Newbie needs help - stall/sputter shifting into first

[Guest]

Hi all,

i have a '79 425 that hasn't been that well maintained but had fluids replaced, carbs cleaned, and battery swapped last week. I took her on a maiden run and she rode pretty well.

Yesterday I went out to ride, fired up nicely, but she kept stalling when trying to shift into first. Today is presenting a similar situation but put some new ethanol free gas in and wasn't stalling but was just on the verge and sputter trying to get into first. Got on the street shifted into two nicely but then slowed for a turn and the sputtering returned.

Any thoughts anyone may have would be greatly appreciated, esp since I don't have much experience with bikes.

Thanks

[allojohn]

OK, I'll be first up with the bad news. You have a 37 year old bike that needs a ton of maintenance and a few $$ from an owner that is willing to learn about his bike and make it a reliable and safe machine. Is this you?
If it is then download the manual from here.
Read this.
And read this and this.
That will get you started, there are no easy fixes, no shortcuts and if you do not do the maintenance you will get problem after problem. Sorry but it's the truth.

Welcome to the forum and put your location in your profile - help might be nearby!

[Gs425FridayHarbor]

Thanks for the reply and the resources. I've got some tools handy and now have some good reading material - thank you. I'm hoping this will be a good bike to learn about maintenance and I appreciate your help.

[allojohn]

BTW, don't swing your leg over this thing until you've had a look at the brakes. Disk up front, drum on the back? They're probably working at 30% efficiency or less, maybe close to seizing. At the very least the fluid needs replacing, in reality everything needs dismantling, cleaning, rubber boots and seals replaced.

[CrazyCloud]

All good advice above. What are the rpm's when in dies/sputters? if you give it some throttle does it come out of it? Maybe a remote possibility, but it's possible the idle speed is just set too low. Good luck.

[Gs425FridayHarbor]

Hi John,

i had a bike shop look it over before riding. Brakes were seized up when I took it in and he did something to them and checked fluid. Said they are at 35-45 percent. I've been reading all day and found the newbie thread you sent to be helpful.

I took off the exhaust today because shop thought that the plates seating the exhaust pipes were backwards but they weren't. I did notice a lot of oil in one of the chambers though.

Going to to go through basic maintenance checklist and learn about this bike and its parts before I start riding. Hope it's a good project. Thanks again for the help.

[Gs425FridayHarbor]

Hi Jason,

RPMs are just around 2000. If I keep it closer to 2500-3000 it does a little better. I turned the idle screw about one half turn which did increase the idle rpm from 800 to 1000-1200 but still struggling getting into first. I also noticed that riding in second and third it seems pretty sluggish.

Thanks for your help!

[CrazyCloud]

Hmm, should be idling pretty well about 1000-1200 rpms. Does it start easy on choke and idle OK? Runs better the higher the rpm's but then chokes when you slow down enough to downshift into 1st?
Usual suspects are 1.)carbs are still gummed up, esp. in pilot circuit passages, 2.)valve clearances out of spec.

If you can check compression it will tell you a lot about general health of valves/rings. Does it still have stock airbox/filter and stock exhaust? Sometimes a P.O. will change these and not change carb jetting-- causing issues. What do the spark plugs look like?, that can tell you a lot-- google 'plug chops'. Are both exhaust pipes equally warm at idle; how about after a ride (check carefully!)? Air/idle screws about 1 1/4 turns out from gently seated?

Action steps: 1: dip carbs yourself, verify all passages clear, new gaskets, o-rings, etc.; verify jet sizes are correct; return idle screws to stock positions and adjust as needed 2: Check and adjust valve clearances to spec. 3.) try again. At least you're working on it in winter when the urgency to be on the road isn't as strong!

[Gs425FridayHarbor]

Hi Jason,

Starts with choke after about 6 seconds on the electric starter, needs a little feathering to get it going once it turns over, then idles around 1200. There's a little fluttering in idle but not too bad, and then will rest around 1000. It does run better a little higher and then chokes up when I disengage clutch in 1st gear. If I increase throttle around 2000 RPM it will engage in first but I have to feather to keep it from stalling. Once I'm in second and third she seems okay but doesn't have as much power in 2 and 3 as she did when I brought her home from the shop.

Still stock exhaust and airbox with new filter. When I took the exhaust off yesterday I looked in the top of the head and saw one side had a white bell shaped thing (right side) and left side was oily, not pouring out but present. i recall both pipes being warm after a quick ride.

I will try to check compression and dip carbs myself. is this something you recommend a noob can try - I'd like to do it and learn about my bike but I'm hesitant to dive into that kind of project knowing as little as I do. I've read the manuals and carb rebuild tutorials on the site and I get the general idea but still feeling anxious about it. Is this one of those project I should just dive into and take slowly or tackle after I've done some other work first?

Spark plugs are brand new. I havent pulled them yet but will take a look today.

Thanks for your help, I really appreciate it.

Jamie

[Gs425FridayHarbor]

Update: I just took her out around the block and for the first time heard a whining sound in 3 at 3000 RPM, turned around and went back to garage. I touched the right exhaust pipe (the one that had been a little oily in the chamber where the exhaust goes into the header) and it was barely warm. I (stupidly) touched the other pipe and it was scorching hot. I also noticed significant drop in power riding home - maybe running on one cylinder?

any thought as to what this indicates? Thanks!

[tkent02]

Dude, do the maintenance.

[Gs425FridayHarbor]

Going to give it a shot.

[CrazyCloud]

You can do it, diving in is the hardest part. Just do the reading, make a plan, and start turning wrenches and screws while paying attention, and taking pictures/making notes of assemblies. No one, including most mechanics, will have the motivation and attention to detail that you will need to make your bike reliable and safe.

[Gs425FridayHarbor]

You can do it, diving in is the hardest part. Just do the reading, make a plan, and start turning wrenches and screws while paying attention, and taking pictures/making notes of assemblies. No one, including most mechanics, will have the motivation and attention to detail that you will need to make your bike reliable and safe.

Thanks Jason. I'm going to go for it. I'm thinking of doing the carbs and will certainly be paying more attention than anyone else. I was going to run compression test first and then tackle the carbs. Do you think that's a good first and second step or is there something else that I should do before diving into the carbs? also, I was going to use the manuals on basscliff and the carb rebuild tutorial in everyone's signature but that's for a gs1000 - are there better resources for tackling that project?

thanks again for your help. I really appreciate it!

[CrazyCloud]

Both carbs and valve clearances need to be done before you move on. You can do the valves while the carbs are soaking or while you're waiting on parts, etc. Might as well do them both while you've got it apart.

You'll likely need a new cylinder head cover gasket along with some shims when you do the valve clearances. I would wait on doing a compression test until you do the valves, as it will change your numbers.

I think you have CV carbs (the top of the carbs is held on by 4 screws right?) that link should be fine; you will just have 2 carbs instead of 4. Check out this video also https://www.youtube.com/watch?v=95nlrP-yn2I
also see http://members.dslextreme.com/users/bikecliff/images/carb_sync_notes.html