Author Topic: I'm new and need help, primary slips when I take off from stop light (Read 2501 times)

Johnny Armijo · « **on:** May 23, 2012, 06:38:00 AM »

Hi guys I'm new to bikes and need help. I have a 78 cb750f and love it. When I ride it seems to slip when I give it throttle from a stop or slow roll in traffic. It makes a clicking noise as if it was skipping a link in the chain? Like I said I'm new to bikes and don't know where to start looking... Thanks in advance...

Whaleman · « **Reply #1 on:** May 23, 2012, 06:41:12 AM »

I doubt it is your primary chain. Check your drive chain.

Johnny Armijo · « **Reply #2 on:** May 23, 2012, 06:46:04 AM »

Maybe just adjust it ?

Operator · « **Reply #3 on:** May 23, 2012, 07:32:45 AM »

Sounds like your chain is loose and/or stretched. Don't let it go as you can cause yourself a lot of grief by ignoring it.

Your best bet is to replace your sprockets and chain as a set. I normally replace sprockets every 2 years and replace the chain every year. Download a manual here http://forums.sohc4.net/index.php?topic=17788.0

I am mechanically inept at best and use a manual for everything, just jump in and do it. There are plenty of people here who will hop in to rescue you if you get stuck. And don't be afraid to ask..even if you think it is a silly simple question.

Good Luck.

Operator

MCRider · « **Reply #4 on:** May 23, 2012, 07:39:15 AM »

Quote from: Johnny Armijo on May 23, 2012, 06:46:04 AM

Maybe just adjust it ?

You'll need to remove the cover and inspect the drive sprocket. I've seen some incredibly worn front sprockets on the forum. Hard to believe its worn enough that a 630 chain would slip a tooth, but it could happen I suppose and needs to be ruled out pronto.

Adjusting would be the most temporary of fixes until the root cause is determined.

Johnny Armijo · « **Reply #5 on:** May 23, 2012, 07:40:12 AM »

Thanks guys I'll jump in it as soon as I get home

MCRider · « **Reply #6 on:** May 23, 2012, 07:47:36 AM »

Quote from: Johnny Armijo on May 23, 2012, 07:40:12 AM

Thanks guys I'll jump in it as soon as I get home

How many miles does it have on it?

If the front teeth are worn that much, adjusting it will pull the chain into the worn off nubs a bit and make you think you've got it fixed. But at some point, maybe when you don't need it to, it will slip again.

iron_worker · « **Reply #7 on:** May 23, 2012, 07:58:59 AM »

Get someone to sit on your bike and hold it upright. Then check the chain tension. Push up in the middle of the chain with your finger. It should only have about 3/4"-1" (check your manual to confirm) of play. If it's more than this then you can loosen off the rear axle/pinch bolts and slide it back to take up some slack. If you are adjusted back as far as you can then your chain is likely junk.

Also look at the sprocket tooth profile. The tooth should have a nice rounded over profile to it. If the tooth is starting to wear to a point ... it's junk. (look up on google what a bad chain/sprocket looks like)

Another test: take up the slack in the chain (as above) and try to pull a single link up off the sprocket (where the link is completely engaged on the sprocket ... back side of the driven sprocket). If you are able to lift that link up off the sprocket even with the slack removed then your chain is likely junk.

I recently did these tests and found that it failed the first and last test badly. lol I have a new good quality o-ring chain and sprockets on the way from bike bandit that should take care of my issues.

Another thing to watch for is sticking links. When chains get crud in the hinge points the links start to stick in a bent position. Not good.

IF a chain fails while you are riding it can destroy your engine case, lock up a wheel, and cause you to crash. Don't let it happen to you!

IW

MCRider · « **Reply #8 on:** May 23, 2012, 08:20:26 AM »

"Another test: take up the slack in the chain (as above) and try to pull a single link up off the sprocket (where the link is completely engaged on the sprocket ... back side of the driven sprocket). If you are able to lift that link up off the sprocket even with the slack removed then your chain is likely junk."

Took the words right out of my mouth.

DJ_AX · « **Reply #9 on:** May 23, 2012, 08:31:05 AM »

Yeah I wouldn't even ride it if it's that bad... SNAP! CRUNCH! CRASH! UGH! (in that order)
But I'd sure get a new chain and sprockets pronto... set it up right...
and then ride!

Don R · « **Reply #10 on:** May 23, 2012, 08:38:16 AM »

The manual is posted here, you can download it then print the pages you need to take out to work on it. Do a bit of reading. If your chain looks OK then you may have a clutch problem. These machines require the owner to perform occasional adjustment and maintainance. It's not too difficult if you read carefully and think it through. We will be here in case you get stuck. Have fun.

lrutt · « **Reply #11 on:** May 23, 2012, 11:30:21 AM »

JHFC....get a manual and read up on the bike. There are a lot of things you should know about your bike such as checking oil and air pressure etc. if the chain jumping cogs has you stumped. Manuals are free for download online if you google search.

