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Message started by TJWilly1 on 09/28/19 at 00:58:58

Title: Trouble with highway speeds
Post by TJWilly1 on 09/28/19 at 00:58:58

Hey guys new to the savage family. Got me a 98 for a sweet price and only 7000 miles. Been riding it and doing cosmetic changes to it, seat, removing unnecessary stuff for weight, and preparing to bob the rear fender. The only problem is that it struggles to get to 75 on the highway when I need it to. Any good ways to increase the top speed even up to 85 to accommodate. Thanks and easy riding.

Title: Re: Trouble with highway speeds
Post by Dave on 09/28/19 at 04:32:54

Wiseco piston, Stage 3 camshaft, Harley Dyna muffler....a bit of work to the head to improve the ports, Kawasaki 25T front pulley, 140/90-15 rear tire. (Double Kawasaki pulley mod that will lower the rpm at speed).

My bike has the above mods and a double Kawasaki pulley mod with an 18" rear wheel and tire, and I can cruise at 70mph at 4,000 rpm all day long. It reaches 80mph quickly and easily.....but the light weight and altered geometry of the Cafe' conversion that makes it such a joy in the corners begins to make it a bit skittish at high speeds. I have gone 101.1 mph twice (GPS speedometer with accurate reading)......it just doesn't want to go any faster than that and the steering is really wiggly at that speed.

I think cruising at 85mph for extended periods on a Savage is a bit optimistic, as the engine goes through a lot of oil when you keep engine speeds at high rpm for extended periods - but I think 75mph is certainly obtainable with about $2,000 worth of engine/drive train parts!

Title: Re: Trouble with highway speeds
Post by ohiomoto on 09/28/19 at 05:48:03

If you have really clean jetting, it can push 75 mph and have a little left to go up and over 80 mph without too much trouble. But getting that type of performance is only going to happen under ideal conditions.

To illustrate my point, I ride a stock 96 engine with a dyna muffler with an 18" rear wheel. My speedo is spot on for my rear wheel. I would mostly discount the effect to the wheel, but it could be argued that my tire and rim lighter than the stock rubber and steel rim.

I like riding cruising at 60-65 mph. It will run 75 mph all day. From that point on, performance becomes firmly tied to the current conditions.

On those cooler 55-60 degree mornings, it will pull 85 mph flat out without much of a struggle and stretches out to 86-88 mph. But riding home when it's above 80 and humid shows that my bike is just a tad too rich up top because it will struggle a bit to hit that 80 mph and beyond. There is just not enough HP to pull that kind of performance under all conditions with my fatass on it. (I'm 6'3 250 lbs.)

When you are only working with 25-30hp, you need to maximize it's performance with jetting. And, the closer your jetting is to spot on, the more you'll notice things like air temperature, humidity, elevation has on your bikes ability to reach its full potential.

I think it's worth the effort. I my case I found slightly leaner jetting than what is typically recommended unlocked a good bit of untapped potential.

Maybe the person who owned you bike did what the PO of my bike did. Threw a 55 pilot and a 155 main jet it there so it sounds "FAT" like a harley wannabe as it rumbled/blubbered its way down the highway, getting 35 mpg ,and struggling anytime you try to go much past 65-70 mph. ::)

Title: Re: Trouble with highway speeds
Post by TJWilly1 on 09/28/19 at 07:29:18

The 2 things I've been reading the most is a chain conversion and performance cams that make the biggest impact. I was thinking of chain converting it with some gs550 sprockets and chain. If I feel like I need more, I can get more by upgrading my cam. I've played with my carb already. The jetting seems pretty good. It just feels like the bike has so much untapped potential up in the top end. Good point on weather conditions. I'll pay more attention to my morning commute and how it runs compared to 90 degree Texas heat when I ride on the weekends.

Title: Re: Trouble with highway speeds
Post by ZSteele on 09/28/19 at 08:05:59

One of the OGs will hopefully chime in but I'm under the impression that a wiseco piston to up the compression to 10.5 is a more significant upgrade than the cam.

Title: Re: Trouble with highway speeds
Post by Gary_in_NJ on 09/28/19 at 09:25:34

Of all the bikes I own, the S40 is the one that I have no interest in riding above 65-70. The sweet spot is well below that speed. Wanna go fast, you’re on the wrong bike. Doesn’t have the brakes or suspension for high speed. And I say that, with optimized brakes (320mm rotor and R1 caliper) and suspension.

