GS650 fork, twinpot discs, DID rims, GS1100E swinger, Fox Factory Shox
    '77 GS550 650-740cc susp/brake mods

  3. #3
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    Default

    interesting dilema.
    SUZUKI , There is no substitute

  4. #4
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    Hey there Chuck. Got any pics of these MTC pistons? My experience, back in the day, was the true compression ratio was much higher than advertised. The result was overheating on the street when stopped. Not to mention pump gas was not going to cut it. I have an old pic of the MTC 1175cc (10.5/1) pistons next to a Wiseco 1238cc (13.5/1) piston and its obvious the MTC's were probably more like a 12/1 CRPistons 003.jpg

  5. #5
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    Very good to know. I do not have pictures of them, they are sitting in the back of MTC's warehouse gathering dust still. They have 20 sets of them, 74mm 10.5:1 GS1000 pistons @ $250/set
    Right now I'm leaning towards the K1100 Wiseco kit for 1.5mm overbore into 1100G cylinders @ 73.5mm after your comments and my friend who has a BIG bore Z1 1100cc or 1075cc or thereabouts, with MTC pistons.
    He reiterated what I have heard from others, that MTC has never really stepped up their game with technology since they first started making forged pistons, and their metallurgy is still old school, machining is not state-of-the-art like JE or even Wiseco, but they still are a decent go fast option especially at this price.

    1135cc stroker/big bore 74mm MTC's @ $250+Shipping
    vs
    1120cc stroker/big bore Wiseco 73.5mm K1100 kit $470 shipped...

    $212 extra for Wiseco, & that may include a head gasket. Definitely lighter pistons.

    This bike (GS1000 powered Rickman CR road racer) won't get ridden a ton, but definitely may see some leisurely track days and vintage racing. I really think I may build a wheelie bar for it so I can still run the very short Rickman original swingarm, but be able to do ECTA's "Ohio Mile" airstrip 1 mile drag races. Rickman/Avon fairing, 1120cc ported head CR31's Yoshimura cams & pipe... should be a blast, road race course or straight line! I'll have to definitely add a steering stabilizer to it for top speed 1 mile runs with 1 up on front spocket vs normal gearing...


    Thanks Billy for the feedback!

    '77 GS750
    920cc, 4-1, GS1100E swinger, 18"rims, Fox Factory Shox, twinpot dual disc, VM29's, Yoshi cams
    '99 Kawasaki KDX220 rugged terrain ripper
    '74 Rickman VR250MX
    PROJECTS:
    '77 Suzuki PE250 Pure Enduro trail beast, ported, Wiseco, TüBliss, Fox Factory Shox/RaceTech
    '76 Rickman CR GS1000-1120cc roadracer, Yoshi cams&4-1, RF900R fork, Works ProRacers
    '79 GS425 489cc, GR650 cams, GS650 fork, twinpot discs, DID rims, GS1100E swinger, Fox Factory Shox
    '77 GS550 650-740cc susp/brake mods

  6. #6
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    Aug 2012
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    Hmmm...

    Does the GS1100GK D-Port head have a larger combustion chamber than the GS1000 8V small port head?





    I'm looking at potentially trading some shop labor hours at my buddies' salvage shop, for a spare partial GS1000 bottom end...
    I already have a spare welded crank from another which I got there dirt cheap.
    I'm thinking of a budget build now, spare engine... perhaps if I ever sold the Rickman, swap out the high dollar engine for a budget build former high dollar engine without ported head etc
    GS1000 bottom
    1100G/E basket
    1100G D port head
    1100G cylinders
    MTC 74mm pistons for 1115cc...

    '77 GS750
    920cc, 4-1, GS1100E swinger, 18"rims, Fox Factory Shox, twinpot dual disc, VM29's, Yoshi cams
    '99 Kawasaki KDX220 rugged terrain ripper
    '74 Rickman VR250MX
    PROJECTS:
    '77 Suzuki PE250 Pure Enduro trail beast, ported, Wiseco, TüBliss, Fox Factory Shox/RaceTech
    '76 Rickman CR GS1000-1120cc roadracer, Yoshi cams&4-1, RF900R fork, Works ProRacers
    '79 GS425 489cc, GR650 cams, GS650 fork, twinpot discs, DID rims, GS1100E swinger, Fox Factory Shox
    '77 GS550 650-740cc susp/brake mods

  7. #7
    Join Date
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    Location
    APE Willow Springs, Ca.
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    Let me correct a misconception. MTC pistons do not set up loose. In fact they will tell you as tight as .001" I have set them up that tight and no problem. I say that as a warehouse distributor for all major brands, Wiseco, JE, CP, Wossner, MTC and Vertex.

