Paulwhite

soz chris i cant ring u iv got no cred, pm me and il get back to you, have you got a volt meter? if so put it on the terminals of the battery it should read at least 13 volts! if anything the very last thing it could be is the starter motor. check everything else 1st m8. if you have cleaned the cable connection from the starter motor then next step is to check the earth. run a wire from the negative terminal of the battery to a bolt on the starter motor then try to start it. if none of this works then its defo the motor.

nice one just what i was lookin for !

when i had mine i didnt keep it up to date with the service as it cost too much i was 17 when i bought it and moved out of my parents when i was 18. i could get it up to 65 at a push (had to rev the bollocks off it) but kept it at 60 max to be on the safe side lol. but it was just an example for the equation and christoff im afraid ur friend is a bit confused! the only possible restriction on a icu or ecu or cdi is a rev limiter and the advance curve but that is only on bikes like the aprillia rs 125, nsr 125, cbr 125 (mainly sport 125 bikes and dirt bikes and 2 strokes) on a cruiser 125 4 stroke there wont be any reason for a slower advance curve, possibly a rev limiter (not sure but it makes sense) so the cheapest and best option is the sprocket sizes

make sure all the connections are clean (wire brush them if you have to) and also make sure that all the plugs are in properly! if you have gone through everything that you can and nothing works and you need a starter motor then pm me (iv got one in the shed that works fine that i can sell u) but make sure that there is no other possible cause! dont want you spendin cash when you dont need to, probably a good idea to get some new spark plugs to be on the safe side and clean the air filter. also check the cable comming from the starter motor! undo it, wire brush it, then put it back on!

ahh didnt think of that cheers in short hand the equation works ot like this r/f = h1...............................r = original rear sprocket (number of teeth) r2/f2 = h2............................f = original front sprocket (number of teeth) .........................................r2 = new rear sprocket (number of teeth) h1-h2 = n...........................f2 = new front sprocket (number of teeth) h1+n = p............................h1 = original ratio .........................................h2 = new ratio .........................................n = number 1 h1/top speed = u................p = number 2 .........................................u = number 3 p/u = estimated top speed

right there has been a few posts lately askin what gains ppl would expect from changing sprocket sizes so im going to show you how to roughly work it out. (and it is only theoretical estimated top speed) count the number of teeth on each sprocket, so for an example the rear sprocket is 59 teeth and the front sprocket is 16 teeth (original sizes on a xvs 125) divide 59 by 16 = 3.6875 (round it up to 3.69) 3.69 is the number of times the front sprocket turns to 1 turn of the rear sprocket (called a ratio). now work out what ratio you would get by changing the sprocket size. so say i want 2 extra teeth on the front. 59/18 = 3.2777777777777778 (round it up to 3.28) now here comes the tricky bit! figure out the top speed you have had on the bike (on a flat road) mine was 60mph so the 1st ratio (3.69) we know gets us to 60mph now minus the 2nd ratio from the 1st ratio so 3.69 - 3.28 = 0.41 now add that to the original ratio (3.69 + 0.41 = 4.1) we will need this figure in a min. divide the original ratio (3.69) by the top speed (60mph) 3.69/60 = 0.0615 (dont round it up) now you need to times that number by how many mph you think you will get with the different ratio till you get that number that i said we would need in a min (4.1) so 0.0615 X 75 mph = 4.6125 too high 0.0615 X 70 mph = 4.305 still to high 0.0615 X 65 mph = 3.9975 too low but we are close! 0.0615 X 68 mph = 4.182 too high but nearly there 0.0615 X 67 mph = 4.1205 0.0615 X 66 mph = 4.059 right so what we have figured out is that with 2 extra teeth on the front sprocket your top speed would be about 66 to 67 mph which is at least 6mph more than the original! (60mph) anyone lost? lol and please note this is just an educated guess! the actual top speed depends on allot of factors like wind resistance, how big the tiers are, how much torque and so on.

what do you mean by size? cause as far as i know there all the same (as long as its a mikuni) and is round not hexagon. cant you just order one off ebay? here iv put a link up for you (for the correct 100 main jet) 100 main jet and if you scroll down on the e-bay page its got the measurements of the jet

cheers joe

just need some idea what wire to use to re make the loom for the xvs 125 bobber, could anyone give me a clue? i know its got to handle 12v but other than that im lost lol.

as long as its the same numbers, then there wont be any problem putting it on top of the old one, as all they will do is check in the data base and everything will tally up, ur not doing owt wrong so why worry? legality wise your not tampering with it your just replacing the damaged one with an exact copy so no worries there m8.

cheers, is that dry weight or with a full tank and oil ?

