running rough

#1 PostAuthor: **paul doran** » Sat Oct 03, 2009 7:00 pm

I have just replaced the head gasket on My ELR11
the carbs have been thoroughly cleand and reset but the bike is running rough below two thousand rpm
above that it is fine
any ideas?

02GF74 · #2 PostAuthor: **02GF74** » Sat Oct 03, 2009 7:07 pm

hey, at least it runs!! :shock:

#3 PostAuthor: **paul doran** » Sat Oct 03, 2009 7:11 pm

02GF74 wrote:hey, at least it runs!!

not quite the answer I was looking for :twisted:

Robw · #4 PostAuthor: **Robw** » Sat Oct 03, 2009 7:19 pm

Air leaks between the carbs and head ?

Rob

#5 PostAuthor: **paul doran** » Sat Oct 03, 2009 7:25 pm

if it leaked there it would be running rough all the way up the rev range but it is not

m1ks · #6 PostAuthor: **m1ks** » Sat Oct 03, 2009 7:39 pm

I'm assuming that you know the valve clearances etc are correct / within parameters.

First place i'd look is your pilot jet / idle jet circuit, also check floats and needle valves, if it's revving cleanly over 2000 RPM this is where the mainjet circuit kicks in.

If you've rejetted for pods or similar have you rejetted the pilots too?, or the previous owner for that matter, you'd be amazed how many people don't

prowlerz1 · #7 PostAuthor: **prowlerz1** » Sat Oct 03, 2009 9:39 pm

recheck valve timing 1 tooth out can cause these symptoms

breakdown · #8 PostAuthor: **breakdown** » Sun Oct 04, 2009 10:00 am

Hi Paul,
Does it start and tickover fine!!, I'd agree with m1ks something to do with the carb settings, If it's ok above 2k your valve timings ok, don't know that model of bike to well but what about the timing advance unit if that was sticking open, just a thought.

hillbilly · #9 PostAuthor: **hillbilly** » Sun Oct 04, 2009 10:27 am

did it run ok before you changed the gasket,if so the carbs shud be ok,i would look elsewere,like torquing the head down again,and all the other bolts in volved in a gasket replacement job.

#10 PostAuthor: **paul doran** » Sun Oct 04, 2009 10:22 pm

ok the bike is standard carbs airbox etc
it ran perfectly until I attended the Yorkshire Rally
it started to run rough on the way to the Rally
and has continued to do so since
I have cleaned the carbs twice with no improvement
it runs perfectly above two thousand RPM

#11 PostAuthor: **paul doran** » Sun Oct 04, 2009 10:23 pm

prowlerz1 wrote:recheck valve timing 1 tooth out can cause these symptoms

no it was doing this berfore I removed the head

BShaw · #12 PostAuthor: **BShaw** » Sun Oct 04, 2009 10:29 pm

float heights ?
Have you put a colour tune on it
If you are pulling your hair out paul, bung it on a dyno.

#13 PostAuthor: **paul doran** » Sun Oct 04, 2009 10:55 pm

BShaw wrote:float heights ?
Have you put a colour tune on it
If you are pulling your hair out paul, bung it on a dyno.

Baz the bike was perfect until the journey to Yorkshire
I have not altered any of the carb setting's

breakdown · #14 PostAuthor: **breakdown** » Sun Oct 04, 2009 11:28 pm

Hi, since the bike runs fine above 2k then mechanicly the engine should be sound, so that leaves the fuel system and the ignition system.
If your 100% sure that the carb is clean and ok, then the problem has got to be in the ignition system. When you say running rough does it backfire/ pop?

BShaw · #15 PostAuthor: **BShaw** » Sun Oct 04, 2009 11:37 pm

It's gonna be a simple one WHEN you find it, that's why I said to bung it on a dyno, if it don't find it, you should have a blody good idea where to look.
It's a bugger when something is going wrong but you don't know why or what caused it.
I take it you have checked your spark at tickover with a jumper (can't remember what tester is called 7mm gap)
Is it charging ok

running rough

running rough

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