Title: Re: Trouble with highway speeds
Post by TJWilly1 on 09/28/19 at 12:58:05

I mean here in Texas, everything is so spread out that you need to ride on the highway. With most highways around here it's at least 65 sometimes 75. I'm not looking to smoke a sports bike or even go very fast. I just want to pass this big truck at a comfortable 80. I understand that this bike's sweet spot is well below highway, but I also need a good mode of transportation, so I'm gonna make do with what I can do. Right now, that doesn't include getting a bigger bike. When I do cruise at 65-70, it really feels pretty comfortable. Maybe not compared to some dedicated highway cruisers, but for what I need, it does the job. I just need that untapped top end that I know it can get.

Title: Re: Trouble with highway speeds
Post by justin_o_guy2 on 09/28/19 at 13:34:16

If the bike won't do what you want it to, you may need to adjust and accept it and its limitations. I have. It's just such a cool around town ride that I accept its highway limitations and look for ways to avoid the slab.

Title: Re: Trouble with highway speeds
Post by hotrod on 09/28/19 at 13:43:47

Just returned from a 1400 mile trip. 700 miles each way, only stopping for gas and a burger each way. The bike ran great, without burning any oil. My setup was ; chain drive with 18- 37 sprockets ( 17-37 at home ) 36mm Mikuni with UFO, DR cam, 140-80-15 tire. Mostly highway, it was comfortable with the lower rpms. I'm a old guy and wasn't sure I could do it. I'll do it again. :) :)

Title: Re: Trouble with highway speeds
Post by BrokeAss on 09/28/19 at 13:56:10

This one does 85mph and the motor was never opened. Just drop a lot of weight, install a 160 main jet with a proper intake and pipe, and convert to chain with a better highway ratio.

Title: Re: Trouble with highway speeds
Post by batman on 09/28/19 at 16:28:10

A stock bike is rated to go 85mph (150 lb. rider?) The bike should go 80 even if you weigh 250lbs. mine does.

Title: Re: Trouble with highway speeds
Post by SpamyToo on 09/28/19 at 18:44:24

Mine cruises at 85+ pretty easily. Noisy, but no other worries. Pinned it will climb and sustain 95-98, but its a little shaky. Its got to be on a downhill grade to get over 100, just wont do it on its own. My speedo is GPS, so it ought to be accurate.

Stock motor, belt and pulley's,
5 speed gearbox
aftermarket Keihin PWK38 carb with pod filter,
Dunstal type pipe
18 wheel on back
Im at about 200lbs naked, but I ride with clothes usually.

Title: Re: Trouble with highway speeds
Post by Yoshi on 09/28/19 at 23:36:15

Like others said, I also think 60-70 is the sweet spot
I have airbox k&n filter and a drilled dyna muffler and travel at 75 on the speedo no problems all the time, im around sea level I'm in ny, 52.5 pilot and 152.5 main seem good

Title: Re: Trouble with highway speeds
Post by DragBikeMike on 09/29/19 at 02:27:58

I've had two Savages, an old 4-speed and my current 2016. Both of them would run up to 80+ pretty much stock (a little jetting work, but otherwise stock). Just as Dave said, they will run up to 80 pretty quick, but from that point on they start to struggle. I personally believe the rate of acceleration drops dramatically past 80 mph due to the single-cylinder engine.

An average 650 twin has much better acceleration above 80 mph, and a 650 inline 4 even better. That big single cylinder spends too much time between power strokes to overcome the aerodynamic drag.

That being said, let's address your issue with acceleration at higher speeds. Keep in mind that due to aerodynamic drag the horsepower required to power a vehicle increases by the cube of its speed. The stock Savage makes about 30 to 31 HP, but it starts to go flat at 4500 rpm (65 mph) and signs off right about 5500 rpm. With stock wheels & gearing, the engine is running 5600 rpm @ 85 mph. So right at the point where you want the power building to overcome the exponentially increasing aerodynamic drag, it's flatlined. And when you approach the desired speed (85 MPH), power is declining.

You can extend the power band by installing an inexpensive camshaft along with modifying your stock airbox and muffler, and rejetting the carburetor to suit the engine mods. The cam will set you back about $165. The airbox mods are free (keep the stock filter, it flows well enough to support significantly more horsepower). The muffler mods are inexpensive as long as you have a decent set of tools and the skills to use them. The jets will probably set you back $25 or less.

