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Discussion Starter #1 (Edited)
OK, I realize this is weird as most people prefer riding solo. I almost always ride alone but was giving a lift to someone today and was shocked but my bike really did feel better. More specifically, the rear felt more planted and the whole thing was more stable. Even in corners it felt great. How come ? Would it mean something's wrong with my suspension ? I've also been having issues with my rear tire recently as it locks up very easily. As soon as the pillion got off, I felt like the rear was about to lift off the ground under braking and it just didn't feel as stable anymore.

The bike is a Yamaha Fz150i so very lightweight.
 

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The ride over rough roads felt better.......sort of like my pickup truck with a load. Maybe that can be interpreted as more stable. But the handling in curves was worse and it felt like stopping distance was increased.
 

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Your bike is small, light weight, inexpensive and relatively nimble. As mentioned by @McRider01 the ride with a pillion may have been smoother and felt more planted by addition weight, but did you corner as normal, lean as normal, accelerate as normal? I'm not familiar with your bike, but most likely it doesn't have full adjustment of front and rear suspension, preload, rebound, compression, as other larger more expensive bikes may have. If not, that doesn't mean you cannot adjust the suspension, just that it may take switching out parts as opposed to turning an adjustment.

Generally, when you place more weight on the rear, as in a passenger, the rear end has more sag, that will increase the rake and trail of the front making the bike more stable at slower speeds and in relatively straight lines and mild corner (sweepers), but less agile in tight turns. This may give it a feel of more stability depending on the road you traveled. More weight on the back means it will normally be smoother over road imperfection as well. The difference in weight between you and the passenger can have an even greater effect. Things like tire pressure also come into play.

Heavier, longer wheel base, bigger bikes in general by design make better smoother, stable and planted bikes for cruising, where lighter, shorter, bikes are more nimble for carving canyons. The heavy cruisers feel less difference between solo and 2-up because the additional weight of the passenger is much less of a difference in total gross weight. Lighter bikes there is a much greater felt difference because the weight of the passenger is a larger percentage of the total gross weight.

For every bike and solo rider combination, with all else being equal, there is an ultimate suspension setup and tire pressure depending in the drivers style of riding. Putting 100 or so pounds on the back and all those settings will need to be changed to return it to ultimate. Without changing the suspension or tire pressure what you feel could be better or worse, depending on where you start from as a solo rider.
 

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As soon as the pillion got off, I felt like the rear was about to lift off the ground under braking and it just didn't feel as stable anymore.
Sounds like you don’t have the suspension set for a single ride. Plus you may be braking incorrectly. Front first then rear, maintain more front than rear. It almost sounds like you only use the rear brake. That’s a sign off pending disaster if that’s what you are doing.
 

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Discussion Starter #5
Sounds like you don’t have the suspension set for a single ride. Plus you may be braking incorrectly. Front first then rear, maintain more front than rear. It almost sounds like you only use the rear brake. That’s a sign off pending disaster if that’s what you are doing.
The thing is though, my bike doesn't seem to have an adjustable rear shock.

As for the braking technique - not at all. I'm a fairly experienced rider (more than 2 years of riding, around 13.000 miles done so far) in hectic traffic having to perform emergency braking daily and practicing this and other maneuvers regularly. But I don't know much about the maintenance perspective.

I'm going to try lower tire pressure on the rear tomorrow although I never pump it up to more than the recommended pressure of around 33 psi and usually run it a little lower due to slippery roads full of potholes. I guess the next thing would be upgrading to an adjustable monoshock so I can reproduce the feeling of the bike with a pillion.

How about putting a slightly larger tire on ? Something like 130/70 or even 140/70 vs the stock 120/70. Would it make the bike feel more planted ?
 

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I don't think we have that model in my part of the earth but I would expect the rear shock to have an adjustment for spring pre-load.
If it does have that adjustment, back off the pre-load a bunch.
Or better yet, keep a pretty girl handy for your "pillion". :D :sneaky:

S F
 

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I'm going to try lower tire pressure on the rear tomorrow although I never pump it up to more than the recommended pressure of around 33 psi and usually run it a little lower due to slippery roads full of potholes.
You might be onto something. Are you certain the gauge you use is accurate? I have or rather had one gauge that was measuring almost 10 pounds more than my other gauges. It's history. But you might have a similar one. Mine was the pencil type that measured up to 200 pounds or something really high, I can't remember for sure right now without going to the garage and checking another similar gauge. I prefer the lower range gauges.
 

