84 vf 500 problem

So Ive got my bike on the road taxed and tested and finally get a day when its been clear enough to ride(lots of snow recently) and I discover an issue.

She will not go above 55mph she seems to have the full rev range in lower gears but just wont go past 55mph unless its down hill . Any suggestions gentleman.

Cheers in advance

Alan

 

Check sparkies !!

Suggest that you first check each cylinder's header for heat cuz one might not be firing. Next pull plugs and check for a proppa colour on all 4. Ultimately, a likely carb problem, maybe holed diaphram on one or more carbs. How many miles on the little ould lass ??

 

Cheers for the reply squirrel. In anticipation of clean your carbs replies I've pulled them tonight and potentially had two blocked main jets. Could that cause the issue. Once I get the carbs cleaned and rebuilt I will check the above. Ill also throw you a line regards mileage as I can't remember of the top of my head.

 

You say you have a full rev range in lower gears, but 2 =nd or 3rd would pass 55mph if it revved out, so are you sure ?
Check that all 4 carb butterflies open fully, then check that all carb slides have a full range of movement. Did you strip the carbs during the recommission ?

 

Clean out the fuel tank--off the bike, with alota shaking and a proppa flush --to eliminate whatever rust, water or debris collected there after prolonged non-riding whilest it resting in yer nan's garden shead on the allotment or more carb clogs are alikely dune tha motaweey.

:mechanic:

Usually, clogged main jets means much more stuff is gummed up too. And the tank, right filffy or yer tha lucky man, ye are ! So tidy-up and tip-up, lads! :drinker: :drinker: Put on your aprons and get mucked in !!

:joker:

 

You could also have an air leak somewhere in the system. You should check your boots to see if they are old and cracking.

 

Sorry for the late reply. After I un clogged the jets it seems to be much better. I do however have another query. What size should my fuel line be? Im currently running it with 8mm gravity feed as was done by the previous owner. I have acquired a fuel pump for it however this has 6mm Lines any ideas?