Go Back   Horizons Unlimited - The HUBB > Technical, Bike forums > Yamaha Tech

Yamaha Tech Originally the Yamaha XT600 Tech Forum, due to demand it now includes all Yamaha's technical / mechanical / repair / preparation questions.
Contact Overland Solutions for all your custom modifications and setup for overland travel.

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 13 May 2013
Registered Users
Veteran HUBBer
 
Join Date: May 2013
Location: Wisconsin, USA
Posts: 349
'88 XT600U bog and backfiring

I recently bought an 88 XT600 that wouldn't start easily or stay running, but sounded good when it did. It sat for 2 years so I figured clogged carbs. Well I cleaned them(twice actually) and made sure no plugged holes. I got it running and it ran great, full throttle and all.
I filled with gas(it was old gas in it), 93 super unleaded here in the states, went 2 miles toward home and it suddenly bogged like it was working real hard and kept popping/ backfiring. till it died, wouldn't restart. after a bit with full choke it did start but same thing and died. Recleaned carbs, made sure no air leaks(even put light silicone sealer on some things).

It then started up and ran perfect, idle smooth, let idle for a couple minutes then bog and popping again and it died. I belive it would be the cdi or coil( it didn't seem to have great spark, but the bike is new to me so I don't know how good it should be) the plug color looked a bit lean and even after kicking on full choke it was dry. That says fuel issues, but outside of some internal air leak or out of spec part it isn't a clogged jet or port. BUT the popping and bog when it gets warm says cdi. Any of you that have been running these bikes have some possible solutions? Thanks JJ
Reply With Quote
  #2  
Old 13 May 2013
Registered Users
Veteran HUBBer
 
Join Date: Feb 2010
Location: Border Ranges Northern NSW, Australia
Posts: 778
Did you check the float needle valve filter to see if there was any shit blocking the fuel flow?



Mezo.
__________________
http://www.tenere.co.uk/
Reply With Quote
  #3  
Old 13 May 2013
Registered Users
Veteran HUBBer
 
Join Date: May 2013
Location: Wisconsin, USA
Posts: 349
No I didn't , the pin wouldn't come out easily and until I had a new needle valve and pin I didn't take it out, which I have ordered because I wanted to replace it anyways. I also didn't know it had a screen like that and that would make sense. The one question on that would be, when it did quit, I opened the bowl drain screw to check for fuel and it did come out, but whether there was enough,I don't know. It wouldn't start this morning after 8 kicks on full choke. I'm going to squirt some gas and a little oil in the cyclinder tonight. If it fires up, I know it is mostly fuel related.

Thanks for the picture, it shows what is in there.
Reply With Quote
  #4  
Old 14 May 2013
Contributing Member
Veteran HUBBer
 
Join Date: Sep 2009
Location: Australia
Posts: 168
Try a simple one first - a new spark plug. I had an XTZ that did something similar thing once and it turned out, after multiple carburettor cleanings, to be that. The plug gave a fine spark when out of the cylinder but was breaking down when under load.
__________________
Martin

back on the road again


http://awayonmybike.blogspot.co.uk/
Reply With Quote
  #5  
Old 15 May 2013
Registered Users
Veteran HUBBer
 
Join Date: May 2013
Location: Wisconsin, USA
Posts: 349
A quick update today, I put in a different plug, still nothing but backfiring( had to stop and sleep with icepack around my ankle, afraid of it being broke from one nasty pop). Now decided to kick with my motocross boot on right foot.
I decided to rollback to when it quit running, about 1.5miles AFTER filling up with 93octane GAS. Drained gas out of tank and float bowl and got 87octane from a different company. About 6 good kicks it fired up and is running, let it idle for 3-4minutes, went around the block a couple times. It does still have a skip in the firing, runs perfect under acceleration(easily hit 85mph and still going), with a steady throttle it has a stumble.

Any ideas what the steady misfire would be? Has no backfiring, plug now looks good color. Over tightened valves? Do these motors get tight or loose with wear? No knocking or ticking at all, entire motor sounds smooth and has great power. I'm going to really like this bike once it is straightened out.
Reply With Quote
  #6  
Old 15 May 2013
2499's Avatar
Registered Users
HUBB regular
 
Join Date: Jul 2012
Location: Yverdon Les Bains, Switzerland
Posts: 89
Dirty fuel filter
Carb failure
Faulty ignition coil
Faulty pickup coil
Bad CDI unit
__________________
Christian
Reply With Quote
  #7  
Old 15 May 2013
Registered Users
HUBB regular
 
Join Date: Apr 2011
Location: Southampton, England
Posts: 92
Quote:
Originally Posted by 2499 View Post
Dirty fuel filter
Carb failure
Faulty ignition coil
Faulty pickup coil
Bad CDI unit
Leaking inlet rubbers causing a weak mixture.

