| Author | Message | ||
     Fast1075 |
After another spooky run-in with twitchiness when i crossed a paint stripe and hit a slightly rough patch of road...I am dead set on "fixing" it...it did it bad when i first bought it...when i changed from the dunflops to the Pirellis it seemed to "cure" the problem...the problem has returned as my confidence and ability has improved i push it a bit harder...just poking along it is not a problem..but amp it up a bit and it gets scary...specially in lefthanders. Looking at it logically...it's not my weight...im only 150 dressed out...the tires are properly inflated...the wheel bearings and swing arm bearings have no slack...the axles are not bent...they are properly torqued...the forks are properly torqued...the bike has plenty of rake and trail and actually steers heavier than my buddys zx10 so that shouldnt be the problem...hell that thing steers like it has a direct brain interface...you THINK it in a different direction. It feels like there is a hinge in the middle when it does it..thinking about it...it DOES have a hinge in the middle...the swingarm is attached to the motor...but the motor is attached to the frame with a flex mount front and rear...the wheels are held parallel by the tie links (excluding the lateral flex in the isolators..im HOPING there can't be THAT much lateral flex in the isolators) WHAT IF the tie links were never properly adjusted, causing the wheels to be out of parallel?? (if the links are set too short, the front wheel will lean right relative to the rear wheel and if too long, vice versa)...i think i will set the bike up on my lift and use a level to set the front wheel perfectly upright and check the rear wheel to see if it is out of vertical...what do you guys think?? im running out of ideas... | ||
| Gearheaderiko |
EZ claims above that its the swingarm. I dont doubt thats one piece of the puzzle, but there are others. I do know that when you get some miles on the Blast, none of the mounts are as tight as they were when new. An old worn Blast will feel like it has a hinge in the middle!!! The tie bars are set to a specific distance and shouldnt have be adjusted per individual motorcycle. Of course with wear that may change. Have you done anything to your suspension yet? There is really a lot you can do. You'll pay a price in comfort, unless you spend the big $$ for a rear shock and fork parts. Then you can more easily find a compromise (if thats what you want). | ||
| Ezblast |
Fork brace, and triangulate the swing arm. Tri-angulating the swing arm is going to be my next major project as well - lol EZ | ||
| Fast1075 |
Maybe I could see the swingarm flexing if I was REALLY throwing it into the corners...I'll check the alignment first and go from there...maybe the alignment squad was having a bad day...maybe the bike has been down hard and fixed with a tweak in it..maybe the pencil thin front axle is twisting up under load...(if so, I will upgrade it to unobtainium or something)...I also just ordered a new set of tires...the fork brace sounds like a good idea but it don't FEEL like the forks are flexing (no twist on hard braking). | ||
| Swampy |
Dem BIG tires make things work nice also.... Of course, what do I know....I don't ride all year round.... EZ can you splain the tri-angulation of the swingarm, it really seems to be a substantial piece, do you mean it is flexing from one axle mounting point to the other through the axle? Or is it flexing more towards the piviot end giving differences on axle ends when loaded in a corner? | ||
| Ezblast |
Yes - Terry said the neck is good, the area I questioned - that the steel frame is solid,however, he said the real week link of the Blast was the swing arm, which will flex/bend when enough power is applied to the rear - you can see that the swing arm is tri-angulated on the horizontal frame, but there is nothing strengthening the vertical plane - so if enough power is applied to the one side - it flexes, and if enough power is added - it bends. I figure it needs triangulating in the verticle plane - if you notice a lot of mc swingarms are tri-agulated in that fashion. EZ (Message edited by ezblast on December 02, 2008) | ||
| Gearheaderiko |
I honestly dont think the swingarm is an issue unless you're putting down some serious power. I think all the rubber will tweak before the metal. I know places in the frame that bend real easy. I do know a steering stabilizer will band aid the problem. But if you havent done any suspension work, added a fork brace or stiffened the mounts, I dont think you'll solve the 'articulated' problem with just one fix. | ||
| Ezblast |
What part of the frame are you talking about I have 2 I can look at - I don't see any area thats easy to bend - or I'd have done it - lol - yeah he was talking about more power - which is one kind of force, I think some fast hard turns could bring up forces as strong? On another train of thought - one of the first Blast racers noted that he had to shift his weight to the rear of the bike in real fast turns/transitions to keep things steady - perhaps this is what you may try to remedy your situation a bit. I know the faster I'm going the more I shift my weight to the rear and I haven't hit serious wiggling - yet. Of course my suspension is altered. EZ | ||
