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View Full Version : Curvy misfire/splutter at 7500 rpm.

apchara
01-10-13, 10:01 PM
hi there guys firstly HEEEELLLLOOOOOOO, i love a good forum makes like so easy, you get to meet some standup chaps on these "enthusiast" forums!!

I recently bought a SV650s, on a Y plate(99?)*Being a young(ish) lad of 25 its all injection and sensors and computers, carbs are a new world to me:smt090
As for the bike i bought it for £470 as a non runner from a guy who would just chuck it in the garage whenever anything needed doing, he wasnt a "have-a-go-hero" so everything is above board, the bike had been sitting for 10 months open street in Paddington, no cover, so there was water and crap going in everywhere after some research I have flushed carbs and got virtually all the water and gunk out, flushed tank too, new plugs fitted, also going to be doing an oil change with filter and air filter this weekend and new water/coolant. It does not rev past 7.5k without a good splutter?!?! I ran it airboxless to get it home as filter was too wet to let a proper flow through. i noticed one crank breather blows more than anotheralso Both manifolds warm up so i doubt its a misfire. i managed to ride it home to walthamstow, being carbs im a tad clueless, i know HOW they work and whats what but as for stripping i dare not until ive been told that is HAS to be done. i really enjoyed the ride back on the SV it's a VERY VERY different feel to the XJ6 i'm using at the moment, i love the torque and the light handling of the SV!

any ideas on solving the splutter at 7.5?
wideguy
01-10-13, 11:21 PM
Does it do this with the airbox and filter installed?
apchara
02-10-13, 06:17 AM
ill fog out n abut 12 hours, will put new filter in and give it a whirl, it didnt run with the airbox on

whats the difference between curvy and pointy?
Mauler
02-10-13, 06:38 AM
Horrible styling on the pointy with an injected engine and fancy dash. ;)

Real techical info I'll leave to someone who is a bit more familiar with pointies than I am...
atassiedevil
02-10-13, 09:24 AM
Sounds like fuel starvation at higher revs. Partially blocked main jet, bent needle, etc?
Could just be the lack of filter too. Get that back in to start, and we'll see where we go from there.
Choke plungers are known to stick in various positions and cause issues too. Does the problem go away wtih the choke on full?
maviczap
02-10-13, 09:43 AM
Sounds like fuel starvation at higher revs. Partially blocked main jet, bent needle, etc?
Could just be the lack of filter too. Get that back in to start, and we'll see where we go from there.
Choke plungers are known to stick in various positions and cause issues too. Does the problem go away wtih the choke on full?

Also make sure carb rubbers are properly seated in the airbox
apchara
02-10-13, 04:13 PM
So pointys are **** and modern and do everything better than a curvy!! Got it!!

Goiing to carb cleaner tonigh are the choke plungers the big black things over the needles?
The front carb rubber is a pain to fit but I have the tools to get it on, will try full throttle with choke on once the box and new filter is fitted
Biker Biggles
02-10-13, 05:04 PM
The choke plungers are the bits that go into the sides of the carbs at the end of the choke cables.Held in by a plate with a screw through it which can be difficult to get off.A very common cause of poor running so need unsticking regularly.
apchara
03-10-13, 12:36 AM
SHE LIVESSSSSSS

hence the late post, stripped carbs, flushed float bowls new air filter refited airbox (nicelly), greased the front plug lead seal, wiped down most of the MUNK (mud, soil, dust, grease and other road crud)

OMGGGGG what a ride!!!! she pulls like a dream and can just go and go and go

now to strip, proper clean, respray, replace the seat and repair some fairing cracks!
apchara
05-10-13, 01:05 AM
So....... had an awesome 5 hours out and about, met a few guys from here up frith street on the way home, lost all power, bike rides and idles fine but all the oomph has gone, it revs ok but under load it does nothing! !

Ideas?
Vinc
09-10-13, 10:36 AM
Strange.. is it firing alright?
Have you changed the spark plugs recently? (Maybe they aren't calibrated correctly)
atassiedevil
09-10-13, 10:47 AM
I would say as it was running fine, something you have done has come loose somewhere. Check everything you did, make sure nothing is loose?

If you can get it to me, you can compare side by side with my curvy. Not running on one cyl or something silly? Check exhausts for heat, see if it's one cyl or both etc.


C.
apchara
09-10-13, 10:52 AM
As it stands shes running fine just needs sprocket and chain plus brakes sorted and a new kick stand sprinf