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Discussion Starter #9
You might be onto something. Are you certain the gauge you use is accurate? I have or rather had one gauge that was measuring almost 10 pounds more than my other gauges. It's history. But you might have a similar one. Mine was the pencil type that measured up to 200 pounds or something really high, I can't remember for sure right now without going to the garage and checking another similar gauge. I prefer the lower range gauges.
It's a pretty simple, analog gauge I have that measures up to 100 psi. No idea how accurate it is but I've been using it for more than a year and it never gave me any nonsense values. I'll take it with me tomorrow and compare it against whatever the mechanic uses because...

I took the bike to a different garage today and the guy said my rear shock needs to be replaced. Not sure if he meant it's non-adjustable and needs to be replaced or just the latter, but he's the second guy who suggested this recently. I didn't really trust the first one because I had bought and installed this shock absorber at Yamaha less than a year ago so I didn't think it would break so quickly.

Either way, I've ordered a better, adjustable rear shock (YSS) and will have it installed tomorrow so fingers crossed it'll make the bike feel better.

Thanks for you help guys. I'll let you know if the problem has been fixed.
 

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Discussion Starter #10
OK, so I've got the new $140 YSS gas shock absorber installed.

Feels like a different bike now to be honest, but definitely better. The rear tire doesn't lock up that easily anymore so it's made a huge difference. I took it for a spin and asked the mechanic to adjust it and make it a little softer and more comfy, but he said it's because the shock is new and that it will get softer. He definitely seems to know what he's doing, but is he right ?

Not sure about the cornering yet - it just started drizzling as I was testing the new suspension so in the first corner I tried to take more aggressively the rear started sliding. Not exactly the best conditions and I didn't want to risk crashing so I'm going to wait for a proper cornering test till the roads are dry.

Even throttle control is easier now. My bike used to be jerky when opening / closing the throttle - now I know it was the suspension.

Now I just need to ask a cute, petite girl to help me test ride the bike under load :D
 

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Good to hear you are getting improvement. You paid $140 and got a magic shock that improved the throttle, that's interesting. And it even improved your rear brake, I want one of those!

One of the first things to do with a new bike is to adjust the suspension and tire pressure. This would be the same with a new shock. Of course you have to ride it a few miles to test the difference from the old shock and determine what adjustments need to be made. As time goes on you may need to make additional adjustments as you get used to the suspension and/or your riding style changes, or your total gross weight load changes.
 

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I don’t know what you are calling aggressive in corners, but a little moisture should not be causing the rear to break traction unless you really nailed it. What kind of tires and how old are they? It almost sounds like you might need new tires as well.
 

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Discussion Starter #13
Good to hear you are getting improvement. You paid $140 and got a magic shock that improved the throttle, that's interesting. And it even improved your rear brake, I want one of those!
Are you being sarcastic ? :D

@hogcowboy, it was a slow, almost 90 degree corner right by a lake and I think I might have hit some oil. But yeah, the roads were really slippery - even my riding boots were sliding easily when I put my feet down to check. Anyway, it's happened just once so I guess it was due to the road condition and/or me not being used to the different handling characteristics. I've done some 25 miles today and, with a cute 100 pounds on the back, the bike felt very good, including in corners. I'll go for a proper solo ride tomorrow to make sure it corners well.

But yes, I might have to change the rear tire. I bought a new set of Pilot Street tires around a year ago. They both still look good, but the rear has been repaired after I got a flat which might have compromised its performance.

P.S. My gauge turned out to be slightly inaccurate - reading approximately 2-3 psi low. Not a big deal but good to know.
 