| Gearheaderiko |
I think you were right when you mentioned the neck. You've done enough work on your bikes to see how it moves around when disconnected and the only thing that stops it from moving is the rubber bushed tie bar (soft rubber bushed). It would also make sense that if you moved further back, you'd take some weight of the neck area too. Certainly some hard cornering would bring up the forces on the swingarm. | ||
| Fast1075 |
I did a quick check last night and the front end looks to be a degree or two out of vertical compared to the rear wheel using an angle finder..i will jig it up while i have the wheels off this weekend to mount my new oversize Viper Strykes to be sure...one possibility i want to eliminate is the flattish center of the rear tire (Pirelli with 3k on it) isn't contributing to the problem...and i will pull all the bodywork off and take a close look for anything wrong with the chassis...if the tie bar ends are getting worn i will replace them with aircraft grade heims. | ||
| Gearheaderiko |
Changing the tie bars to solid heims is a bad idea for a street bike. Race bike, fine. Changing any rubber mounts to solid is almost always a bad idea on any HD/Buell. You're bound to get stress fractures. However, the much talked about of late twin isolator is a step up as are tuber Buell tie bars which are much stiffer. Dont forget to add the 3rd 2000 model tiebar. The last week link is the rear mount. Though no better replacement (besides a new mount) that I know of is available, it too can be stiffened up (how you do that is up to you- but I know you're resourceful). | ||
| Fast1075 |
To catch up on this thread...after further review  the chassis seems to be straight as near as I have the equipment to check..(if it was a dragbike, I would feel very confident on it)....yesterday I went on the regular club ride and rode pretty hard. Taking into account the stock suspension, the bike handled pretty well...the tires made a HUGE difference in the way it handled (As everyone here predicted)..as one of the guys that rides an utterly sweet X-1 said..."I looked in the mirror and you were right there...the next straight and I pulled on you...but exiting the next turn, you were right there again" I rode mid pack on purpose so it wouldn't cause a lot of passing in the straights, I mean we are talking running with some serious machinery..two 1125's an assortment of XB's, toss in a couple of "zuks, a BMW, and a ninja or two...all in all a completely satisfying ride....with none of that scary stuff in the fast sweepers...maybe my bike likes old school bias ply tires best. | ||
| Krjoseph |
Anyone modified the rear shock by shimming the spring? Think you can do it again? I've got a spare Blast shock and don't feel like doing it myself. I've read the post, but don't feel like buying the spring compressor. I'll gladly pay someone to put a little shim on the spring for me. | ||
| Ezblast |
The shop quote I paid was 25 bucks, lol and they had to buy a new tool to do it - a fancy stand alone spring compressor - nice toy - KC is an old shop though and really know motorcycles, and they specialize in tires, wheels, accessories, service - type things - second generation now. EZ | ||
| Gearheaderiko |
EZ: Do you have the part number for the Race Tech gold valves? They seem completely clueless on fork springs and valves for the Blast. Do you know if the Blast front forks directly cross over (use the same parts) as anything else? (I do know the Ninja 250 and others are close, I dont know if they are the same). Thanks | ||
| Ezblast |
I used the Ninja 250 - lol EZ | ||
| Newsboyny |
Ok, so after reading through all the archives I'm confused as hell. LOL! Here's my situation: Lil Blastard got backed into by a Verizon truck while I was waiting behind it at a stop light. The damage is mostly cosmetic, but they're gonna have to do the fork seals and I'll have them replace the bushings while they're at it. (It's a 2001 with almost 15k miles, it's definitely time.) While they're in there, what other modifications do you recommend? Like most I find the Blast fork to be way too soft, dives hard under braking, and is about as stiff as a stick of string cheese. I weigh about 145 pounds. | ||
| Gearheaderiko |
Fork springs- Works performance or Progressive Suspension (either or both make springs). appx. $120 Gold Valves from Race Tech. order the Valves for the 2008 or earlier Ninja 250 (right EZ?). Race tech also does springs and they can be custom tailored for your weight and use (IE: race or touring) however, they dont have a clue as to what the Blast uses so they want you to send your forks to them so they can charge YOU to find out (but they will install the springs and valves for that price). I'd just change the fork springs unless you want to spend the $$ for the best handling you can get (appx $430+ shipping from race tech for valves and springs, installed). Adjust preload as necessary and add heavier fork oil as necessary (unless you get the gold valves)- but this may be beyond whoever is doing your forks. Confused yet? | ||
