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280 kit and BAD handling

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I need your help....

I have been racing (GNCC) my 01F since Dec 2000. I know what the bike is supposed to feel like. At the start of this season I installed a Thumper 280 kit, along with hot cams and a Vortex ign and Dr D pipe,14th on front, stk rear. Now the same bike that I used to be able to "think" around a turn, won't turn to save my life!!! I have tried everything (clickers, sag, fork height, diffrent tank, diffrent valving both ends). Nothing I have tried even comes close. I am ready to trash the big bore kit and go back to stock. I really don't want to do this cause, in current form, this thing RIPS!!!

Please help....I'm getting tired of this bike slaming me to the ground.

Thanks,

Jeff

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I have pretty much the same kit. I never noticed a problem, and I think it handled as good as my 04 25f which I just sold. Raise the forks 5mm, run 95mm sag, go back to 13 tooth in the front.

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How can you run the stock gearing? When I run with the 13 on front I can't keep the front wheel on the ground. The motor trurns up so quick I am always on the rev limiter, even in 5th. The 280 wants more gear and can pull it with no problem.

I will try the stk gearing again this weekend, and see if that effects the handling in any way.

Thanks for the input,

Jeff

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instead of 14/48 maybe try 13/45 or 44?

your motor mods really should NOT have affected handling in the ways you describe unless..... :thumbsup:

how much chain slack do you have and where are you measuring it?

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I know this is probably a stupid question but... any chance your front axle is pinched from the last tire change? :thumbsup:

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I too tried a 14t on the front and liked the gearing change but moving the rear wheel forward increases the traction and made it a stunt bike, now I have 13/50 or 49 and have good gearing and the front tire gets used now.

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The only way I can think of for the power to effect the handling if for the bike to "pull" me farther back on the seat put more weight on the rear of the machine and "lighten up" the front end. But this will only happen when I am against the throttle stop. The bike handles poorly under ALL riding conditions, even coasting. This is why I am so confused....

I have 2 01's. one with a bad motor, and the big bore. The old one (bad motor, but still runs) is ridable and handles perfect. So, my thinking is to swap motors and see if that does anything. I did and now the old bike handles like $hit. All I did is swap the motor and change the gearing (the big bore does not like stk gearing). I have the motor set-up for low-end power. With the stock gearing 1st gear is usless and the motor revs so fast the other gears are VERY short, and I am constantly shifting to keep the motor from blowing up. Late in the races(3+ hr mark)I have run with the stk gearing, I can't rember what gear I'm, and bad things start to happen....

I will check my sag again tonight, and let you know where it is.

Chain is at 2 fingers at the end of the guard.

Jeff

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Good point about the axle wheel change. My handling had gone straight out the door and I couldn't figure out why. So I thought it was the steering head bearings. So, after I get the new bearings to the garage, I start taking things apart, starting with the axle. I hear a POP, and start thinking to myself, SUMBICH!!! :thumbsup:

So I decide to put crap together and try it out, and wouldn't you know, handling problem cured. :devil: So now I have a nice set of steering bearings for when they do go out. :awww:

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Chain is at 2 fingers at the end of the guard.

Jeff

jeff,

2 fingers is NOT enough (unless you wear a size 25 ring!).

needs to be 3 fingers at the buffer hold down bolt.

other good comments posted above as well.

so does the bad motor in the other frame ride fine?

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....I'm getting tired of this bike slaming me to the ground.

Thanks,

How is the bike putting you down, frontend washing out, ass end coming around, low/high siding?

:thinking:Just a thought, could it be a mental thing? Your stock 250F handled corners with ease right? Since you built up the engine your trying to step up your racing, true? Could it be your concentrating on the performance of the bike rather than riding smooth? The big bore is causing you to entering the corners faster so your breaking a little harder, it's also got a little more compression breaking, when you go back to the gas it's coming on harder. These thing can now be distracting you from your natural flow through the corner. If your thoughts are being directed to the bike rather than flowing through the corner it'll be throwing your timing off, you could be tightening up a little and we all know when you ride tense things start to go to hell.

You know the bike is running good, you know how to race, now go out there stop thinking and just let things flow again. :thumbsup:

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I have yet to install the "bad" motor in the other frame. I had planned to rebuilt it while it was out.

