New to this, bike cut off and now wont start.

[peanut]

yes thats part of the problem when we bolt on new parts or alter things when we have an unknown fault because we can never be sure that we haven't introduced another fault and unwittingly added to the initial problem.

The fact that you have good compression and no oil is great news . I'm inclined to think that your main problem now is the fuel delivery system.

These carbs are over 30 years old and thats a big ask to expect them to perform faultlessly .

Have you checked to make sure that you haven't got an air leak around the inlets and air filters etc ? that would screw you fuel mixture big time but on reflection it wouldn't give you the intermittant problems you seem to be experiencing.
I would be inclined to strip and check the carbs again particularly the floats and needles and try operating the floats when holding the carbs at various angles to make sure everything is really smooth with no friction anywhere.

very frustrating .... well done for sticking with it .

 

[MFJustin]

When I pulled the carbs recently I noticed that one of the carb holders did have a chunk missing that would perhaps cause an air leak. However, I wouldn't think that something like that would cause the bike to practically die at highway speeds; run like absolute crap perhaps but certainly not bog down and cut off. Now I can't even get it restarted. I'm going to start over with the usual suspects first to make sure everything's still good to go and work my way from there.

 

[MFJustin]

Peanut here's a picture of the spark plugs, keep in mind these came and were installed with the Pamco kit that I put in a few weeks ago so they really are not that old. Left plug is left cylinder, right plug is right cylinder.

Also just for reference, here's a quick pic of the amount of oil that came out when I drained it, both plugs and the sump removed. I would have expected a lot more to come out than just that, considering that I recently did an oil change right after the bike stopped running the last time.

 

[peanut]

well both the plugs look fine but then i would inspect mine with a magnifying glass lol . There is a lot more carbon on one ground electrode than the other. You can improve the spark a lot by carefully filing the end of the ground electrode square so it has a nice sharp edge . Sparks love a sharp edge . Double check the gaps too

I don't know what the engine holds. There will probably still be some left in the engine but would have expected more oil than that too. You must still be burning some I guess

If the air leak is on the inlet side of the carb then it will have a significant effect yes. If its between the carb and filter than very little effect I should have thought.

These intermittant faults are the worse to try and pinpoint . If you are not getting backfires from either of the exhausts or inlets and you are getting fuel and spark to the plugs then my guess that the timing isn't out either . It doesn't rule out an intermittant bad earth or electrical / ignition short though.

If you are getting fuel and a nice stong blue spark to both the plugs and no backfires from either of the exhausts or inlets and it still won't even try to start on the kickstart its got me beat.

clutching at straws here but have you checked the petrol tank is venting and you're not getting a vacuum building up ?

 

[5twins]

You're using a ton of oil so it looks like it really does have to come apart. It's awfully black too considering you just changed it a short time ago. That could indicate major blow-by past the rings, oil going out (using it up) and carbon from the combustion process going in (making the oil black).

 

[MFJustin]

I noticed that the oil was extremely dark as well and you're right I did just change it recently. It also has a smell to it, I've done a lot of oil changes in my life and this is the first time I've ever noticed that the oil just smelled completely burnt. Yeah maybe if the bike hasn't been maintained properly but considering this is relatively new oil with probably less than 200 miles on it, something just doesn't add up.

 

[peanut]

You're using a ton of oil so it looks like it really does have to come apart. It's awfully black too considering you just changed it a short time ago. That could indicate major blow-by past the rings, oil going out (using it up) and carbon from the combustion process going in (making the oil black).

agreed definitely but that wouldn't stop it starting and running and the compression is still 150psi which is excellent ! .

I think justin needs to solve the reason for the intermittant cutting out and non starting before tearing the head apart . The running problem is still going to be there when the head is rebuilt.

 

[5twins]

It may have died this time because it got so low on oil and over heated. And it may be dead for good, lol. If you can't get it started again then that may indicate running up that hill low on oil has really done her in, damaging stuff internally. Have you re-checked compression now after this second crap-out?

