Author Topic: 1970 cb750 ride issues. Need help!!! (Read 3375 times)

guitarkev66 · « **on:** August 13, 2012, 05:02:41 PM »

Okay I have a new bike a 1970 cb750 with 31,000 miles. It has what feels like a hop to it when it rides down the road more noticeable at lower speed. I swapped out the front wheel and tire from another bike that has no issues with no change. So I started to look at the rear wheel,chain, and sprocket. I noticed the chain had no slack in it. So I went to adjust and before I did I rotated the wheel by hand and noticed I had slack so I rotated it again the slack went away. So is that the hop I am feeling, tight /loose? What would cause this?? I tried to adjust both adjusters the same but it didn't help. Any ideas??? Second question is I bought some re-pop honda emblems for the tank they came flat instead of contoured for the tank. The comapny said you have to heat them up to form them to the tank but I'm not real sure on how to do that without either breaking the emblem or screwing up the paint on my tank. I do have another tank to use that I don't mind hurting. Anyone ever bend emblems? Thanks Guys!!!!

Stev-o · « **Reply #1 on:** August 13, 2012, 05:25:13 PM »

Chan is stretched, replace it. Sprockets too.

Old Scrambler · « **Reply #2 on:** August 13, 2012, 05:47:11 PM »

The chain is probably stretched but could also be stiff from sitting so long. I like to use spray teflon with graphite while rotating the wheel to work it in a bit before riding. It may not work but might get you down the road until you decide what your doing with this ride.

Regarding the emblems.........try heating them in an oven to about 250-degrees and then hold them at the rear-ward ends with gloves on and small blocks of wood and place them on a spare tank or try to shape them to the curved end of a large anvil......or a basketball or the outer edge of a large metal garbage-can lid......especially the foward half of each emblem......I have used a rubber mallet with good results. When cool they should be OK to put on your good tank.

Toxic · « **Reply #3 on:** August 13, 2012, 05:56:53 PM »

You probably have some links that are frozen solid. With the wheel off the ground try to bend each and every link if they don't hinge easy at the pin they are probably rusted tight. You can take the chain off and soak it in penetrating oil and see if it loosens up.
But if it were me and a bike of unknown history I would replace both chain and sprockets. Cheap piece of mind and have you seen the pics of what a broken chain can do to your cases?

Stev-o · « **Reply #4 on:** August 13, 2012, 05:59:12 PM »

Quote from: Toxic on August 13, 2012, 05:56:53 PM

But if it were me and a bike of unknown history I would replace both chain and sprockets. Cheap piece of mind and have you seen the pics of what a broken chain can do to your cases?

Good advice.

MCRider · « **Reply #5 on:** August 13, 2012, 06:19:13 PM »

The chain is shot. But the more complete explanation is that part of the chain is more shot than the other.

Where the pins of the outside links enter the rollers of the inside links, there is friction which needs to be lubed. It takes experience to lube the chain uniformly around its entire length, and a little luck. The pins wallow out the holes of the bushings/rollers into an oval. Some of the ovals in a section of the chain are bigger than others, so as you spin the wheel you feel the dreaded "tightsie, loosie" There is no cure other than new parts.

The ovals, which are not visible, are what make us think the chain has "stretched". This is simply an inappropriate but convenient, term for the ovalling of the bushing holes.

Tews19 · « **Reply #6 on:** August 13, 2012, 06:23:36 PM »

I had the same issue with my 550 this past summer. I got off the road and noticed how tight she was. Did an adjustment and went down my block and she was tight again. Godffrey took a look and told me my chain was wore. New chain and sprockets and she has been great all summer. Kinda weird!

tlbranth · « **Reply #7 on:** August 13, 2012, 08:09:17 PM »

Well it's been said: chain is a goner. I'd stard clean with a new chain and new sprockets. I'd highly recommend using an RK x-ring chain. You'll never regret it.

guitarkev66 · « **Reply #8 on:** August 14, 2012, 04:31:33 PM »

Thank you guys yet again for such great support... I replaced the chain today and WOW what a diffence very smooth and a great ride. I am currently baking my new tank emblems I will post back with the results......

