3G steering issues (?)

Well, the bike is finally together enough to get some seat time on the 'new' VFR. It's a streetfighter conversion as the PO threw it down the road and the upper plastics, gauges, lights etc were irrepairable. Still waiting on the full computer setup from Acewell but at the moment I'm running a cycle computer for speedo and tripmeter.

I've noticed that this bike seems to fall in a bit and have very heavy steering in slow corners compared to the 4G 94-97's and VTEC VFR's I've ridden, even compared to my old 625 pound yamaha FJ1200. I'm not sure whether this is my cable routing binding up at the steering head, bad steering head bearings, or just the nature of the beast (which I doubt as it feels dangerous in slow speed maneuvers). Seems to smooth out a bit with speed, but corner entries take a lot of muscle and it really lacks front end feel. Come to think of it, this might explain the PO throwing it down the road.....

Anyone with suggestions as to what to look at?? The bike has been lowsided in the past but nothing appears to be bent under the plastics. No obvious notchiness in the steering head bearings or anything like that.

 

Cool bike. Got a 4th gen fighter myself. As far as your steering, i would start by turning it to one sides steering lock and checking the tension on your cables/hoses. It won't hurt to inspect and grease the steering head bearings either. have to let us know how the Acewell works out and the work needed to set it up. all so don't know if you checked it out but heres a good street fighter web site.
www.customfighters.com
Good luck

 

Hows the tires?

 

The bike is running BT012SS battlaxes front and rear, 120/70-17 in the front and a wider 180/55-17 rear. The front has about 30% left with moderate cupping, certainly less than the point it has been an issue on other bikes, and the rear is about 50% or better, but almost imperceptibly flattened in profile at the center, smooth in radius but a slightly flatter profile than new.

Maybe a combo of the larger rear tire (IIRC the manual calls for a 170/60 even though the bike has a 5.5" rim) and the slightly flattened profile in the rear???

I'm certainly open to suggestions. BTW, I'm running 36 psi in the front and 40 in the rear.

 

Thanks, rear tire size is fine, yep any squareness we give you a weird feeling and the cupping front don't help at all, try going 33psi both front and rear those BS are a good tire still sounds like they've seen better days IMO doubt very much it's much more than a tire thing here. but on thing you can do thats pretty easy, that's if you have the center stand. is to get the front of the ground and double check for smooth transition from right to left, should move really fairly easy (pinkie finger easy) feel how the head bearing act, you'll know if it doesn't feel right, but actually there's very if any turning done once over 5mph so that takes me back to the tires.

 

Have you checked for bad steering head bearings? If not, put the bike on the center stand and have someone sit on the passenger seat to hold the front tire off the ground. Then slowly move the handlebars to the left and right. If it feels like there is a notch, especially when centered, then this indicates bad bearings and it might contribute to your steering problem. If they are bad you might consider replacing them with roller bearings. Good luck.

 

Thanks a ton for all the feedback, guys.

Having ridden it a bit more after freeing up all the cable routing and checking the steering head bearings (which are fine as best I can tell) I'm inclined to believe that this bike is perhaps more sensitive to tire profile than previous bikes I've ridden. Once it's leaned over, the stability is there - it's just that it really has a funky turn-in behaviour like it wants to fall in on slower corner entrances, feels a lot heavier than I expect for initial turn in on faster entrances, and is *much* more sensitive in its attitude to throttle input in the corners than my FJ or CBR were. Really likes to stand up on even moderate throttle and run wide, and drops in when the throttle is closed on entrances until you pick it up near the apex.

With such a minor amount of flattening on the rear, I'd be surprised if it's just that the bike is that sensitive to tire wear. I've ridden a Honda Hawk with the Single sided swingarm, and that bike was nearly impervious to noticing profile changes as the tire wore. Ditto with CBR's I've ridden.

I'm wondering about going to a new set of tires with a 170/60 - 17 rear as called for in the manual. There's probably another thread for 3g tire suggestions, but any thoughts on tires that work well on 3G vfr's for neutral handling, and whether the turn in is significanly more nimble with the 170 (without major tradeoffs in rear traction on corner exits?)

 

Bob, I've checked the bearings on the stand with an assistant, and while they appear fine, I'm tempted to try the roller bearings anyways if they will improve the steering feel and feedback on the bike. Can you tell me what the impact was on your bike, and where you sourced yours?

Thanks.

 

How is your tire pressure? I know stunt junkies like to lower their tire pressure quite a bit to get extra grip when doing stoppies and such.

The other thing I can suggest is add 3-7mm of shims to your upper rear shock mount. This will increase your ride height a bit, but it will also steepen the rake on your forks making for quicker turning. BE WARN, too much can cause your bike to be unstable.

 

And the winner is.... tires.

Just went for a 155 km 'shakedown' run this morning and although I did change the front wheel bearings (no play but a bit more drag than there should have been) with new AllBalls units it was IMHO totally a tire thing. I went to the Conti Road Attacks and after starting gingerly to scrub them in they are now right to the edge on the right and about 1/8" of a chicken strip on the left (ran Thermal Drive in Ioco for the curious Vancouver area BC'ers)

The confidence factor with these tires is amazing, the steering is light, linear and precise and they feel solidly planted with more grip than the (admittedly old and in poor condition) Bridgestone BT012SS tires that were on the bike before. On one corner with rocky poor pavement at the apex the little slide was more of a gentle push and extremely controllable with great feedback.

This with an OEM size 170/60 on the back instead of the 180/55 that was on it (I'm sure a part of the better turn-in), and running OEM recommended tire pressures of 36/42 psi. I'd highly reccomend this tire. It may not have the absolute grip of a hypersport tire (which you might use if you like to be ham fisted with the throttle at full lean) but the tradeoff is light, light steering, great feedback and a nice ride to boot. Did I mention they're cheap too??