My bike doesn't allow me to adjust my gears as it was too stiff. I loosened everything up with WD40 however it still didn't help and now I can't tense up my cable. Please can someone tell me how I could just temporarily keep my bike into 1st gear. I have even tried tying it back but it still goes straight to 6th gear. Any help is appreciated.
I agree with rellachs post, it sounds very much like your shift cable is gone and needs replacing. Frayed cables also eat up the smooth surfaces of the cable housings, so it is recommended to replace those, too - or shifting with a new cable won't be as crisp as it should be.
You mention you wantit to stay in 1st gear (assuming lowest sprocket the way shifter scales are usually numbered): If you want a roadside hack to temporarily stay and ride in another (lower) gear than it currently is in, you can force it by using the corresponding limit screw or pull out the cable of the shifter/housing and tie it in between the adjustment bolt and the clamp to simulate the cable length and tension for a specific gear. It gives you only one gear but somewhere in the middle of cassette proably gives you a good enough ratio for most rides, especially if you have a double or triple chainring.
(GCN makes a knot to stop the cable from slipping through but I've also seen versions where the cable stop that sits in the shifter is used on the adjustment end)
It is best illustrated in this video:
Given this brief problem description I need to make some assumptions here.
If your goal is simply to run your bike in one of the larger sprockets without addressing the actual problem, you could try to intentionally misalign the rear derailleur by tightening the stop screw that would normally prevent your chain from slipping past the smallest sprocket of your cassette. While you may be able to push the chain up a few sprockets, it is unlikely that it will reach the 1st gear this way.
To effectively resolve the problem your best course of action is to thoroughly inspect the shift cable first (along with the cable housing). Loosen the shift cable at the rear derailleur (usually an Allen screw) and check if it can move freely everywhere. Also try to push the other end of the shift cable out of the shift lever to check if the cable was damaged inside the shift lever. You probably should replace the shift cable and/or the cable housing in case you find:
- corrosion or
- a kink in the cable or cable housing or
- a (partially) broken shift cable
PS: In case you do not have much experience adjusting bike gears, maybe try to find a tutorial on Youtube - a picture is worth a thousand words.