79 850 realy cold blooded

[daverx1]

My 850 is realy cold blooded, it starts fine, and races on the choke, but will not take ANY throttle while on the choke. After several min of racing on choke, you must ease off the choke and play with the throttle to get it to rev with out stalling. One you finally get the bile to accept throttle you need to rev it up to 4-5K once and after that the bike runs and carburates great. I realize that these bikes are known for being cold blooded, but this is too much (my 1980 550 and 1982 750 were much better as far as cold blooded)


I have attempted to ritchen the low speed fuel screws 1/4 turn (no effect) and I have adjusted the air screws 1/4 turn cw (no effect)

I am thinking that the "starter jets" may be plugged or I may need to raise the needles one notch?

Any ideas???

[BassCliff]

Hi,

It's a bum rap, I tell you! These bikes are "cold blooded" only because of neglected maintenance.

I recommend adjusting your valves.



Thank you for your indulgence,

BassCliff

[daverx1]

Thanks for the reply, valves were done +/- 1000 miles ago.

The bike is a 79 with VM carbs

I havent synched the carbs yet

[daverx1]

I have had this bike for 5 years, allways has been cold blooded, but is worse now. We also has E85 fuel for past 18 months

[officerbill]

Burrrrrrr

I have the same problem. I will accept lack of maintenance as my problem. This weekend... er, I mean tomorrow, I plan on doing some overdue work. I am looking forward to some other remedies for cold bloodedness.
Thanks,
Bill

[BassCliff]

Hi,

Well, tight valves are usually the first suspect in this situation. You may be correct in suspecting the carbs, but I know zippity-do-da about the VM carbs. Is the air intake system tight with no leaks? New intake boots and O-rings? Sealed airbox? You know, all the stuff on the "mega-welcome" maintenance lists? Sorry I can't be of more help. I'll give a shout out to Ms. SqDancerLynn1. She knows everything about the '79.


Thank you for your indulgence,

BassCliff

[SqDancerLynn1]

First thing I would do is make sure you have 12V at the coils and a good spark. For a stock bike. The bottom fuel screw should only be turned out 5/8-3/4 turn. Side air screw about 2.5 turns. You could also have an air leak? Did you change the intake O rings and adjust the valves. Seal the airbox?

[Nessism]

If you have never rebuilt the carbs I'd do it now. Replace all the various O-rings along with the intake pipe boot O-rings too. Perform a vacuum sync when done. Other thing to do include adjusting the valves and making sure the airbox is properly sealed. Cold bloodedness is a sign of lean mixture so you were on the right track by tweeking the fuel mixture screws, but that's a waste of time unless you are positive the carbs are properly clean and sealed with fresh O-rings.