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.

LinkBack Thread Tools Display Modes
Old 28 Mar 2007
jim jim is offline
Gold Member
Veteran HUBBer
Join Date: Aug 2003
Location: Cape Town South Africa
Posts: 229
Help Please - 34L "popping"

Hello all,
Im on the road and my bike is worrying me. Firstly i think its overheating, but im not sure, how the hell do i know- when i touch the engine its very hot and it hurts. Also, on the open road she rides well, when i slow down to 2nd / 3rd gear range (ie slow ridng) it give little backfires, not shotgun blasts, but popping sounds when i decelerate to change gears. Been fiddling today with pilot screw, and i thin k its a bit worse now. Also, usually its a bitch to start her in the morning but today she started ok and later on was difficult to start when hot.

"If we don't find something good at least we will find something new." Voltaire
Reply With Quote
Old 28 Mar 2007
*Touring Ted*'s Avatar
Contributing Member
Veteran HUBBer
Join Date: Jul 2005
Location: Wirral, England.
Posts: 4,489
Your symptom are those of an over lean mixture.

The popping when you close gear is called over run and while it is normal of large singles, popping is the sign of too much air in the fuel mixture..

Tell me, does this occur at closed throttle only ??

If it is hard to start, is this even with full choke ??

There are many reason for hard starting and a lean mixture is one of them.

You could try unwinding the pilot screw a little and trying then. If adjustment doesnt help then a larger pilot jet maybe required.

Have you changed the exhaust system or air filter etc ?

Wind the pilot screw in until its seated (not too tight now) and then unwind 1.5 turns and start from there.

The XT is aircooled so yes it does get hot. Check your oil is bubbling though. You can buy oil temp guages which replace the oil cap.
1994 XR650L
2001 NX650 Dominator.

BMW Dealer Technician

Ushuaia - Colombia 2007/8
UK- South Africa 2010/11
India 2012
Yukon 2012
S.E Asia 2014
U.K - Magadan 2015
Reply With Quote
Old 28 Mar 2007
Registered Users
Veteran HUBBer
Join Date: Jan 2001
Location: Stockholm
Posts: 651
Talking Leaks or settings


We meet again?

If she runs fine for the rest I would not worry too much. Even if the idle mix is too lean, this has no influence whatsoever on the mix with open throttle.

- Is the popping only when you close the throttle? If yes, there's a hole somewhere in the exhaust system or the enrichment device is gunked up. It's the thing on the l/H side of the left carb, little cover with the vacuum operated valve, vacuum from the throat of the second carb.
- If there is popping, with the engine not pulling at the same time, your mix is indeed too lean, but as carbs do not get offtune by themselves it must be something like the intake rubbers leaking air, that's the black thingies between carb and cilinder head.
- Hard starting: Adjust idle mix: heat up engine. With a flat screwdriver turn in pilot screw till engine speed drops, then turn out till max engine speed is reached. do this slowly, gove engine time to react. The higher engine speed will be over a range of screw settings, leave it just before the point where the speed starts to drop again. This setting should give you good starting with cold engine, full choke

Succes! and happy travels!
Reply With Quote
Old 1 Apr 2007
Registered Users
HUBB regular
Join Date: Aug 2006
Location: Cape Town
Posts: 28

Hey Jim,

Not good to hear you having problems so early in the trip! Where about are you guys now? I definatly agree its a mixture thing, Mac,(bryan) bike does the same thing ansd its very lean, my bike however i feel is running slightly rich, this never gives me hastles to start when cold, but can be a little tricky when the bike is hot. i normally just use a little patience and wait as opposed to kicking new vents in my boots! Are you guys still in S.A.? will give you a call if you are!

All the best, regards to Anniken!

Reply With Quote
Old 2 Apr 2007
jim jim is offline
Gold Member
Veteran HUBBer
Join Date: Aug 2003
Location: Cape Town South Africa
Posts: 229
Thanks Guys

Turns out there was an air leak in the intake rubber, which fortunately I had a spare of.. She's running pretty now!

"If we don't find something good at least we will find something new." Voltaire
Reply With Quote

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

Similar Threads
Thread Thread Starter Forum Replies Last Post
XT600Z 34L silencer question andylarkin Yamaha Tech 0 24 Mar 2007 14:43


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


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 06:38.