 

[MFJustin]

I have not done a compression test after this second crap out. I need to put the exhaust pipes back on and button up a few things I took off and then I will most certainly do that.

I can get the bike started, barely. When turning the ignition I have to rev the throttle and it will fire up, run like absolute crap and then as soon as I let off the throttle immediately die out.

The one possibly crucial detail that I left out at the beginning of this thread is that the last time that it died I drained the oil when I got it home and it was low, possibly even lower than it was this time that it died. From what I've learned here so far, when I was battling the low compression it was recommended that I add some oil through the spark plug hole and see if the compression went up which would indicate....bad piston rings? I had low compression in the one cylinder, drained the oil filled it back up and ran it for a bit and the outcome was heavy smoking and a noticeable increase in compression from that cylinder. I guess what I'm trying to ask is, could something similar happen the way I did it? I refilled the oil to normal levels and the compression went back up.

I know as Peanut says that that doesn't necessarily indicate why it would suddenly bog down and cut off but it does leave me puzzled. I really have no problems with tearing it apart, considering I picked up this bike rather quickly because it was a good deal, I didn't get a chance to really go over it thoroughly with the seller. Haste makes waste of course but I have zero problems with rebuilding the motor over the winter as something to do, even if it doesn't necessarily need it. At least then I'm content in knowing that my motor has been given some extra years, who the heck knows what the seller did or did not do to it properly but that's a mistake I made not asking more questions. Everything seemed fine though and I rode it probably close to 800 miles after buying it before I had my first major problem. Even if I rebuild it and find I still have the same problem, I'd be working from the inside out which would be completely ass backwards of common practice but hey at least I'd stay occupied haha.

And I once again want to say you guys have been awesome in helping me, I've learned a hell of lot in the past few weeks and coming from the Jeep/offroad world to here, this has to be hands down the most successful and helpful first post I've ever had.

 

[peanut]

It may have died this time because it got so low on oil and over heated. And it may be dead for good, lol. If you can't get it started again then that may indicate running up that hill low on oil has really done her in, damaging stuff internally. Have you re-checked compression now after this second crap-out?

you think that overheating caused by low oil levels was starting to sieze the pistons ?


Justin you are right that the engine is definitely going to need a top end rebuild at the very least and as a winter project its ideal but I still think however frustrating it seems you need to solve the intermittant hard running problem you have first.

Your oil loss problem is obviously significant but it shouldn't cause your engine to stop running .If the engine is severely worn you could be having oil coming up past the rings and down past the valves being burnt in the cylinder but you would see considerable blue smoke especially on hard acceleration.

I still think the running problem lies with electrics or fuel delivery. Its so frustrating not being there to see and hear and test stuff even though your descriptions are excellent and testing has been thorough

 

[Dennis]

well atleast now you know why it quit smokeing

 

[MFJustin]

you think that overheating caused by low oil levels was starting to sieze the pistons ?


Justin you are right that the engine is definitely going to need a top end rebuild at the very least and as a winter project its ideal but I still think however frustrating it seems you need to solve the intermittant hard running problem you have first.

Your oil loss problem is obviously significant but it shouldn't cause your engine to stop running .If the engine is severely worn you could be having oil coming up past the rings and down past the valves being burnt in the cylinder but you would see considerable blue smoke especially on hard acceleration.

I still think the running problem lies with electrics or fuel delivery. Its so frustrating not being there to see and hear and test stuff even though your descriptions are excellent and testing has been thorough

Here's the thing about the smoking though, it looked white to me but it very well could have been blue smoke. It would smoke especially bad when on the throttle, I really wish I had taken a video when all of that was going down like I had planned on but I didn't. I'm going to button everything back up, put in new oil and maybe cross my fingers I can get it running long enough to check a few things out. I'm just baffled because when I started going through all the things to check for everything matched up, carbs were squeaky clean, nothing seemed out of place at all. Brand new high output coil, plugs, wires....I triple checked the wiring and it was good to go with an excellent bare metal ground. It's baffling because nothing jumps out at me as a potential problem as to why it just randomly dies, and you would think it would be something obvious at this point.