Stev-o · « **Reply #9 on:** August 14, 2012, 04:33:14 PM »

That was quick. What chain did you get?

guitarkev66 · « **Reply #10 on:** August 14, 2012, 04:47:20 PM »

I got what my local Honda shop carried, DID chain. Any good?

mycb750k6 · « **Reply #11 on:** August 17, 2012, 03:15:40 PM »

Wow. What a nice bike and great color. What did you pay if you don't mind saying?

guitarkev66 · « **Reply #12 on:** August 17, 2012, 05:52:05 PM »

$4500.00 Its a lot of money but I think well spent.....

guitarkev66 · « **Reply #13 on:** August 17, 2012, 05:55:41 PM »

When I take pictures of this bike the color looks very blue when actually its more blue/green in person. Weird, pictures don't do it justice!!!

gonzobrian · « **Reply #14 on:** August 18, 2012, 05:52:27 AM »

It looks like the emblems turned out well? Did they attach to the tank like the original or did you use some other method? Any tips you might share since you just did yours? I'm about to do my blue KO. Thanks.

lucky · « **Reply #15 on:** August 18, 2012, 07:34:22 AM »

WOW!! 4,500 and the chain was that messed up??

754 · « **Reply #16 on:** August 18, 2012, 08:02:45 AM »

How long have you guys been riding?, that ajust a chain without first finding the TIGHTest spot, then adjusting?

Pretty hard on the bike..if you dont do it that way...

tlbranth · « **Reply #17 on:** August 18, 2012, 11:20:15 AM »

Quote from: 754 on August 18, 2012, 08:02:45 AM

How long have you guys been riding?, that ajust a chain without first finding the TIGHTest spot, then adjusting?

Pretty hard on the bike..if you dont do it that way...

I'll agree with that

736cc · « **Reply #18 on:** August 18, 2012, 04:38:08 PM »

Nice early 750's you got there!

Quote from: guitarkev66 on August 17, 2012, 05:55:41 PM

Now you need a red one to complete the set.

Stev-o · « **Reply #19 on:** August 18, 2012, 04:40:13 PM »

wow, I'm seeing triple?! In the house, nice.

guitarkev66 · « **Reply #20 on:** August 20, 2012, 05:23:30 AM »

Gonzo, I made forms out of a 2x4 to bend my emblems. I took a 8 inch piece of 2x4 laid it flat on my work bench and traced the radius of an original already bent emblem then extended the lines straight for about an inch for screws. Cut carefully on the line then drilled holes in the 2x4 to accept the tabs on the back of the emblem and pre-drilled the holes for the screws. Place the emblem in the form and screw it together. I then put it in the oven for an hour at 300 degrees. I was not to happy with the outcome, there was not enough bend at the very front of the emblem so I have a gap between the emblem and the tank ( bugs the #$%* out of me). The rest of the emblem sits nice on the tank. I think I am going to make a new form and over bend the emblem. I will keep you updated on my progress and maybe post some pictures..

736cc · « **Reply #21 on:** August 20, 2012, 05:59:33 AM »

Heat the emblem up w/ a hairdryer and tweak it by hand

bjatwood · « **Reply #22 on:** August 20, 2012, 06:12:45 PM »

I have a Blue/Green HKO Trail 70 that doesn't photograph real well color wise either. The digital pixels pick up the Blue easier than the green pixels. So what you get is a Blue bike in the pics. This pic of my frame fresh from the painter in the early AM is about as close to what it looks like to the naked eye as I have seen..

gonzobrian · « **Reply #23 on:** August 21, 2012, 05:33:18 AM »

Quote from: guitarkev66 on August 20, 2012, 05:23:30 AM

Gonzo, I made forms out of a 2x4 to bend my emblems. I took a 8 inch piece of 2x4 laid it flat on my work bench and traced the radius of an original already bent emblem then extended the lines straight for about an inch for screws. Cut carefully on the line then drilled holes in the 2x4 to accept the tabs on the back of the emblem and pre-drilled the holes for the screws. Place the emblem in the form and screw it together. I then put it in the oven for an hour at 300 degrees. I was not to happy with the outcome, there was not enough bend at the very front of the emblem so I have a gap between the emblem and the tank ( bugs the #$%* out of me). The rest of the emblem sits nice on the tank. I think I am going to make a new form and over bend the emblem. I will keep you updated on my progress and maybe post some pictures..

Thanks for the reply.

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Author Topic: 1970 cb750 ride issues. Need help!!! (Read 3375 times)