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Coldbloodedness & Carb Fiddling

2K views 15 replies 11 participants last post by  rwantin 
#1 · (Edited)
Hi again. I think I have reached my VTX Noob Quota, so hopefully this is the last bother for a while. I love this damn bike so much (and am a bit of a perfectionist), so just trying to get it all dialed in.

I'm at the office, and just rode it this morning, so top of mind. I love riding this time of year in Michigan, and stubbornly keep at it until temps are consistently below 40. Because the VTX has a windshield, it will be a go-to and often.

I get that a big, liquid-cooled V twin is going to be coldblooded, but am wondering if it can be improved. And if my carb situation is making it better or worse.

I installed a Dynojet Stage 1 kit (stock airbox and pipes), something I have done with numerous other bikes and was always happy with the results. And that is the case here. When it's warm out, the bike runs and pulls great.

I pull the choke fully, give it a few seconds, go about halfway (maybe 1500 rpm) for another half minute, and then give it a few revs as I close it (and make sure it is off completely), and it settles into a nice idle. I gave it another five minutes or so after that. It was in the upper 40's this morning. Even after a generous warmup, I was still getting random sputters and coughs, even a few miles in. And what responded so perfectly in warm weather feels, well, laggy from the low-end in cold. This is counter to my normal experience. Most of my bikes run great on the cool, dense air.

Do you think the jetting is helping or hurting in this situation?

I'm playing with some ideas for the weekend.

-Adjust A/F another 1/4 - 1/2 turn out (from memory, it's two turns out), use the stock diaphragm spring (an inch or two longer than the kit), adjust the Dynojet needle (also from memory, 3rd position)

-Swap the entire kit out back to stock (easy enough to do, but reluctant as it runs so well otherwise).

-Shut up and just deal with it, it's cold outside.

One thing to add, this appears to be under load only - the throttle responded nicely to small inputs from one finger once I got here, but that is static in the parking garage (and well warmed up).

Again, many thanks in advance.
 
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#3 ·
And maybe I go back to stock to have a sound baseline. It was noticeably improved after the kit, but realistically, that could also have been the result of a thorough cleaning. Maybe a little of both.
 
#5 ·
I spent $350 + jets and had my bike dyno tuned. I have a wide open airbox. My bike puts out tons of power, and runs well even in the cold. I actually removed my choke. If you do mess with the jets, my personal believe is, spending the money will get you where you need to be. I don't have an exhaust sniffer to know if it is rich/lean, and I think people can at best get it close without one.

 
#6 ·
Thanks guys, this helps.

I've always had pretty good luck with mild Stage 1 kits, if only because modern (at least non-injected) bikes always seemed on the lean side. It paid nice dividends in response. That may not be the case here, at least in the cold. For now and the forseeable future, I'm going to keep the stock pipes and airbox, as I am often leaving at 6:00 am and like my neighbors for the most part (the exception being the old Duc, which has the mandatory Termis). Then again, bolt on pipes sound appealing as it were (intrigued by the V&H if they're not too loud nor need a lot of fiddling and tuning).

I'm leaning towards putting her back to stock for now. In the end, just want her running well, especially in the cold.
 
#9 ·
#10 · (Edited)
rwantan,
I put a "Dyno-Jet", stage 1 kit on my 1300 about 3 years ago. I have stock air box and stock pipes. I live in N.E. Ohio and have the similar weather related stuff to deal with as you. Becaues it has a carb it will take a few minutes to heat up but after that it runs just fine.

The Dyno-Jet package clames 5% boost in HP, and better gas milage... My bike runs great but as for the 5%...? I did this just before a long trip I had taken (just over 800 miles), mostly all highway and got slightly (and I mean slightly) better gas milage. I still have the stage 1 kit in the bike because it did help - slightly. The stock air box and pipes do allow it to breath normally as designed, thats important.

Keep your carb fuel filter clean and keep your spark plugs cleaned & gapped often, even if they look like they don't need and attention.

The only other thing you could do is every so often, use a little Sta-Bil or some other fuel additive - I forgot which one Honda recommends. Help keep fuel moving smoothly throughout the system even during the lousy weather.
 
#11 ·
My 1300 is temperamental in the morning when it’s cold out. I often ride below freezing in the morning. For the first 1/2 mile she will chatter her teeth, but then warms up and runs like normal.

When I first got her last Aug she did this when it was warm out as well. Cleaned the air filter and the carb and that took care of that.


Sitting on my VTX making vroom vroom sounds.

https://www.vtxoa.com/forums/members/95246-smurfy71-albums-my-vtx1300-picture40314-img-1373.jpg
 
#12 ·
When my X was new out the door of the local dealer on a cool to cold day (17 degrees) I pulled the fuel enrichment (choke) knob, hit the starter, and let run long enough to get my helmet on then pushed the "choke" in just a little, then put on my gloves. I pushed in the "choke" all the way and then off I would go.

Well now 11 years later and almost 140,000 miles I do the same procedure but I twist the throttle a couple of times before starting. After I have my helmet and push the "choke" in a little, then on with the gloves but I let it run for a short time then push the "choke" in all the way before taking off. Usually at most only one sputter after this ritual. Engine is all stock except a K and N air filter.

Both of us are 11 years older and need just a little more warm up time before performing like we did in our youth.
 
#13 ·
Thanks so much for all the feedback. Helps to learn a bit about the bike to make some informed decisions. :)
 
#16 ·
I was getting more coughs and sputters than anything else. To give myself a good baseline, I swapped everything back to stock last weekend, so at least I'll know it's not the jetting/needles. The only unfortunate thing is on the test ride after it seemed to pull slightly, and I do mean slightly, less hard from low and mid-range. Upside? Getting really good at pulling and installing the carb. :) I'll reconsider next spring, or may just leave the damn thing alone.

Again, thanks for all the insights.
 
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