Help needed: Carb setting issue

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Tywaugh
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Help needed: Carb setting issue

Post by Tywaugh »

Hey Everyone. Long time reader, first time poster.

I have searched extensively online but can't find anything that pertains to my situation exactly. I would greatly appreciate if someone could chime in and offer some insight.

I recently picked up a very clean 2003 SH with 11000kms on the ODO.
Bike has Yoshi RS-3 slip-ons, K&N filter and jet kit installed (Dynojet I believe, short stout taper at the end of needle approx 1/2 inch)

The situation I am experiencing is...

In 4th gear, when I roll on the throttle hard anywhere from 2k to 5k rpms the bike will feel flat and accelerate slowly then the bike will "hitch" or "hiccup" as the revs are climbing. Lean? The bike never feels like it is going to quit but it is lackluster in power.

This scenario is evident in every gear, and the "hitches" are directly related to the amount of load on the motor. I can roll on the throttle easily in 4th gear and it will accelerate smoothly but slowly.

I pulled the choke out a bit while accelerating, thinking; if the bike is running lean this will make it run better but instead it perhaps made it run a little flatter. Rich?

The bike will eventually smoothen out a bit once it gets up to 7k, but it still feels a little weak. I would expect it to pull a bit harder than it does.

The bike will rev freely in neutral and as the revs are dropping they will hang for 1 second at 2000rpm then drop to 1200rpm. Lean? Pilot jet too small?

I know this bike sat a lot in it's life so this weekend it removed the carbs to inspect and clean. The floats looked brand new, there was no discoloration or varnish anywhere inside the bowls or floats. I removed the jets and cleaned them.


Carb settings:

- Front main jet: 190
- Rear main jet: 195
- Pilot jets: Unsure of size
- Front and rear needles: second clip from bottom
----> I adjusted this. Clip is now on the bottom as I thought the bike was running lean
- Pilot screw does not appear adjustable, they are capped off
- Diaphrams looked good


While the carbs were off, I inspected the intake valves and was surprised how gummed up they were, it doesn't look normal. Old/bad gas run through it? I added seafoam to my tank to help clean it up a bit over the next few months. Rich? Pics attached.

I pulled the rear plug and I thought it looked a tad white-ish. Lean? Pics attached.

I have read these bikes are hard to tune with a K&N filter installed. I only found out about the filter and jet kit this weekend. I am debating going back to stock jets and stock filter but I have a few questions...

- Will I need to rejet with the OE filter and Yoshi slip-ons?
- Would the pilot jet affect the rev range between 4k-6k?
- How much effect does the pilot jet have on the entire rev range?

I used to think I knew a little bit about this stuff but now I am feeling more confused. I am sensing both rich and lean symptoms, unless I am interrupting them wrong.

I have thought the symptoms do almost feel ignition like so I am going to install new plugs, however considering the AM filter and jets and low kms on the bike I am focusing on the carb's as the issue first. I've done a complete service on the bike, all fluids changed.

I can't think of anything else to add. I really like the bike and I am eager to get it dialed in.

-Ty
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tony.mon
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Re: Help needed: Carb setting issue

Post by tony.mon »

Sounds likely that the cam timing is 180 out.
Have you had cct work done lately?
It's not falling off, it's an upgrade opportunity.
Tywaugh
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Joined: Sun Aug 20, 2017 12:06 am

Re: Help needed: Carb setting issue

Post by Tywaugh »

Hey Tony,

I have not done the CCT's. I plan to but for now they are the stock auto tensioners. I did not see any evidence that valve covers had been off, I do not believe the bike has had any valve train work. I could of course be wrong. I should mention I did not remove the carbs or sensor from the cages as I know this can cause timing issues. I wonder if that could be an issue, maybe someone removed it before.
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KermitLeFrog
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Re: Help needed: Carb setting issue

Post by KermitLeFrog »

The plugs look too rich to me. Also, they should be Iridium. I would change them.