They are rubber bonded to steel and they deteriorate over time. Unless they have been replaced in the bikes life you almost certainly have this problem.
Reply With Quote
  #8  
Old 15 May 2013
Registered Users
Veteran HUBBer
 
Join Date: May 2013
Location: Wisconsin, USA
Posts: 349
The boots are in perfect condition, the previous owner apparently recently replaced them. This morning it took squirting gas down the spark plug hole to get it fired up without a bunch of kicking, then it ran as normal. Dies when I pull the choke out, so it is working. Spark plug now is all sooty black. I'm looking into getting a CDI and coil, even if they turn out to be backups. More carb work is in the works also.
Reply With Quote
  #9  
Old 15 May 2013
Registered Users
Veteran HUBBer
 
Join Date: Feb 2010
Location: Border Ranges Northern NSW, Australia
Posts: 778
So have you checked the filter like i suggested? take out the screw (pictured) put a pair of pliers on the valve body & twist from left to right pulling at the same time.

They are in there fairly tight.

Mezo.
__________________
http://www.tenere.co.uk/
Reply With Quote
  #10  
Old 16 May 2013
Registered Users
Veteran HUBBer
 
Join Date: May 2013
Location: Wisconsin, USA
Posts: 349
Yes, it has now been replaced along with the needle(or plunger) since the parts came in yesterday morning. It wasn't plugged, but it wasn't completely clean either. ran it to work today and bombed around, takes about 8 kicks on full choke or a squirt of gas down the plug hole to get started after it sits for a couple hours and has that steady stumble but stays running and runs perfect accelerating. It's definitely something in the pilot circuit(low speed) or an electrical thing.
Time to put in my pair of Mikuni's from a Raptor 660

This bike is awfully skittish, it wants to shift back and forth like on glare ice. Picture hanging the bike by the frame and swinging it side to side, that how it drives, even on asphalt, worse on gravel. Needs some better tires.
Reply With Quote
  #11  
Old 16 May 2013
Registered Users
Veteran HUBBer
 
Join Date: Feb 2010
Location: Border Ranges Northern NSW, Australia
Posts: 778
OK does it have an aftermarket inline fuel filter? and have you checked the filter on the petcock as well?

Bogging to me normally means a fuel problem or air leak, are you getting a decent spark?

Mezo.
__________________
http://www.tenere.co.uk/
Reply With Quote
  #12  
Old 16 May 2013
Registered Users
Veteran HUBBer
 
Join Date: May 2013
Location: Wisconsin, USA
Posts: 349
There was no inline filter other than the petcock tank one. I have one that is going in. Right now it will hardly start unless I squirt fuel directly into the cylinder through the spark plug hole or kick with all I've got 8 to 10 times(it messed up my ankle again this morning when it backfired trying to start it normally). That says it isn't getting enough gas to start, BUT, once it starts, it'll run till the tank is empty, so I know it is getting enough fuel into the carb, plus I've made sure the bowl is full repeatedly.
It simply is the carb start circuit or a spark issue, I've checked spark multiple times now and it really snaps, but whether it is doing it on-time(aka bad cdi or coil) or under compression is the question. If it was an issue with fuel delivery to the carb, it would run out of gas after it is started, but it doesn't and plenty of fuel comes out of the bowl when I open the drain screw.
My ankle is telling me to walk away from this bike right now.Or should I say limp!! My Honda XL600r starts up in one kick!! But the Yamaha is in way better shape.
Reply With Quote
  #13  
Old 16 May 2013
bacardi23's Avatar
Registered Users
Veteran HUBBer
 
Join Date: Sep 2007
Location: XXX<-Portugal->Azores->Santa Maria (island)
Posts: 1,524
your problem with having to kick it 8 times is either technique or decompression cable is not well adjusted.

Personally, I believe the decompression cable/adjustment is The weak spot on the XT

I do not have the decompressor assembly fitted on my 1990 XT600E (retrofitted the kickstart) and I find it very easy to kickstart her in one, sometimes two kicks if she's been sitting in the garage for weeks..

Have you gotten your ankle checked out before?
heal fast!
Reply With Quote
  #14  
Old 16 May 2013
Registered Users
Veteran HUBBer
 
Join Date: May 2013
Location: Wisconsin, USA
Posts: 349
When it pops is imediately after the decompression lever snaps back shut. With it set right now, as soon as the kick starter starts its cycle the cable begins pulling on the lever. It opens it further all the way till about the halfway point(kick start lever is approx level with the ground), then the lever on the motor snaps closed, so from that point on there is no decompression. Its at the point the the motor fires, if it starts, or pops and kicks back on the lever.
As for my ankle , right now it is swollen and a big black and blue bulge , hurts like h**l to walk on. If it turns greenish-yellow, time to get an exray!
Reply With Quote
  #15  
Old 16 May 2013
Registered Users
Veteran HUBBer
 
Join Date: Feb 2010
Location: Border Ranges Northern NSW, Australia
Posts: 778
Mate thats not right at all, Vando hit the nail on the head there i think.

