Trying to use Titan motor on Grubee center mount Stage III kit

Discussion in 'Frame Mounted Engines' started by chrisnbush, Sep 5, 2010.

  1. chrisnbush

    chrisnbush Member

    The shaft is too short - looks like DAX saws them off maybe. But it also looks like it might be too narrow.

    The GRUBEE instructions say the shaft needs to be 15.8 mm dia x 33.5 mm long. I actually can't be sure the Titan shaft is too narrow until I get the DAX clutch shoe mounting plate off the shaft.

    Got all the shoes + springs off OK, and the bolt off the end of the shaft + washer, but the triangular shaped mount is still on the shaft, and firmly. I expect this is keyed, and so it is pressed on ?

    Sure wouldn't want to use a torch on that momma to try to get it off. Bye Bye engine (and maybe me).

    Any advice (or does anyone want a Titan cheap ?)


    Chris Bush

  2. ocscully

    ocscully Member

    What you are trying to accomplish can not be done easily. The Titan has no output shaft for the Type III clutch bell to mount to, first off. Second the mounting bolt pattern on the left side of the Titan is different than the pattern for the Type III gearbox. Third the width of the Grubee III gearbox is two wide for the clutch bell too align with the shoes of The Titan clutch. Dax offers a Duplex Chain driven reduction box that will allow the Titan to be frame mounted. I think they sell for $60.00.

  3. chrisnbush

    chrisnbush Member

    Thanks ocscully - lack of research on my part. I can use the mounting plate, throttle, tank, etc. etc. and am going to try the dax transmission. So I am selling some of the unused stuff (and other stuff from previous kits) on ebay. I went with the Grubee III mounting kit cause I had the motor and eventually wanted to get the Grubee 4G, but looks like I will just stick with DAX all the way.
  4. chrisnbush

    chrisnbush Member

    Have 220 miles on my Titan + Grubee 4g centermount - some questions

    So I ended up going with the Grubee 4G mount that fits the Titan (thanks ocscully).

    Loving it - I have it geared pretty low, but that is good for the winter season here in NH.

    I am unable to find any maintenance information on the 4G clutch. Saw something about a "cam" to tighten the drive belt, but no details. Also, it is painfully obvious that these freewheels can fail over a shorter period of time then I would hope (as per Irish John) so I am wondering if a regular greasing schedule would help ?

    Additionally, somewhere I THINK I saw that Grubee now has a 4G with a fixed drive gear (not freewheel) having worked the freewheel function into the clutch somehow. Is this true, and if so, which motor does THAT one fit ?

    Just trying to see down the road a little for my "migration" path if you know what i mean. Do all roads lead to GEBE ?

    Last edited: Oct 29, 2010
  5. ocscully

    ocscully Member


    I currently have the 4G for the Honda motor on my bike with the SBP 4-stroke Shift Kit. My solution to the cheap output freewheels is to have a local fabricator weld them up and make them fixed. The cam you mention for adjusting belt tension is an egcentric mount for the output shaft of the drive. There are 4 M6 bolts that you loosen and then by rotating the mount the output shaft moves fore and aft to adjust belt tension. On your version of the 4G Drive I believe these bolts are accessed from the outside of the drive below the 11t output freewheel? There is a spanner wrench/lock ring wrench for this but I haven't found the need to have this wrench with my drive. The egcentric mount moves easily when you loosen the four bolts. If you end up making the output of the drive into a fixed sprocket you will find that you will want to back off on the belt tension to maintain some ease in the normal pedaling function.

  6. chrisnbush

    chrisnbush Member

    Yes, thanks - see my other post

  7. chrisnbush

    chrisnbush Member

    Oc -

    Thanks for everything. I ordered some shaft keys from Grainger (3/16x3/16 by 1/2) - going to make a "kit" for key replacement including the 10mm coarse shaft bolt, a lock washer, the keys, and a 17mm socket + extension bar (to fit the bolt). Want to keep the freewheel.

    Along that note, any idea what the shaft output diameter is on that 11t shaft ? As it is a 10mm bolt, and the shaft appears to continue with that diameter where the freewheel slides on I am assuming it is 10mm. Don't want to take it apart (!) to measure it though. Just if you know - I am considering going to Staton to find a 11T or so freewheel, doing a little research on the quality. Hey, maybe there is a titanium (!) freewheel out there or something.

    Thanks again - this forum is great