The top of the inlet valves look horrid. Leaky valve seals perhaps? Letting oil onto them?
"I spent a lot of money on booze, birds and fast cars. The rest I squandered" (George Best, RIP)
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fabiostar
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Re: Help needed: Carb setting issue

Post by fabiostar »

silly things like vac pipe ok?
diaphragm in the petrol tank petcock ripped?
carb rubbers tight?.
the older i get,the faster i was :lol:
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freeridenick
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Re: Help needed: Carb setting issue

Post by freeridenick »

KermitLeFrog wrote: Mon Aug 21, 2017 7:02 pm The plugs look too rich to me. Also, they should be Iridium. I would change them.

The top of the inlet valves look horrid. Leaky valve seals perhaps? Letting oil onto them?
I was thinking rich too. If they're DJ needles they will have six slots and the clip on the second from bottom (nearest the pointy end) with a washer underneath iirc.

I think the mains are too big and the DJ kit suggests the same size front and rear. Also check the fuel screws and balance the carbs. TPS maybe too.

Loads of info on this in the Welcome in section.
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VTRDark
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Re: Help needed: Carb setting issue

Post by VTRDark »

Wow those valves are yuk. I wouldn't bother with seafoam and stuff as often these kind of additives don't always help and can actually add to the gunkyness, damage oil seals etc. Sometimes a little gunkyness is a good thing as it helps block small leaks. If the bike has been sitting around a while it should all hopefully burn itself off with good use once dialled in and things are running nice. Leaky stem seals is a good shout so keep and eye on them.

End cans alone wont make all that much difference accept weight and a good sound. A full system on the other hand is something else as well as other engine modifications. 190/195 mains even for dyno jets is most likely a bit rich and now you have richened up the needles adding to it. I'd try 180/185 dynojet mains, needles 4th clip from the top on dyno jet needles should be good. And you don't need the extra lift hole drilled out either in case someone has followed dynojets instructions by the letter. If you have the extra lift hole then fill with epoxy and smooth off. Try not to poke epoxy through the hole leaving a massive build up behind the hole so poke a bit of card or something down the back (inside the slide) while your fill the hole. Pilot jets wont be on full tap between 4 -6k but it will filter through a bit and taper off the higher it gets right down to a little trickle on the mains. Fuel mixture screws are your fine tuning for the pilot jets. Stick a standard filter in too and you may be amazed the difference that will make.

I wouldn't worry about the plugs just yet. Keep them as they are easier to read while tuning. Iridium's are not reliable enough for looking at the colour when trying to work out what's going on.
I should mention I did not remove the carbs or sensor from the cages
Are you referring to the TPS here. I would not worry too much about that right now. It wont make a massive difference to your issues.

Oh and one more things. Where about in the States are you (I presume your US). Your not in Denver or some other elevated place are you.
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popkat
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Re: Help needed: Carb setting issue

Post by popkat »

I agree it seems rich and the 180/185 DJ jets would be a better option (this is dynojet sizes, don't put any other make jet of this size in as they will be different). If the slides have the extra lift holes leave them I never had a problem, also leave the K&N filter in. Do one thing at a time, jet it first then see how it performs.. Have you had a V twin before ?, they are different. 2k rpm is pretty low to expect it to pull in 4th gear. There may be an issue with your bike but you may also be not quite riding it in the right way.



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freeridenick
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Re: Help needed: Carb setting issue

Post by freeridenick »

popkat wrote: Tue Aug 22, 2017 9:15 pmHave you had a V twin before ?, they are different. 2k rpm is pretty low to expect it to pull in 4th gear. There may be an issue with your bike but you may also be not quite riding it in the right way.
That's a fair point. I'm using mine on track only but I like to keep it above 6k. Any lower than that and it's back a gear. Peak torque is typically around 7k and is pretty flat from there to the red line. On the road though between 4k and 7k will have you smashing past pretty much everything.
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Stephan
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Re: Help needed: Carb setting issue

Post by Stephan »

popkat wrote: Tue Aug 22, 2017 9:15 pm I agree it seems rich and the 180/185 DJ jets would be a better option (this is dynojet sizes, don't put any other make jet of this size in as they will be different). If the slides have the extra lift holes leave them I never had a problem, also leave the K&N filter in. Do one thing at a time, jet it first then see how it performs.. Have you had a V twin before ?, they are different. 2k rpm is pretty low to expect it to pull in 4th gear. There may be an issue with your bike but you may also be not quite riding it in the right way.
I agree, smaller jets and needle clip at g4 (4th groove from top) could be good start. Choke is running properly?
Tywaugh
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Re: Help needed: Carb setting issue

Post by Tywaugh »

Hey Guys,

Sorry for delay been busy with work.

