2023 Quarterly StarBike Photo Challenge - Spring! Is Now Open For Entries!

Hot Rear Cylinder on the Exhaust Side!! (Video included)

1671 Views 16 Replies 7 Participants Last post by alan1551964, 10 d ago

Mikew3689

Discussion Starter · May 2, 2022

Hi Everyone, new here but the owner of a 2003 Vstar 1100 Classic for the last 6 years. For context, I have had one problem after another with this thing but I love it too much to be rid of it (perhaps a glutton for punishment.) Anyhow, I just replaced the starter clutch, made sure the timing was correct, put everything back together and now the bike has a really rough idle. It will run for about a minute after I turn the choke off and then dies. I then noticed that the exhaust side of the rear cylinder get very hot very quickly as well. I tried to do a bit of research and diagnostics myself but I'd really appreciate some guidance. It seems like the likely issues are a clogged rear carburetor jet or a valve clearance issue. I have a video of the bike after I turned the choke off below if that will help. It seems to run fine, die out a bit, then went to come back alive then die out again....the bike completely stalls out not two seconds after this video ends.

photos.app.goo.gl

New video by Michael Warnet

photos.app.goo.gl

Reactions: 1

1 - 17 of 17 Posts

scootersage

· #2 · May 2, 2022

Hi from Palmyra, New York. Just a guess but are the valves adjusted right. You don't have one hanging up or to tight. Is that rapping noise always there.

Reactions: 1

Mikew3689

Discussion Starter · #3 · May 2, 2022

scootersage said:
Hi from Palmyra, New York. Just a guess but are the valves adjusted right. You don't have one hanging up or to tight. Is that rapping noise always there.

I will be getting into the valves on Wednesday as that is my leading suspect at the moment. And by rapping noise, I am assuming you meant tapping? I didn't necessarily hear a tapping noise when I recorded the video, it might be an acoustics thing because i am in a small garage. Is it possible i threw off the valve adjustment when I was in the crank case adjusting the timing?

lesblank

· #4 · May 2, 2022

Can you pull the plugs and post pictures? That will answer if it's running lean or not. One thing for sure, your idle is set way to low. Idle needs to be 950 to 1050 for oil pump to operate correctly. The Vstar can not be set lower than that without issues. Yes, it seems high, but they are engineered that way.

Font Parallel Rectangle Diagram Document

See less See more

Reactions: 2

nick57

· #5 · May 2, 2022

its hard to tell. but it sounds like its running on one cylinder. are both exhaust pipes getting hot.imedietly

Reactions: 1

Mikew3689

Discussion Starter · #6 · May 3, 2022 (Edited)

lesblank said:
Can you pull the plugs and post pictures? That will answer if it's running lean or not. One thing for sure, your idle is set way to low. Idle needs to be 950 to 1050 for oil pump to operate correctly. The Vstar can not be set lower than that without issues. Yes, it seems high, but they are engineered that way.

View attachment 116613

The spark plugs are black/soot covered. I'll try to post some pics Tuesday night. (In my mind this is a side effect of the valve being too open, and exhaust fumes not being able to exit the cylinder properly) I had always thought the idle was too low but wasn't sure if it wasnjust idling lower due to a fuel delivery issue or not. Thanks!

Mikew3689

Discussion Starter · #7 · May 3, 2022 (Edited)

nick57 said:
its hard to tell. but it sounds like its running on one cylinder. are both exhaust pipes getting hot.imedietly

I felt both exhausts and it feels as though both cylinders are pumping. The rear cylinder exhaust is the only one getting super hot right a way, front exhaust starts to get "normal" heat after a bit of running

Mikew3689

Discussion Starter · #8 · May 4, 2022

2

Hey all, sorry for the delay. Spark plug photo below, both look about the same, maybe a little less soot on the rear plug. (sorry for the out of focus pics! my eyes were barely open last night) So I found a few interesting things last night.