| Ezblast |
7.5 fork oil, gold valves, works spring, fork brace - and your front end becomes a much more stable and assured in the faster stuff, a stabilizer is still a flip of the coin in my book. EZ | ||
| Gearheaderiko |
Stabilizer: track use only, unless you're really aggressive all the time (seriously), otherwise its a waste of $$. It will hide many sins, but its better to fix them. The more your front end is dialed in the less you'll need it. | ||
| Newsboyny |
LOL...yeah, a little confused. But less than before. Race Tech doesn't appear to make gold valves for the Ninja 250, but they do make a "Fork Emulator Kit." This is the part list for the Ninja 250: http://old.racetech.com/evalving/english/Srchpr.as p?bikeid=277&manufacture=Kawasaki&model=EX250&year =86-08&TABLEINFO=street&langname=english http://www.phatperformanceparts.com/photos/FEGV300 1.jpg Is that what I want? Also appreciate if you guys can give your thoughts on the gold valve & 7.5wt oil vs stock valves and 20-30W oil. Is it worth the extra $100 or so for the gold valves? The Works Spring kit seems like a given, with a 3/4" or 1" spacer. I'll order a Superbrace once I find out if they're still making them, and how long it'll take to get one. And I don't think this will be beyond the capabilities of my shop, I'm having H-D of NYC do the work for me. | ||
| Ezblast |
Yes - the emulator is the ticket their 37 is too big, it seems our forks are barely 37 and the Ninja is a 36.8mm - thus the .02 milling job on the fork brace for the Ninja to convert to Blast, the valve-emulator though is still way in tolerance - this is all pretty simple work on stock Blast forks, after you modify them, they become more stubborn to take apart. - lol EZ | ||
| Newsboyny |
I've opted to leave it stock for now. I think the stealership is trying to take me for a ride. The service manager insisted on replacing the turn signal lenses post-accident, and they weren't even scratched! He's telling me the fork lowers are bent, and the front wheel bearing needs replacement. The wheel bearing I can believe, but the fork lowers being bent? Gimme a break. If that was the case the whole front end would be bent. Probably just needs to all be loosened up, aligned, and re-torqued to spec. I'm gonna let him do the lowers, I was going to have the bushings and seals done anyway, they have 15k miles and 8 years on them. This way I'll know everything that slides is brand new. (The fact that the other party's insurance is paying for it helps sway me.) Suffice to say I don't trust them to do what I say to the internals, I'll do that myself when I get it back. Ordered a Superbrace, they say they're doing a production run in 1-2 weeks. | ||
| Trufflehyla |
There is a lot of discussion about shimming the rear shock, but not much consensus that I could find with what hardware to use. Some stated pvc, others rubber hanger rings and I think i remember one conduit. What is the current thought on what to use and is 1/4 still the norm? I weight about 220, like to ride 2up with wife and am about to put on a Jardine which I'd rather not bump like the stock. Also is this a take to shop operation? I know theres a lot of power, but some people seemed to be fine with a motorcycle spring compressor. | ||
| Gearheaderiko |
1/4" is generally good for performance one up riding. If you want strictly 2-up riding I'd go with at least 1/2". Pvc or anything as sturdy will do fine, but more than 1/2" may require a metal shim  Removing the shock is easy (dont forget to support the bike), but it needs serious force to compress the Blast shock and a special spring compressor. Standard (aka Progressive Suspension tool {aka junk}) wont fit or work. Look to spend about $100+ for a tool that will work or find a shop to install the shim in the shock for you. I used a custom built tool for the job, but I really havent seen that many people list a tool that will work (they are available-but where?). A Badweb search should find the other tools available. | ||
| Gearheaderiko |
PS 1/4" at the rear shock = 1" of preload. 1/2"=2" | ||
| Rusty7983 |
i am trying to do fork seals. i have it torn down, what size is the center bolt on the bottom? its between 7/32 and 1/4. and i cannot find my metric set. i cannot find the size in any posts. thanks. | ||
| Rusty7983 |
i am guessing it is somewhere around 6mm. 7/32 is just about 5mm and 1/4 is just over 6mm. what has anybody used to get this bolt out? the factory manual says its metric, and shows a long allen wrench on a impact gun. | ||
| Rusty7983 |
fork oil weight is 7.5 or 10 right? if you go up on weight will it stiffen the forks up? | ||
| Rusty7983 |
ok, it was 6mm. i bought an allen wrench, cut it off and put my new piece in the holder from the 3/8 drive set. how do you get the seal and sleeve back in? the manual does it from the top. how do you guys do it that don't take the forks off? brass punch? |
