carb mods

ive just fitted k&n filters to my xj 650 4ko model,now runs like shite,anyone any ideas wherei can possibly get the jets to uprate the carb inners to go with the filters,archie uk

 

http://www.xjbikes.com/Web_Links/l_op=visit/lid=41.html

Here's 1 place to try.
Good luck

 

Have you tried adjusting the idle mixture? extra 1/2 or more turn out maybe....

 

Dynojet kits are available from most vendors and mail order houses in North America (don't know about the UK). Expensive ($150 USD?) but readily available - kit #4102 fits XJ750s - not sure about 650s- includes new slide needles. Check on the web for 'Sudco' - they have jets and other goodies for Hitachi carbs - $2-3 each, pilots and mains available - they also have throttle shaft seals, important items if you've never replaced them.
As a last resort, you can strip the jets out of a donor Hitachi carb set and go to work with your drill. Jeweller's drill bits are fairly cheap and I've found them to be quite effective.
As a last resort (if you're desperate or just unbelievably cheap like me) jets can be fabricated from 'Clippard' 10-32 pneumatic brass plugs using the above mentioned drill bits and countersink. My pilot jets were made this way, and work very well.
Factory Pro (factorypro.com) has an excellent CV carb jetting/tuning procedure - highly recommended.
Beware the local dealership - special order (translation - they'll be here a week from next never) and conveniently priced at about $18 (each!).

 

motorcyclecarbs.com is a good source. I will tell you that it will be a struggle to get the carbs running well with pod filters. You will most likely have a dull or dead spot somewhere. What is needed are velocity stacks. Seems easy enough to do but our frame tubes get in the way on the # 1 & 4 carbs.