shercoben12 Posted November 17, 2012 Report Share Posted November 17, 2012 hi everyone I've been out on the bike to day and quite a bit recently . but its a 125 is and is so gutless! could someone suggest ways of getting more power- except for a bigger bike! btw its just had a new piston and iam 13 and weigh 50 kg help greatly appreciated thanks,ben Quote Link to comment Share on other sites More sharing options...
laser1 Posted November 17, 2012 Report Share Posted November 17, 2012 Clean Midbox and repak silencer, verify jetting with locals. New carbon fiber reeds and High comp head are typical upgrades on 125's. Keihin carb and Short Ti Pipe will help up top as well. Quote Link to comment Share on other sites More sharing options...
lee99780 Posted November 18, 2012 Report Share Posted November 18, 2012 Apparently you can fit a 200 piston and barrel straight on. Quote Link to comment Share on other sites More sharing options...
dombush Posted November 18, 2012 Report Share Posted November 18, 2012 Hi Ben There are some things you can do, but the danger will be making it peaky or losing what low-end it has. I suggest Fitting a correctly jetted Dellorto VHST, or a Keihin carb Refreshing the basic engine components (piston and rings or just rings) Reducing the piston to cyl head clearance (squish) by adjusting the thickness of the cylinder base gaskets. Cleaning the header and silencer sections of the exhaust systemThe header pipes on 125 Shercos feature a horribly stepped transition in diameter at the early part of the header. This causes carbon deposits ("coke") to build up around the transition. I "de-coke" this by heating the header with a blow torch allowing the oil in the carbon to burn away. The coke then just crumbles away. Do something similar with the aluminium midbox. A word of warning here, aluminium's melting point is much lower and therefore damaged easier. Also make sure you remove the o-rings first. Other methods i've used are just running the bike on the road for 20 mins (needs an insured, road registered bike) or using a hot air gun directly into the large opening of the silencer. [*]Gear it down to give yourself more usable gears when in section (i use 9-48). [*]Changing the reeds from the reed valve is a possibility, but i've found the reeds on recent model years to be as good as anything else. Dom Quote Link to comment Share on other sites More sharing options...
shercoben12 Posted November 18, 2012 Author Report Share Posted November 18, 2012 thanks everyone for the advice where can i get a 200 barrel and piston and would this still be allowed in the trials i go to where the limit for under 16 is 125 would a high compression head insert make much difference thanks ben Quote Link to comment Share on other sites More sharing options...
jandyb Posted November 18, 2012 Report Share Posted November 18, 2012 First.. unless you are riding expert level, even a worn 125 should make you fly. In fact it makes me fly and I weigh almost (I repeat almost) the double of your weight. Are you using its potensial? I am talking about throttle and clutch here.. But of cause there can be something wrong. As others said: Clean air filter, carb, exhaust are essential. Check the reeds too. I south of england original jettings should be good.. (unless someone changed the jettings). You put in new piston, but on a 08 the barrel could be worn enough to need an oversized piston, but that requires exact measureing to find the right size. New barrel would of coause do it, but now we are talking too much money. Before spending a lot of money on it, consider selling and buy a newer bike.. -Jan Quote Link to comment Share on other sites More sharing options...
laser1 Posted November 18, 2012 Report Share Posted November 18, 2012 thanks everyone for the advice where can i get a 200 barrel and piston and would this still be allowed in the trials i go to where the limit for under 16 is 125 would a high compression head insert make much difference thanks ben No - you cant use a 200 in the 125 class. Yes - The HC head makes a big difference in power - mostly a mid range hit, but will really wake up the bike provided everything else is in good nick. However - the tradeoff is that it becomes a bit lumpy, can stall easier and requires high octane fuel. The bikes from 2010 and on, have a 2 pc head that accepts different compression inserts to make changing this easy and inexpensive. Adding the Keihin helps reduce the lumpyness down low and adds alot of over rev on top. Low budget options: Instead of a HC head - you can get increase the compression by reducing the thickness of the base gasket. (as mentioned above) However, you need to make sure you dont go too thin. (measure squish to make sure the piston doesn't hit the head and become a very expensive "upgrade") The change of port timing is a complaint by some. But you can always change it back. Find a used Keihin or use a OKO - (A lower cost copy of the keihin) - you will need a Raga manifold or Jitsie adapter to fit the 28mm carb correctly. The VHSt is a good carb as well - but can be hard to jet correctly. The optimal keihin jetting is well known. All of these "hot" carbs are less user friendly than the stone simple PHBL and require more frequent cleaning. There pilot circuits have very small holes in there atomizers and can easily clog. Run a good fuel filter. Keep your air filter very clean. The edge of too lean jetting is where 125's like to be for max power. Verify what the top riders in your area are using. If you have an 08 with alot of hours - change the reeds even if they look OK. As mentioned above - verify piston clearance and ring end gap (Im assuming these where done already when you changed the piston) make sure you dont over oil your air filter. +1 on the gearing comment - many folks here run 9T. Verify you have a quick turn throttle. (white tube) Quote Link to comment Share on other sites More sharing options...
