assam

can someone please tell me why is it that when a aftermarket dumpvalve is fitted the revs go up and down??

scoobykevuk

shouldnt do????????

Fur

its because of the spring on the after market dump valve not being strong enough to keep it clsoed when idling, its ok when on the move

Something like that anyway

I think you can either try and stretch thr spring abit in your after market dump valve or go back to the standard one

fujack103

check to see if the dump valve is being sucked open on idle i shouldnt be as this would be the same as having an air leak. adjust the screw if it has one so it preloads the valve more to stop it.

fujack103

LOL beat me there FUR

assam

cheers guys makes sense..ive changed the dump valve on 3 different scoob when at a stand still the revs move up and down but like people say on the move its fine..... i think ill be adjusting the screw bit at the end ( the d/v is a hks style one)

cheers guys

thebothy

my blitz needed tightening till there was hardly any thread showing and it runs nicely

Fur

haha the funny thing is i know bugger all, i picked that info up from someone elses post about it that i read

If i keep reading here for hours and hours maybe one day ill be able to do an oil change on my own?

[Davey]

Get a twin piston dump valve, the inner piston remains closed until positive pressure is present, this means at idle it remains closed thus no problems with an irratic idle.

Elmer Fudpucker

Better still re-fit the std item,too easy really!

fujack103

I got a collins dump valve it has a double piston so it dont need any setting up unlike others that your rip your hair out trying to seal at idle and also make a noise