Anyways I'm going to put it back together and see where it leads me. Considering I've been here once already maybe I just need to retrace what I did the first time to get it up and running again. Obviously not rideable but running at least.

 

[MFJustin]

Well gentleman, looks like when I had asked for something to jump out and say "fix me, fix me" I got my wish. That is most certainly a hole in my piston, which I believe was a result of the most recent episode of the bike cutting out on me because I examined the piston as best I could through the spark plug hole the last go round and didnt see anything wrong with it. Looks like we've finally got a solid reason to pull the motor haha. From what I've briefly read in the past few minutes, this is a result of the timing being too advanced? Not really sure how that happened because I sat right there with my mechanic friend as we adjusted the timing and it was spot on where it should have been, unless the adjustment screws somehow loosened up and it decided to move around. Any other reasons why something like that would happen?

 

[MFJustin]

Time to break it down and see what kind if damage I'm looking at.

 

[XSLeo]

When you set the timing did you just check it at idle or did you check it both at idle and 3000-3200 rpms? The adavancer gets worn where the rounded ends of the flyweights fit into the notches in the disc. The end of the flyweight more so than the notches. This lets the advancer advance to far. The idle timing is 12-15 degrees, at full advance it should be 38-40 degrees. The extra wear in the flyweights and notches the advance timing could be much more, like 45 degrees. This is too much.
The combination of the worn advancer and low octane fuel holes pistons.
You can peen the tips of the flyweights, this makes the rounded part bigger.
If you have a caliper you can measure the notches in the disc and peen the flyweights so the tips are just a bit smaller than the notches.
Grizld1 is the guy that figured this out. He has a measurement to peen the tips too but I can't recall just what it is. That's why I suggested peening to just a bit smaller than the notches.
Or you can replace the advancer with a new one from Mike's.
Leo

 

[5twins]

...... or it could have been from running it so low on oil. Things get pretty hot when you put a load on the motor (going up a hill) and there's not enough oil to go around. No matter, you know for sure it needs to come apart now.

 

[MFJustin]

Leo I'm pretty sure when we timed it we checked it first at idle and then advanced the RPM's. I dont have a tach so I cant say if it was around 3k but I'm pretty positive we did it the right way.

I know this isn't exactly what I wanted to have happen but I was planning on doing a tear down over the winter anyways to paint the motor and redo several things on the bike that I'm not entirely happy with, then again I never seem to be satisfied its always in need of something more.

I'll keep updating this thread as I go along, probably just turn it into a rebuild thread because there has been some excellent info in here so far and I'd like to keep it going for my own knowledge as well as any other noobs in the future.

 

[MFJustin]

So wanted to update this thread since it's been a little while and I wanted to keep this thing going as sort of a semi rebuild thread.

Pulled the motor out of the bike by myself, wasn't as heavy as I thought it was going to be. Today I started pulling pieces off of the motor following a very excellent video by I Am Carbon on motor removal. I got to the part where he removes the cam chain tensioner and then in the video his cam chain is loose enough that he can just slide it off of the cam sprocket and pull the cam bearings out.

I completely removed my cam chain tensioner but the cam chain is still on there tight enough that I can't wiggle it free from the cam sprocket or even loose enough to pop the bearings out. Any advice, or is there something I'm missing causing it to stay in there??

 

[peanut]

there should be enough slack in the chain to allow you to slide the bearings off the ends of the camshaft and then lift the chain off

 

[MFJustin]

Unfortunately there isn't even enough slack for that, I tried that little trick and it was a no go. I got a bit hasty and started a new thread on that issue, Punkskalar (Hugh) said he's had a few like that before and had to cut the chain.