Hesitation Help !

[old750]

1980 750E

Bike was a time capsule, all stock configuration. Was stored INSIDE a basement for 20 years. Carbs were rebuilt by suppose'd "shop" and then sat for 10+ years and never installed. Owner prior to me opened them back up and when I bought the bike we went through them carefully each jet ( the carbs were spotless clean to start with) and he sent me on my way.

Bike runs but is hard to start, always requires a full choke regardless of conditions and hesitates in the low rpms. Get it out on the hiway and let it loose and pulls like a freight train from about 4,500 to redline. Changed the plugs yesterday and gave the plug caps a good lookover, probably should just change if I can find the ones I need. A friend suggested I may be running lean but he also said could be electrical too.

I'd take any thoughts, you guys are the experts

Thanks in advance

 

[Nessism]

Is the bikes maintenance all up to date?

BTW, please check the Newbie Mistakes thread linked in my signature as a reference of things to look out for.

 

[old750]

Is the bikes maintenance all up to date?

BTW, please check the Newbie Mistakes thread linked in my signature as a reference of things to look out for.

Yes, previous owner was meticulous about his record keeping. At some point about 10 years ago or so he apparently decided to get it "up to date", carbs were rebuilt, valves adjusted, chain, fluids, etc but then never followed through. Only thing that was not specifically mentioned, plugs and plug caps. I changed the plugs but old ones appeared nearly new, plug caps I ordered today.

 

[Rob S.]

...always requires a full choke regardless

That part is normal. Battery got a nice full charge?

 

[rphillips]

Yep, what Rob said. Around here, if we ever had the carbs off, would go up a size or 2 on pilots to help the starting problem..

 

[eil]

#1 rule on a new-to-me bike is that I don't trust anything the previous owner says regarding maintenance, even if there's paperwork or a log. If the work was done, how would I know it was done correctly? Whenever I get a bike, I go through all the maintenance items so that I know for sure the bike is up spec. That means a full fluid change, carb rebuild, airbox inspection, valve clearance check, clean all electrical connections, and so on. Even when the bike looks terrific, I always find something that was clearly overlooked.

The symptoms that you're describing are carburetor problems, my bet is clogged idle jets. But you won't know for sure until you dig in.

There's a link in my signature that leads to all the info and tutorials you could ever want about maintenance of these GSes.

Oh, and welcome! We'd love to see pictures of what you have.

 

[Nessism]

Yes, previous owner was meticulous about his record keeping. At some point about 10 years ago or so he apparently decided to get it "up to date", carbs were rebuilt, valves adjusted, chain, fluids, etc but then never followed through.

10 years ago? Hope you don't consider that up to date.

 

[chuck hahn]

Hesitation can be from too lean at idle OR too rich. May be pilot size..or not. FIRST thing i would do is gently seat the mixture screws and set them 2 full turns out and test ride.

 

[old750]

10 years ago? Hope you don't consider that up to date.

Bike was never ran again, carbs were never even put back on bike. Something went awry with the original owner ( in his life) and he never touched it again after that. The person I bought from had for a short time and basically passed it through to me as he has dozens of bike projects & running bikes and he wanted to see it back on the road.

With my sellers blessing and assistance I contacted the original day one owner, fantastic guy with no reason to lie about anything as it was NOT him he sold it to me. I have seen the receipts, he kept everything. We have talked extensively about the bike, he can talk GS750E for days but at this point can't offer much. He thinks probably carbs.

 

[old750]

Hesitation can be from too lean at idle OR too rich. May be pilot size..or not. FIRST thing i would do is gently seat the mixture screws and set them 2 full turns out and test ride.

Yes, I guess this is probably the most logical place to dig in, 2 turns out is very good information, thanks!

 

[old750]

#1 rule on a new-to-me bike is that I don't trust anything the previous owner says regarding maintenance, even if there's paperwork or a log. If the work was done, how would I know it was done correctly? Whenever I get a bike, I go through all the maintenance items so that I know for sure the bike is up spec. That means a full fluid change, carb rebuild, airbox inspection, valve clearance check, clean all electrical connections, and so on. Even when the bike looks terrific, I always find something that was clearly overlooked.

The symptoms that you're describing are carburetor problems, my bet is clogged idle jets. But you won't know for sure until you dig in.

There's a link in my signature that leads to all the info and tutorials you could ever want about maintenance of these GSes.

Oh, and welcome! We'd love to see pictures of what you have.

When I bought the bike the carbs were off the bike in a box. Me (with the sellers assistance) literally stood there and pulled each jet and ran wire through them all, they are all clean. The carbs had been rebuilt years ago but never reinstalled, no gas had been through them. They were pristine. I am thinking though maybe some crud in tank could have made it down...maybe.

 

[old750]

That part is normal. Battery got a nice full charge?

My 850 required a good choke but when it was hot it was choke on for about 5 seconds and off, this 750 needs it for at least a minute, maybe longer. I will check the battery again but it seems to be in good working order and charging system is putting out right at 14 volts which seems to be about typical

 

[chuck hahn]

If its taking a minute to catch i would be checking the timing advancer is free and snaps back when manually twisted. Then get it running and throw a timing light on it. Hard to start is also an indication of tight valves. I would also be doing an adjustment. In the services section we have a shim club. find out what shims you need and Ray will send them. Then send him your old ones. DO NOT turn the crank without a shim in the bucket.

Store this place for future use. i would google a service manual online if none of the ones hehas listed fits your bike,

http://members.dslextreme.com/users/bikecliff/

 

[old750]

If its taking a minute to catch i would be checking the timing advancer is free and snaps back when manually twisted. Then get it running and throw a timing light on it. Hard to start is also an indication of tight valves. I would also be doing an adjustment. In the services section we have a shim club. find out what shims you need and Ray will send them. Then send him your old ones. DO NOT turn the crank without a shim in the bucket.

Store this place for future use. i would google a service manual online if none of the ones hehas listed fits your bike,



http://members.dslextreme.com/users/bikecliff/

Ding, Ding, Ding, we have a winner! Chuck, tried your previous 2 turns out on the mixture screws and now the bike starts up right away. Still running a bit rough, think a carb sync is in order. This bike had its valves adjusted by odometer about 300 miles ago, but in time many years ago. This bike also does not use the shim pads the way my 850 did, it has adjusters and I haven't looked into it yet but believe the valve cover needs to be removed to do it.

Did also look at advancer and it is in good condition and snaps right back

Thanks for the help!