Tallest Practical Gearing ??

[B-Man]

Searching and reading multiple threads did not help much so I thought I would just ask.

2005 750 with no engine mods, currently running factory sprockets. I want to lower the highway speed RPMs but do not want to go overboard.

Looking at the gearingcommander.com page, it appears that going with a 16 in front and a 42 in the rear gives a 715 RPM decrease at 75 MPH. However, the same-tooth same-link calculation takes a crap big time. However, if I remove 1 link from the chain the length calculation is improved AND the same-tooth same-link calculation improves dramatically.

With that said, do any of you guys have real world riding experience with a taller gearing setup ?

Driveability around town ?

Riding on two lanes through the mountains ?

Interstate long haul ?

MPG increase or decrease observed when cruising on the Interstate ?

Increased or decreased chain / sprocket wear ?

Is there a reason why removing a link would be bad ?

I am planning a big trip and will be mixing stretches of Interstate and back country highways with routes in the mountains and such. I am hoping to reduce engine RPM at highway speeds to lower the "buzz" factor a bit and maybe pick up a little MPG increase too.

Thanks in advance for help / guidance / experience sharing / etc.

[ZukiFred]

I am running 15/45 and run about 6000RPMs at 80MPH in 6th gear on the highway.

[92xjunker]

Question, why? I Kat gets great mpg already. You gain highway speed but kill your take off. 45-47 is a balance of both torque and speed. 16 tooth front will require some grinding to fit.

[B-Man]

I am running 15/45 and run about 6000RPMs at 80MPH in 6th gear on the highway.

Do you have any idea about your MPG at that speed ?

Question, why?

From above:

I am hoping to reduce engine RPM at highway speeds to lower the "buzz" factor a bit and maybe pick up a little MPG increase too.

[92xjunker]

Carb sync and OEM bar end weights should reduce that buzz greatly. Some have even used BB's in the bars. You should be getting around 45ish mpg. I wouldn't go below 43 on the rear, it would make your take off resemble a scooter.

[B-Man]

Carbs are sync'd and the factory bar weights are still there. I believe the buzz is present in most people's bikes, judging by the posts I see here anyway.

[92xjunker]

Yes, it will always be there, typical I 4 engine buzz. Gell grips help also.

[ZukiFred]

MPG is between 45-47MPG.

[TRPUT]

With that said, do any of you guys have real world riding experience with a taller gearing setup ? Yep. On a 2005 750 as it happens. I ran 16/39 for almost 50 000 miles. The smallest rear sprocket in a 530 chain is 42T. You could go to a 520 chain to access a 39T. But I had GSXFJim make a couple of 530 39T sprockets for me. And BTW, they were awesome quality!

Driveability around town ? A little slower on initial launch with a tad more clutch control required, but once moving there is no real difference as long as you are in the right gear, which may be lower than with a stock set up. The advantage if you are in a hurry is you can hold 1st gear for a lot longer. If wheelies are your thing, this is not a mod for you.

Riding on two lanes through the mountains ? No worries. I did a lot of that.

Interstate long haul ? Perfect. I was expecting to have to drop a cog or 2 to accelerate when over-taking, but that was rarely necessary except when travelling up hill, heading into a strong headwind, or if the over-taking window was small.

MPG increase or decrease observed when cruising on the Interstate ?Massive improvement. Although that also depends on how you use the throttle and engine tune. When most 750s have run dry, I was switching to reserve. I achieved over 60mpg often when lightly laden, and averaged over 50mpg which included carting some serious crap.

Increased or decreased chain / sprocket wear ? A 16T front sprocket is the largest that will fit, and that requires minor grinding on one of the legs holding the sprocket cover to achieve chain clearance. An even number of sprocket teeth is not ideal, so the sprocket will tend to wear slightly faster. From my experience, changing the front sprocket each 15 - 20K miles prolonged the life of the chain and rear sprocket.

Is there a reason why removing a link would be bad ? Obviously, you need to remove 2 links, not one. Not bad at all if you keep the F-R sprocket distance roughly stock. With the smaller rear sprocket, the chain may tend to rub more on the swingarm pad.

Although there is enough power / torque in the Kat engine to go even bigger on the front or smaller on the rear for touring, if I did it again, I would probably run 16/41 simply due to the swingarm-chain clearance.

The disadvantage is your speedo will be way out. I installed a Speedo Healer. Then, by the time you get the speed reading correct, the odometer will be out slightly ... about 3 - 4 %.

[B-Man]

Although there is enough power / torque in the Kat engine to go even bigger on the front or smaller on the rear for touring, if I did it again, I would probably run 16/41 simply due to the swingarm-chain clearance.

The disadvantage is your speedo will be way out. I installed a Speedo Healer. Then, by the time you get the speed reading correct, the odometer will be out slightly ... about 3 - 4 %.

That is too funny. Knowing I was going to do something, I ordered a Speedo Healer on Monday night. It arrived here today.

I can't thank you enough for the response. I suspected the performance would be fine but your experience is so much better than opinions and conjecture. I appreciate you taking the time to answer in such detail.

Based on your advice, I am going to go with the 16/41 combo and I'm going to order an additional 16 front sprocket to take with me.

If you don't mind me asking, how many mechanical failures or wear-outs did you experience during those 50,000 miles ? Any advice on mods or things to bring with me for a long trip (>5,000 miles) ?

