WOT at starting

Ok my bike is in process of being fixed. day by day i am fixing the problems. This morning to start it i tried the choke in meny different posistions, and the choke open got it to "burp" fire over once. but than i tried the throttle and i had to hold the throttle wide open to get it to start.

WOT only had it running at 1100RPM about, the best idle it ever had perfectly smooth. but if i let off the throttle it died. so i held the throttle till the bike warmed up and than it ran ok as normal.

my question is why would i need to hold wide open throttle to get it to start and idle at 1100rpm? this could also be related to my problem with while riding about 20 miles at different points in the trip my idle will fluctuate. half way threw it would be idling to high, near the end idleing to low, etc.

 

with my bike I don't need choke when it's warm enough outside to wear a t-shirt. Just 10-20% throttle while starting and there it goes.

Normally, like when it's colder or if the bike has been sitting for a week or so, I just open the Choke all the way and press the starter.

The engine will then idle immediately at around 1000-1500 rpm, then when "the fuel comes" after about 10 seconds, it'll go up to 2000-2500+, and I set the Choke to about half and drive off.

I would suggest that youhave a fuel problem (or rather, lack of fuel) in the carburetors.
Maybe also check if the gas cable sticks.

 

You need to properly service your carbs, get your valves in spec and then adjust the carbs.

If it will only run 1100 rpm at WOT something is seriously wrong.

 

it only is at 1100 rpm @ WOT untill the bike is warmed up, about 2 minutes. after that it will race up to redline if i do not pay attention. than it will settle out when i release the throttle, and respond normaly to throttle movement.

 

LISTEN to FITZ!!!!! If you don't do the work he has out line the bike will never run right!!!!!!!

Take care of it and the work in proper order and, you and your bike will be happy for many years. If this is too much trouble to bother with SELL the BIKE!!!

 

im hoping to tear into the carbs this weekend, following the many guides on this site. im very nervous about opening a can of worms, fear of messing it up more. but the guides are very well written and thinking it will make it easy. Do i need to replace a gasket if i remove the valve covers? and i have feeler gauges in english not metric. but they should work right?

 

There's quite a few posts about people having issues with SAE feeler gauges. Metric is what is called for, and seems to work better.

I'd suggest them, but you can work with the SAE, but will need to be more precise, I'd think.

For the gasket, if you've ( or PO has ) previously done the valve cover yourself, and put on a new one in the manner outlined in Fitz's walkthrough, then you should be able to re-use it. But, if the existing is original, then it can be cooked ( or rather, very stuck ) to the head, thereby needing a new gasket. Also, the valve retaining donuts are a good idea too, as the old ones compress and don't return to normal pressure, thereby letting the cover be held on with less than required pressure.

 

ok so ill find metric feelers. ill order some donuts too, both types glazed and rubber . shims i found a shop localy with an assortment of dfferent shims, he says he has shims for the xj yamaha's, so ill use him.

 

Sounds like the choke passages are plugged. So the choke isn't doing anything when it's cold. When it warms up, it runs normally on it's own.

There's a few write-ups on cleaning out carbs, and what the choke ( or enrichment ) circuit looks like.