Walk away from it for now before you do serious damage, i guess the next step is your electrics (pick up coils) don't suppose you have a spare CDi ?

Mezo.
__________________
http://www.tenere.co.uk/
Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 Registered Users and/or Members and 1 guests)
 
Thread Tools
Display Modes

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
Trackbacks are On
Pingbacks are On
Refbacks are On


 
 
 

NEW! HU 2015 Motorcycle Adventure Travel Calendar is now available! Get your copy now for some terrific travel inspiration!

HUGE, 11.5 x 16.5 inches, beautifully printed in Germany on top quality stock! Photos are the winning images from over 600 entries in the 9th Annual HU Photo Contest!

Horizons Unlimited 2015 Motorcycle Adventure Travel Calendar.

"The calendar is magnificent!"

"I just wanted to say how much I'm loving the new, larger calendar!"

We share the profit with the winning photographers. YOU could be in the HU Calendar too - enter here!

Next HU Eventscalendar

See all events

 

HU DVD Autumn Special!

Take 40% off Road Heroes Part 1 until October 31 only!

Road Heroes features tales of adventure, joy and sheer terror by veteran travellers Peter and Kay Forwood (193 countries two-up on a Harley); Dr. Greg Frazier (5 times RTW); Tiffany Coates (RTW solo female); and Rene Cormier (University of Gravel Roads).

The first in an exciting new series, Road Heroes features tales of adventure, joy and sheer terror by veteran travellers."Inspiring and hilarious!"

"I loved watching this DVD!"

"Lots of amazing stories and even more amazing photographs, it's great fun and very inspirational."

"Wonderful entertainment!"

Check it out at the HU Store! Remember to use Coupon Code 'HEROES' on your order when you checkout.



Scottoiler automatic chain oilers. The most important accessory for your next motorcycle adventure!


Renedian Adventures


Renedian Adventures

What others say about HU...

"I just wanted to say thanks for doing this and sharing so much with the rest of us." Dave, USA

"Your website is a mecca of valuable information and the DVD series is informative, entertaining, and inspiring! The new look of the website is very impressive, updated and catchy. Thank you so very much!" Jennifer, Canada

"...Great site. Keep up the good work." Murray and Carmen, Australia

"We just finished a 7 month 22,000+ mile scouting trip from Alaska to the bottom of Chile and I can't tell you how many times we referred to your site for help. From how to adjust your valves, to where to stay in the back country of Peru. Horizons Unlimited was a key player in our success. Motorcycle enthusiasts from around the world are in debt to your services." Alaska Riders

contest pic

10th Annual HU Travellers Photo Contest is on now! This is an opportunity for YOU to show us your best photos and win prizes!

NEW! HU 2014 Adventure Travel T-shirts! are now available in several colors! Be the first kid on your block to have them! New lower prices on synths!

HU 2014 T-shirts now in!

Check out the new Gildan Performance cotton-feel t-shirt - 100% poly, feels like soft cotton!


What turns you on to motorcycle travel?


Global Rescue, WORLDwide evacuation services for EVERYONE

Global Rescue is the premier provider of medical, security and evacuation services worldwide and is the only company that will come to you, wherever you are, and evacuate you to your home hospital of choice. Additionally, Global Rescue places no restrictions on country of citizenship - all nationalities are eligible to sign-up!


New to Horizons Unlimited?

New to motorcycle travelling? New to the HU site? Confused? Too many options? It's really very simple - just 4 easy steps!

Horizons Unlimited was founded in 1997 by Grant and Susan Johnson following their journey around the world on a BMW R80 G/S motorcycle.

Susan and Grant Johnson Read more about Grant & Susan's story

Membership - help keep us going!

Horizons Unlimited is not a big multi-national company, just two people who love motorcycle travel and have grown what started as a hobby in 1997 into a full time job (usually 8-10 hours per day and 7 days a week) and a labour of love. To keep it going and a roof over our heads, we run events (22 this year!); we sell inspirational and informative DVDs; we have a few selected advertisers; and we make a small amount from memberships.

You don't have to be a Member to come to an HU meeting, access the website, the HUBB or to receive the e-zine. What you get for your membership contribution is our sincere gratitude, good karma and knowing that you're helping to keep the motorcycle travel dream alive. Contributing Members and Gold Members do get additional features on the HUBB. Here's a list of all the Member benefits on the HUBB.


Books & DVDs

amazon

All the best travel books and videos listed and often reviewed on HU's famous Books page. Check it out and get great travel books from all over the world.


Motorcycle Express for shipping and insurance!

Motorcycle Express

MC Air Shipping, (uncrated) USA / Canada / Europe and other areas. Be sure to say "Horizons Unlimited" to get your $25 discount on Shipping!
Insurance - see: For foreigners traveling in US and Canada and for Americans and Canadians traveling in other countries, then mail it to MC Express and get your HU $15 discount!




All times are GMT +1. The time now is 03:43.