    We sell a lot of MTCs for the vintage stuff we do, KZ and GPZ Kawasakis, etc. There is nothing wrong with MTCs.
    Speed Merchant
    http://www.gszone.biz

  8. #8
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    Quote Originally Posted by Big Jay View Post
    Let me correct a misconception. MTC pistons do not set up loose. In fact they will tell you as tight as .001" I have set them up that tight and no problem. I say that as a warehouse distributor for all major brands, Wiseco, JE, CP, Wossner, MTC and Vertex.

    We sell a lot of MTCs for the vintage stuff we do, KZ and GPZ Kawasakis, etc. There is nothing wrong with MTCs.

    I feel a lot better about that after your comments Jay, as well as Cliff from MTC checking back with me today on wanting to purchase any. Check out the tiny piston to wall clearance!


    Quote Originally Posted by email from Cliff@MTC

    We set the bores straight to the mm size as our pistons are ground smaller for the clearance.

    Example-72mm bore=2.8346
    The Piston should measure at the very bottom of the skirt 2.83385 this will be .00075 piston to wall clearance.

    Our Pistons do not have any silicon in them so the expansion is minimal.

    This would be the same on all of our 10.5 to 1 pistons.


    The 74mm that you want I am thinking 10.5 to 1 is this correct?

    The cost to bore and hone -$200.30
    The cost to deck the block-$43.20


    Best regards,
    Cliff Jones
    Piston Marketing, Piston
    Development & Tech Support

    428 Shearer Blvd
    Cocoa , FL 32922
    321-636-9480 x207
    www.mtceng.com


    Last edited by Chuck78; 12-13-2017 at 02:35 PM.

    '77 GS750
    920cc, 4-1, GS1100E swinger, 18"rims, Fox Factory Shox, twinpot dual disc, VM29's, Yoshi cams
    '99 Kawasaki KDX220 rugged terrain ripper
    '74 Rickman VR250MX
    PROJECTS:
    '77 Suzuki PE250 Pure Enduro trail beast, ported, Wiseco, TüBliss, Fox Factory Shox/RaceTech
    '76 Rickman CR GS1000-1120cc roadracer, Yoshi cams&4-1, RF900R fork, Works ProRacers
    '79 GS425 489cc, GR650 cams, GS650 fork, twinpot discs, DID rims, GS1100E swinger, Fox Factory Shox
    '77 GS550 650-740cc susp/brake mods

  9. #9
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    Dec 2004
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    JaxFL
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    Such a detailed email, but no images?

  10. #10
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    Quote Originally Posted by BadBillyB View Post
    Such a detailed email, but no images?
    Here are images of their 10.5:1 72mm 920cc GS750 pistons, if that helps clear anything up...
    72mm piston x 56.4mm stroke for 920cc 10.5:1




    the GS1000 setup will be 74mm piston x 64.8mm stroke for 1115cc and 10.5:1 supposedly
    Attached Images Attached Images

    '77 GS750
    920cc, 4-1, GS1100E swinger, 18"rims, Fox Factory Shox, twinpot dual disc, VM29's, Yoshi cams
    '99 Kawasaki KDX220 rugged terrain ripper
    '74 Rickman VR250MX
    PROJECTS:
    '77 Suzuki PE250 Pure Enduro trail beast, ported, Wiseco, TüBliss, Fox Factory Shox/RaceTech
    '76 Rickman CR GS1000-1120cc roadracer, Yoshi cams&4-1, RF900R fork, Works ProRacers
    '79 GS425 489cc, GR650 cams, GS650 fork, twinpot discs, DID rims, GS1100E swinger, Fox Factory Shox
    '77 GS550 650-740cc susp/brake mods

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