idling/stalling issue...

[nabrams]

You don't have to put ANY of that stuff back on in order to do a compression test (valve cover can stay off too - oil will be flung about, but the compression test is for the pressure in the cylinder). Just make sure you read the instructions that come with the compression tester.

I'm glad I've been helpful, but the truth is you don't need me - everything I've been telling you has been posted here a million times. If you spend some time using the search feature and doing some reading, you'll save yourself a lot of aggravation, time, effort and money.

 

[Fare]

To be completely honest, I spend a great deal of my time, at work, at home, and whatever (don't let my boss see this!) reading the forums, inside and out. I either lack confidence in what I read pertains to me or I just want confirmation that I'm doing what I'm supposed to (never touched a ratchet set before my bike, so I'm not exactly mechanically inclined). I apologize if I've been annoying or whatever, suppose I'll take that bullet for the next person who is in my shoes...

I'll do that compression test as soon as I get the opportunity to then. I was under the impression that I should do the compression test when the engine is warm...

 

[nabrams]

I wasn't biting your head off. It's just this - If you wait for me (or someone else) to answer every question you have, then it will take even longer for you to get on the road. You've got to dive in. It's true that a warm compression test more accurately reflects real-time running conditions, but a cold compression test can tell you a lot - see other posts. By the way, I've learned EVERYTHING I know about bikes myself - you can too.

Good luck, and let us know. Now, I'VE got to get back to work

 

[Fare]

ok, more not so good news....

cam cover not screwed, bad valve gasket, no airbox, no carbs, no tank

numbered left to right, as sitting on the bike...

1 dry = 90 wet = 240 (stopped as oil gushed from all orfices)

2 dry = 0ish wet = 40

3 dry 30 wet 70

4 dry 110 wet 170

 

[nabrams]

Obviously 2 & 3 are worrisome right now (they probably also have the worst valve clearances). Proceed with the valve adjustment and measure compression again. In many cases that will bring compression back up to acceptable levels. Let us know.

 

[Fare]

Kinda a question, more of an observation.

I spent the weekend using the tool to do the necessary valve adjustments. as mentioned earlier, they are way off. Using a 2.30 shim that I bought at a local dealer (for a heavily scalped price...) and some math, I was able to deduct what shims I need. My questions are:

1) do the large gaps make us believe that the bike didn't have a valve check ever or just recently.

2) do you think that the large gaps are the reason for the low compression.

At this point it all theory-craft until the valves come in later this week, I was just wondering and perhaps you all can help me wonder more correctly.

here was my results...
___________________________CYLINDER____________
__________________||__1__||__2__||__3__||__4__||
Present Exhaust Shim_|| 2.75 || 2.55 || 2.65 || 2.65 ||
Needed Exhaust Shim_|| 2.70 || 2.35 || 2.50 || 2.65 ||

Present Intake Shim__|| 2.60 || 2.60 || 2.60 || 2.55 ||
Needed Intake Shim__|| 2.50 || 2.40 || 2.40 || 2.55 ||

Dry Compression_____|| 90 || 0 || 30 || 110 ||
Wet Compression____|| 240 || 40 || 70 || 170 ||

I know not much can deducted till the shims come in and I can know for sure, but it just seems like the compression results were good on the shims that were dead on or close to what they needed to be and the ones that are 20 or 15 off, they were very poor (which hopefully means my engine is still good and wont have to be taken apart and whatnot).

Thank you to Steve for his excel spreadsheet,

Fare

P.S. are the cylinders properly labeled? 1 being the leftmost if you were on the bike, 4 being the rightmost.

 

[Uncle Jetski]

I had a similar problem

I had a similar problem

On my 1982 450T, it would go for 200 yards, then stall. I could start it up right away however, and that's the key. If it takes 15-20 minutes to re-start, it's probably the coil. If it takes 5 minutes, the bowl might not be filling. In my case, it re-started in 10 seconds. Check for a short/loose wire, or replace the igniter.

 

[Fare]

Ok, getting closer.

Everything is installed, valves up to spec, a quick compression test (cold) vields significant increase. (125 where it was 0)

Plop the tank on (i wanna hear it start) and it doesn't start. checked #4 spark plug, theres a blue spark (no clue if its a strong or weak, nothing to compare it to) so i'm getting a spark somewhere. My guess, however, is an air leak somewhere. after i crank longer than i should, i sometimes hear a soft hiss.

going to do some more searching while i wait for the battery to charge, since it reads ~11.40 now (hasn't been charged via bike or charger in a few weeks, plus the excess cranking and it accidently getting wet (damn faulty tent thingy)). Anything quick i should check? losen carb screws, look for particular leaks somewhere?

Thank you,

Fare

 

[Fare]

guess i'll treat this thread as a journal, and just document my road to gray hair....

testing the coils, with the caps on, 1-4 is 20kohms, 2-3 is is the same. the caps are brand new. looks like i'm investing in coils now...

