bobthebuilder
|
| posted on 17/3/12 at 10:20 AM |
|
|
engine problems cbr1000fp
hi peeps need some help with my bec honda cbr 1000 fp
i have just done the engine conversion and on start up all seemed ok (apart from finding the water pump was goosed)
the car will start, run and rev to 5k with no issues.
the problem is when you rev it hard it will just die if you leave you foot down. if you take it off quickly it will tick over fine.
also if you leave it ticking over for a couple of minutes then rev it hard it will go to 11k clean then die.
i have changed the plugs,leads and caps when installing the engine to relocate the coils.
i have checked the carbs and balanced them.also you can see the fuel going in if you remove the airbox.
i have 12v to the coils
i have changed the ignition pulse generator as i thought it was this but made no difference.
it is really buggin the crap out of me because all seems ok with the car and i am dying to get it on the track.
all help welcome.
cheers rob
|
|
|
|
|
wylliezx9r
|
| posted on 17/3/12 at 10:32 AM |
|
|
Sounds like a fuelling issue to me. Have you checked the pump is delivering enough fuel?
I spent a lot of money on booze, birds and fast cars. The rest I just squandered.
George Best
|
|
|
rf900rush
|
| posted on 17/3/12 at 10:46 AM |
|
|
My first BEC engine had bad running problems simular to yours.
1995 RF900 running 36mm Minuki carbs.
Main jets had to be changed.
Mine went from Size 112.5to 140 before it ran any were near correctly.
as I understand 140 is 1.4mm
To do this, I was advised to drill them first in 0.1mm steps.
I also had to buy a Set of 1-6mm drill set with 0.1mm increments.
If yo try this, just be careful drilling brass.
I also found the airbox (or lack of) had a big effect on the fueling.
|
|
|
jambojeef
|
| posted on 17/3/12 at 10:50 AM |
|
|
Agreed it sounds like fuelling.
Id check:
* everywhere for air leaks head to carbs etc
* that the little 90 degree steel pipe to the left of the bank of carbs is blanked off.
* that the choke is off fully not stuck on or something.
* all the slides are free and moving ok.
* that under the caps of the carbs that all the diaphragms are ok and not split etc
What have you done with the slide vents and float chamber vent pipes btw?
Geoff
|
|
|
maccmike
|
| posted on 17/3/12 at 01:08 PM |
|
|
check my thread 'zzr1100 running issue' (or similar)
turnt out to be fuel pump relay, I strongly advise you change that first, cheapest and easiest
|
|
|
bobthebuilder
|
| posted on 17/3/12 at 04:37 PM |
|
|
thanks every one for your replies.
fueling is by a brand new facet pump on its own switch.
carbs have been stripped and checked. all jets look clear. slides are free and diaphrams ok.
vent pipes are open to air.
all connections from carbs to the head are sealed.
i will check the choke side later as i havent checked this yet
also jet size maybe something to look at as i have larger bore exhaust and a different air box which is free er flowing.
|
|
|
bobthebuilder
|
| posted on 17/3/12 at 04:41 PM |
|
|
forgot to say that when its running and you rev it you can see the fuel going in when the airbox is off.
well will start with the choke first.
i will also try a gravity feed on the fuel like on the bike to see if that makes a difference to rule out the fuel pump.
thanks again everyone.
|
|
|
mad-butcher
|
| posted on 17/3/12 at 07:40 PM |
|
|
why does the word Facet make me cringe, bike carbs need to be fed by low pressure. would def try what you've said "gravity
feed".thinking about it though if the pump was wrong it would tend to flood the engine
still think it's more than likely pump
tony
[Edited on 17/3/12 by mad-butcher]
|
|
|
bobthebuilder
|
| posted on 17/3/12 at 08:30 PM |
|
|
it is a low pressure pump for carbs. no problem with overfueling.
cheers
|
|
|
Westy1994
|
| posted on 18/3/12 at 03:19 PM |
|
|
Hi Rob, Found your post eventually, lol.. Great to meet up with you today and keep us posted on the gravity test , hope you had a great day with the
family and got home ok, with not too many issues on the M6...!!.
Rich.
[Edited on 18/3/12 by Westy1994]
|
|
|
bobthebuilder
|
| posted on 18/3/12 at 05:41 PM |
|
|
yes good day out, nice to meet you too.
no m6 was fine.
