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SuzukiSavage.com
/cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> Maximum RPMs /cgi-bin/YaBB.pl?num=1428811648 Message started by Kris01 on 04/11/15 at 21:07:28 |
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Title: Maximum RPMs Post by Kris01 on 04/11/15 at 21:07:28 I've read on this site that the engine redlines at 6500 rpm. With a 3.7" stroke that's 4008 feet/min. In case you're wondering, that's stroke * rpm / 6. With this engine being decidedly low tech, how can it "live" at such rpms? The maximum "rule of thumb" is around 3500 fpm, which is about 5676 rpm. Did Suzuki actually give us a decent bottom end that will handle high rpms? Long stroke engines don't like high rpms. 3.7" is a pretty long stroke. |
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Title: Re: Maximum RPMs Post by WD on 04/12/15 at 00:21:11 Roller crankshaft and rod bearings if I remember right. Straight out of the late 1890s. Just like every other motorcycle manufacture uses or used at some point. I know they are better than the oddball bearings Hardly Able-son used in the 1993 "Evilution" Big Twins... I have yet to wipe out a Savage engine or transmission, yet killed 4 engines and 6 transmissions in 6 months on a 93 FXWG... Now, carburetors and electrical parts, the HD was fine, and my 98 LS650 needs 3x its value in new parts... If you ever hit the limiter on a Savage, you'll know it, the thing shuts down like you rear ended a garbage truck. |
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Title: Re: Maximum RPMs Post by justin_o_guy2 on 04/12/15 at 05:18:14 I rode the snot outta mine and never hit the limiter. |
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Title: Re: Maximum RPMs Post by Kris01 on 04/12/15 at 07:23:12 Can you actually hit the "limiter"? I've also read that the so-called limiter is just a lack of power beyond a certain rpm. It's not really an electrical gizmo that stops the engine from speeding up. 6500 seems awfully high for a thumper. I was just wondering why Suzuki lists that rpm as max. I doubt there's even a shred of power up that high in this engine. |
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Title: Re: Maximum RPMs Post by Ed L. on 04/12/15 at 15:23:43 Maybe Suzuki wired the throttle wide open and the engine tached out at 6500rpm. Can't see much use for a rev limiter when the stock engine can't spin that fast unless you rev it in neutral. |
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Title: Re: Maximum RPMs Post by verslagen1 on 04/12/15 at 15:54:03 there isn't a electronic limiter. I think that was proven by the one guy that looked at making his own CDI unit. and if you put in a cam and exhaust it'll run well past 6500 in 5th. |
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Title: Re: Maximum RPMs Post by Gary_in_NJ on 04/12/15 at 18:56:21 142D362C6F6E5F0 wrote:
I'm pretty sure that my YZ250F will hit 12,500 rpm. |
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Title: Re: Maximum RPMs Post by Kris01 on 04/12/15 at 19:11:04 Thumper? What length stroke? |
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Title: Re: Maximum RPMs Post by Kris01 on 04/12/15 at 19:12:11 1F3E0516745A0 wrote:
Sounds like backyard, redneck engineering! ;D |
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Title: Re: Maximum RPMs Post by Ed L. on 04/12/15 at 19:37:18 Seen 5500rpm on my '02 with a stage 1 cam and other mods. Just don't have the nerve to rev it up higher. Guess I'm not redneck enough (yet) ;) |
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Title: Re: Maximum RPMs Post by Kris01 on 04/12/15 at 21:08:59 Anything even approaching that RPM and my bike sounds like it's going to explode! I guess I'm just paranoid. |
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Title: Re: Maximum RPMs Post by verslagen1 on 04/12/15 at 21:12:01 you know too much. |
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Title: Re: Maximum RPMs Post by jcstokes on 04/12/15 at 21:51:46 Don' t think I've ever seen anymore than 5500 in fifth, but my rev counter's a cheap one |
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Title: Re: Maximum RPMs Post by Art Webb on 04/12/15 at 22:00:42 I've no idea what the stroke was, but my GN400 redlined at 8k, IIRC (it's been years, i could be wrong) well, looked it up, 2.6 inch stroke, max HPat 7400 RPM, so 8k for a redline sounds about right |
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Title: Re: Maximum RPMs Post by justin_o_guy2 on 04/12/15 at 22:13:26 F1 cars,, big bore, short stroke, crazy RPM.. |
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Title: Re: Maximum RPMs Post by Dave on 04/13/15 at 05:31:26 Long stroke engines make good torque at low rpm - but are limited in engine speed because the long stroke makes for high piston speeds (up/down). Shorter stroke engines don't make as much torque at low rpm because the shorter stroke of the crankshaft doesn't provide as much leverage for the piston rod to push on - but the shorter stroke reduces the speed of the piston at high rpm's. As an example the LS650 engine has a listed HP of 31 HP at 5,200 rpm, and a torque value of 50 nm at 3,400 rpm. The LS650 has a 94mm bore and a 94mm stroke. The second generation Suzuki DR650 is a very similar engine - but it has a shorter 82mm stroke and a larger 100mm bore. The engine is in a higher state of tune and has a better flowing head and a more aggressive cam grind - and it makes more HP and torgue....but it occurs at a higher rpm. The HP number is 46 HP at 6,800 rpm and the torque is 56.6 nm at 5,000 rpm. In comparison the Ducati Panigale V-Twin 1,198 cc engine makes 195 HP at 10,750 rpm and 133 nm of torque at 9,000 rpm - using a 112mm bore and a short 60.8 mm stroke. (Cut in half this would be a 599 cc engine that makes 97.5 HP and 83 nm of torque). The long stroke of the LS650 allows it to develop the maximum torque at 1,600 rpm less than the DR650.....and 5,600 rpm less than the Ducati. Long strokes are great in tractors, trucks, boats...things you want to have lots of pulling power.....more than you want higher rpm or higher HP to weight ratios. For the LS650 the piston speeds are 3,330 fpm for the 5,400 rpm HP value, and 2,097 fpm for the 5,000 rpm torque value, and 4,009 fpm a the 6,500 rpm redline. For the DR650 the piston speeds are 3,658 fpm for the 6,800 rpm HP value, and 2,690 fpm for the 5,400 rpm torque value. For the Ducati the piston speeds are 4,288 fpm for the 10,750 rpm HP value, and 3,590 fpm for the 9,000 rpm torque value. (The Ducati has lightened engine internals, including titanium connecting rods). The bottom line is that the LS650 does not have exotic materials, and it is made to be a durable low speed engine. The 6,500 rpm does not have a piston speed that is unusually high at 6,500 rpm - but it is a rather large and heavy piston and it most likely doesn't like those kind of speeds for too long. Folks who do run at the 70-80 mph speeds for any duration report an increase in oil consumption - not sure if the oil is going past the rings or out the breather. If you are bumping the performance of the engine up - you should build the engine to make more torque below the 6,500 rpm limit - higher rpm values really aren't realistic on this engine. |
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Title: Re: Maximum RPMs Post by LANCER on 04/13/15 at 08:01:37 6B4A7162002E0 wrote:
Yep, gotta work on that dude ! ;D |
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