How To: Install The ‘Ascot’ Exhaust System (Specials)

This ‘Ascot’ street tracker exhaust system ( 07-0751 ) is designed to give your XS650 that street tracker look, while offering a slight upgrade in performance. The 42mm headpipes ( 1.5″ ID ) are perfectly matched with mufflers with OEM-type internals for that sweet, unrivaled sound. The all-inclusive kit is beautifully chrome-plated with complete mounting brackets and hardware.


Fitment:  1978 – 1984 Yamaha XS650 “Special” models


Installation Instructions


  1. Do not install this system without having your bike tuned and running properly in its existing configuration. Suggested jetting is as follows:


A) If you have a 1980 – 1984 model with the stock Mikuni BS34 CV carbs, we recommend that you rejet to a richer mixture before installing and running this system, as the BS34 is usually set very lean.

Main Jet:  #142.5 – #147.5 range

Pilot Jet:  #45.0

Air Jet:  #127.5

Idle Mixture Screw:  2 1/2 – 3 turns out from the bottom

Once properly jetted, synchronize the carbs.


B) If you have a 1978 – 1979 model with the stock Mikuni 8S38 CV carbs, we recommend that you rejet to a richer mixture before installing & running this system. A main jet of #140.0 or higher is required.


NOTE : These are approximate jet sizes. Every motorcycle differs and your bike will be further affected by any changes to the air filters. Final jetting should be set by someone who knows how to do a spark plug reading and knows how to tune. The normal end result should be a good running bike that pulls cleanly to redline when running through the gears.



2. Remove the old exhaust system and gaskets from the cylinder head ports, as well as the rider footrests and passenger pegs.

3. Unpack the new 07-0751 exhaust system. Examine, wax and polish the chrome mufflers and headpipes.

6. A hardware kit is included with your exhaust system and is packed with related parts in sequence.

07-0751 -- 30

7. Install the new headpipes, cylinder head port gaskets and headpipe flange crown nuts and lock washers (HDW Ref. A).

8. Tighten but leave just loose enough that the headpipe will still rotate in the head. Note: there is always an even gap between the finned headclamp and the head

  1. Remove slider bracket hanger straps included with ascot mufflers and discard.


19. Push in the outer headpipe as shown and hold this position while tightening the finned head clamp flanges. If the exhaust system is in the correct alignment, check that all other nuts & bolts are tight.

22. XS650 “Special” models require the stock curved kickstarter.

23. The centerstand can be retained when mounting the Ascot system on a “Special” but the large ugly centerstand loop will hang out unless you modify it.

24. Wipe down the entire exhaust system and remove all dirt, oil, and fingerprints from it before starting or these markings will embed in the chrome plating once the exhaust is hot.

25. Start the bike and let it warm up a few minutes. Check for any exhaust leaks and adjust the idle speed as needed. Shut off the engine and re-tighten all the mounting hardware.

26. Road-test, adjust jetting and idle as necessary and re-tighten all fasteners again. Enjoy!




You have now installed the Ascot Exhaust System for “Special” models.

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