Good day all,
I just got this precious bike and the previous owner told me that it runs only if the choke is at half way down otherwise it dies when idle. What could this be? Carbs out of sync? Idle pilot screws out of whack? I've read you have to seat them then 2 1/2 turns back. I just got a motion pro carb balance tuner which i'm going to try tonight to see, but i figure i could ask the experts in this blog. This bike was used a few months last year (1 or 2months) and prior to that was seating for 2 years. I've been working on it basic maintenance but that's about it. Coolant flush, oil/oil filter change, radiator hoses replacement, and soon brake & clutch flush.
Please share your ideas or comments about this issue. I want to get it up and running just like on its glorious days.
I'll upload pics later. At work now LOL...

 

When the choke is on, you are manually making the mixture richer by cutting off the airflow. When you take it off, your mix is too lean for the bike. First thing to check is vacuum leaks. Carb boots, vacuum lines, etc. If all that checks out, look into the carb jets. They may be plugged up or too small for your altitude. Something is starving it for fuel....

Good luck!

 

Thanks 74Demon for you prompt response. Now that you mentioned. I lifted the fuel tank and i did see cracks around the carb boots and the air box. I will stop buy my local shop and buy some sort of sealant (poxy). Any thoughts on how to remove the air box. I attempt to do it but i couldn't get it out at all. I unscrew it at least every where I saw and disconnected the carb boots too.

As for the vacuum lines, is there a diagram to see where they need to be connected to? I see there are two vacuum lines coming out of each side of the carbs (#1, #4) that are extended to the back of the air box. I started the bike and with my finger block the air opening of the vacuum line going to carb#1 and the bike turned off. Now the air suction wasn't any strong, in fact i thought it was an extra line. Do this vacuum lines have to have strong suction? I really don't know how to explain what's strong or barely sucking out air in words...

 

Some vacuum lines can have less than others. It just depends where the come from. It's designed to work that way, so the need to be correct.

If you can, replace the boots if they're bad.

All the "how to's" can be found in the "how to" section or a manual. The manual can be downloaded from all kinds of places. Any more specific than that, one of the hurricane guys should be able to help you. I don't have a cane....

 

Thanks again! I had downloaded the manuals in the "How tos" section. Great resource to have. I will look for a new set of boots on ebay or other online store and update this post.

 

I'll be doing a thread on Pilot Orings later tonight

I had a similar problem and for the life of me could not get the bike to idle
no matter how I tweaked the idle and pilot screws !

New Pilot O-rings - she hums a sweet tune on idle now\

Basically the old o-rings let air past the idle screw so it won't
idle right

 

Sprock,
Thanks for your advise. I'll be looking forward that Pilot o-ring thread. Thanks

 

Removed the carbs and cleaned them. But I couldn't remove the D shape pilot as I don't have that tool. I read in another post you can sand to it to make a "flat" head screw. What do you think about it? Also, how far do you screw in this pilot? I think I've read 2 1/2 out. Thanks

 

I seem to remember Sprock does something ingenious with a shell casing To make a 'D' shaped tool. Can't remember what size though.

 

Nah that was Trout the cheapster - he took a spent .223 bullet casing and dinged it
to resemble a "D" shape - which works

me : I just went with the Motion Pro D socket @$3.00 and my recent MP 90 Degree carb tool came with some more bits

Worth noting only straight rail 93 ---> carbs require the D Socket - everything else
simple slotted / flat head

Yeah when you get them out you can dremel a slot in the head for simple screw driver use later.

I'll add a few pic's here of the air needles (slotted type) from my 1990
and the special screw tool I used to get the washer and old o-ring out.

Order of needle components are

1 needle
2 spring
3 washer
4 oring (lube the new oring a tiny bit with light oil)

Pics
1 - new o-ring left , old right
2 - proprietary washer & o-ring extraction tool
3 - order of assembly