I don't see how it could be any of the bearings or "binded" forks (pinched axle), the bike was perfect before the motor swap. Nothing else was changed, only the motor and gearing.

With 2 fingers (loose on fingers) at the end of the "slider", the slack measures ~1 3/4" from the hold down bolt to the centerline of the chain.

I forgot to mension the bike that had the big bore kit in it, handled very well before I put the kit in. I purchased the bike from a friend of mine and raced it a couple of times before I installed the kit. I even won the first race I ran it in... :thumbsup: I couldn't believe how much more power it had than my wore out bike (before the kit).

I will attempt (again) to check my sag tonight and measure the fork height.

Thanks again guys,

Jeff

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your are exactly right, that IS what is happening, but only after a short time in the woods. I can normally "think" my bike around "things" (roots, rocks and turns). I know my bike will suck-up the nasties on the tail and I know it WILL turn when I tell it to. I focus on the trail about 30' in front of me and set-up for anything the trail and other riders throw at me, and all is well in the world...

Here's what happens NOW....I am on the line with a positive attitude waiting for the flag to drop. 10 seconds...now were off. Hey I finially got a good start (3rd in the woods. 4stk A class). I am staying up front, but the bike is all over the place and wont hold a good line. It is pushing in the corners, and causing me to have to correct comming out of the turn, now I am off line and the leaders are leaving me. This continues untill I'm not racing anymore, I'm just trying to get back to the truck without killing myself. I have lost ALL confidence in the bike. When this happens, you can't race the bike, you are out for a very bad "trail ride". The harder and more aggressive I tend to ride the better the bike reacts (well, used to anyway) :thumbsup:

You are correct in that I have tried to step it up a notch.

I moved to 250A for the last 2 races of the year last year and during thoes races my bike was handling better than ever. I wound up taking 7th and 5th at thoes races. The reason I decided to move up this year was based upon how good the bike felt. Now this was on the wore out motor. It wasn't going to last a few more races, much less another season. Hence the "new" used bike and the big bore kit. Thats where we stand today, riding like a spode, and getting passed by guys I was lapping last year. Needles to say, that is why I am so frustrated. I know what myself and the bike are capable of, I just can't make it happen.....

Jeff

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ok...just checked my sag and it is way off...almost 5" (4 7/8). I am in the process of adjusting it, but I think my shring is going to be too soft. If so, I have another shock I can try. Forks are set at 9.3mm from the top of the cap to the triple clamp. I can raise or lower according to what the sag adjustment does.

I will keep ya'll informed,

Jeff

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5" of sag will certainly make it handle like a non-turning slug.

so, does 9.3mm of fork showing expose the first ring on the tube or not?

i set mine at the first ring for turning in the woods.

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I don't think your 280 kit should affect the handling of your bike, I think your handling problems are either related to crash damage or worn out suspension components or misaligned wheels. I would check your rear wheel chain adjusters, I use a measuring tape to make sure both chain adjusters are set to the same length. I never use the adjuster marks on the swingarm. I would try running your chain a little loose from your current settings, I use the three finger method next to the chain buffer pad. When was the last time you serviced/greased your rear shock linkage and swingarm bearings, if it's been long time since your last service, the suspension and linkages maybe binding or frozen bearing which all could affect your handling. I would loosen all of your pinch bolts on your triple clamps, drop your fork tubes so only 5mm are showing above the triple clamps and then retorque to factory specs. Lastly, check your front axle for proper alignment, loosen pinch bolts and axle bolt, apply front brake and compress front forks 5-6 times then retorque pinch bolts and axle bolt to factory specs.

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9.3mm does expose the top ring, not quite the second. After adjusting sag last night I rembered I had to change shocks when I put the big bore in this frame (I hate getting old...I can't rember anything :thumbsup:). So, it would appear that the shock has been the problem all year( although I haven't ridden it yet). I will need a heavier spring, I am just past min spring height at 100mm. O well, I'm just glad I found something wrong :devil:.

David37....thanks for the info, but I have checked all that. I think it turned out to be something VERY simple (incorrect sag), and I was so frustrated I was "over thinking" the problem.

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