hi my yamaha is registered as a 9kw motorcycle and i would like to squeeze some more power out of the engine. a 125cc motorcycle can only produce up to 14.75 hp to be leagal in this darn country my bike has about 12 hp at the moment my friends dt has about 13 or 14 and it's freaking fast!!!
my bike is a Yamaha dt 125 from 1998 and my friends dt is from 2001. i know that the cylinder head has been changed to a bigger one for lower compression and that there are restrictions in the exhaust system and i do not want to remove the restrictions in the exhaust system because that would make the bike illeagal to drive on public roads .
i would like to get it to 14 hp but i guess that a bit over 15 hp would be good too. any sugesstions?
dont bother with all that, just derestrict it :) gut your stock exhaust so it still looks restricted, take the speedo restriction out and your bike will be faster than your m8s 2001 even if he derestricts his, pre 99 DTR's are the fastest
just dont scream past the police doing 80 and you wont even be noticed!
-- Edited by craigbulmer on Tuesday 1st of September 2009 06:12:08 PM
it gets a lil louder, i dont know anyone whos lost their license because of that lol everyone does it! its kinda rare to find a pre 99 not derestricted :S everyone i looked at was derestricted lol .. yeah you could do that, its what i would have done tbh but the guy i bought it off sold the stock one lol
well as i have an a1 license i can only drive motorcycles with the maximum engine size of 125 cc and max 14.7 horsepower derestricting the yamaha would make it a larger motorcycle by law and for a 125cc and above i would need an A category license . thats why im so scared of losing my license,
I WONDER if replacing the cylinder head would add just a little more juice to the engine if you know what i mean bc when importing the motorcycle to sweden from japan they changed the cylinder head to a larger one to lower the compression in the cylinder and therefore it's slower than the other yamahas =(
DTPOWER just do what you think is right, another thing you could do is ask your bike instructer for some advise before going ahead with any modifications, the thing to do though after modifying anything on the bike is ring the insurance company and tell them, proberly better to check first like ring them up and say something like "i was thinking of modifying my bike in these ways bla de bla..." see how much it will cost, then if you do screem past the police they pull you and conferscate your bike strip it and find all the fluff taken out of your exhaust with no insurance damb, you looking at more than losing your licence thats driving with no licence no insurance on a public road, thats like riding with the intent of murder you can do anything from 30 - 40 years for that kind of stunt !
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When the chips are down, make like a tramp and pick them up !
damn i think that you're right getting caught without restrictions would be really bad but the question is if they really would notice if i remove the restrictions?
In UK they can take you ride down their garage and strip it down to find out , but just go on like goust rider, when they try to pull you over just ride off, do a bunny hop over a fence or something lol.....
seriously its up to you though, just dont get caught...... me i've told my insurance company so i'm all legal, when the 5.0 pull me now i'll pull out my paperwork and be on my merry way, hopefully.........
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When the chips are down, make like a tramp and pick them up !
you like worrying him dont ya frogboy haha .. dont ring your insurance company your insurance will triple .. if you have doubts about it and your happy with your bike as fast as it is, just spend the money cosmetically, with a rear dep :) dont put a dep expansion chamber tho, thats destricted. i think it would be worth taking your front cowelling off, remove the speedo restriction and leave the exhaust :) then it will have a higher top end but not be louder wont make that much difference to the acceleration tho
Derestricting the power value on my DT (2007 model) probably gave it at least 2hp, it was amazing... extra 11mph top end and it felt like a new bike. Not sure what its like messing around the older models though.
and for a 125cc and above i would need an A category license 
. thats why im so scared of losing my license, 
hehehehe that comment made my day