UPDATE
right tried gravity feed and no difference.
but what i did do was whip the airbox off, then just by chance i held my hand over 2 of the carb inlets restricting the airflow to see how it was
drawing and it reved up ok.
so i got a flat bit of steel and held it over all 4 covering about 3/4 of the inlet and it revs ok,so i guess this points to the main jets being
wrong.
anyone got any thoughts?
cheers rob
|
|
|
maccmike
|
| posted on 18/3/12 at 05:57 PM |
|
|
Its no guarantee but Il say it one final time. fuel pump relay. cheap. plug out. plug in. one thing off fault check list. dont go stripping carbs and
changing jets until you know its not something simple. you could upset the whole balance when the fault is finally sourced. I personally doubt its
anything to do with jetting. has it got a ram air pipe for the floats?
|
|
|
maccmike
|
| posted on 18/3/12 at 05:58 PM |
|
|
ps where you based?
|
|
|
bobthebuilder
|
| posted on 18/3/12 at 08:44 PM |
|
|
hi i am based in middlewich cheshire.
it cant be the relay because it doesnt have one.
it is just on a live feed with a switch.
also i tried gravity feeding from a bottle like the original bike setup and made no difference.
the only thing thats worked is restricting the air intake then it revs up spot on
thanks for your input, many heads make lite work or somthing like that.
cheers rob
|
|
|
maccmike
|
| posted on 18/3/12 at 08:50 PM |
|
|
haha i see, sorry.
Im in Macclesfield if I can offer assistance. I have an inline fuel pressure guage if you want to check pump?
When I had my fault, I changed anything and everything including stripping carbs twice which was a ball ache and it ended up being such a simple fix
in end, gutted I didnt try it first.
Leads, coils + igniter check next, again simple plug out plug in checks
|
|
|
maccmike
|
| posted on 18/3/12 at 08:57 PM |
|
|
what year is engine?
|
|
|
maccmike
|
| posted on 18/3/12 at 09:12 PM |
|
|
Iv got spare jets too, 132-138 that you could try.
spray easy start around carbs, that'll identify any leaks if revs rise.
|
|
|
bobthebuilder
|
| posted on 18/3/12 at 09:15 PM |
|
|
right i think i have got to the bottom of the problem.
after a bit of google while watching tv found a guy on a honda cbr forum with the same problem same bike.
turns out that as my bike is an import and it is restricted to about 100bhp.
this is done solely in the carbs and a restrictor plate in the airbox, hence why mine revs fine when i restrict the air flow.
according to his thread all he needed to do was replace the main jets (dynojet kit) and all was fixed.
makes sense to me as i have checked everything else and it all checks out.
fuel fine
spark fine
runs fine when restricted.
keeping my fingers crossed.
|
|
|
maccmike
|
| posted on 18/3/12 at 09:25 PM |
|
|
cool I hope thats it.
Is the restriction not done by the carb tops?
|
|
|
bobthebuilder
|
| posted on 18/3/12 at 09:39 PM |
|
|
no as far as i can tell its jets and air restriction.
that would be fantastic if we could try your jets before i by a kit to make sure i am going in the right direction.
would it be possible for you to come round on saturday with your jets?
cheers rob
|
|
|
maccmike
|
| posted on 18/3/12 at 10:04 PM |
|
|
yeah Iv no problem with that. Il have to make sure the missus hasnt got plans though. u2u me details
|
|
|
bobthebuilder
|
| posted on 19/3/12 at 08:38 PM |
|
|
no problem will send u2u.
right it is definetly the wrong jets as i phoned up a honda parts place and got a price and size for a uk bike the same and they came back with 1.22
size.
i have just whipped out 1 of the jets from the carb and it is a 1.02
so quite a difference in size.
as the jets are no good to me as they are i might give drilling a go. worth a try.
looks like you were right rf900 rush. good shout.
cheers everyone for your help will let you know if i get it sorted
|
|
|
bobthebuilder
|
| posted on 24/3/12 at 09:58 PM |
|
|
just like to say thanks for all the help and input.
drilled the jets tonite and all is good.
looking forward to a track day.
cheers rob
|
|
|