Appreciate the info, that is massively helpful.


KermitLeFrog:
I assumed those were the factory stock plugs. One thing I noticed when I took the K&N filter off there was approx 2 tablespoons of filter oil pooled in the airbox. I wonder if it's possible the filter was over oiled and some of that was breathed into the engine. Maybe a bit of a stretch. Would bad gas cause this issue? Wouldn't it be odd for such a low mileage bike to have leaky valve seals? I will run a compression test next time to verify this.


Fabiostar:
All of my vacuum lines looked in great shape and the clips where solid, I don't believe there are any leaks.


VTRDark:
Great info, thanks! I am in Nova Scotia Canada, pretty much sea level. I am getting ready to put 1000kms on the bike this weekend, it will be a good time to feel the bike out after cleaning and changing the carbs, however, I am now worried that I may have richened it up too much. I will pull it apart as soon as I get back and order up some new jets. I will post some picks of the needles and jets to hopefully determine what kit I have as I am aware of the jet sizes differing between brands of kits.


Popkat:
That is also a very good point. This is my first v-twin and I assumed it was meant to lug a bit I am going to start riding it higher in the revs. I just found it flat feeling in the higher revs, it feels stronger in the lower revs but I assume that is related to carb setup. Under 3/4 hard throttle in 1st I can feel the front wheel getting light so it pulls hard I just don't know what is normal, if it is meant to pull harder than this, bring it on. I have owned inline 4 sport bikes prior and I would ride those higher in the revs as that's where they felt best.


Stephan:
I believe the choke is working proper. The cables and SEV's all appeared free moving and in good shape. One thing I have noticed is if I pull the choke out the knob will spring back approx to 1/4 I have to hold the choke out to start intially. I will leave it in this 1/4 out position as the bike warms up and if it gets to warm I will hear it starting to stall (too much fuel) so I will push the choke in and the bike will idle nice and fine. I assumed this meant everything was operating normally.


Next steps:
I am going to order 180/185 jets, adjust the needle clip positions back to 4th after I verify it is in fact a DynoJet kit, install new plugs, and order an OE filter and try it back to back with my K&N. I will post pics of what I see as it comes apart and let you guys know how it works. I believe the rider may be some at fault here as this is my first v-twin but I know it should work better than it does.

Thanks again guys!
-Ty
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KermitLeFrog
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Re: Help needed: Carb setting issue

Post by KermitLeFrog »

A bit of oil mist in the airbox is OK but 2 tablespoons? That seems an awful lot.

Are you sure it's filter oil. If it's red it probably is but if it's yellow or brown it's probably engine oil which indicates blowby from the crankcase breather.
"I spent a lot of money on booze, birds and fast cars. The rest I squandered" (George Best, RIP)
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Stephan
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Re: Help needed: Carb setting issue

Post by Stephan »

I never saw better results than with kn filter, dynojet needles and open cans, properly set. Try this configuration to work at first.
tony.mon
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Re: Help needed: Carb setting issue

Post by tony.mon »

To rule out an over oiled filter just run it for a short ride without the filter fitted.
With a k and n it's easy to over oil and it makes the bike gutless at the top end.
If it's that causing a problem it will make the bike run badly but all you need to do is wash the filter in hit soapy water and re oil but lightly, just so you can see a pink colour but not red, and certainly not enough to have oil running or dripping off the filter.
It's not falling off, it's an upgrade opportunity.
tony.mon
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Re: Help needed: Carb setting issue

Post by tony.mon »

tony.mon wrote: Thu Aug 24, 2017 10:20 pm To rule out an over oiled filter just run it for a short ride without the filter fitted.
With a k and n it's easy to over oil and it makes the bike gutless at the top end.
If it's that causing a problem it will make the bike run badly but all you need to do is wash the filter in hot soapy water and re oil but lightly, just so you can see a pink colour but not red, and certainly not enough to have oil running or dripping off the filter.
It's not falling off, it's an upgrade opportunity.
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