DJ_AX · « **Reply #12 on:** May 23, 2012, 01:07:39 PM »

... I do agree with the other replies here of course.

and I'll be happy to help if I can...

Just wanted to make the other point though ... it's important (like with rock climbing)
that you understand and know your gear is safe before you depend on it with your life.

... stack the odds in your favor

lucky · « **Reply #13 on:** May 23, 2012, 01:35:05 PM »

A motorcycle is not like a car.
If it has a defect it can get you killed.

Operator · « **Reply #14 on:** May 24, 2012, 04:49:03 AM »

Check the member location, there are lots of members down in your area that would likely give you a hand with getting to know your bike and the basic maintenence aspects of it. It is always nice to have an experienced eye looking over your shoulder....

Best of luck.

Operator

bollingball · « **Reply #15 on:** May 24, 2012, 05:40:36 AM »

If you end up replacing the rear sprocket that is a good time to look at brakes,bearings and cush drive. while you have the wheel off.

Ken

somesuch · « **Reply #16 on:** May 24, 2012, 08:42:31 AM »

Chances are it is the first gear that is jumping out of gear and not the chain skipping a tooth. A worn chain/sprockets that have a tight spot *can* cause a marginal (first) gear to pop out. The variation in load is what does it. A new chain/sprockets can sometimes band-aid it enough to get you through until you can split the cases to repair it.

To test my theory, try any other gear and see it it still "skips"

754 · « **Reply #17 on:** May 24, 2012, 08:46:47 AM »

Sounds like sprocket with no teeth to me..

MCRider · « **Reply #18 on:** May 24, 2012, 08:53:12 AM »

Quote from: somesuch on May 24, 2012, 08:42:31 AM

Chances are it is the first gear that is jumping out of gear and not the chain skipping a tooth. A worn chain/sprockets that have a tight spot *can* cause a marginal (first) gear to pop out. The variation in load is what does it. A new chain/sprockets can sometimes band-aid it enough to get you through until you can split the cases to repair it.

To test my theory, try any other gear and see it it still "skips"

I hear what you're saying. There was even a thread here with similar symptoms ended up there were several chipped teeth.

Problem with jumping out of gear is when they do that they seldom jump back in.

nevertheless, still a viable option. My money is on the worn front sprocket. It can "skip" in first only, as that's the hardest pull. Once underway, 2nd + don't pull so hard and may not skip.

somesuch · « **Reply #19 on:** May 24, 2012, 09:21:11 AM »

Quote from: MCRider on May 24, 2012, 08:53:12 AM

Quote from: somesuch on May 24, 2012, 08:42:31 AM
Chances are it is the first gear that is jumping out of gear and not the chain skipping a tooth. A worn chain/sprockets that have a tight spot *can* cause a marginal (first) gear to pop out. The variation in load is what does it. A new chain/sprockets can sometimes band-aid it enough to get you through until you can split the cases to repair it.

To test my theory, try any other gear and see it it still "skips"
I hear what you're saying. There was even a thread here with similar symptoms ended up there were several chipped teeth.

Problem with jumping out of gear is when they do that they seldom jump back in.

nevertheless, still a viable option. My money is on the worn front sprocket. It can "skip" in first only, as that's the hardest pull. Once underway, 2nd + don't pull so hard and may not skip.

I had a 1976 CB750 that would go in and out of second gear rapidly when on the gas hard......I had ridden the bike years before (and right before it was parked for many years) and it did not have that problem. The only thing that I did in between, was rob a (good) chain/sprockets from it when I need such for my other project. When I decided to bring that bike out of storage I wanted to ride it first around the block before tearing it down for a rebuild, so I just grabbed an old chain that I was throwing away an put it on just to go around the block......that's when the second gear problem showed up. I came back in, put new chain on it, and the problem went away.

MCRider · « **Reply #20 on:** May 24, 2012, 09:43:20 AM »

"I had a 1976 CB750 that would go in and out of second gear rapidly when on the gas hard"

Nothing like first hand experience!

MRieck · « **Reply #21 on:** May 24, 2012, 09:54:42 AM »

Quote from: 754 on May 24, 2012, 08:46:47 AM

Sounds like sprocket with no teeth to me..

You just described my mother in law Frank.

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Author Topic: I'm new and need help, primary slips when I take off from stop light (Read 2501 times)

bollingball