suzuki ts125r timing , backfires

[liamk199]

just did a engine change on my ts125r as the old one blew up.
the new one wont start and backfires while kicking it over, how do you adjust the timing on these never done 2 strokes, does the flywheel need to come off , any help would be great thanks
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l d kirton

[bladerunner]

You can't really adjust the timing on this bike....unless your woodruff key has snapped......try a new plug and check the timing with a strobe light if you can borrow one
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Current bikes...cbr929, KDX200's, Rd125lc mk2, RGV250's

[unitynotsocri...]

the points ,if the older models....are behind the flywheel and difficult to set.Basically there should be two marks on the flywheel,one 'T' is for lining up against a casing marker,this marker indicates when the spark should fire as the points open.

basically you have to set the points gap...WHEN THE POINTS ARE WIDEST ON THE TIMING CAM to the required setting,usually between two settings in practice.

on many points systems the plate that the points are fixed on can be adjustly slighty,usually rotated,...so the 'timing',as in spark at right height of piston is correct.I.E. the point the contact breaker surfaces seperate and open.

CD ignition does he same but uses a tiny magnet to 'trigger' a tiny 'pulse coil' to trigger the main spark coil.Timing on CDI (pointless) motors is usuallly very accurate and reliable.On points system the timing generally wanders and has to be checked,severe timing issues can melt pistons and waste petrol and power.
many years ago the timing was the first thing to check on many motorbike faults and since CDI sparks,fuel issues seem to cause as much hassle as the high voltage side ,as opposed to two third ,points ignition problems. to one third feul probs in 'the olden days'

you can use a multimeter or simple 6 v bulb to find the point when the contact breakers open,or you could use a strobe if you get it running.Try looking closely at the points and see if there's any scratch marks from sideways screwdriver levering of the points plate......this should show minor adjustment,after 'gapping' the points (main adjustment) is possible....moving the plate moves the points on the cam on the end of the crank....and as other poster has said make sure the flywheel has been replaced ACCURATLY...its amazing how many little bikes I've seen with em on wrong...usually a flattend woodruffe key ...eased to death with a pipe bar!!!!!its amazing how strong small engines are.
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nearly a normal tax paying tosser.......with ferrileness suzi100,cg125,cb125scb100n,cb175,cd100,cj250t,kh250,c15,125 bantam,super 6,rickman gs750,xt500,250rs,dt175,lifan125,dolomite1850,metro,Morris220ld,morrisfg,leyland princess,range rover,corsa,vw camper .now struggling with legs. MORE ORDER = MORE CHAOS

[liamk199]

have looked at it there one small pick up coil on the outside off the flywheel , it wont adjust round but does move closer and away from the flywheel, i manged to get it running fine the it just lost power and cut out and know wont start , has a good spark and compression , carb has been cleaned and set up, one thing i noticed is the power valve has been welded wide open which have been told can change the timing , if you hold the throttle open it back fires . not sure what went wrong it happend so quick . does having the exhaust wide open stop it starting , pulling my hair out lol.
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l d kirton

[bladerunner]

Having the power valves welded open will not effect the ignition timing. On some suzukis they open the power valves just above tickover( so you can check adjustment without having to rev the nuts off it ) then close them again before 3k rpm........ Deffo try a new plug and cap and a bit of fuel down the plug hole.I've seen plenty of dead plugs that spark when not under compression but fail when exposed to the working end of an engine.....and deffo try a strobe to check timing. And like I said possible woodruff key failure. Mark a line from the crank to the flywheel, kick it over a few times and see if the marks move?

Failing that if your sure compression is good. Maybe check the reeds
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Current bikes...cbr929, KDX200's, Rd125lc mk2, RGV250's

[unitynotsocri...]

the pickup magnet should nt move on the flywheel and should be an even distance from the sensor for even timed sparking......if its old then it may have dropped its magnetism
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nearly a normal tax paying tosser.......with ferrileness suzi100,cg125,cb125scb100n,cb175,cd100,cj250t,kh250,c15,125 bantam,super 6,rickman gs750,xt500,250rs,dt175,lifan125,dolomite1850,metro,Morris220ld,morrisfg,leyland princess,range rover,corsa,vw camper .now struggling with legs. MORE ORDER = MORE CHAOS

