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Exhaust Mod?

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purplesea

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I was thinking about throwing a nice exhaust mod on my C650GT. That's when I get it, of course. What do you guys think about this? Would it be a good/bad idea? If you think it could be a good idea, what are some options I have for this model?
 
just adding the Aprakravic you gain 2hp at the wheels and a nice sound. I have documented by dyno testing. if you want more sound and HP then you have to either have a muffler shop cut the Catalytic converter out, or pay arrow for the full exhaust. in europe, probably better to buy the arrow pipe. in US cheaper to cut the cat out. I paid 200 to remove it.DSCN1825.webpDSCN1818.webp
 
Question for Doraemon... how loud is your exhaust after you removed your cat. was thinking the same..( thinking about getting the GPR ) where are you going for service? did you contact the dealer about warranty issues after the mod? sorry about all the questions
 
saekee said:
Question for Doraemon... how loud is your exhaust after you removed your cat. was thinking the same..( thinking about getting the GPR ) where are you going for service? did you contact the dealer about warranty issues after the mod? sorry about all the questions
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I would think the warranty would be shot on the engine and the exhaust. The engine needs an exhaust with a specific back pressure which I am sure does not exist anymore more. The valve clearances and timing may also be different

The one thing that you can change is the type of oil you would use as the oil bmw specifies prevents damage to the cataletic converter.

Just my opinion and thoughts. If you do any modifications to the scooter bmw will use any excuse not to warranty the scooter and you are on your own. I say do not do any mods till your warranty is up, or at least close to the end
 
justscootin said:
I would think the warranty would be shot on the engine and the exhaust. The engine needs an exhaust with a specific back pressure which I am sure does not exist anymore more. The valve clearances and timing may also be different

The one thing that you can change is the type of oil you would use as the oil bmw specifies prevents damage to the cataletic converter.

Just my opinion and thoughts. If you do any modifications to the scooter bmw will use any excuse not to warranty the scooter and you are on your own. I say do not do any mods till your warranty is up, or at least close to the end
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If the engine can't handle my mods to the exhaust, do you really wnat one? better let me take the hit and then you know to dump the bike based on that. I am not worried about the cat or any exhaust mod. further more making the engine breath and exhaust better will not only improve HP but MPG as well. If in fact there was an emmisions O2 sensor that would alarm on poor exhaust, then I would not have removed it. however the O2 sensor is before it and the backpressure for scavanging air ends at the point the cylinder pipes join, anything after that is not essential.

Besides that i have also keep Dyno records of my scooters progression, and have added alot of fuel all along the curve as the BMW stock curve is WAY lean, which is worse for heat and wear than what I have done.


I have never heard of cat friendly oil, if you are getting oil bypassing the rings more than normal this early you got serious problems before you even recieved the scooter.

thanks
 
Aside form making the exhaust note different, what benefit are you getting, You won't even notice 2 horse power up grade, and the mpg will be very small if any, seems a very expensive add on for not much benefit.
 
Doraemon said:
I have never heard of cat friendly oil, if you are getting oil bypassing the rings more than normal this early you got serious problems before you even recieved the scooter.

thanks
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I called castrol the manufacturer of bmw oils and was talking to them about engine oil versus motorcycle engine oil. The oil off gases (or burns) and that is what will damage the cataletic converter. If you were to measure precisely how much oil you put in the engine and then measure your oil when you drain the oil out you will have less. We cannot do this because we also have to account for the oil filter. That is what they told me, oil has been manufactured for the engine 15W50 MA2 or whatever the engine calls for, bmw if they wanted to could void your warranty if you do not use the specified oil. Why would bmw specify that particular oil in the owners manual Certain oils are for engines with wet clutches versus a dry clutch. When I had my K75 I dropped whatever oil I wanted in it generally a 20W50 synthetic and the engine drove strong for well over 200,000. When my warranty is over in 2 1/2 years I will choose a different oil of my choice based on cost, name brand and grade.
 
Ok, in fact that is about the phorpourus in the oil. and only would apply to a high mileage vehicles. you lower the phospourus in the oil to reduce burning up the catalytic converter. If you have a vehicle that has a feedback system for you emmisions (O2 sensor after the cat) then you have to be careful. If, like our scooters, it is not so important, and less so since they are so new. This again relates only to the cat and not the engine.
 
Update,
I went in for the first service yesterday, this is with all the mods that i have on now; Rizoma turnsignals rear, s1000rr tail tidy, blue led daytime running lights, cat replaced with srtaight pipe, Power commander V with tune adding fuel (O2 sensor is unplugged). The dealership said nothing, furthermore, when I inspected the checklist for items checked, there was a line saying diagnostic check. I specofically asked "you connected to the ECU and there were no error codes?" the Maintenance manager said "yes, and there were no error." This goes along with what I saw when I unplugged the O2 sensor for the Power commander install.

So, at least with my dealership, they are cool with the mods I have done.
 
