Author Topic: Front end "hop" at 35 mph.  (Read 9845 times)

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Offline Retro Rocket

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Re: Front end "hop" at 35 mph.
« Reply #50 on: July 06, 2009, 12:51:30 AM »
Quote
I'm voting for the hard tail and less than optimal brand front tire

I spend a lot of time making my bikes handle as good as they can. I would junk the cheng shin {only ever used one and it nearly killed me} and stick, at least, a pair of shorty shocks, sounds like the rear is transferring the road irregularities to the front of the bike, deadly in corners.........i don't get the rigid thingy on a stock framed bike, as far as i am concerned it is a recipe for disaster.  Each to his or her own i suppose but safety first for me.

Mick

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Offline johnny_from_bel

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Re: Front end "hop" at 35 mph.
« Reply #51 on: July 06, 2009, 12:54:53 AM »
I have the same problem. I am posting this to tag along.

Offline Inkscars

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Re: Front end "hop" at 35 mph.
« Reply #52 on: July 06, 2009, 06:07:11 AM »
I'm certainly not running the struts for looks. That's for sure. I'm short, at least in the leg. The bike had the struts on it when I got it, and the front end sat up too high, so I lowered the front so it wouldn't have to be driven around all uneven.
Havoc shortened some shocks for me, but it seems with the front lowered as well, I bottom out too much with the struts on there, I can only Imagine the shocks would be worse.
The hop is definitely related to the road. On smooth bits of road, it completely goes away at all speeds.
When I first experienced this issue, I found my pressure in my tires to be under 20lbs. After adjusting them just under 30, I found that the hop had gone. Now, where I live, in johnson county, I would call it a nicer area, most the roads are newly paved and had minimal potholes and uneven pavement. Most of my riding is done in johnson county.
Now, where I went the other day, in kansas city, mo, isn't well known for their roads.
I was on vivion east of choteau trafficway.

Anyway, all that aside. I'm not made of money. I'm currently accumulating parts for a complete rebuild of the engine, and I'll be painting my frame and cleaning up my wiring and etc etc etc. I really don't have any problem putting different tires on it if it will make it handle better. However. I simply DO NOT HAVE 200 dollars to spend on 1 tire.
If someone can recommend a decent tire, that are readily available, that don't cost an arm and a leg, I will absolutely consider it. When I bought the tires I have on there now, I just wanted some new rubber, cheap, so I could get a feel for riding. This is why I also haven't gone much farther on my build. I'll just be redoing it in a few months anyway, and I wanted to ride it NOW. hahaha.   






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Offline mlinder

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Re: Front end "hop" at 35 mph.
« Reply #53 on: July 06, 2009, 07:52:03 AM »
What do you mean, bottoming out with a hardtail? You mean the front is bottoming out?
What is your inseam? I'm sure someone has some shorter shocks they could send you for a reasonable amount.
Before you spend money on painting the frame and rebuilding the engine, make your bike safe to ride.
I'm sure the cheng shin is fine for now. You need suspension, though.
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Offline CBGhia

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Re: Front end "hop" at 35 mph.
« Reply #54 on: July 06, 2009, 08:19:00 AM »
If your front tire is new, don't worry about it.  i have the same brand of tire, but they are brand new and they have not let me down, and I have never felt like I would lose traction at any time (I am a somewhat spirited rider, but I am not dragging my knee on a 110 tire).   

You might try a heavier fork oil to help dampen the front end a bit.

I think that the hard tail is adversly effecting the handling on bumpy roads, but the heavier fork oil might keep it from bouncing too much. 
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Offline HavocTurbo

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Re: Front end "hop" at 35 mph.
« Reply #55 on: July 06, 2009, 09:09:04 AM »
You mean I go to all that work to get you and Ben out my way just to say hello.

And not only do you not mention me in the MVR thread but you haven't even tried them on yet?!?!?!?!?!

WTF!!

