Proper RPM's with choke/enrichener full open on 79 gs850g

[Guest]

HI everyone,

Ive been dealing with a "hard start" issue with my old 1979 suzuki gs850g when cold.

The valves have just been adjusted, the factory airbox is sealed and attached with no leaks, new intake boots on other side, and the carburetors have been rebuilt, synched, cleaned.

When first done, (and with warmer temperatures) the bike would start when cold with choke engaged and a stern look at the starter.
It started to have starting problems of a hard start, Steve recleaned the carburetors and even in cooler weather was starting well. (He had suggested if this problem happened again to use some techron and see if that cleaned up the issue.)

It began to start hard again. I dumped in a bottle of techron complete fuel system cleaner (rated for 15 gallons) into 2.5 gallons of gas.

I have been waiting for the bike to get ice cold, going out to the shed, cracking open the choke fully and starting the bike to try and clean out the choke circuits. One pattern I was noticing is that cylinder 4 (right hand side, outer) was staying cold longer than the others.

The bike would start to catch, catch a few false starts, then finally turn over, running at 800-1000 rpm's.

(This is at temperatures between 26 degrees F and up to 41 degrees F)


after a bit the rpm's (with choke all the way out) was getting originally up to 2500 rpm's.

The last try when I "REALLY" pulled on the choke lever I got it up to 3500 to almost 4000 rpm's (of course after being warmed and running.)

I am hoping this means the clog in the circuit was dissolved.

Can anyone shed an opinion on this for me ?

Thanks

Sean

[jsandidge]

Did you do a vacuum synch after Steve cleaned them for you? I'm sure his bench synch was close, but you always need to put the gauges on a running bike to truly synch the carbs. That could be the issue with your cold #4 at idle.

[seanarthurmachado]

yes, bench synched and vacuum synched.

this is not a maintenance issue.

The # 4 seems to start off colder then gets to the same temp as others.

Steve did everything precisely and perfectly (valve adjustment, boot replacements, spark plugs, air cleaner, airbox, carb strip and dip, new orings, all cleaned out, adjusted, bench synched, vacuum synched) and was running perfectly. An issue appeared (since only happens when cold) with what seems to be the choke circuit. When warm starts and runs fine. when cold is very hard starting.

Steve re-cleaned the carbs and issue was fine, then reappeared.

I used the techron as suggested. What I am trying to find out is what the proper RPM's should be with the choke fully engaged, hoping that I can use that as a guide as to whether the choke circuit is clean now.

(I am suspecting a clog cleared since the huge difference in RPM's I am seeing.)

Sean

[tom203]

"used the techron as suggested. What I am trying to find out is what the proper RPM's should be with the choke fully engaged, hoping that I can use that as a guide as to whether the choke circuit is clean now."

It's hard for techron to reach the "choke" passages- likely take repeated cold starts. On my bike a cold start with "choke fully engaged" the rpms will soar to 4000 quickly.
If you can ride this bike safely, find some long downhills ,get up to speed ,shut throttle' rinse/repeat - the vacuum increase in intake can suck hard on idle and "choke" passages.