Author Topic: changing front sprocket (Read 10879 times)

maliveline · « **on:** September 24, 2011, 06:06:53 pm »

so im changing my chain and i already changed my rear sprocket now the last thing to do is change my front sprocket. So first do i have to take off my shifter cover??? If so i tried loosening some screws on the shifter cover with a manual screw driver and they were so seized up i couldn't get them to move. then i tried a cordless screwdriver bit and i stripped the #$%* out of the 2 philips head screws on the shifter cover. can someone point me in the right direction please and thanks.

jakecb420 · « **Reply #1 on:** September 24, 2011, 06:25:52 pm »

you need an impact driver with a #3 phillips bit. but since you buggered up the what i am assuming is the 2 screws that hold the sprocket cover on, you may have to take a #3 bit and hammer it into the screw's heads to try and reshape it. as far as taking the off the shifter cover, the one with the shifter sticking out of it, you dont have to mess with it. good luck and learn how to use the impact driver, it will make your life easier.

maliveline · « **Reply #2 on:** September 24, 2011, 08:03:11 pm »

it looked to me like you had to take the shifter cover off to take off the sprocket cover. I stripped 2 screws on the shifter cover not on the sprocket cover

Gordon · « **Reply #3 on:** September 24, 2011, 08:17:31 pm »

The sprocket cover will come off without removing the shifter cover.

maliveline · « **Reply #4 on:** September 24, 2011, 09:55:05 pm »

hmm i might have to re evaluate that.

Gordon · « **Reply #5 on:** September 24, 2011, 10:08:03 pm »

Quote from: maliveline on September 24, 2011, 09:55:05 pm

hmm i might have to re evaluate that.

Is this the '72 750 you're talking about?

Upon close inspection, it doesn't seem like it can come out on its own, but it can. It's a Chinese (Japanese

) puzzle of sorts. The main thing to remember is that once you find the angle and path it takes to get it out, make a strong mental note of it, because it has to go back in exactly the same way.

Even so, you should still deal with those stripped screws you ended up with on the shifter cover. You don't want them coming back to haunt you later on when you really need to get them out.

Johnny5 · « **Reply #6 on:** September 24, 2011, 10:24:17 pm »

Quote from: Gordon on September 24, 2011, 10:08:03 pm

Quote from: maliveline on September 24, 2011, 09:55:05 pm
hmm i might have to re evaluate that.

It's a Chinese (Japanese ) puzzle of sorts.

Tru dat.

maliveline · « **Reply #7 on:** September 24, 2011, 10:31:53 pm »

ya unfortunately i dont have air tools at my current location so it would be nice to get the bike mobile again so i can drive to my work where i have access to air tools

Gordon · « **Reply #8 on:** September 24, 2011, 10:52:32 pm »

Quote from: maliveline on September 24, 2011, 10:31:53 pm

ya unfortunately i dont have air tools at my current location so it would be nice to get the bike mobile again so i can drive to my work where i have access to air tools

An impact driver doesn't have to be air powered. You can get a manual impact driver for $25 or less, and it's pretty much a required tool for working on an old sohc4.

You don't have to use it all that often, but when you need it, it's invaluable.

lone*X · « **Reply #9 on:** September 25, 2011, 09:01:05 am »

My manual impact driver holds a place of honor in my tool collection. Had the same one for at least 40 years.
It probably does not have the quality of my 40+ year old US made tool, but the following tool will not hurt anyones budget and should prove serviceable.

http://www.harborfreight.com/impact-screwdriver-set-with-case-37530.html

Johnie · « **Reply #10 on:** September 25, 2011, 09:47:44 am »

Could and would not be without the impact driver. I hope you can get those screws out man. Could be a real pain in the butt now. Good luck and let us know how you come out.

maliveline · « **Reply #11 on:** September 26, 2011, 12:21:33 pm »

ok i got the cover off. so the front sprocket seems to be loose. I was able to wiggle it. is this normal? do you think that this has any thing to do with why my chain broke? anyway. so how do i pull it off just unscrew the 2 small nuts and then unscrew the larger nut in the middle of the sprocket?

