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My new to me 2013 C650GT is limited to 97mph indicated speed. Previously modified?

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CyberNate

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Hello,

I recently bought a 2013 C650GT with 48K miles. The price was good, so I thought, why not. It seems to run well but seems to require a lot of revs for speed and acceleration. I had seen mention of people modifying the variator and roller weights and how that affects the acceleration and effective gear ratio. As a test, I took it up to maximum speed a couple of times and see that I hit the rev limiter at 97 indicated consistently. The tach bounces at that point off the last bar. Acceleration is linear and I don't sense any slipping. It has very strong acceleration from around 40 to the rev limiter.

Do you think there is a good chance that the roller weights were changed to be very low and that's why my top speed is so limited? 97 indicated is probably more like 93 or 94 mph. It really accelerates hard, but then again, I've never ridden another C650GT to benchmark it. I absolutely love this thing. Coming from an R1200GS LC and Tiger 1050, both I still own, I feel in the tight stuff, I can ride this scooter just as fast despite having far less power.

I have ordered the parts I need for a belt change (including the special tool to lock in place) as I have no idea on the health of the CVT belt. At that point I'll have a look at the roller weights and CVT assembly.
 
I had my 2016 650 up to right about 105 mph just once. I have the OEM parts in the bike.
It was smooth sailing at that speed i also had hit 100 mph one other time. It maybe the
bike is a 2013 with 43K miles on it??? But i am curious to see what others have to say.
 
This could be about "norm" for a 60hp Bike with so much wind protection, ahem resistance.
You may go higher if you pay attention to the air filter (K&N) and exhaust (GPR or Arrow).
My bet it is mostly exhaust that is the limiting part. When the gases expelled faster, you get more power but perhaps less ecology.
 
My 2017 GT got to 107mph on the GPS, 2 up, on a deserted Spanish motorway.
Interestingly the speed did not increase on the slightly down hill section after the test. I do wonder if they are limited in some way.
 
RollaCosta said:
This could be about "norm" for a 60hp Bike with so much wind protection, ahem resistance.
You may go higher if you pay attention to the air filter (K&N) and exhaust (GPR or Arrow).
My bet it is mostly exhaust that is the limiting part. When the gases expelled faster, you get more power but perhaps less ecology.
Click to expand...
It was at the rev limiter as tack was bouncing off last bar. Definitely had plenty of power to go faster if it had more gearing. I'm fine with that top speed, more just interested if it's modified. I'll know for sure once I service the belt and check roller weights.
 
I never even get to the last 3 bars, no matter what I do, with stock transmission - aside from Dr.Pulleys HiT clutch. Next year, I have plans to install J.Costa with 25g rollers (no heavier available) to get just a tad more rpms than stock. I'm actually after the smoothness and fast reaction time of J-Costa compared to the classical system, and I despise over-revs that sound obnoxious, spend more fuel and limit top-speed on a maxi (IMHO).
Another thing is less rattle at idle and no need to replace the main pulley of J.Costa, ever. Well, maybe after 100K?..
Yours is definitely modded. Please post back weights and spring details when you get to open that up.
 
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Just for the record, stock transmission + GPR Furore Evo4 exhaust increases top speed of C650 Sport by about 10Kmh (touches 180 on odo with a bit more possible). This with baffle in ;) stock cans are "eco" = "suboptimal", as usual. Furore is homologated so I am clean before the law.
 
I hit 110 mph on my 2014 Sport more than a few times, and wasn't even at wide-open throttle, and was still capable of breaking 100 mph after I'd swapped to 28g Dr. Pulley rollers (I just don't specifically remember it going to 110, so I can't vouch for it.

Yours should be similarly capable, assuming there's not a major compression issue inside the engine, and that yes, your rollers are either of stock weight of 33g or the "usual" lighter pick of 28g most folks choose to run.

In the service DVD documentation, I vaguely recall there being a HP/top speed restriction checkbox for the build notes when you're speccing out precisely what model the tech is servicing, but I thought that was for a few non-US markets, and I could totally be making that up (I'm away from my Windows box, so I can't fact-check myself).

How's your fuel efficiency?
 
Minister of Etc said:
I hit 110 mph on my 2014 Sport more than a few times, and wasn't even at wide-open throttle, and was still capable of breaking 100 mph after I'd swapped to 28g Dr. Pulley rollers (I just don't specifically remember it going to 110, so I can't vouch for it.

Yours should be similarly capable, assuming there's not a major compression issue inside the engine, and that yes, your rollers are either of stock weight of 33g or the "usual" lighter pick of 28g most folks choose to run.

In the service DVD documentation, I vaguely recall there being a HP/top speed restriction checkbox for the build notes when you're speccing out precisely what model the tech is servicing, but I thought that was for a few non-US markets, and I could totally be making that up (I'm away from my Windows box, so I can't fact-check myself).

How's your fuel efficiency?
Click to expand...
There are no engine issues. It is gearing limited. I suspect that there is wear on belt and rollers that results in lower effective gear ratio, or perhaps an aftermarket belt. The mileage is on the low side at around 44 to 46mpg.
 
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