Some suspension questions for you guys

[JonGu]

I had a few issues while racing with my R6 for the first time at a track that I'm used to and noticed some issues that I wasn't sure how to fix.

Problem #1, the bike is very difficult to turn while on the brakes. I normally try to turn in while braking and trail it in to the apex with my other bikes but on the R6 I just can't do it. I have to let off the brakes significantly just to initiate turn in.

Solution... tires too soft? I've heard a lot of guys that run Pirellis are using the harder compounds because the soft compound buckles too much under braking and makes it hard to turn. Or is it a suspension set up issue?

Problem #2, the bike tends to run wide, it doesn't seem to matter if I'm on the gas or not. It's just hard to hold the line. For example, a right handed carousel at Blackhawk Farms, normally I turn in, clip the apex and then go hard on the gas all the way through. If I do the same thing with the R6 it runs all the way to the edge of the track and I have to wait almost a second past where I normally get on the gas to accelerate.

Solution... Usually I'd correct by raising the rear, but on that bike its already jacked up too high anyway so I don't think that is the issue. Not sure where to go from there.

Problem #3, the bike overall just feels nervous and not very well planted. Turn-in is nervous and it's just not a very comfortable ride in the corners. I think this is related to the problem above. Feels OK on turn exit though except for the running wide issue.

So let me know what you guys think. And BTW, yes this is Ryan's old R6 that I demolished at Road America. I got her back up and running, nowhere near as pretty as before but it is a damned good bike. Even with all the suspension issues I had, I ran almost a second faster than I had on my ZX6R, with the same top speed (126mph vs 127mph) shown on my GPS timer. I attached a pic if you wanted to see the new paint job. It is now sporting the Team Hunter (milfhunter.com) gas tank and rear wheel And yes I already bought the pics

Thanks for your feedback!

 

[TheGrouch]

Sounds like the front end needs softened up (less spring/preload/comp damping). Has the sag been rechecked? Are you using all of your travel? In that pic it looks like the forks are at almost full extension. That seems odd considering the lateral G's generated in the carousel.

 

[JonGu]

Sag was set up some time ago with Lithium, I believe 36 in front 32 in rear? I tried loosening the front by a few clicks both comp and rebound but it felt worse. I loosened the rear up also by 2 clicks on both comp and rebound and it felt better. I'm thinking in the carousel pic that the front is extended because it is a corner where you are pretty hard on the gas except at the entrance. Zip tie on the fork shows that almost full travel is used, about 15mm from bottoming out.

 

[Andrei]

Jon,

It seems your bike has no rebound damping on the front. It must stand up waay to quick now that you say it feels "nervous" and very difficult to turn in (and then runs wide). Have some look at how you bounce the bike. Geometry is important. But when braking and accelerating geometry changes by inches withing fraction of a second. rebound and compression is everything in controlling dynamics of that.

Too hard on front compression will manifest in different aspect. The bike will start pivoting around the front axel on the brakes, which should feel like rear comes of the ground every time you brake.

Andrei

 

[sobottka]

The running wide could be a number of things shock related (usually too much squat), such as- too much rebound, too little compression, not enough spring or even not enough ride hight (not likely on an r6). All these things will cause you to run wide on corner exit. The turn in could also be a number of things (fork related) such as- too much spring, too much compression, too little ride hight or even improperly built forks. All these things could cause turn in problems. I dont run pirelli's so I dont know about your tire theory but i guess its possible. Are you going to putnam? if so I will be there sunday and would be happy to look over your bike and give you my opinion :dunno: -Rob

 

[beechkingd]

Assuming the spring rates are correct for your weight and your sag is set. My guess for #1 is to little front rebound or the forks could be bottoming out so you might need to increase preload a turn or two. (could be a combination of both though)
#2 sounds like you need to increase rear compression damping, if it was to much rebound you would have mentioned the rear end sliding around a lot after the apex, to little rebound it would be bouncing a bit.
#3 sounds like to little front rebound.

 

[JonGu]

Thanks for all your input guys. Too bad I can't do any of this stuff until next year but it's good for learning.

The front springs were swapped out earlier in the year from .90's to .95's, which helped tremendously with the rear end coming up under braking and in just making the bike feel more planted. The only issue with tightening up the front is that I'm already out of adjustment. Maybe I need to get those Ohlins R&T forks revalved for me.

Rob, I'm down in Florida right now for Daytona. Thanks for the offer though, although you shouldn't be offering help to your competition for next year. I'm going to wipe the floor with you if I can get this bike sorted out or at least I will be in my dreams

 

[beechkingd]

JonGu;21094 wrote: Zip tie on the fork shows that almost full travel is used, about 15mm from bottoming out.

I don't know R6's but on a lot of bikes the forks bottom out internally before the axle fitting.

 

[JonGu]

Forgot to mention, the forks are not stock, they are Ohlins Road and Track forks, if that makes any difference.

 

[beechkingd]

Actually, I'm almost positive that they bottom out right at 17mm from the axle casting. I'm not positive on the 17mm but I remember the Ohlins were one of the examples of that in the video I have that were made by Dave Moss about the Ohlins forks on a f4 agusta. I would recommend his videos.