My COMET GT250!! Done just 1400Kms!!!

Sankar · 17th February 2009, 09:24

The jetting might have to be changed depending on how restrictive the stock exhaust system was compared to the new one. Even if the jetting needs to be changed, you won't have to jump many sizes (its advised not to), prolly jumping one or two sizes up is all that would require.What's the stock jetting of the Comet? Change the filter to a freer flowing one, either universal pod or a stock replacement, i'm sure K&N would have a stock replacement filter for the GT250.

faithless_1984 · 17th February 2009, 13:49

Missed this thread.....Congrats Buddy.!
The bike looks great.
Post more pics after you get the exhaust.

P.S - Coming for the meet ?

speed0mania · 18th February 2009, 01:10

@sankar: the jet sizes are as follows, Main Jet Front 92.5 Rear 95,
Main air jet Front and Rear 90, Pilot jet (P.J.) Front and Rear 20. well couldn't find a stock replacement K&n online but saw a pic of someone in bamgy who had put in 1! Most people use a BMC though. The new exhaust is a straight through glasswool type whereas the stock one is a baffled one (reactive type) so i'm guessing there would be a decent enough difference in restriction, wouldn't running it on a richer setting (needle) suffice? not going in for the filter immediately.

Hey thanks faithless!will put up pics as soon as i get it should be soon! Don't know about the meet, Really wanna attend but got work, I'm off on mondays! :( so lets see, its been really long now! will try and make it!

Sankar · 18th February 2009, 08:01

Ok. I think you can use the rear mainjet for the front cylinder and try a 97 or 97.5 mainjet on the rear cylinder. Prolly these numbers should get you closer to optimum. Do check how the bike's running with the exhaust before you play with the jetting, plug chop would be helpful. Raising the needle will effect a change in the midrange mainly.

speed0mania · 18th February 2009, 16:42

I think ill try out the new exhaust with the stock jetting first, if need be then might as well get the filter also and then rejet accordingly! thanks again sankar!

speed0mania · 20th February 2009, 14:05

alright guys the cans here!! can't wait to get home and try it on!!!! will put up pics and videos tonight!

speed0mania · 21st February 2009, 03:31

ok! the mufflers on finally!! sounds great but after lots of work! the muffler wasn't big enough for the catcon to fit on! so had to take out the end plate, which itself was a task, take it to the machining shop increase the dia on the lathe, then came back home then had to make slits in the inner perforated part, which didn't work out so had top hack it off after measuring the length of the catcon then had trouble centering the whole thing as the glasswool that came to support the catcon! so after 5 hours of work got it on!
sorry the video on my cam refused to work so have a few pics i shall post tomm along with a video i shall take tomm!
p.s. Sounds awsome!!! Loving it!!!!!
Also seems to be much quicker through the revvs, i think thats more placebo effect than anything substantial!

speed0mania · 21st February 2009, 12:00

ok guys here are the pics! video shall follow!

After stock one was removed and before the new one was put in! Thats the catcon sticking out, gave me lots of trouble!!

speed0mania · 21st February 2009, 12:10

something up with my cam still not recording videos so shall put one up as soon as i find a decent camera!

speed0mania · 21st February 2009, 20:08

OK heres a short clip i managed to click! sorry for the bad lighiting will take another one in the daytime!
Well the video doesn't do justice to the sound as its much deeper! but nonetheless gives a nice growl of the vtwin!

YouTube - Comet GT250 Custom exhaust!

akshay4587 · 22nd February 2009, 01:25

The fit and finish is extremely good,as good as OEM.
What is that brown thing attached to the bend pipe? I guess its the CAT CON,so with the new muffler,you still have the CAT CON isnt it?
Hope you are having fun

speed0mania · 22nd February 2009, 14:48

hi akshay! yeah the finish is excelent! that is indeed the catcon! which i still have on, as i don't want any issues with getting a PUC! totally enjoying it!

The accleration and throttle response seems to have improved it feels much better! And of course sounds amazing!

speed0mania · 24th February 2009, 13:39

Hey a question to the Gurus, Ive noticed that the idle RPM has gone up by about 100 from 1450 to 1550, i guess this is due to the engine breathing better with the new end can, which makes me wonder if thats an indication of it running significantly leaner and hence require rejetting?
Some people say its better to rejet after an exhaust swap while some say its not really required so im a little confused, also how do you decide the correct size of jets and wether its required or not!?

speed0mania · 25th February 2009, 12:15

Where are the gurus?? anyone who can help me out with the same?

desideep · 27th February 2009, 09:59

Hey Speedomania. your exaust looks great. why not meet up some time.

contact me at 9910337897

17th February 2009, 09:24	#61
Sankar Senior - BHPian Join Date: May 2005 Location: Location Posts: 5,780 Thanked: 9,232 Times	The jetting might have to be changed depending on how restrictive the stock exhaust system was compared to the new one. Even if the jetting needs to be changed, you won't have to jump many sizes (its advised not to), prolly jumping one or two sizes up is all that would require.What's the stock jetting of the Comet? Change the filter to a freer flowing one, either universal pod or a stock replacement, i'm sure K&N would have a stock replacement filter for the GT250.
	() Thanks

17th February 2009, 13:49	#62
faithless_1984 Senior - BHPian Join Date: Oct 2006 Location: Delhi Posts: 1,575 Thanked: 327 Times View My Garage	Missed this thread.....Congrats Buddy.! The bike looks great. Post more pics after you get the exhaust. P.S - Coming for the meet ? Last edited by faithless_1984 : 17th February 2009 at 13:50.
	() Thanks