[shpielers]

I've been running a 42t on my 600 for 2 years, about 50k miles. It's a little slower, but nothing major. Really not that noticeable. Didn't see any mpg increase, but fewer vibes and quieter engine. On a 600, I personally wouldn't go any lower.
It also changed my speedometer to be 100% dead nuts on. Which is a rather nice benifit (GPS verified)

[katanarider]

I ran a 16 front and 43 rear on my '96-600cc and loved it. Yeah, its a bit on the high side as far as taking off from a dead stop, but I really didn't have any problems. I'd rather wear a clutch out faster than wear my rings/cylinders out. People told me that it was too high and it is for a post-98 600cc in my opinion. How do I know ? Because I did a engine swap in my '96-600cc and I can tell you the older pre-98 cams seem to make better power. They definitely pull stronger/higher RPM. I'm currently running a 15-43 with the post-98 600cc engine and it feels all most the same as my old 16/43 set up with the older cams. I'm over 200lbs too.

[the wind]

I did a 17/42 a while back,had to modify the gear cover to make it work.now I'm at 14/47 and avoid the highway.

[TRPUT]

That is too funny. Knowing I was going to do something, I ordered a Speedo Healer on Monday night. It arrived here today.

I can't thank you enough for the response. I suspected the performance would be fine but your experience is so much better than opinions and conjecture. I appreciate you taking the time to answer in such detail.

Based on your advice, I am going to go with the 16/41 combo and I'm going to order an additional 16 front sprocket to take with me.

If you don't mind me asking, how many mechanical failures or wear-outs did you experience during those 50,000 miles ? Any advice on mods or things to bring with me for a long trip (>5,000 miles) ?

No worries. Sorry for the tardy reply ... I'm on holidays so have been busy. And after a short stint on the dark side with a Triumph Trophy, I've just come back to the Suzuki fold with a new V Strom 650 and I've been dedicated to running-it-in.

If touring is your thing, you should like the 16/41 set up. I actually ordered my new Strom with different sprockets for touring. The dealer thought I was nuts. But once fitted, the mechanic took it for a spin and was quite surprised and impressed. So far, with no luggage, it's achieving an unbelievable 550 kms per 20 l tank. ie same size tank as the Kat for around 350 miles! And it's not loosened up yet. Yeah, it's a little slower at launch, but on a good day, I launch it 3 or 4 times about 2 hours apart.

The ONLY issue I had with the Kat beyond regular servicing was the notorious connector behind the headlights. Some preventative treatment like adding dielectric grease and zip tying higher so it can't sit in rain water or condensation may help???

You don't need to carry a spare sprocket. There are 2 schools of thought re chain and sprocket care. One school says ALWAYS change both sprockets and chain as a set. The other advocates replacing the front sprocket 2 to 3 times more frequently than the rear in order to extend the life of the chain and rear sprocket. I subscribe to the second theory. It's maths based ... the front sprocket turns about 3 times the rate of the rear so it's teeth contact the chain 3 times as frequently. But more than that, each tooth therefore has 3 times the load of a rear tooth. So, the front sprocket will wear about 3 times as fast as the rear. If you replace it before it is severely worn and begins to damage the chain and hence the rear sprocket, you will increase their life span considerably. If you wait until the front sprocket is toast, then you really need new everything. It's a PITA to do, but front sprockets are cheap. Unfortunately, I don't have exact facts and figures because A) other factors always intervened (like a very expensive EK chain that had major tight / loose sections from new and really ripped into the front sprocket - and caused uneven wear on the rear tyre - yet the rear sprocket still looked ok but I replaced it anyway), and B) the Kat is now 3 bikes ago and my memory is fading.

There are several threads in the touring section with advice on what to take on long trips. For a well maintained Kat, a 5000 mile trip is nothing - I wouldn't pack too much outside some basic tools and the usual consumables like fuses. But then, I was fastidious in pre-trip preparation of things like brake pads, discs and fluid, fork servicing, engine oil and filter, carbs tuned etc. I didn't even carry spare bulbs because they were only ever a town away. I ran synthetic oil and the Kat never used a drop between 6000 mile changes. I fitted a chain oiler and carried a can to be extra sure. On a big trip, like my lap of Australia, there was generally someone at a camp ground more than willing to lend a hand and a few tools for things like oil changes and chain tensioning - perhaps in exchange for a beer or three. The ONLY thing that failed on that trip of almost 20 000 miles in sometimes scorching heat - apart from the shitty EK chain that only just made the distance - was a relay for my auxiliary lights, which I sourced at the next town. During that trip, I adjusted the chain a few times, had a new rear tyre fitted, replaced that relay, and changed the oil/filter twice. That's it! Of course, it was over-due for a lot of love when I arrived home, but nothing beyond general servicing.

Mods??
Coil relay mod.
Ignition advancer.
Chain oiler (as mentioned)
Auxiliary lighting. I had mine switch between DRLs in lieu of the headlights during the day then come on as spot lights with high beam at night.
12v plug for charging stuff.
Solidly mounted, secure luggage.
Throttle lock.
Oil cooler guard (fitted with fly mesh to keep the bugs away from the core).
Taller screen.

Have fun making it your touring Kat.