Alright. Hello there. Where to start.

I've been working for the last while to get a 1967 sportster xlch on the road. Right now I'm still struggling to get the blasted thing to actually start. I have a lot of mechanical experience but it's all based in 4-wheeled creatures, this is my first venture into motorcycles and I'm kinda learning this as i go.

The bike is a kickstart magneto system with no battery. It's a 67 engine case but somehow ended up with an 84 Keihin carb on it.

The magneto has been overhauled and it now sparks beautifully. so that's not the problem.

I've cleaned the carb thoroughly, replaced the jets and set the float level.

When I try to kick it over I can get it cough once or twice about ever 5 goes. But that's it. When I run it through with the kickstart if easily cycles through, ie. doesn't feel like anything is stuck or fighting em.

I'm sorta running out of things to work on so I thought i'd throw it open and see if someone else knows the thing i need to know.

Based on my clymer and chilton repair guides/troubleshooting lists this is what i have tried to narrow it down to.


- clutch. could the clutch slipping cause the bike not to start? the chilton guides lists that as a possible non-start cause, but would that be noticable as some sort of resistance in the kickstart? i'm not sure how to tell if that's the problem.


- kickstart itself. like i said i'm new to motorcycles so i'm sure how the kickstart is acutally supposed to feel. I know that there must be some issue with the ratchet mechanism because about once every 5-6 tries the kickstart arm will slip and send my foot straight to the ground. also, in the all the youtube videos i've seen of harley kickstarts the ratching sound of the kickstart returning to the vertical position is much much more pronounced than it is on my bike. which makes me wonder if something fishy is happening with the starter/clutch ratching mechanism. maybe it's not delievering enough of the kicking energy into the rotation of the engine??


- valves sticking. another thing listed that i can't totally rule out but like i said it doesn't feel like anything is fighting me and the engine cycles. when i take the carb off i can see the intake valves opening and closing properly. i think.


- engine oil too heavy. the engine right now has the recommended sae 40 weight oil. but who knows. is there someway to drain the engine oil that is sitting in the system outside of the oil tank?


- poor compression. i should probably test this anyways. but wouldn't the occasionaly coughing inidicate that the cyldinders were getting enough compression? i'm not sure on that though.


-carburetor. it's be cleaned and should be ready to go. i know that fuel gets to the float bowl, but is there anyway to test to make sure the jets and such are actually working properly?



where else do i go from there? is there something obvious i'm missing?


any and all feedback would be greatly appreciated. i'm just about to the point of hitting my head against a brick wall.

 

buy a user manual for a bike that old. first off you keep to lightly press the kickstart lever until you feel the compression in the motor build, it takes a few strokes of the lever, but you can feel the point where you are moving it down and it feels like it doesnt want to move anymore but you can also push through it.

then retard your spark, there should be a small lever or **** SOMEWHERE, but im not sure, you have to read your owners manual or find one online.

then you prime the bike by slamming down against the compression. a well tuned motor should start right up, but if not, then at least now there is charge in the cylinder and you can repeat this.

repeat until it runs, then take off the spark retard and keep a high idle with the throttle until its warm.



the way you wrote your post it sounds like you are just kicking it over and over and over without feeling for compression or retarding the spark.

if this doesnt work you have really low compression AND/OR a slipping clutch AND/OR a bad ratchet mechanism inside the transmission.

try the correct technique first, then take it to a shop and do a compression test, if it comes up good then while your there have them look at the clutch and transmission. best advice i can give

 

Also see if your plugs are wet,if it's getting fuel and not starting they should be wet,clean and try again,kick starting is not easy ,it takes a little style,different bikes different style,three prime kicks with choke on ,choke off,one good kick twisting throttle at the same time,should have her running,one thing,make sure you are on the compression cycle or you could end up over the handle bars or break your ankle.Make sure your six volt battery is up to par even if you have a mag.

 

Did you check the fire ring clearances? Incorrect height can cause compression loss and difficulty starting plus will blow gaskets after running.

 

okay. going down the list.

i do have a manual for it. actually i have several. i do know about the feeling for compression on the kickstart and the timing retard/advance.

taking it to a shop isn't an option, and regardless i wouldn't want to give it over to anyone else anyways. it's my project.

i'll try that three-prime kick routine with the bike and see how it does.

also, it doesn't have a battery either.

what's the fire ring clearance? and how would i check that?

 

They can be a bear to start without a battery,you didn't say if your plugs were wet,I don't know what the hell a fire ring is,unless he was talking of plug gap.

 

Funny: couldn't find this in my SM either although the fire ring is pictured; imagine that! "Guy I know" had problem starting his bike after repairing for a blown head gasket and turned out to be excessive fire ring clearance causing loss of compression from blow-by of the gasket. The fire ring height was too high so the gasket didn't have enough crush. You'll see the raised portion around the top of the head (around combustion chamber) after you remove the cylinder head which has corresponding recess for fire ring fitment when gasket is installed. To measure for required .010" clearance between head and cylinder: Disassemble and place a .010" feeler gauge between the head and the top of the of the cylinder head with new gasket installed and pull the feeler gauge out. You should feel resistance on the gauge and hear a slight "clunk" when you pull it out. If no drag or clunk, ring clearance is too high. Obviously, elliminate all other possibilities first since this test requires some degree of disassembly to check!

 

man that would be nice to hear running again.
you say it pops
should do real compression test for sure.
that old baby just might have a burnt valve there.
but compression test would take all that out of the equation.
the very best to you and that sweet bike

 

after alot of backfiring and flames out the carb i finally GOT IT TO IDLE!! I played around this pattern for a while until i figured out what was working and what wasn't and eventually it took! not for long but whatever, at least i know it WILL start. a good place to start.

thanks for the advice!!

i still have mountains to overcome before this thing is back on the road where it belongs, but i'm thrilled.

 

Congrats! FYI I gave the wrong info prior: NO GASKET in when checking for fire ring clearance. Future reference anyhow. Good luck!