ziegman

This can happen when the bike gets hot, ( running lean, low coolant) it also can happen from carbon buildup on your pistons. I run 300s at 1000' with t5s and pods, stock bore and no port job, 4+ timing with vforce 3s.

I read alot about people who like amsoil and others that dont. Here is my experience. 1984 yamaha yz 490 gets a new piston and bore job every year, year after year on yamalube or golden spectro at 32:1 also gets a new plug every 2-3 days. Switched to amsoil dominator, it used to be called something else besides dominator but dont remember. Anyway the last 3 years I had it it was run with amsoil, no new pistons or bore jobs, AND I HAVENT FOULED A PLUG IN 6 YEARS ON ANY AND EVERYTHING I OWN!! Not 1 single plug in my 490, not my 86 yz 250, not my98 yz250, 83 yz100, 99 blaster, 2004 blaster, or my 2003 banshee. No engines have had to be rebuilt either. And this is running dominator at 50:1 not 32:1. You believe what you want, I know from 6 years personal experience. Oh by the way dont buy from any dealer just pay amsoil 20 bucks and they will sell direct to you at dealer cost for a whole year and they have very good ups rates. I use it and nothing else. my 02 cents.

First if it is stock jetting and you have aftermarket pipes you are way too lean. As far as idling is concerned make sure you dont have the slides in backwards, make sure the choke tube is in place between the carbs and get them synced.

J arm in 90 A arm in 91

Check the gap on your pickup coil should be 15 thousandths. Also make sure your choke crossover tube is in place between the carbs, and make sure the slides are not in backwards

Slides are in backwards. Make sure choke crossover tube is in place between the carbs

make sure your slides are not in backwards

In order to sync the carbs you first need a carb sync tool. then carbs must be synced at idle and with the throttle engaged just off idle. Is this what you have done?

sync the carbs, already been down that same road. sync the carbs.

make sure the slides are not in backwards and check the choke tube between the carbs

Only octane booster that works is octane supreme 130. Do a google search on it. Contains tetraethyl lead and actually DOES increase the octane as described. Its what I use and I am pushing 181 psi.

Make sure the slides are not in backwards and make sure the choke crossover tube is in place between the carbs

Make sure you didnt put the slides in backwards, the curved part at the bottom of the slides should face the back of the carbs, make sure the choke crossover tube is firmly in place. Sync your carbs.

As far as the air filter set up is concerned. I purchased dual k&n filters, a pro design plate and foam filter, a k&n filter and plate for the stock air box ect ect. The absolute best set up I have found is the stock air box with the k&n filter with plate and a k&n lid. This flows just like the dual k&n pods and gives protection from mud and water. Plus you get double the filtration of a dual pod setup and your intake stays lenghtened with this setup instead of shortened as with the dual pods. This helps get rid of the dead spot off idle that my bike had with the dual setup. Its more pricey but well worth it in my opinion.

check with jeff first. http://www.farmandsandtoys.com/ If he doesnt have them then rocky mountain has the K@N lid and mod quad plate with filter. Toomey has the set of 12 airbox vents.

The absolute best air filter/ airbox combo IMO is the stock airbox with pro design plate mounted inside with a k@n filter attached with a k@n lid and 12 toomey 1" mini filters installed. Max air flow, better filtration than a single k@n, Good protection against mud, and doesnt have the short intake dead spot of just running pods.

If it will only pull start then look to make sure the choke tube is in place between the carbs. Also make sure the slides are not in backwards. Then check the distance between your flywheel notches and the pickup coil ( should be 15-20 thousandth) and finally sync those carbs.

Was it a new chain. If it was the old one then yes it wont match the teeth on a new sprocket because the old chain is stretched. New chain needed.

Had the same prob as you several months ago. Take your stator cover off and check your pickup coil. The distance between the coil and the 2 notches on the flywheel should be 15-20 thousandths. Check it with a feeler guage.

either the slides are in backwards, the carbs are not synced, or you might be missing the washer that goes under the main jet that holds the nozzle secure, this would allow the nozzle to be sucked into the carb body. most likely its the slides or sync or both.

be sure not to reverse the slides. sync the carbs with a carb sync tool. The throttle response is great.

Tell ebay to F off. Item sold locally. Dont like it pucker up buttercup.

Is the choke tube in place between the carbs?

broken piston skirt?

Found tetraethyl lead to add to fuel to raise to 100 octane. Ran for a few hours to burn of assembly lube. Now reads 168 psi. That a little better. Runs great, thanks for everyones help.