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Post by ogri211 on Nov 8, 2013 19:05:54 GMT 1
When I got my F2 it had 31K barrels fitted I also got a spare set with pistons and a head which are the correct ones for the F2 could someone tell me what the difference is , also I got a spare set of carbs I assume the ones fitted are the 31 k's and the spare ones are for the F2 how can I tell the carbs apart. I have had the bike running before I stripped it down the 31ks were allegedly a set of Stan Stephens tuned ones that were fitted but the compression is down and I think they are knackered, I will be fitting the f2 ones I just had a quick look and the pistons are .25 o/s they look OK so I may just fit new rings but I will size the barrels with my internal mic when I get home and check for wear if so I will get them rebored.
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Post by midlifecrisisrd on Nov 8, 2013 20:00:24 GMT 1
just slightly different porting
heads are near identical
f2 carbs should have a rubber hose on the side from the float to the powerjet and should have a 1ua 00 or 10
31k marked 31k
steve
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Post by ogri211 on Nov 9, 2013 9:54:19 GMT 1
Thanks for that I will check when I get home I assume I have a set of carbs to go with each set of barrels.
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db8888
Thrash Merchant
Posts: 329
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Post by db8888 on Nov 9, 2013 10:17:43 GMT 1
Hi the inlet ports are a lot bigger on the 1ua barrels and the liner is thicker to support the bigger ports .the power valves are different to increase the flow when fully open
the 31k power valves can be modified to the same spec as the f2
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Post by billyboy on Nov 9, 2013 10:26:57 GMT 1
never knew the valves were different , you learn something every day !
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Post by ogri211 on Nov 9, 2013 11:40:01 GMT 1
I will need to check I have the correct power valve is it stamped with a number?
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Post by midlifecrisisrd on Nov 9, 2013 11:51:07 GMT 1
I will need to check I have the correct power valve is it stamped with a number? all genuine valves are same, all were 31k. only the aftermarket ones are different. easily sorted by checking the fully open position and filing away the excess valve or simply set the valve to match the port by looking up the exhaust rather than using the locating pin. f2 pv controller does not fully open till 10200 so a bit useless. either carbs will work with eithe barrel set but if using filters you will be best using 31k carbs. f2 barrels do have slightly bigger inlets and 1 mm higer exhaust port steve |
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Post by ogri211 on Nov 9, 2013 13:58:51 GMT 1
Thanks Steve I will be out with the torch and magnifying glass when I get home
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db8888
Thrash Merchant
Posts: 329
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Post by db8888 on Nov 9, 2013 16:16:02 GMT 1
inlets are about 10mm longer and about 1mm wider power valves I have are from legend motorcycles and the f2 ones are cut away more in the centre
just checked the f2 part number and it starts 3ik so the gen yam ones seem the same both barrels I have are standard porting the 31k barrels
are mint and on 64.75mm might sell at the write price or part exchange some 4l0 barrels + cash
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