blocked idle curcit

which jet is the idle?

 

ill go give it a run now ( being cold ) and see how it goes... if still shit.. that should cross out the valve clearence problem?

Cheap and nasty way to clean carby.

 

Swap 2 and 3 plug leads around.

 

Hold foot flat

 

Crank engine

 

Watch it backfire through carby a couple of times

 

Swap plug leads back to where they should be.

 

Oh and make sure you remove the aircleaner before you do this....................

Cheap and nasty way to clean carby.

 

Swap 2 and 3 plug leads around.

 

Hold foot flat

 

Crank engine

 

Watch it backfire through carby a couple of times

 

Swap plug leads back to where they should be.

 

Oh and make sure you remove the aircleaner before you do this....................

ill give that a go... also, if anyone knows... what rpm should my idle be at?

 

10:1 compression

32/36 weber

25/65 cam with .440 lift

2 1/4" exhaust

pacemaker extractors

I didn't, I just took my head off and got a place in town to shave it. And put hd valve springs in.. I don't understand how I adjust the valves though?

 

 

Arrrgh! 5K ! Hydraulic tappets... You don't set them.

 

Much more likely to be carb than anything else in that case.

 

Shaved the head and put it back on without adjusting anything.

 

If it is like any over head cam hydraulic lifter then they pump up to a preset volume, correct me if I am wrong but I don't see the lifters in a 5k being that far advanced that they auto correct themselves.

 

EDIT: where I got the clearances from - http://www.club-k.co.nz/Forums/viewthread.php?tid=6801

Edited December 23, 201114 yr by Trev

Never had any issues with the 5k's I have had in the past. Anyway, there is no adjustment anywhere in the 5k valve train from memory, so I am unsure how you would adust anything without resorting to machining or making shims etc.

 

And Trev, a 5k is an overhead valve engine, not an overhead cam :P

Edited December 23, 201114 yr by coln72

Never had any issues with the 5k's I have had in the past. Anyway, there is no adjustment anywhere in the 5k valve train from memory, so I am unsure how you would adust anything without resorting to machining or making shims etc.

 

Ok, now I am with you.

yeah 5k don't have adjustable valve train.. thats why i was getting a little confused before..

 

my valve train geometry? should be perfect, due to taking 40thou off my base circle, and 40thou off my head.. there for, everything ( lifters, pushrods, rockers, valve's are all the same as at the start..

 

I'm leaning towards the carby.. i did the 2-3 lead swap around.. and it will idle at around 1000 now, but starts to die any lower.. so I'm thinking either do it again, or it could possibly be.. my carby is missing the secondary linkage's.. ( the old owner siliconed the shaft on the outside so it couldnt spin) so I'm thinking somewhere along the line's of changing the spring, iv bumped it and its moved.. there for, running like a bitch at idle?

coln do 5Ks run with a tappet gap??

 

The only ones I've had experience with in OHV had no gap. You pushed the rocker down with a big screwdriver and set the tappet gap to 75thou, then when the motor ran that gap vanished completely. That's why the hydraulics were silent compared to mechanical.

 

5Ksev, the idle is the lowest speed you can make it run at nicely. So it is a balance of speed versus smooth running. Just wind the idle screw right in, then out 1.5turns and run the motor. Wind it in and out 1/2 a turn and go the way that makes it increase revs or run smoother. Then change the idle speed screw to suit.

 

If you chase 'Weber tuning' through google they will have something about how many turns out it is and what that means about your idle jet being too big or too small.

coln do 5Ks run with a tappet gap??

 

The only ones I've had experience with in OHV had no gap. You pushed the rocker down with a big screwdriver and set the tappet gap to 75thou, then when the motor ran that gap vanished completely. That's why the hydraulics were silent compared to mechanical.

 

5Ksev, the idle is the lowest speed you can make it run at nicely. So it is a balance of speed versus smooth running. Just wind the idle screw right in, then out 1.5turns and run the motor. Wind it in and out 1/2 a turn and go the way that makes it increase revs or run smoother. Then change the idle speed screw to suit.

 

If you chase 'Weber tuning' through google they will have something about how many turns out it is and what that means about your idle jet being too big or too small.

it shouldnt be the idle jet size, due to it running fine before i put the cam in it?

coln do 5Ks run with a tappet gap??

 

 

Not 100% sure - my oldest is now 6 and it was well before that I last pulled a 5K apart. All I remember is that there is no adjustment, so I'd assume that the clearance or gap is looked after by the lifter as on any hydrolic cam engine.

And Trev, a 5k is an overhead valve engine, not an overhead cam :P

 

I know that, I was referring to the lifters being like a over head cam lifter.

Ok, so side-cam hydraulics are self-adjusting. If they are pumping up and holding the valves open a little then it won't idle. I don't know how you would check that.

 

If the cab was running on it,then only the overlap from the cam should be a factor. I think 1000rpm may be your idle speed. What is it like running at that?? Smooth??

 

Grumpy and threatening to stall?? My rolla on SUs is grumpy with a 270deg cam, less lift than yours, and although it sounds like it will stall, when its warm it will sit on 1000rpm for 5minutes no trouble.

Ok, so side-cam hydraulics are self-adjusting. If they are pumping up and holding the valves open a little then it won't idle. I don't know how you would check that.

 

I know it is a different motor but with the VG you can pre oil the lifters prior to installing but you can also put too much in and it holds the valves open otherwise you put them in and the oil pressure bumps them up to where they need to be.

my speedway car wont idle below 1000rpm

also depends how much timing your running.

 

if i ran 28 degrees it wont idle under 1200 rpm. if i run 22 degrees it idles at a lump 600 rpm :D