| Author | Message | ||
     17blast |
I'm in the process of modifying my swing arm for the xb shock. The center brace must be removed. Two clevises are welded to the under side of the swing arm where the brace was. A "U" shaped peace of tubing is bolted into the clevises. At the bottom of "U" there is a mounting hole for the shock. The fabing is almost done. I will give more info once I have had a chance to test it. | ||
| Spooky |
Matty, I'm referring to the Blast. | ||
| Matty |
And how did you arrive at that number? | ||
| Spooky |
That was the number that Works Performance gave me 3 years ago, when everyone here was looking for a shock to replace the stock one. | ||
| Matty |
Gotcha. That explains it. Thanks! | ||
| 17blast |
Here are the R1 front forks and the custom stem to mount them.   | ||
| Ezblast |
Using what trees? GT - JBOTDS! EZ  | ||
| 17blast |
The trees are off the 02 R1 that the forks came from. | ||
| 17blast |
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| Naustin |
17Blast - Those scans you sent me were in ".max" format, and I couldn't open them, even with photoshop. I'm excited to see your modified swingarm and XB shock setup. Moving the mount point to the underside of the swingarm sounds like a good solution to cope with a long shock assembly. In regard to the Honda 919 Shock I mentioned earlier, and assuming the estimate of 3" of increased ride height is correct (meaning the 919 shock has a similar spring rate as the Blast's and does not sag) than I estimated the approximate change in the steering head angle to be 2.5-4 degrees. The stock Blast steering head angle is 25 degrees. The new angle would be 22.5 to 21 degrees. Or, roughly the same as a Firebolt which has a stock steering head angle for 21 degrees. I did a little photoshop of Stock verses 3" raised rear ride height, and it looks viable to me... (Message edited by naustin on January 24, 2006) | ||
| 17blast |
I have run into some problems with the xb shock. The location of the bottom shock mount is to close to the swingarm pivot. This changes the leverage ratio. I am now looking into a linkage system. There are two ways to go, design my own linkage to simulate the same ratio as the xb, or use the linkage from another bike. I have found some 04 R1 shocks with linkages for under $75. I would prefer to use the xb shock since I already have one. The xb shock also has a remote reservoir which works better for the Blast's tight quarters. If there is any one out there with a very strong grasp for geometry or auto-cad your help would be much appreciated. I can supply sketches and measurement as needed. With any luck, we may find a cheap solution to give all blasters fully adjustable rear suspension. | ||
| 17blast |
Another thing we need to watch for when changing the angle of the swing arm is belt tension. For me it isn't as much of a concern since i'm switching to chain drive. But the belt tension changes in relation to were the swing arm is in its travel. I removed my shock and let the swing arm drop 3 inches and the belt became so loose I could remove it. | ||
| Naustin |
I wondered about Belt tension; that could be a big problem for the 919 shock proposal as well. I didn't think it would be enough of a change to make a difference though. I figured the distance from the center of each pulley would only change a few millimeters.  | ||
| 17blast |
It has to do with the swing arm pivot position. I believe its actually online or a little above the output sprocket. This works great for lowering but not for raising. (Message edited by 17blast on January 24, 2006) | ||
| Gearheaderiko |
Changing the steering head angle to 22 degrees (by raising the rear) could seriously affect trail and lead to a very unstable bike. Might be great for battletrax, but deadly on the highway. (I havent done the math though). Through experience, research and opinion, the Blast is too 'front loaded' already, adding any height IMHO to the rear would be unwise.If you raised the front and/or got a little more front tire under it that would make raising the rear more plausible. As far as the 919 shock and the blast shock, the body (valve/piston housing)length is still the most important factor.There are ways to possibly shorten it. I dont think there is a shock that will directly swap in without some modification. | ||
| Naustin |
I don't know enough about the technicalities and subtleties of suspension to know any better. It is unfortunate that raising the rear-end isn't viable, because it would look a hell ova lot better, and would give more lean angle and keep my pipe from dragging on the ground. However, I'm not giving up hope until it is proven impossible in the real world... Anyway, I improved my Photoshop and made it into a gif...  | ||
| Gearheaderiko |
