Exhaust options '74 850

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Now , I still think itd be worth moding the cross over duct ( essentially removeing . AS THEY DO on the 850 Norton . :) ) and iit may well be better .

Castrol , in the Scaysborough book he mentions the jap Top Brass , as it was the release of the bike there , and they expected big things .apparently
one threw its rods through the cases comeing past the pits , right in front of them . oh dear , as john cloney the TX 750 rider was apt to declare . :wink:

" Yamaha had released its super-trick TX750 and had signed a string of stars to ride the machines; Toombs, Hinton, Hindle, Knight, Hatton, Spooner, Rob and Keo Madden, Ahearn and Richardson were amongst them. "

http://www.the6hour.com.au/content/history1972.html

" Earlier in the race, the Yamaha TX75Os had made an embarrassing debut. By twelve o’clock Toombs/Hinton, Hindle/Knight and Hattonl Spooner had all retired with mechanical woes. The TX never recovered from the publicity and faded from the showroom within 12 months.

The MV Agusta went out of the running with a blown clutch at 12.07.

Len Atlee’s Norton Interstate ran out of brakes and crashed after one-and-a-half hours. The eight laps lost in the pits was the exact distance Len lost by at the finish. "

Id had difficulties avoiding running over one in a bend once , driving the Olde 51 Rover . Itd come past at 80 + so Id got off after it , entering the sweeper just after id
latched on a safe distance behind , he threw the picks out . Was obliged to follow suit , with all the weight of the mighty 2150 cc I.o.E. over the tyres , pulling right to go
around it got the tyres flapping , or the left one . Straightened , nailed the brakes and pulled left , both flapping .Danger is theyll exit the rim beads . :shock: Nevertheless
manadged to get of a safe distance behind it , accelerateing then easeing thrice . The old Cyclops was without his gentle weave slipstreaming it . :D

After This , we were a bit warey of being in close company of rice burners on the highway , prefering to go as round clear of them , rather than decend into the realms of
indecision and disorganiseation as regards manouvreability .
 
Rohan said:
Aha, the old cracking-around-the-balance-pipe problem !

A good aircraft welder could probably weld that up with stainless mig, and not make it look like a dogs breakfast. Would have been easier if the the crack was shorter though - probably now cost similar to new pipe(s). (And might re-occur).

Supposedly the balance pipe was mostly for noise control (trim a dB or 2), doesn't make much difference to the performance.

Interested to hear what you go with, how they perform and sound, I have old balanced pipes that probably don't have much life left, when I get it back on the road...


Got the head back Friday and got her up and running yesterday. I went with a set from Commando Specialties. 750 style with no crossover. The sound is a little different but I can't quite put my finger on the difference. I do have a vid of it running from awhile back and I need to video it now. The pressure coming out of them when holding my hand about 12 inches away seems much stronger and for lack of a better word, more defined. There seems to be less of a rumble and more of a bap bap bap sound. Under power they sound and feel great.

Here is a pic of one of the inserts done by Jim Comstock.

Exhaust options '74 850
 
Jim did a great job with your exhaust threads. I was wondering if there was some way to fabricate a flange to go around the pipe exhaust and put a couple of studs threw the exhaust opening and actually bolt the exhaust opening to the port instead of using the exhaust nuts to hold it in place. Just an idea, but of course I am not brave enough to partake in such a project.
 
drones76 said:
Rohan said:
Aha, the old cracking-around-the-balance-pipe problem !

A good aircraft welder could probably weld that up with stainless mig, and not make it look like a dogs breakfast. Would have been easier if the the crack was shorter though - probably now cost similar to new pipe(s). (And might re-occur).

Supposedly the balance pipe was mostly for noise control (trim a dB or 2), doesn't make much difference to the performance.

Interested to hear what you go with, how they perform and sound, I have old balanced pipes that probably don't have much life left, when I get it back on the road...


Got the head back Friday and got her up and running yesterday. I went with a set from Commando Specialties. 750 style with no crossover. The sound is a little different but I can't quite put my finger on the difference. I do have a vid of it running from awhile back and I need to video it now. The pressure coming out of them when holding my hand about 12 inches away seems much stronger and for lack of a better word, more defined. There seems to be less of a rumble and more of a bap bap bap sound. Under power they sound and feel great.

Here is a pic of one of the inserts done by Jim Comstock.

Exhaust options '74 850
Had your ports been previously sleeved/welded? Trying to figure out the milled flush thing
 
Had your ports been previously sleeved/welded? Trying to figure out the milled flush thing

Mine were the original aluminum threads. There were no inserts or welding done previously. I think Jim can answer the question better than I can regarding the milled flush thing.
 
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