1980 GS250 "dirty little brat"

[nikola25]

Bike isn't running yet so I'm not sure about what it sounds like with the exhaust. I plan to spray some fluid in soon and get a battery to see what she purrs like....... that's assuming it does actually start. As for the pipes I want to do essentially what you did except 2 into 2 on that side. Similar to what the Honda CL's exhaust is like.

[Zbradley1215]

yea, please keep me up to date on those. i like them a lot

[pureitx]

What size rear tire did you get? I can find the Shinko 244 tire size for the front but not the rear.

[nikola25]

120/90/17. I saw someone running a 130/90/17 on the bike on Ebay which is the max and probably pushing it.

[nikola25]

I cant get her to run unfortunately. Here is what I can tell you to help me diagnose the issue.

plugs are new and it sparks from both sides. I tried switching the coils to the opposite sides I had them on in case i have them on backwards and that didnt work. Fuel is flowing just fine, airflow is fine. The carbs went through a super cleaning and the jets were replaced. The bowls fill properly, fuel should not be the issue and air should be ok.

Even without carbs I can usually get a bike to start and run for a second by spraying some starting fluid directly in the spark plug holes or where the carbs attach. (typically how i diagnose a fuel/air issue) This bike will not start when I do that. I do not have a compression tester but my fingers get blown out of the holes pretty much like every other bike I've worked on and evenly from both holes I'd say. I do intend to get a tester in the next couple of days to definitively rule out compression.

Strange things-

The bike cranks as normal unless I pull on the choke in which it suddenly really really struggles or stops cranking (can this tell me anything?)

I bought a brand new ballisitic li-ion battery and it gets hot while cranking. I was under the impression that this is not supposed to be happening.

[pete]

I don't recall if you've checked the valve clearances or not, but that can definitely be a cause of hard starting if they're not right...

[tkent02]

The bike cranks as normal unless I pull on the choke in which it suddenly really really struggles or stops cranking (can this tell me anything?)

Could be you timing is way too far advanced. You pull the choke, it fires once, but it is too far before top dead center so it stops the piston moving up. Check the ignition timing again.

[gustovh]

Pull the valve cover and check that the cams are timed right. That said, it brings to mind something that happened on the way home from the PNW ralley last year....are you sure that your exhaust is not plugged? We found that not only does a bike need spark, fuel, and air, but needs to breath out as well, or it will not run.
V

[musicman]

Pull the valve cover and check that the cams are timed right. That said, it brings to mind something that happened on the way home from the PNW ralley last year....are you sure that your exhaust is not plugged? We found that not only does a bike need spark, fuel, and air, but needs to breath out as well, or it will not run.
V

Hah, I learned that one years ago. I used to have this honda c70 scooter forever that didn't run, never could get it to do anything, even with starting fluid. One day I'm out messing with it again, and looked down at the exhaust and saw something brown in the end of it, was a some kind of bee nest, made out of dirt or mud or something. Broke it up with a screw driver, kicked the old passport over, and it spit out 4 dead bees, chunks of nest, and came to life

[nikola25]

The pipes are clear for sure as I made the exhaust custom. I actually had nearly the same thing happen to me with a honda cub (hornet's nest inside the pipe) Timing/valves is most likely the issue. I've never done valves (except on my brother Royal Enfield which is ridiculous easy) or timing before which and am nervous about opening up the top of the bike but I suppose it's time to learn.

[pete]

Take your time, double check everything you do, be careful, and it's a lot easier than you think.

Definitely daunting at first, but definitely doable!

[nikola25]

What do I need for tools/parts to do the timing and valves? Valve cover gasket and...?

[pete]

Have a read up on the processes on BassCliff's site... they'll steer you in the right direction.

At a minimum I would say valve cover gasket and feeler gauges.

Given yours is the 4 valve per cylinder motor, I'm pretty sure you will have screw and locknut type adjustments for the clearances, and I'm pretty sure there's a write up on how to make a very handy tool to adjust these on BassCliff's site as well.

I've only done shims on my 2 valve motor so can't comment on that one...

[nikola25]

Ugh..... bad news. The compression tests today showed 60 in each cylinder ; ; I thought it might be the tool since i got a harbor freight cheapo and tested my gn250 and the results there were 140+ psi so it works fine and my motor is.... well screwed. When I added oil in the port it increased to 90 psi for a half dozen cranks. That means rings correct? and possibly cylinder walls? With this issue and the clutch not working on it (shifts fine but clutch doesnt work) I'm debating between full teardown/rebuild in a couple of months when we move into our new place or just buying a working used motor. I found a complete running bike for 700 and was just thinking of pulling the motor from that.

[nikosg]

ooo what are those shocks you put on it?

loving this build so far