1. Front carb PMS was SIX TURNS from light seat!
2. Rear carb PMS was missing the washer and gasket (Had a mechanic do a rebuild on my carbs two years back because I had too much going on)
3. Rear cylinder exhaust valve cover has a pretty bad leak (yes I should have noticed this just from a visual inspection)

I did not have thin enough feeler gauges to check the valve clearance last night, picked one up today along with some carb cleaner. Valve cover gaskets are also on the way. Hoping these are the issues and once resolved in a few days the bike will run well again.

Sleeve Automotive tire Wood Material property Bag

Finger Material property Auto part Close-up Metal

See less See more

lesblank

· #9 · May 4, 2022

My concern is if PMS was out that far from being rebuilt by a "mechanic", what else might not be right? Seems you are on right path to get it figured out.

warnet.michael

· #10 · May 4, 2022

lesblank said:
My concern is if PMS was out that far from being rebuilt by a "mechanic", what else might not be right? Seems you are on right path to get it figured out.

Right?! He was only supposed to rebuild the carb so I looked through the carb pretty thoroughly and it seems like those are the only two issues 🤞

warnet.michael

· #11 · May 9, 2022

Alright all, i got the carbs, clean and valves adjusted. Rear cylinder exhaust valve had ZERO clearance, Clarence. So I am sure that was not helping with my bikes idle. I set the valve clearance to the middle of the appropriate range and put everything back together. Wouldn't ya know it she starts up and runs.......BUT, 10-15 seconds or so, I hear a click in the rear cylinder and the bike bogs down while the bike is idling cold. Once it warms up, this goes away. I am at a loss for words because I thought this would be THE fix. HELP! I can try to post a video of this tomorrow.

lesblank

· #12 · May 9, 2022

What RPM is your idle set at?

Mikew3689

Discussion Starter · #13 · May 9, 2022

lesblank said:
What RPM is your idle set at?

That's a good question, I do not have a tachometer. I turned it up two full turns after your recommendation. Do you have a recommendation for a "remote" tachometer to dial it in?

lesblank

· #14 · May 10, 2022

There are several cost effective ones that are pretty good. I do not mount it to bike, only use it for tuning purposes.

Tusk Tach/Hour Meter | Parts & Accessories | Rocky Mountain ATV/MC

Shop for Electrical, like Tusk Tach/Hour Meter at Rocky Mountain ATV/MC. We have the best prices on dirt bike, atv and motorcycle parts, apparel and accessories and offer excellent customer service.

www.rockymountainatvmc.com

Product Font Screenshot Material property Gadget

See less See more

Mikew3689

Discussion Starter · #15 · May 23, 2022

Hey all, back again. Spent about a half hour letting the bike run to try and diagnose the problem I'm still having. Not a new problem, but seems to be getting worse. I have this white wispy smoke coming from somewhere on the back of the rear cylinder. Didn't have anything with me to pinpoint exactly where. The bike seems to run OK but you can hear a misfire around 4-5 seconds in the video below. I think my next step is to check for vacuum leaks around the manifolds/carburetors? Maybe this is causing the lean condition/white smoke? Also seem to still have a small oil leak from somewhere on the rear cylinder i need to pinpoint as well.

Google Photos

Home for all your photos and videos, automatically organized and easy to share.

photos.google.com

Strat man

· #16 · 7 mo ago

Mikew3689 said:
Hi Everyone, new here but the owner of a 2003 Vstar 1100 Classic for the last 6 years. For context, I have had one problem after another with this thing but I love it too much to be rid of it (perhaps a glutton for punishment.) Anyhow, I just replaced the starter clutch, made sure the timing was correct, put everything back together and now the bike has a really rough idle. It will run for about a minute after I turn the choke off and then dies. I then noticed that the exhaust side of the rear cylinder get very hot very quickly as well. I tried to do a bit of research and diagnostics myself but I'd really appreciate some guidance. It seems like the likely issues are a clogged rear carburetor jet or a valve clearance issue. I have a video of the bike after I turned the choke off below if that will help. It seems to run fine, die out a bit, then went to come back alive then die out again....the bike completely stalls out not two seconds after this video ends.

New video by Michael Warnet

photos.app.goo.gl

Sounds like it's starving for air

alan1551964

· #17 · 10 d ago

Mikew3689 said:
tried

1 - 17 of 17 Posts