Please, don't give up hope, I haven't! That gif is freaky, it doesn't look like much, but 3 inches is a heck of a lot though (no jokes!). Other options include shimming your front and rear suspension to reduce sag and/or increase ride height. Both are easy to do and will give you extra cornering clearance. Re drilling the rearsets for clearance will probably necessitate you going to the stock high or Corbin (or custom) seat. You've got a lot of clearance with that pipe so I'm guessing you're compressing your suspension quite a bit. | ||
| Jprovo |
Naustin - What is your bike doing to that piece of wood??  Seriously - Shim the stock suspension for preload first... then worrk about high $$ options. | ||
| Jprovo |
17 Blast - send me what you have, I'll see how I can help. | ||
| Naustin |
Gear - As far as the pipe - it only drags when I'm carrying my wife on the back, and running through an uneven or off camber turn. So - it isn't a problem most of the time, but it bugs me none-the-less. James - LOL  | ||
| 17blast |
The suspension is on hold but the swingarm is almost done. Here it is mocked up and ready to be welded.    And yes that's a 180 tire.  | ||
| Saltyblaster |
Looking good 17Blast. That is a full "package"! How difficult was the gear/chain alignment to the front sprocket? What are you using for a front sprocket / gear set ratio? Thanks for sharing and keep us posted on your progress. | ||
| Naustin |
Looks Great! I'm really interested too see what you come up with for the suspension. | ||
| Naustin |
Here's some pictures of Ralph's bike with the experimental 919 Shock installed for the 1st time....   You can see the amount of slack that resulted in the belt... Doesn't seem too bad, and according to Ralph, it isn't so much that the belt could come off. Just worried about it snaping under hard throttle. (Message edited by naustin on February 13, 2006) | ||
| Naustin |
One More. Ralph hasn't had an opportunity to test-ride it yet as his detent clip broke and he's waiting for parts, but he said the spring rate feels pretty good just from bouncing on it a bit - and the bike settles down quite a bit when he sits on it (on lowest preload setting).  (Message edited by naustin on February 13, 2006) (Message edited by naustin on February 13, 2006) (Message edited by naustin on February 13, 2006) | ||
| 17blast |
I'm glad to see someone doing some leg work on the rear suspension. Since I'm reworking my bike front to rear there has been no time for the rear suspension. Hopefully the 919 shock will work better for the Blast than it does for the Honda. The 919 has been known for its poor suspension. | ||
| 17blast |
I found a Progressive replacement shock for a 919 that is fully adjustable for $350. To know how well this will work we need 2 measurements. First we need the distance from the swingarm pivot to the shock mount. Second is the distance from the swingarm pivot to the rear axle. Once we have these we can compare them to the Blast and see where we're at. If the geometry is close enough this could be are best bet. | ||
| Naustin |
Those are measurements I wasn't able to get. Maybe somebody on a 919 BB would measure for us... Ralph's test ride (when he gets the chance) will tell us 98% of what we need to know about the viability of a 919 or (919 aftermarket) transplant.... I saw that progressive unit on ebay too... I didn't know if they are the real deal or what. The stock unit almost seems to be better quality - but lacks preload adjustment of course?? | ||
| 17blast |
Well this is what I have so far. I printed off a picture of the 919, scaled the rear rim, and came up with some measurements on the swing arm. I plugged those numbers into AutoCAD. I measured my stock Blast swingarm and put those measurements in also. This is what I got, 1 inch of travel on the 919 shock is 2.894 at the axle. The same 1 inch on the Blast is 2.898. I think we may have a match. There is going to be some error in my measurements because I scaled from a picture but I still think its going to be pretty close. Close enough that I'm going to use the Progressive shock. Progressive's are good shocks, one step down from Ohlins witch run in the $850 range. | ||
| Naustin |
Don't forget that works builds a shock for the blast too and that runs $700 I think. That option would be custom made for your weight and they'd probably be able to give you some good input and suggestions about how the bigger rear wheel will affect the whole package and build in extra compensation for that too.... I mean, I'd either try to get a stock 919 shock for $20 and see what happens, or go for the whole 9 yards from works. I can't see spending $350 on a "maybe". Maybe you should test a stock 919 shock and get it off ebay for $20-$50 and see how it works. And, if it is pretty good, but just not quite right, then spring for the Progressive unit to get you the rest of the way there. It would suck to get the progressive shock and find out it is just doesn't work...} |
