Suzuki DT 100 misfire on high speeds

[florrolf]

I have a 2 stroke Suzuki DT 100 from 1990 that misfire on high speeds on 2 cylinders. First I<br />changed the charge coil, it helped for a while but then the problem came back. Then I changed the sensor coils. It also helped but the problem is<br />back again. Whats the problem?

 

[mrn714]

Re: Suzuki DT 100 misfire on high speeds

Have you run a compression check on the cylinders. All should have 120 - 130 lbs with less then a 5 lb deviation between each. If not, you may need to take the carbs off, pull all jets and clean well with pressureized gas. May also use small amount of starter fluid, but be sure all are dry and clean before reinsall. May have debris in center jet.

 

[florrolf]

Re: Suzuki DT 100 misfire on high speeds

Thank you for the reply. I have not done a compression check. However I have checked the sparks with at spark tester and I can see that one cylinder misfire on high RPM.

 

[florrolf]

Re: Suzuki DT 100 misfire on high speeds

I have now measured the resistans between the percussion cap and after the coil (F6T530) and the resistans was 12000 ohm on 3 cylinders an 3500 on one cylinder. Could this be the problem? Do I have one or three that is fault? Could this cause other coils to break? (The mechanic has changes the charge coil and 2 sensor coils.) Where do I get at F6T530?

 

[vidar]

Re: Suzuki DT 100 misfire on high speeds

discoooonect wires from cdi box to coils then mesuure fromwire to ground on all and plug cap to ground.. if diffrences on ht side try to take of plugcap and messure again it couud be a def cap.. you cant get any new oem but yoou can get new ngk caps from a mc dealer. hope this can help..

 

[florrolf]

Re: Suzuki DT 100 misfire on high speeds

I replaced all plugcaps, no difference. However, the sparks are bad beacuse of previous problems. I will try to replace the sparks.<br />Any ideas why the sparks turns black?

 

[florrolf]

Re: Suzuki DT 100 misfire on high speeds

No improvements when I changed to new sparks. Do I have to do something about the ignition when I changed to plugcaps with lower resitanse?

 

[vidar]

Re: Suzuki DT 100 misfire on high speeds

check every connection and every ground...check for cleen fresh gas and fuel pump and carbs for proper operation...if all check out ok thenyoou have to use an insulation tester on coils and windings for leakes of voltage...if all ok...MAYBE cdi box..