Johnie · « **Reply #12 on:** September 26, 2011, 01:51:30 pm »

You will have some "wiggle" in that sprocket to account for chain movement. That is normal. Take those 2 bolts out and then you should have some tabs that need to be bent to be able to remove the large center bolt. You will need to hold that sprocket with something to unscrew that large bolt. I generally use a wood block. Keep in mind when you put those 2 smaller ones back in you should put some blue Locktite on them.

steam-powered man · « **Reply #13 on:** September 26, 2011, 02:05:57 pm »

there's a thin/notched plate under the 2 screws, gotta rotate it a little to remove it. go to bikebandit.com, find your bike and look for "final drive shaft/sprocket" under "final drive". you'll see how the whole mess goes together.
bobp

maliveline · « **Reply #14 on:** September 26, 2011, 07:44:30 pm »

can't i just put the bike in gear to hold the sprocket stationary while i try to unscrew the bolts?

HondaMan · « **Reply #15 on:** September 26, 2011, 07:51:02 pm »

Quote from: maliveline on September 26, 2011, 07:44:30 pm

can't i just put the bike in gear to hold the sprocket stationary while i try to unscrew the bolts?

Yep. And if that's not enough, you can tighten up the rear brake to hold the wheel still for you, too!

maliveline · « **Reply #16 on:** September 26, 2011, 08:38:54 pm »

how nessecary is the lock tight? has anyone tried this without using locktite?

Johnie · « **Reply #17 on:** September 27, 2011, 05:38:36 am »

Blue Locktite is best. These 2 small bolts have been known to back out. If you want to take a chance without that is your call. I am sure some guys here are not using it. What would be the reason to not use it?

madmtnmotors · « **Reply #18 on:** September 27, 2011, 06:22:39 am »

Blue locktite is bolt-holding insurance (liquid lock washer) and it is easily disassembled.

Johnie · « **Reply #19 on:** September 27, 2011, 10:51:32 am »

Amen and piece of mind. For the little time and expense compared to what happens if the bolt backs out...it is a very wise investment to do it.

maliveline · « **Reply #20 on:** September 27, 2011, 08:03:55 pm »

i have red loctite but not blue

madmtnmotors · « **Reply #21 on:** September 28, 2011, 09:13:46 am »

Red loctite is semi-permanent and very difficult to disassemble. Use at your own risk...

HondaMan · « **Reply #22 on:** September 29, 2011, 05:38:37 pm »

Quote from: maliveline on September 26, 2011, 08:38:54 pm

how nessecary is the lock tight? has anyone tried this without using locktite?

I have never used it on the sprocket bolts, even in racing. They see very little load or stress. All they do is hold the little plate in place: the splines do all the heavy lifting. If you're concerned, get some that are a few mm longer and add lock washers to them.

maliveline · « **Reply #23 on:** October 01, 2011, 06:20:20 pm »

omg this is turning out to be a major head ache.......................

Picture #1 : This is the two front sprockets side by side. they aren't exactly identical but the spline matches and there is 18 teeth on both so I think its fine.

Picture #2 : This is my main problem. The center bolt slides right through the splined hole in the middle of the sprocket. This will in no way secures the sprocket on to my bike. To be honest I have no Idea how the old one stayed on this long because this is all the parts I have that were holding the old sprocket on.

Picture #3 : This is just a picture of the center bolt. Im not sure if im missing something or what.

jakecb420 · « **Reply #24 on:** October 01, 2011, 07:03:53 pm »

that center bolt has your chain oiler in it, id reccomend looking at a parts diagram on bikebandit or some other site that has the parts diagram to get a better understanding of what all is going on there.

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Author Topic: changing front sprocket (Read 10879 times)