Motorcycle Repair: 1970 CT90

Question
WHY DOES MY LOW RANGE GEAR KEEP POPPING OUT OF GEAR, UNDER A HEAVY LOAD? LIKE GOING UP HILLS, ETC.
BIKE WORKS FINE IN HIGH RANGE.
THANKS YOU!

Answer
Mike, the shift selection parts seemed to have had some updates. I would swear that I have seen some kind of service bulletin on the Hi-Low range components, but am not able to locate it at this time. I would buy some gaskets and seals in advance of disassembling the side case components to look at the parts involved and determine if any are damaged or worn excessively.

There are LOTS of parts on eBay for sale and numerous CT90-110 forums on Yahoo and elsewhere.

I found this, too, but it is more of a transmission bulletin that the Hi-Low range bulletin.

http://www.allworldauto.com/recalls/NHTSA_66V003000_9999_HONDA_CT90_recall_38890

http://ct90-ct110.com/PDFs/CT90_Pre-1977_Bundled_Shop_Manual_PDF.pdf  about half way down is the "Posi-Torque" Hi-Low range function mentioned, but nothing of great detail about troubleshooting it.

After digging around in my archives I did find this reference to your problem, depending upon when your bike was built....

Honda Bulletin CT90 #8   Sliding low gear part number 23932-053-010 and Spring, ball set part number 24271-053-010.  For use on bikes with frame numbers up to 179373.... If your bike is beyond that frame number, then it will already have the correct parts and there is a possibility that something is damaged inside the transfer unit.

Bill Silver