shercoben12 Posted November 18, 2012 Author Report Share Posted November 18, 2012 where can i get a high compression head? and is this simple to fit? what octane fuel do i need? i currently run 98 thanks ben Quote Link to comment Share on other sites More sharing options...
laser1 Posted November 19, 2012 Report Share Posted November 19, 2012 http://www.trialendurodirect.com/products.php?S3__STARS__GAS_GAS_PRO_CYL_HEAD__outer_part__862&manufacturers=15 http://www.trialendurodirect.com/products/S3__STARS__Cylinder_head_inserts_for_GAS_GAS_PRO125_864.html s3 star heads are typically used. they are better than the OEM 2 pc heads on the newer GG's (also s3). Id guess that the high comp insert would be fine on 98 - not sure about the very high insert. Might check with the shop you buy them from. Head fitting is fairly easy, but must make sure the o-rings are installed correctly (use new ones) and head is torqued properly. not sure what your capability is - wouldnt cost much for a dealer to do it - 1hr of labor max for a pro mechanic. Quote Link to comment Share on other sites More sharing options...
shercoben12 Posted November 19, 2012 Author Report Share Posted November 19, 2012 hi thanks laser for that. i am going to get it now - and i will write up a review for others in the same situation:).... once I've had a chance to try it out. the barrel was re done recently. maybe partly because I've been riding a 280 for the last week the 125 seems gutless. it is not too bad but i still would like that little more power;P ben Quote Link to comment Share on other sites More sharing options...
jandyb Posted November 19, 2012 Report Share Posted November 19, 2012 (edited) Sorry Shercoben for beeing a negative dumba**, ( ) but I still think you should go put that £130,- in the bank and save up for a newer bike. Comparing gut with a 280 your 125 - and any other 125 - will loose every time no matter what you do with it. My very honest opinion! -Jan Edited November 19, 2012 by jandyb Quote Link to comment Share on other sites More sharing options...
laser1 Posted November 19, 2012 Report Share Posted November 19, 2012 Sorry Shercoben for beeing a negative dumba**, ( ) but I still think you should go put that £130,- in the bank and save up for a newer bike. Comparing gut with a 280 your 125 - and any other 125 - will loose every time no matter what you do with it. My very honest opinion! -Jan I think he's gonna have a tough time getting the 280 past the marshals. He is in the under 16 class. Otherwise, I agree with you - get the right size bike upfront and save the aggravation of making a bike something it itsnt. Quote Link to comment Share on other sites More sharing options...
jandyb Posted November 19, 2012 Report Share Posted November 19, 2012 I think he's gonna have a tough time getting the 280 past the marshals. He is in the under 16 class. Otherwise, I agree with you - get the right size bike upfront and save the aggravation of making a bike something it itsnt. I was more thinking about a newer 125. Dont know how the market looks like in UK, but here the difference between a 2008 and a 2011 is now about £1.000,- maybe less. Probably less in UK? £130,- is a good start on the savings.. Enjoy the 08 for a while. Do your technique training well. Unless you are riding 2 meter ledges a guttier bike wont help you much. -Jan Quote Link to comment Share on other sites More sharing options...
laser1 Posted November 19, 2012 Report Share Posted November 19, 2012 I was more thinking about a newer 125. Dont know how the market looks like in UK, but here the difference between a 2008 and a 2011 is now about £1.000,- maybe less. Probably less in UK? £130,- is a good start on the savings.. Enjoy the 08 for a while. Do your technique training well. Unless you are riding 2 meter ledges a guttier bike wont help you much. Is his bike clapped out? I thought he just freshened up the top end? -Jan That's about 1 yr depreciation here - 1st year = $1500. 3 years is around $3K difference. Quote Link to comment Share on other sites More sharing options...
shercoben12 Posted November 19, 2012 Author Report Share Posted November 19, 2012 Quote Link to comment Share on other sites More sharing options...
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