[Yazman]

Finally got my 87 250 all wrapped up. Everything is great except it vibrates like crazy all over the bike--I can't see anything in the mirrors, it's annoying on my feet and hands, to be honest it's not that pleasurable of an experience. Under 25 or 30 it's fine, but anything over that and it's like being on one of those hourly motel beds where you put the quarters in it (not that I would know what that's like 😉).

Is this just something I'm going to have to live with? Does this just come with a territory of a side-by-side twin?

I've searched the forums and read about people puting rubber under the gas tank mounts, but it is the whole bike that is shaking, not just the gas tank.

 

[leebrown66]

It certainly shouldn't shake the way you describe. If it's speed and not rpm's and no unusual noises, things I could image having that effect, and apologies for asking the obvious:

Are both wheels true?
Are both wheels balanced?
Are both tyres in good shape (as in round)?
Are both tyres inflated to correct pressure?
Is the steering pre-load correct?
Is the chain correctly tensioned?
Are all the engine mounting bolts tight?

 

[Kreuzi]

I would ask the same question:
Is it really speed or rpm?
How does the bike behave when in neutral with running Engine and does it change if you give more rpm there?

 

[Yazman]

Good questions. I just installed a new front tire I got off amazon. It was a little odd shaped when I got it because they taped the label to it. I didn't balance the tire, and there was no "dot" for balancing. I don't have a tool for runout, but they "look" true for what it's worth.

Engine mounting bolts I will check
I'm not sure how to adjust preload, but I will look in the manual.
I adjusted the chain to about 3/4, but I will check to make sure I measured right
I just checked the psi today, it was a tad low

Maybe you guys are right about it being speed and not rpm; it does seem much better under 30. I'll rev in the driveway and report back.

Thanks guys! I appreciate the help

 

[SoakedKarma]

you don't need a dial gauge to check runout..
tape a straw, or stick to one side of fork 1/4" from rim outer edge. spin wheel, watch for left/right wobble up/down out of round..
adjust spokes to correct any problems found..
With wheel in air heavy spot will rotate to bottom.. place weights opposite heavy side.

I have 1" fore aft movement of handlebar due to riser rubber mounts and I see your handle bars don't appear to have vibration cancelling weights that are installed in each end of stock handlebars.

 

[Yazman]

I revved it in the driveway, and the vibration does start at mid to higher rpms. Now the bike runs like garbage though, so I have bigger problems. Check out my post in the engine forum if anyone is interested in helping on that issue. Thanks!

 

[Emil]

Being as your Rebel is 35 years old, I'd definitely check all of the engine mounts. The rubber will deteriorate with weather and age.

 

[leebrown66]

Some motorcycles consider it rude to discuss their age, let alone their sagging parts 🤣