 :D :D :D

Seriously give em a shot. Ride it like that for a few days. If you don't like it change em back.
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Offline Inkscars

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Re: Front end "hop" at 35 mph.
« Reply #56 on: July 06, 2009, 09:13:49 AM »
With all do respect, Why would I rebuild an engine for a motorcycle that is unsafe?
I'm certain I've projected that I'm not just "throwing" it together for next season.
Please give me SOME credit.  ;D
I will be replacing bearings, fork springs, bolts, nuts, fluids, cleaning up wiring, finishing my seat, getting actual shocks, I mean, I'm doing it the right way. I'm not gonna treat it like some trashy 20 year old throwing a revamped 350 into and s10 that doesn't even have floor pans.
It's a solid, reliable bike, that has potential to be a first bike that I could still have when I'm in my 50s. Even though I how it looks like the whole "rat bike" thing, it really does run and handle well, and I don't lose parts while riding down the road.
My inseam is a 30. I've only had people with 550s try and assist me in ride height issues. I believe my issue is that my frame is wider where I sit than on a 550. By bottoming out, I mean my exhaust scraping. Not the whole bike. The joint where the pipes meet on the kerker is very close to the ground anyway. I'd really like to find some sidewinders in non-leaking condition for a good price. that would solve my scraping issue.
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Offline HavocTurbo

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Re: Front end "hop" at 35 mph.
« Reply #57 on: July 06, 2009, 09:25:06 AM »
What are you using as a seat now?

The 750 is wide sure, but there are a few things that can be done to overcome the height issue. Exhaust is one of them to allow for lowering.

Another would be to shorten your struts. But if you scrape exhaust now...
'48 HD Panhead - Exxon Valdez
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Offline mlinder

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Re: Front end "hop" at 35 mph.
« Reply #58 on: July 06, 2009, 09:37:24 AM »
30 inseam should be fine with pretty much stock height.

Go ahead and throw on the shocks ASAP and see how she does for you.
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Offline Inkscars

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Re: Front end "hop" at 35 mph.
« Reply #59 on: July 06, 2009, 09:41:42 AM »
I could barely tippy toe with the "stockers" that I found to put on there. I'll put them on tonight and take her for a spin. I'll report back tomorrow.
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Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Front end "hop" at 35 mph.
« Reply #60 on: July 06, 2009, 01:41:45 PM »
There have been/are shock lowering blocks/things on EBay.


I've been running Bridgestone Spitfires on mine. Like em fine.
« Last Edit: July 06, 2009, 01:44:49 PM by Jerry Rxman Griffin »
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline Inkscars

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Re: Front end "hop" at 35 mph.
« Reply #61 on: July 06, 2009, 02:20:29 PM »
What'd those run jerry?
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Offline Alan F.

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Re: Front end "hop" at 35 mph.
« Reply #62 on: July 06, 2009, 04:36:22 PM »
I had a little hop issue like this on my Nighthawk, my little hop wasn't scary but noticeable for sure. It would regularly happen only at certain speeds even on decent roads. My rear shock preload was set on the lightest setting by the PO, and I never messed with it until recently.  I cranked the preload up all the way but then it rained for 3 weeks straight... finally got to take the thing out today any burn up most of a full tank. No hop whatsoever.
I'd checked or changed everything else that could have caused it.

My point is that although I had changed rear spring preload, I wonder of changing your front fork springs' preload spacers for longer ones will do the trick for you while you keep your struts.

KingCustomCycle.com comes to mind for someone I'd ask directly since he builds hardtail bikes, I wonder if he changes the preload spacers in his bikes?

I'm gonna search around for more references.
-A

Offline Retro Rocket

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Re: Front end "hop" at 35 mph.
« Reply #63 on: July 06, 2009, 04:50:55 PM »
Hi Inkscars, if you put shocks on for a try, make sure you raise the front as well or it will sharpen up your steering and could make it a little "twitchy" or even unstable.

Mick
750 K2 1000cc
750 F1 970cc
750 Bitsa 900cc
If You can't fix it with a hammer, You've got an electrical problem.

Offline Jerry Rxman Griffin aka MuthaF'er

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