18th February 2009, 01:10	#63
speed0mania BHPian Join Date: Jun 2005 Location: new delhi Posts: 463 Thanked: 7 Times View My Garage	@sankar: the jet sizes are as follows, Main Jet Front 92.5 Rear 95, Main air jet Front and Rear 90, Pilot jet (P.J.) Front and Rear 20. well couldn't find a stock replacement K&n online but saw a pic of someone in bamgy who had put in 1! Most people use a BMC though. The new exhaust is a straight through glasswool type whereas the stock one is a baffled one (reactive type) so i'm guessing there would be a decent enough difference in restriction, wouldn't running it on a richer setting (needle) suffice? not going in for the filter immediately. Hey thanks faithless!will put up pics as soon as i get it should be soon! Don't know about the meet, Really wanna attend but got work, I'm off on mondays! :( so lets see, its been really long now! will try and make it!
	() Thanks

18th February 2009, 08:01	#64
Sankar Senior - BHPian Join Date: May 2005 Location: Location Posts: 5,780 Thanked: 9,232 Times	Ok. I think you can use the rear mainjet for the front cylinder and try a 97 or 97.5 mainjet on the rear cylinder. Prolly these numbers should get you closer to optimum. Do check how the bike's running with the exhaust before you play with the jetting, plug chop would be helpful. Raising the needle will effect a change in the midrange mainly.
	() Thanks

18th February 2009, 16:42	#65
speed0mania BHPian Join Date: Jun 2005 Location: new delhi Posts: 463 Thanked: 7 Times View My Garage	I think ill try out the new exhaust with the stock jetting first, if need be then might as well get the filter also and then rejet accordingly! thanks again sankar!
	() Thanks

20th February 2009, 14:05	#66
speed0mania BHPian Join Date: Jun 2005 Location: new delhi Posts: 463 Thanked: 7 Times View My Garage	alright guys the cans here!! can't wait to get home and try it on!!!! will put up pics and videos tonight!
	() Thanks

21st February 2009, 03:31	#67
speed0mania BHPian Join Date: Jun 2005 Location: new delhi Posts: 463 Thanked: 7 Times View My Garage	ok! the mufflers on finally!! sounds great but after lots of work! the muffler wasn't big enough for the catcon to fit on! so had to take out the end plate, which itself was a task, take it to the machining shop increase the dia on the lathe, then came back home then had to make slits in the inner perforated part, which didn't work out so had top hack it off after measuring the length of the catcon then had trouble centering the whole thing as the glasswool that came to support the catcon! so after 5 hours of work got it on! sorry the video on my cam refused to work so have a few pics i shall post tomm along with a video i shall take tomm! p.s. Sounds awsome!!! Loving it!!!!! Also seems to be much quicker through the revvs, i think thats more placebo effect than anything substantial! Last edited by speed0mania : 21st February 2009 at 03:33.
	() Thanks

21st February 2009, 12:00	#68
speed0mania BHPian Join Date: Jun 2005 Location: new delhi Posts: 463 Thanked: 7 Times View My Garage	New endcan! ok guys here are the pics! video shall follow! After stock one was removed and before the new one was put in! Thats the catcon sticking out, gave me lots of trouble!! Attached Thumbnails
	() Thanks

21st February 2009, 12:10	#69
speed0mania BHPian Join Date: Jun 2005 Location: new delhi Posts: 463 Thanked: 7 Times View My Garage	pics with the new one! something up with my cam still not recording videos so shall put one up as soon as i find a decent camera! Attached Thumbnails
	() Thanks

22nd February 2009, 01:25	#71
akshay4587 Senior - BHPian Join Date: Mar 2005 Location: Chandigarh/Mohali/Ambala Cantt Posts: 4,152 Thanked: 4,561 Times View My Garage	The fit and finish is extremely good,as good as OEM. What is that brown thing attached to the bend pipe? I guess its the CAT CON,so with the new muffler,you still have the CAT CON isnt it? Hope you are having fun Last edited by akshay4587 : 22nd February 2009 at 01:27.
	() Thanks

22nd February 2009, 14:48	#72
speed0mania BHPian Join Date: Jun 2005 Location: new delhi Posts: 463 Thanked: 7 Times View My Garage	hi akshay! yeah the finish is excelent! that is indeed the catcon! which i still have on, as i don't want any issues with getting a PUC! totally enjoying it! The accleration and throttle response seems to have improved it feels much better! And of course sounds amazing!
	() Thanks

24th February 2009, 13:39	#73
speed0mania BHPian Join Date: Jun 2005 Location: new delhi Posts: 463 Thanked: 7 Times View My Garage	Hey a question to the Gurus, Ive noticed that the idle RPM has gone up by about 100 from 1450 to 1550, i guess this is due to the engine breathing better with the new end can, which makes me wonder if thats an indication of it running significantly leaner and hence require rejetting? Some people say its better to rejet after an exhaust swap while some say its not really required so im a little confused, also how do you decide the correct size of jets and wether its required or not!?
	() Thanks

25th February 2009, 12:15	#74
speed0mania BHPian Join Date: Jun 2005 Location: new delhi Posts: 463 Thanked: 7 Times View My Garage	Where are the gurus?? anyone who can help me out with the same?
	() Thanks

27th February 2009, 09:59	#75
desideep Senior - BHPian Join Date: Sep 2005 Location: Adelaide Posts: 1,160 Thanked: 325 Times View My Garage	Hey Speedomania. your exaust looks great. why not meet up some time. contact me at 9910337897
	() Thanks

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