Those modifications will increase your power by about 3 HP and 4 ft-lbs. Of more significance, your powerband will be extended all the way to 6500 rpm.

After performing these relatively simple mods, when you reach 85 MPH (5600 rpm) the engine will be in the sweet spot and still have another 900 rpm of reserve to maintain your momentum.

Don't think you will be riding a Top Fuel dragbike. It's still gonna struggle past 85. It's that single-cylinder thing. There's 580 degrees of crankshaft rotation between powerstrokes. So 75% of the time, it's not making power.

That brings to mind an interesting topic, the flywheel. Some of us are using lightened flywheels. I have a very light flywheel on my bike and I believe its probably beneficial to my quest for faster acceleration, at least in the lower gears. But I have a suspicion that once my speed starts to get past a certain point (maybe 70 to 80 MPH), the absence of flywheel mass starts to work against me. Flywheels are primarily intended to store energy. You get it rotating and it doesn't want to stop. So during that 75% of the time that the engine isn't on a power stroke, the flywheel inertia keeps things moving forward. That helps to maintain higher speeds, and might possibly aid in acceleration at higher speeds because you won't lose as much ground between power strokes. Since you want to improve your bike's ability to cruise and pass at high speed, I would leave the flywheel as-is.

You could reduce your final drive ratio by installing a smaller rear pulley, a larger front pulley, or both, but it seems to me you aren't looking for a more relaxed high speed cruise but rather faster acceleration at high speeds, so I suspect engine mods are more suitable for your situation.

If you are interested in the cam and simple airbox and muffler mods, LMK and I will post the links.

Title: Re: Trouble with highway speeds
Post by TJWilly1 on 09/29/19 at 07:32:56

Yeah I can take all the research I can get with this bike. Thanks for the advice. You do not recommend a chain conversion instead of belt? From what I've seen, that belt loses some power and it's pretty inexpensive to do. I know belts are more durable and less maintenance, but performance is a bit more important for me at the moment.

Title: Re: Trouble with highway speeds
Post by DragBikeMike on 09/29/19 at 18:24:34

Reducing the final drive ratio will bring your powerband into better alignment with the speeds you want to operate, but it will not improve your rate of acceleration. It's a good modification for Texas where the speed limits are high. You should consider it. I'm not a big fan of chains. IMO Dave's pulley mods are a much better solution. If you haven't seen the post here it is.

http://suzukisavage.com/cgi-bin/YaBB.pl?num=1384949185

I doubt that there is any more parasitic power loss with a belt vs an o-ring chain, and you don't have to deal with that filthy mess and the constant adjustments. The belt is "set it & forget it".

If you want to give that 40 incher a bit more air this old post should be helpful. The airbox mods are free and they work good. I like the airbox because its quiet and provides excellent weather protection. There's a lot more flow to be had on the cheap.

http://suzukisavage.com/cgi-bin/YaBB.pl?num=1523302904

The stock muffler can be easily modified and, contrary to popular opinion, it works well. It's also very quiet, even with the mods. It's a bit of work, but well worth the effort. I admit that I made my fittings on a lathe, but they are all simple, and a resourceful type could pretty much achieve the same results with some conduit and steel plate fabricated with a hacksaw, files, hand drill, and vice. It's the concept that matters. This old post gives all the specifics on the stock flow path and how to improve it. You could just punch a big hole through the internal plates but that's crude man, and the noise sucks. I've actually kicked mine up a notch further by drilling more and larger holes in plate "C", and increasing transit tube 3 from 1/2" to 3/4". It's still very quiet and plenty frisky.

http://suzukisavage.com/cgi-bin/YaBB.pl?num=1526453881

The cam in question is for a 1995 or earlier DR650. It's cheap. Installation is easy. It works good. It seems to hold up well even without the oil holes in the lobes. This old post gives you the low down on the DR650 cam.

http://suzukisavage.com/cgi-bin/YaBB.pl?num=1525327311

If you change your cam, this sealant applicator works wonders. Correct sealant application is very important on this engine. If you apply too much it fouls the oil flow path and can result in serious damage.

http://suzukisavage.com/cgi-bin/YaBB.pl?num=1525551307

I am confident that if you do these three mods you will be much happier with your freeway trips. 8-)