head up arse... engine is driving me out of my mind.

[antoine]

the fuel went in just before i dropped the engine in feb, and then i topped up about a quarter of a tank last monday. so its not that old and shitty.

 

[moler]

Do the ratio rockers really offer that much more over standard rockers on a fairly standard engine, that they're worth using?

So, running on 2, backfires clearing unburn't fuel, runs on 4, rev it up, back on 2! Maybe a fuel pressure issue that the righthand carb isn't coping with so floods that side? New needle valve? Punctured float? Fuel pressure regulator?

Just sounding off ideas

 

[antoine]

Just sounding off ideas

any ideas are good.

the fuel pump is a lecky one, that only pushes 3.5psi, i shall have to have a look inside and see if the carb has any issues.

 

[sparkywig]

Have you set the float valves?

 

[67panel]

dont know if it would make any odds ,looked on your thread in gallery and I wouldant have fitted fuel pump there it higher than carbs .all the ones I have done have been fitted above drive shaft to chassis rail area.I know why then dont it affect both carbs ,just a thought.we had probs with our drag beep fouling plugs and ticking over on 2 cyl that was poor spark and knackered floats(idfs)

 

[Bluesnailman]

I'm not so familiar with these carbs, but having had horrendous problems with some twin SUs last year it seems like a fueling issue to me. Check the manifold bolts are tight, and that there is no other unintended air intake. If you get the cylinders running, squirt some carb cleaner around the joints and see if you get a change in revs.

 

[antoine]

dont know if it would make any odds ,looked on your thread in gallery and I wouldant have fitted fuel pump there it higher than carbs .all the ones I have done have been fitted above drive shaft to chassis rail area.I know why then dont it affect both carbs ,just a thought.we had probs with our drag beep fouling plugs and ticking over on 2 cyl that was poor spark and knackered floats(idfs)

the pump is only there atm to get things running, i was going to re-route things once i had everything set up, it was just ease of accessibility at the time, but if this could be causing some of the issues i shall shift it sooner rather than later.
I didn't set the floats but i had the problem carb off earlier to get to number 1 plug so shouldn't be too difficult to pop them out and have a fiddle. if anyone has suggestions for the right jets at the same time, i may as well get everything right whilst I'm at it, even if it turns out not to be the problem at least it won't be another problem that gets thrown up.


air leak wise, i had a nightmare originally with this so i know everything is good and tight and there are no air leaks.













got to learn somewhere :roll: :lol:

at least i will know my engine inside and out once its sorted.

 

[antoine]

ok ok i know its been a while, iv been busy buying a house fiddling with guitars and sitting on a greek beach :msn4:

still doing my nut in though, i finally got out today since the sun has shown itself, measured the clearances and how much the rockers move and all is even, so had to nip out and borrow Ems' car key so i can get enough drive space to move the van about and think about shifting the fuel pump and all the pissy little things whilst i ponder a bit more.



I'm beginning to think i may have to drop the engine and fiddle with the heads again...

:evil:

 

[antoine]

ok, so i practically shut off the fuel to the 3&4 carb opened up 1&2 a bit more and managed to get it running a bit lumpy on that side only. so I'm in the process of moving the fuel pump to try and reduce the work it has to do. its fiddly as hell without taking out the engine and i don't have a great deal of skin left on my arms but its getting there. after that I'm hoping it works, but if not, I'm guessing ill have to have yet another go at cleaning out the carbs and making sure nothing is blocked.




one day i'll get to drive this thing. :lol:

 

[jonboylaw]

Have you done a leakdown test. This will quickly eliminate valve or ring problems and let you focus on the spark and fuel.

If compression and valves are fine, I'd start by stripping the carbs and checking for blocked jets and crap in that carb. As you have problems with 1&2, it would leave the sparks until last as unlikely to be a dizzy fault knocking out a pair of cylinders, more likely to be a shared carb. I am betting on some crap in the jets or bores...

 

[antoine]

Have you done a leakdown test. This will quickly eliminate valve or ring problems and let you focus on the spark and fuel.

If compression and valves are fine, I'd start by stripping the carbs and checking for blocked jets and crap in that carb. As you have problems with 1&2, it would leave the sparks until last as unlikely to be a dizzy fault knocking out a pair of cylinders, more likely to be a shared carb. I am betting on some crap in the jets or bores...

I'm going to swap the carbs over tomorrow and see if it changes anything, if it does ill strip the dodgy one and get it properly cleaned through.

 

[antoine]

bit late on this since i ended up doing other stuff. but i swapped the carbs reset the mixture and timing and we now have fire on all 4. no idea what it was but it sorted itself out instead of pinpointing where the problem was. oh well. my favourite kind of fix.

 

[jonboylaw]

....until the next time...

 

[antoine]

....until the next time...

i was thinking that, got some new jets to go in so who knows, i could make it better or i could kill it all together, should be fun finding out. lol