[liamk199]

yeah that was the first thing i did change the lead and a new plug the only one they had was this irodium one that was like £9, was the right size , but after looking on the internet people dont rate them compered with the standerd copper ones, i will check the flywheel and the timing , but if the timing is off how can i change it if the pick up wont move, also how do i set the distance up between the pick up and the flywheel . thanks guys
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l d kirton

[unitynotsocri...]

the distance between the pickup and flywheel should be constant,if its not then the flywheel is'nt seated on the shaft right(woodruffe key problem)
or its been warped or is not fully tight.A few sensors i've seen are non adjustable,but able to be moved a smidge or have the external pick up mounts drilled a tiny bit to allow some minor adjustment.......but they are usually FIXED.....which is far less hassle than points./To get techy you could use a timing disc card.

connecting a multimeter to the ohm setting and spinning the flywheel around can tell if the sensor is working and be used to set the timing against the timing marks.


usually ....what a word......theres two marks or one on strokers....

some older strokers and nearly all four strokers used an advance /retard sprung bob weight that moved the 'igition timing' ...i.e spark point in relation to piston position..........as the engine revved up.To increase the flexibility of the engines performance the small bob weights adjusted the spark point to make the engine rev higher,and give more power lower down the rev range...


think your welded open powervalve gives you great performance low to mid.The timing should take care of itself.you could connect a 'timing light' on it and check the alignment marks on the flywheel,but i would'nt worry about it.......just make sure the magnet is not rattling out and the pulse coil is pulsing .......(multimeter.....or check for spark from earthed plug with ign on when magnet/screwdriver is whizzed by it).......

if you did play around with the 'timing' options...both cdi units spec ,and microdrilling the sensor screws...(tedious..unecessercary)........i would go for slightly retarded timing,but i havnt much exp on strokers..and hands on tuning em.

it may be worth jetting the carb /filter setup for low to medium grunt,to encourage the welded exhaust powervalve.
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nearly a normal tax paying tosser.......with ferrileness suzi100,cg125,cb125scb100n,cb175,cd100,cj250t,kh250,c15,125 bantam,super 6,rickman gs750,xt500,250rs,dt175,lifan125,dolomite1850,metro,Morris220ld,morrisfg,leyland princess,range rover,corsa,vw camper .now struggling with legs. MORE ORDER = MORE CHAOS

[bladerunner]

Welded open power valve will give you bugger all mid range...and I mean big hole in the power curve! Just a point of interest...Suzuki did tend to use 2 different manufacturers for ignition parts. Are you sure the genny and fly wheel are correct for your Cdi? I had this problem with an RGV 250 a while back. Try your known good genny and flywheel. Sometimes you'll see the pickup lug is in a different position relative to the crank position or the pick up lug is a different length! Deffo worth looking if your using ones supplied with the new motor.
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Current bikes...cbr929, KDX200's, Rd125lc mk2, RGV250's

[liamk199]

right just looked at it and the spark is very retard , the little slip of metal on the flywheel is passing the pick up before the piston is at tdc , looking at my old engine which is spot on. cant see any timing marks but i will pull the flywheel off to have a look at the key and see if it has sliped . hopfully this may have solved it . does the flywheel just have one slot which the key fits into which lines it up or is there a few . thanks
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l d kirton

[liamk199]

also quick question when the piston is at tdc , the bit slip of metal on the flywheel does the pick up need to be in the middle of it or start of end ? thanks
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l d kirton

[Ariel Badger]

[liamk199]

is that with the pick up in the middle of the flywheel magnet ? thanks
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l d kirton

[Ariel Badger]

It is wherever the signal fires, can you put a strobe light on it?
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Bikers make great organ donors, get 115 on your licence today.

[liamk199]

yeah have done that the timing is done , but a new problem has come up . the new piston i put in a few days a go has had it big scores down it, well P**ed off. it looks like there was a hole in the little pipe that goes from the auto oil pump to the carb think this was the problem first and last time i trust autolube systems . i have a good cylinder that came of another engine will get a new piston and just premix the fuel at least i know the engines geting oil. its been one thing after another with this bike , but will see it through .lol thanks
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l d kirton