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Are you being sarcastic ? :D


P.S. My gauge turned out to be slightly inaccurate - reading approximately 2-3 psi low. Not a big deal but good to know.
Yes, no, not really and I meant no offense. As we know the shock is not connected to the throttle nor the rear brake. It should not have caused any significant change to either a jerky throttle or rear tire locking. There may be a mild felt difference in the way the bike rides and handles but nothing directly to address either of those ills. Unless your rear tire momentary locking is due to popping the clutch when down shifting, there should be no direct changed due to replacing the shock.

You started a thread with a reasonable question due to your inexperience, received several valuable replies, and you expressed how you have addressed the problem and making headway. All is good. However, reading your responses you may be making inappropriate conclusions and that was my point, although I did not spell it out, so hopefully I have done a better job with this reply.

Also, your tire gauge being off 2-3 pounds, if it is off that same amount throughout the range of pressures you will be using and you account for that, then I would agree, "Not a big deal but good to know.". I would want to have confidence in the source I compared it to and determined it's inaccuracy, but more important is to know that 2-3 pounds one way or the other can make a huge difference in the performance of any tires we may use. The other importance is that we use the same gauge while making adjustment and checking the cold pressures.
 

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Discussion Starter #16
No offense taken at all. I just asked cause I wasn't sure if you're being serious. And the reason I wasn't sure is, well, because the new suspension has had a huge impact on how my bike behaves and I'm sure of this. I know it may sound to you like an inexperienced rider having the placebo effect, but:

a) the throttle: I've never been satisfied with how smooth, or rather how jerky the throttle on my bike was. Not all the time but mainly when opening the throttle from fully closed without the clutch in, but also when closing the throttle. I had been trying many times to be as smooth as possible, without taking too long, but it never really worked. Until I got the new suspension. Same skills on my part obviously and nothing else was done to the bike since I watched the mechanic the whole time and yet it's noticeably smoother now.

b) the rear locking up: Let me clarify here. I didn't mean that with the old suspension the rear would lock up all the time and now it never locks up. But for maybe 2 weeks before changing the suspension I could definitely feel something was wrong with it to the point I was going to ask the mechanic to change the brake pads. Because of where I'm living and how dangerous it is riding here (for reference, 3 very close calls in the last 4 days), I have made it a habit to practice emergency braking at night on a quiet road, especially since I have no ABS, so I know my brakes very well. And the issue wasn't that the rear would lock up under full pressure - that would be totally normal for my bike. It would lock up under moderate pressure, to the point I had to adjust my braking technique and almost exclusively use the front brake - something I had never done before. However, as soon as I started riding with the new suspension yesterday, I noticed the problem is gone and even stronger rear brake application doesn't lock up the wheel.

Now, I'm no expert (which is why I'm asking you guys here :D ) but it seems to me that it's got to do with weight transfer. I suspect my old shock might have been badly damaged and/or the low weight of my bike might play a role.

I'll keep an eye on the throttle and rear brake and let you know if something changes.
 

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Now, I'm no expert (which is why I'm asking you guys here :D ) but it seems to me that it's got to do with weight transfer. I suspect my old shock might have been badly damaged and/or the low weight of my bike might play a role.
That's it exactly. Sounds like the old shock was toast. I'm glad the new one has made such a dramatic difference. I do question the throttle part though. I really suspect the throttle cable is just redistributing what little oil might be left inside the shrouding of the cables. It sat unridden for some time didn't it? Did the mechanic that changed the shock take it for a test ride? He may have noticed it and really worked the cables hard to try to free them up. Something like that makes more sense to me than shocks making that much or any difference except for in cornering. And there, yes indeed the shocks would make a huge difference in the way the throttle would feel.
 

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Discussion Starter #18
OK, what you're saying about the throttle may be totally right because today it didn't feel as smooth as yesterday. And yeah, he did take it for a ride. If that's the case, what needs to be done to make the throttle smoother ?
 

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Lubricate it to start with to see if that frees things up. There are some excellent YouTube vids on exactly how that is done. Look for anything that might be binding the cables too.
 

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Also possible the service tech found too much slack in the throttle cable and adjusted it right quick.
I do that ALL the time with clutch cables. (Usually not enough free-play in those).

S F
 
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