Zaurst fitment problems
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psychedelicropcircle
- registered user
- Posts: 525
- Joined: Fri Aug 06, 2010 2:03 pm
- Main scooter: Series 1 li150 1958
- Location: north of hadrians wall
- Contact:
I'm running a 60/110 crank and a gori clubman, to try and get better fitment around the bigger crank / packer I drilled out the down pipe manifold stud holes by 2mm. This allowed the zuarst to fit ok but it's still touching the chaincase slightly which will kill it via vibration. Anybody have some ideas to move it away from the chaincase other that replacing the crank with a 58/107 ?
If your exhaust is touching the chaincase, this has to do with the front and rear mounts not the u-bend. You can add some flat washers behind the front and rear exhaust bracket until it is space out enough from the chaincase. Depending on how far you need to space it out, you might need to get some longer chaincase studs for the front and rear mounting points.
Also, by drilling out the u-bend mounting holes you have effectively misaligned the exhaust opening in the u-bend with the exhaust port in the cylinder.
If the problem is that the exhuast geometry will not allow it to properly connect with the u-bend at the proper angle, make your own DIY adjustable front bracket. One of the best features of the new BGM / MBD big bore exhaust is the adjustable front bracket. I have done DIY adjustable brackets on other big bore exhausts before.
What i do is use a JL or PM style front bracket. I do a rough match and cut off the ears of the big bore bracket. I then attach the exhaust to the ubend and the rear and underside (if there) case bolts. I then bolt up the JL bracket and I mark where to drill the holes in the remaining stock bracket. The JL bracket has 3/4-1 inch long horizontal slots for each mounting bolt, i drill in the center of the slot to allow for any adjustment. You can remove and drill the exhaust, or be careful and do it right there. Then bolt it up. I use m8x20 bolts, with a fender washer on the underside of the head, and a neoprene washer, fender washer, and a nylock nut on the back. I drill a third hole above also once the two are bolted on.
The JL / PM flat brackets are $10-$20 at various shops.
Also, on cases with the underside bolt, using a fender washer between the exhaust and case can make a positive difference in fitting an exhaust.
Also, by drilling out the u-bend mounting holes you have effectively misaligned the exhaust opening in the u-bend with the exhaust port in the cylinder.
If the problem is that the exhuast geometry will not allow it to properly connect with the u-bend at the proper angle, make your own DIY adjustable front bracket. One of the best features of the new BGM / MBD big bore exhaust is the adjustable front bracket. I have done DIY adjustable brackets on other big bore exhausts before.
What i do is use a JL or PM style front bracket. I do a rough match and cut off the ears of the big bore bracket. I then attach the exhaust to the ubend and the rear and underside (if there) case bolts. I then bolt up the JL bracket and I mark where to drill the holes in the remaining stock bracket. The JL bracket has 3/4-1 inch long horizontal slots for each mounting bolt, i drill in the center of the slot to allow for any adjustment. You can remove and drill the exhaust, or be careful and do it right there. Then bolt it up. I use m8x20 bolts, with a fender washer on the underside of the head, and a neoprene washer, fender washer, and a nylock nut on the back. I drill a third hole above also once the two are bolted on.
The JL / PM flat brackets are $10-$20 at various shops.
Also, on cases with the underside bolt, using a fender washer between the exhaust and case can make a positive difference in fitting an exhaust.