 

[slugsride]

Your cylinder numbering is correct.

Did you turn it on prime for about 30 seconds?

Maybe one of the veterans can correct me on this, but I think when trying to start with low voltage you still get spark but the advance control is messed up (if yours is electronic advance).

 

[Fare]

tomorrow morning, i'll spend more time making sure theres fuel in the carbs.


coil clarification: completly unplugged, decapped.
coil two (spark plugs 2-3) = 11.58 kohms
coil one (spark plugs 1-4) = 11.56 kohms

::EDIT::

Just looked at the primary terminals (dunno why i didn't check last nite, frusterated?)

both coils are ~4, so that is good ( i think).

off to check float bowls (really hope i don't have to take the carbs apart again...)

 

[Guest]

tomorrow morning, i'll spend more time making sure theres fuel in the carbs.


coil clarification: completly unplugged, decapped.
coil two (spark plugs 2-3) = 11.58 kohms
coil one (spark plugs 1-4) = 11.56 kohms

Gas in the bowls is pretty important to the starting process. :-D

 

[Fare]

When the petcock (it is brand new btw) is on prime, and the tank is on the bike, no fuel flows. when i suck on the vaccum tube, no fuel comes out (when on the bike). when i take the tank off, both work they way they should. the tank is a little less than half full. this is a tube routing problem, foat level problem?

THank you

 

[slugsride]

It's easy to kink the main fuel line when putting on the tank. The OEM line had a spring covering it to help prevent that, but they often get discarded or don't fit over aftermarket fuel hose. With everything hooked up right, even on prime, there should only be flow while the carb bowls are filling.

 

[Fare]

I can get a few puffs of exaust, but nothing optimistic. Time to dismantle and look at the float levels =/

 

[Fare]

Float height was a little low so they were adjusted (when the bowls were dismantled, theres was gas in it, maybe a little too much). Cranks, but still...doesn't...start...

what now? starting to get reeeeal discouraged... hate to quit riding before i got to start...

 

[nabrams]

Hang in there!!!
You got your compression back up to spec with a valve adjustment and the bike was running before, so you're almost there!!
First off, verify that fuel actually flows out of the tank when on prime (disconnect the hose from the carb).
Second, use your car battery (car NOT running) to boost for the initial start. Your starter may be stealing so much current from a weak battery that you're not getting sufficient spark - remember: when your plugs are all in, the starter motor has to work much harder against full compression.
Also, try different choke settings and brand new plugs - your plugs may be fouled from all the starting attempts.
After re-assembling everything on my CB750 (had a blown head gasket), I had to experiment for about 30 minutes of cranking (while hooked up to car battery) with different choke settings to start the bike. I also had to change my severely wet plugs. The final conclusion: the very same bike needed only half choke on start-up (I used full choke for months before the blown head gasket), because of the huge improvement in compression (I adjusted the valves to spec when I replaced the head gasket).

 

[Fare]

once again Nebrams, thank you for replying. You can't fathom how frustrated I was this weekend.

After I drained the bowls and fixed the height, and reassembled everything, I put it on prime and watched the fuel flow from the petcock into the carbs. that should be fine.

I've had to charge the battery twice since the beginning of the weekend from excessive cranking. I'll check the plugs (when you say a plug is fouled, is it no longer usable, or does it just have to be cleaned?).

Does it mean anything to say that when I have the bike in 1st or 2nd, it rumbles a little bit, as if it wants to start? don't experience the same thing in neutral.

For the car battery thing, do you just connect it as if you were going to jump it (but don't), positive from one battery to the other battery's positive or do you connect it to the wire leads?

btw, when I changed the springs and clutch cover gasket, I noticed it was quite dry. there had been no oil in the bike from when I got it... now its not so hard to use the clutch...


Thank you again,

Fare

::EDIT:: maybe this is a nono, but when everything was off, I decided that i ought to clean up a bit, so I removed the tensioner to clean it and the surroundings. Would this have a negative impact on the situation? I didn't play with it though, just some simple green and some wiping....

 

[nabrams]

1. Cam chain tensioner must be installed properly - see other posts.
2. Jump the bike by connecting car battery positive to bike battery positive and car battery negative to bike's frame ground (I use the the gear shift lever) - car NOT running. You should see hugely improved cranking speed/strength.
3. Leave the bike in neutral, on the center stand.
4. USE NEW PLUGS - I've wasted so much time with bad plugs.
5. Like I said above, experiment with different choke settings.

By the way, I'm assuming you've got the airbox and air filter installed and that there are NO air leaks anywhere (see other posts).

 

[Fare]

bah, I just bought these plugs, oh well...

I have a new filter and I went a little overboard with the yellow snot stuff, so it should be good and airtight

looks like I'm removing the carbs+ airbox...again...

just step 13? http://bwringer.com/gs/camchaintens.html


Thank you again,

Fare