Hi Doraemon,
Would you mind telling me little more about the Power Commander V? Do you feel much difference in performance?
Thanks in advance
 
The power commander was really easy to fit. you unplug the O2 sensor and plug the harness in line with both fuel injectors and the throttle position switch. It comes with a fuel curve already made by Dyno jet. If you look at the dyno curves I have put in the gallery, you will see that the A/F ration from BMW stock is very lean on the low rpm side. the PC V curve has a much richer fuel setting. Additionally I have more fueling added and dyno tuned further than dynojet did.
For the dyno, the scooter was actually having trouble with traction.... while the only confirmed pulls on the dyno were curves at 51whp, there were several 53whp pulls but the curves were not consistant enough to count. That being said, this fall after a few miles on it I will put on a Dr. pully clutch and mallossi variator, it should get more power to the wheel. Even now the increase from 47WHP to 51WHP is nice, but if I get 53WHP, WOW! at 51whp you are already 9% hp increase and getting over 10% would be great. My old Burgman 650 with the same mods wouldn't get past 5%, 43WHP was the most we got out of her.

As far as riding, immediattly I notice that I use less throttle across the board. rollon acceleration 60-80mph seems much more pull. I was actually supprised on a few of the first take offs from a light, I was pulled back in the seat more than I was ready for. For fuel mileage, in stop and go traffic I am close to 45mpg, mostly how I ride......drag racer blood he he. On the highway I am usually riding in traffic, so a little hard to judge, but seems closser to 50+. I will know more on a few more tanks of fuel. I am also taking a 350 mile trip next month which should give a better highway milage report.

Now, considering all that, I also have times when is wants to stall, but with the PC V, it doesn't. Before I had the PC V I had a few times that the stalling issue occured, since then, none. There are some times is sounds like it will, but doesn't...my stalling was on different vendors premium fuel, both with Shell and 76. I think my richer fueling helps but fuelling is not the problem, or else it would not even try.

Hope this gives you the info you are looking for. Oh, it was cheaper to purchase directly from dynojet than on ebay.
 
Oh, and I haven't done any mods to the intake.......yet. that may increase WHP more getting more air in. But I am a little hesitant to cut the horn off, which is what would be required. the air intake horn is only an 1 1/4 opening on a long horn leading to the air filter.IMAG0190.webp
 
Doraemon said:
The power commander was really easy to fit. you unplug the O2 sensor and plug the harness in line with both fuel injectors and the throttle position switch. It comes with a fuel curve already made by Dyno jet. If you look at the dyno curves I have put in the gallery, you will see that the A/F ration from BMW stock is very lean on the low rpm side. the PC V curve has a much richer fuel setting. Additionally I have more fueling added and dyno tuned further than dynojet did.
For the dyno, the scooter was actually having trouble with traction.... while the only confirmed pulls on the dyno were curves at 51whp, there were several 53whp pulls but the curves were not consistant enough to count. That being said, this fall after a few miles on it I will put on a Dr. pully clutch and mallossi variator, it should get more power to the wheel. Even now the increase from 47WHP to 51WHP is nice, but if I get 53WHP, WOW! at 51whp you are already 9% hp increase and getting over 10% would be great. My old Burgman 650 with the same mods wouldn't get past 5%, 43WHP was the most we got out of her.

As far as riding, immediattly I notice that I use less throttle across the board. rollon acceleration 60-80mph seems much more pull. I was actually supprised on a few of the first take offs from a light, I was pulled back in the seat more than I was ready for. For fuel mileage, in stop and go traffic I am close to 45mpg, mostly how I ride......drag racer blood he he. On the highway I am usually riding in traffic, so a little hard to judge, but seems closser to 50+. I will know more on a few more tanks of fuel. I am also taking a 350 mile trip next month which should give a better highway milage report.

Now, considering all that, I also have times when is wants to stall, but with the PC V, it doesn't. Before I had the PC V I had a few times that the stalling issue occured, since then, none. There are some times is sounds like it will, but doesn't...my stalling was on different vendors premium fuel, both with Shell and 76. I think my richer fueling helps but fuelling is not the problem, or else it would not even try.

Hope this gives you the info you are looking for. Oh, it was cheaper to purchase directly from dynojet than on ebay.
Click to expand...

Thanks Doraemon,
This was a great feedback. I will look into purchasing a PC V. Also, do you know where to buy the Dr. Pully clutch and Mallossi variator?
 
Thanks Doraemon
I just ordered the Power Commander V with Auto Tune. I found a $100 cheaper price on the PC V and about $70 less on the auto tune than the Dyno Jet website :-)
Also, what do you recommend? SHould I get the Dr.Pully clutch and Malossi variator or the Dr. Pulley clutch and the Dr. Pulley sliding roll? What is the difference between the complete variator and the sliding rolls/weights? I am new to the scooter transmissions so I am not sure which is which.

Thanks again for your help.
 
I haven't used either yet myself. that why I started with what I know. I am leaning to the malossi variator as I see all the Italians on the bmw website talking about it more than the Dr. pulley one.
 
Doraemon said:
I haven't used either yet myself. that why I started with what I know. I am leaning to the malossi variator as I see all the Italians on the bmw website talking about it more than the Dr. pulley one.
Click to expand...

I see. Well, I was just trying to keep the cost down a little but I probably will go with Malossi too.

One more thing, did you remove the exhaust and took it to exhaust shop to cut out the Catalytic converter or he cut and weld it on the bike? I am planning to remove the CC too!
 
since shops in the US don't carry metric stainless steel, he cut the end off of the cat for the exhaust to attach to. Then wleded in a stainless steel pipe. it cost $220. while it is not as fancy and curved around as the Arrow custom, I got it for less and got it quick. he he DSCN1825.webpDSCN1819.webp
 
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