Go Back   Two Wheel Fix > In the Garage or Shop > Mechanical or Tech

Reply
 
Thread Tools Display Modes
Old 10-14-2010, 01:26 PM   #1
Triple
uncomfortably numb
 
Triple's Avatar
 
Join Date: Nov 2008
Location: JOH-JAH!
Moto: WR250R & Bonneville
Posts: 409
Default 1995 Vulcan 1500 only runs to 30mph...

...

Last edited by Triple; 12-02-2010 at 09:23 AM..
Triple is offline   Reply With Quote
Old 10-14-2010, 01:38 PM   #2
Mikey
Raving Lunatic
 
Mikey's Avatar
 
Join Date: Nov 2008
Location: San Antonio, Texas
Moto: Concours 14 ABS, ZX6E
Posts: 902
Default

Rebuild and synch the carbs.

Edit (now that I'm on a computer instead of a phone):
I went through this with my wife's ZZR that had been sitting for a long time. We chased our tail on it forever, but the ultimate fix was getting the bike into the hands of someone who was a LOT better at carbs than I am. I'm not certain if he did a full rebuild or what because he didn't speak English and my Japanese is pretty limited, but after I got it back from him it ran absolutely AMAZING.

If he got the bike for free, it's definitely worth the price of a good carb guy taking care of that for him. He invests a little bit of money and has a great-running bike. Win-win.
__________________
Slow is smooth, smooth is fast.

Last edited by Mikey; 10-14-2010 at 02:06 PM..
Mikey is offline   Reply With Quote
Old 10-14-2010, 01:58 PM   #3
pauldun170
Serious Business
 
pauldun170's Avatar
 
Join Date: Nov 2008
Location: New York
Moto: 1993 ZX-11 2008 CBR1000rr
Posts: 9,723
Default

My ZX-11 would go through this every year at the start of the new season.
Sea Foam and miles.
After about 200 miles it cleared up.

Reminds me that I have to clean those carbs up.....
__________________


Quote:
Originally Posted by Dave View Post
feed your dogs root beer it will make them grow large and then you can ride them and pet the motorcycle while drinking root beer
pauldun170 is offline   Reply With Quote
Old 10-17-2010, 09:21 PM   #4
No Worries
Keyboard Racer
 
No Worries's Avatar
 
Join Date: Feb 2008
Location: Mile High City
Moto: Old Superbikes
Posts: 1,016
Default

Reminds me of a time in the 80's when I was visiting a mechanic friend of mine who worked at a Yamaha dealer. A kid brings in an RD350 and says it won't go over 30mph. Greg lifts the seat and sees a beach towel folded neatly on top of the intake snorkel.

When I see something like this, I check the ignition first. You can fiddle with the carbs until the world ends, but if the ignition ain't working right, it won't run right. Spark to both plugs and check the timing. Then I check the fuel petcock, related hoses including the vacuum and fuel line, change the filter, and check the choke.

As for the carbs, the engine runs on the idle jets until about 30mph, then the needles lift out of the main jets. If the piston/needles are stuck in their bore, the bike will only run on idle jets. And I believe that they are very lean on the big Vulcan. You can run an ocean of Sea Foam through the carbs and it won't clean the pistons or bores. The tops of the carbs have to come off to clean them.

On my 79 Suzuki, the piston needles are connected directly to the throttle cable. They never stick. I think all carbs after 79 used Constant-Velocity (CV) carbs. The piston/needles rise by the vacuum of the engine, and the piston and bore has to be squeaky clean for them to operate correctly.
No Worries is offline   Reply With Quote
Old 10-17-2010, 11:16 PM   #5
derf
token jewboy
 
derf's Avatar
 
Join Date: Nov 2008
Moto: CBR 900, KLR ugly ass duckling, Gas Man
Posts: 10,799
Default

Clean the carbs.

And yes 2 months is enough time to turn gas to shi. Also, did it run once 2 months ago for 2 minutes, again for 2 minutes 2 months before that, and so on, until that gas is a year old.
__________________
derf is offline   Reply With Quote
Old 10-19-2010, 09:24 AM   #6
Dave
Chaotic Neutral
 
Dave's Avatar
 
Join Date: Feb 2008
Location: Cherry Hill NJ
Moto: GV1200 Madura, Hawk gt
Posts: 13,992
Default

Quote:
Originally Posted by No Worries View Post
Reminds me of a time in the 80's when I was visiting a mechanic friend of mine who worked at a Yamaha dealer. A kid brings in an RD350 and says it won't go over 30mph. Greg lifts the seat and sees a beach towel folded neatly on top of the intake snorkel.

When I see something like this, I check the ignition first. You can fiddle with the carbs until the world ends, but if the ignition ain't working right, it won't run right. Spark to both plugs and check the timing. Then I check the fuel petcock, related hoses including the vacuum and fuel line, change the filter, and check the choke.

As for the carbs, the engine runs on the idle jets until about 30mph, then the needles lift out of the main jets. If the piston/needles are stuck in their bore, the bike will only run on idle jets. And I believe that they are very lean on the big Vulcan. You can run an ocean of Sea Foam through the carbs and it won't clean the pistons or bores. The tops of the carbs have to come off to clean them.

On my 79 Suzuki, the piston needles are connected directly to the throttle cable. They never stick. I think all carbs after 79 used Constant-Velocity (CV) carbs. The piston/needles rise by the vacuum of the engine, and the piston and bore has to be squeaky clean for them to operate correctly.
That was my issue when trying out my friend's gs750 bobber. Id never ridden a bike with the old style carbs and with four of em to pull that throttle was HEAVY
Dave is offline   Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 09:05 PM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.