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BLACKCATT -> RE: Secondary Cage Mod for the 700 EFIs, 05-06 650 H1s & 500s (7/18/2008 10:08:52 AM)
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quote:
ORIGINAL: BIGT25
quote:
ORIGINAL: BLACKCATT
Due to so many PMs I received about this mod, I decided to post for everyone. Hopefully, GWC will make this a sticky!!!
Note: I have only verified this on my 05' 650 H1. The drawings look the same for the other models I listed in the subject line, but I have not actually verified to see if they are indeed the same. Please verify before attempting.
Because of the cage design, the secondary pulley halves on these models don't allow the belt to ride at the top of the pulley, therefore causing a higher pulley (gear) ratio than the newer H1s have. There is actually about an 1/8" gap between the pulley halves, so it lets the belt sit lower on the secondary pulley (like having a smaller secondary gear). This is a fix I discovered for these models, but don't worry newer cats, your not missing out on anything. The newer cats already have this problem fixed with a different secondary pulley set-up.
Here's some basic steps to make this belt drive super low, and will lower the overall pulley ratio by more than 20% with the cage mod, spring mod and shims on the primary.
Note: Refer to the attached drawing, or the 2008 700 EFI Transmission Assembly drawing at (alpha-sports.com) to compare the reference numbers I am using.
These instructions are basic, and meant to be more for experienced wrench pullers!!
1. Remove secondary pulley.
2. Use a sharpy to mark jam nut (#15) location.
3. Remove the jam nut (#15) and retaining cap (#16) for the spring.
4. Remove the spring (#7).
5. Remove the spring seat (#13). (Pry it up with a screwdriver.)
6. Remove the pins (#10) and spacers (#11) from the cage.
7. Slip the pulley/cage (#5) out of the inside pulley (#6).
8. Lightly lengthen the slots in the top of the cage (jam nut end!). I used a head porting tool to slightly remove the metal up to the o-ring groove. Be careful not to make the slots wider, only make them longer! Remove a little, then check. You can check by putting the two pulley faces back together. With the pins and spacers installed, you want the two pulley faces to completely touch. If they don't, then remove more metal from the slots until they will touch. It's that simple!!!
9. Once you are through slotting the cage, then clean very well, re-grease the pins and spacers, and put back together in reverse order. When putting the jam nut back on, tighten to the sharpy mark and you will have the same factory location (torque) as before removal.
Spring Mod...
The spring notch is in the hole with the notch bent up. Turn the spring retainig cap to put the spring in the 5th hole. (Factory stamped hole plus 4 round holes.), or simply the last hole furtherest from the factory hole, but not the single hole 180 degrees from the factory hole. This will add pe-load just like the newer H1s secondary mod does. Now press the spring cap down and turn to line up the flat spots on the cage end. Once the cap is seated on the cage shaft, then re-install the jam nut and tighten to the sharpy mark. You can adjust the spring in different holes to make it less stiff, and to tune for your preference. The further out on the holes, the stiffer the spring. A stiff spring will hold it in low gear longer, therefore giving alot more power to turn them big tires.
Shimming the primary...
I put 3 shims in mine (3.63 mm total). Actually I used 1" machine bushings. They have a 1" hole, are 1.21 mm thick, and have a much smaller O.D. than normal 7/8" or 1" flat washers. Place shims (1" machine bushings) in between the end of the spacer (#4) and the pulley face (#1) to space the pulley halves apart. This will cause the belt to sit lower in the pulley (like a smaller primary gear), therefore lowering the pulley ratio. By moving the belt up on the secondary pulley, and lowering the belt on the primary pulley, you have drastically lowered the overall pulley ratio. You will now have a superlow starting gear ratio. Anymore shims than 3 will cause your belt to rub on the housing. I had 4 shims at 1st without belt slip, but it rubbed the housing too much. Shimming the primary will only work without belt slip if you have the secondary cage & spring mod done 1st. These mods are free, except the cost of the shims (50 cents each) and will really wake these belt drives up.
Final Note: These mods are for lowering the overall gear ratio, so they will cause some top end MPH loss.
[image]local://47150/2C8F58D16BB74A278AB2E069697AF9BE.gif[/image]
Thanks for the information you gave me in some pm's , however my secondary 08 500 is different and doest not have the holes to allow it to be clocked right under the nut there is the end of the spring tang sticking thru but there is only one hole 90 degrees to the left and one 90 degrees to the right.. Not 4 or 5 holes. Also my belt ride out of the secondary a fair amount with nothing done to the secondary.. I am going to try the shimming of the primary however no one here has been able to get me a shim like what you use.. I have talked to several industrial places (no mill supplies here anymore ) but industrial related places. aka fastenal, motion industries, etc.. They all look at me like i am crazy and say they don't know where to get it.. Already lightened the rollers some gonna try some more once i get my scale that has been ordered.. However it did much better with just the roller mods i have done so far.. Son placed 2nd in the steel horses bog and wife says it is a TON stronger than when she first got it.. (also clipped the spring and drilled the slide and got the jetting lined out as well) Any other ideas would be appreciated.
Oh i found mention of the "coop mod" on ny roc and read the thread they give part number for a perfect shim off of a yamaha application (that does this same mod and some others) but local yamaha dealer dont' have it and wants 7 bucks a piece for them... Have not got to research it any more yet...
[image]local://20966/DBA2E237C68C46548A5E1C2271CE6CD8.jpg[/image]
Your hole on the left is where my last hole is (90 degrees from the factory hole). Use it first before you drill any new holes. It's the same hole I use, so you should be fine. If it's too stiff for your preference, then you can go back in and drill some holes in between these two so you can custom tune the stiffness. Also, if that doesn't give you the stiffness you desire, then you can also make a 1/2" tall spacer to put under your spring. I've made these too, but it's a little more complicated. I don't think you will need it! I tried the spacer in mine, and it got too stiff, so I had to put in different hole to soften. Either way, you should be able to get the desired stiffness without spending any money. I'm like GWC, I will look for the free, or the cheap, ways 1st!!!!!!!!! Always more than one way to skin a cat without having to spend any money!
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