the rev counter bolts to something ( im making a bracket for mine ) then there are 4 Wier's red connects to the on switch (key), yellow to the lights positive, black to the ground, then green to the negative on the coil, all the electrics are in the headlamp so its easy to connect up it works by using the electrical signal or "pulse" from the coil/sparkplug then converts the pulse into an analogue movement (rpm)

yeah im defo not using it lol its a 1st attempt and i only keep it as a reminder of how not to do it!

id say biggest would be a 250cc just because you would need to upgrade the brakes, forks, and possibly re-enforce the frame, itl just be too much hassle to put owt bigger in there.

right...... the rev counter is an electric one off e-bay it cost £60 and came with instructions and can be fitted to ANY bike it would look good with 2 exhaust exits but its a bit of overkill on a 125 plus it would cost a fortune to get one made. its the original wheel and just a normal size tire, think its because the rear fender is smaller it makes the tire look fatter and that fender on there is just a mock up (its too thick and lumpy but you cant really tell on the picture) and i can see what your sayin with the exhaust lol it would look out of place compared to other bikes of similar stile, but its way too much hassle to straighten out the exhaust (id have to cut a supporting bit of the frame) but saying that i could just take the can off il have to post a pic with the can off. its definitely different but isnt different good? plus im considering selling it as a learner legal custom 125 and to a 17 year old a massive end can is a good thing lol

yeah i know what u mean with the exhaust its been a pain in the neck trying to fit it but it will be closer to the rear fender when its done and chris the one on top is a rev counter (comes in handy!) and defiantly a mod i would recommend! as to the handlebars they need to come up but im not sure if normal bar risers would fit (il have to take some measurements) but i am thinking of making some custom ones with a bracket to fit the rev counter. as to the chrome id rather have no chrome on it at all but sadly i cant do that without it looking a little tacky so im only having certain chrome parts just to set the bike off but yeah im just waiting for the engine mounts to be made (i know a bloke ) then i can secure the engine properly and start getting it finished.

god i bet you need some form of talent to ride that thing! suppose on the good side no one will dare nick it! lol

just the latest update on the project nothing is on properly just wanted to see what it would look like not too sure on the drag bars at the mo, might need to get some handlebar risers or make some. but im loving the look of the exhaust, highly unusual to see on this stile of bike but it gives it some presence.

think some xvs 125 dragstar mirrors would look good and still keep the feel of the bike

yes m8 its the honda cbr 125 (2004) the biggest sprocket size for the engine is 17 teeth and with the smaller rear sprocket the gear ratio would be 3.29 which is better than the 3.9 iv got now lol the problem down my way is its quite hilly so im gonna need some torque to get up them, but want to be able to hit a decent speed. so need to find a happy medium iv done it all back wards and bought a chain and sprocket kit not realizing that the rear sprocket has 59 teeth lol anyone want a brand new 16 tooth front sprocket? for £7? lol

cheers mervin! just what i needed m8

hi all im having a hard time trying to think of the final gear ratio i should use for my project. the xvs 125 has a gear ratio of 59/16= 3.6875 (taken from sprocket ratio) but that is to pull the mass amount of weight that the bike has (dont know exactly how heavy it is) and top speed is about 60mph (with me on it and im 10.5 stone) but the bike im building is going to be allot lighter with a little more powerful engine (cbr 125 has a little more torque) so my question is what gear ratio should i go for? with the front sprocket being a 15 tooth and the rear being 59 tooth im gonna get a ratio of 3.93!! which i admit is mint for acceleration but the top end is going to suffer....allot! also anyone know where i could get my hands on a smaller rear sprocket for the xvs 125? say a 49 tooth? or there abouts. cheers. Paul.

lol love it! "china man" - iv got a wife and 2 kids, my house is number 8 and i live in the richest part of china, in the biggest building! "japanese man" - yea! well iv got a jet ski so il come and get ya!

yup spot on ! and not a bad price! (in dont mind givin advice but i dont like doing the legwork lol )

it shouldnt lower compression no. but the reason why you can smell petrol is because there is a tiney point where both valves are open and because there is no back pressure in the exhaust some of the air/fuel mix is escaping the cylinder and entering the exhaust, this is where the back pressure would kick in and push the air/fuel mixture back into the cylinder. and this is why you need to re-jet when putting on a performance exhaust/ straight through pipe on. just do a spark plug check and adjust the jet needle accordingly then you will need a slightly bigger main jet to help out the top end. should sort it out oh and that perforated metal bit you took out would be the baffle which would keep the back pressure in check. so you could always pop the baffle back in and then compare the spark plugs (saves stripping the carb) and would probably give you a little more top end (say 2-3mph)