Won't start..

Where I'm at:
Valves adjusted (number 2 intake on cly 3 is still kinda tight)
Carbs cleaned
Floats within spec
Petcock rebuilt
New plugs
Fresh oil and filter (oil was gas fouled)
New AGM battery
K&N Filter cleaned and oiled

My bike won't start...It was fine the day I brought it home, started when I looked at the button, just lacked power.

Checked the valves, almost all of them were tight. Took it apart, waited 3 weeks for back ordered shims. Installed shims.

Test rode it after valve job, ran very well, but died when I pulled into the garage at idle. Would not restart for several hours.

Pulled the tank off and gas was pouring out at "on" position. Internal filter had also come out. Re-rebuilt the petcock. Seems I was missing the shim for the diaphragm return, sanded down old tank drain screw gasket/plastic washer and put it in place under the spring, no leaks. Goobed filter with grease to hold it in place.

Opened up the carbs, very clean inside. Pulled out jets, cleaned with brake parts cleaner, all were clear. Put them back on, gas fouled the oil again... Took them to a somewhat trusted shop, they re-cleaned and set the floats.

Reinstalled carbs. Bike started, though not as easily as it did on day one... Would not run on anything less than 1/2 choke. Adjusted idle, reset all pilot mix screws at 2 1/2 turns out, except cyl 4 which was mangled...

Hooked up the carbtune, cyl 1 & 2 were close(around 24 & 20), cyl 3 at 14 and cyl 4 around 18. Matched 1 to 2, tried to match 3 to 4, but my adjustments seemed to do nothing, actually no 3 dropped to 12, could not get it to raise back up no matter how many turns in/out. My goal was to match all to 4 since the screw head was damaged AND it's plug was closest to the desirable "tan".

Looked at my plugs, 1 & 2, sooty, 3 was scary clean, 4 dark tan.

Pulled the carbs off, ordered new mix screw kit for cyl 4. Checked all pilot screws. Passages were clear, screws cleaned. Broke spiral flute off in mix screw 4, left it in there for now. Mix screws 2 1/2 turns out.

Carbs back on the bike, Battery fully charged, fresh plugs, fouled oil changed, new filter. Won't start. Almost started once, but didn't.

What do you think??
Back mix screws out a bit?
Is it the one valve that is still out of spec?
Timing (even though I rode it after valves were done)?

The carb rack was not broken, and I did not find any air leaks with the propane test...

Sorry for the long post and thanks for your help!!

 

O.K.-when you say "valve job", do you mean the head was removed and a complete valve job was done, or did you mean a "valve adjustment"? In any case 3 out of 4 on the valves aint gonna cut it. They ALL gotta be right before any carb work is done. As for the carbs, again 3 out of 4 aint gonna cut it, every one of those mixture screws are real important, so you have to work on that mangled one & get it right. Hope this helps & gives you (re)-starting point.

 

Thanks for the quick response...

It was a valve adjustment, 19 out of 20 of the valves are in spec.

As for the mix screw, it will be coming out...I just have to find a machinist who will drill it for me. I wasn't too worried about it as it was the only one that had a tan color...

I just wanted to get it running before I pull the cams again and start the whole process over.. Even with those two glitches it should run, as it was running before I removed the mix screws for inspection...

 

I'm pretty sure its a carb problem & if it was me, I'd go thru them again, cuz it really sounds like something is wrong in there. Its real easy to miss a plugged passage or something when cleaning. I'm really wondering about the float levels. Lets hope more knowledgable folk chime in here, cuz I'm just guessing. Best of luck to ya.

 

Hi
Just my two cent's but does it start with some help?
Did you try to put some gas in the air box and crank it over to see if it will start? That would tell you if the carbs are not giving you gas through the pilot jets. Did you run a wire though the pilot jets?

 

I've always found that's it's easier to find out what isn't wrong when trying to solve a problem with my bike. Try eliminating spark and electrical, then if those are ok, it has to be gas flow.

 

Did you wet set the float levels? Dry setting them gets them close, not perfect.

 

I think your right about it being carbs, and thanks...

I tried to start it while shooting some propane through the air box, no luck. No wire through the jets, but the brake fluid shot about 4 feet out the other side...

I will check to see if I'm getting spark, but I don't see why it would fail overnight like that...

They set them when I took the carbs to the shop... After I got them back I tried to sync, but was having problems so I decided to check the floats. Pulled carbs off, built a PVC rack, marked 3 cm on a strip of paper, butted paper against the "lip" of the carb body and measured with clear tube. They were pretty much spot on...by that I mean less than +/- .5mm.


Thanks for the responses guys, I wasn't able to do anything to it yesterday, and I probably won't get to it until tonight or tomorrow...

I'm going to try to turn the pilot mix screws out a bit, see if anything changes... I feel like I will have less trouble diagnosing the problem if I can get it running, even if it runs poorly...

I will keep ya posted!

 

Get a Gunson Color tune - when I did my carbs, the idles mix screws were set to starting 2 1/2 turns out and my bike would not idle unless I did crazy things with the idle adjustment screw, choke and throttle. I used the ColorTune and found that there was no fire in cyls 1 and 4 and intermittent in cyl 2. I messed with the pilot screw and got all 4 firing. synced the carbs, checked with ColorTune again, synced again - now it works great, starts quick, idles fine, and returns to idle off throttle quickly.

I bought mine on eBay (for both 12mm and 14mm spark threads) - it was definitely the turning point in my rebuild

 

I have a colortune, I'll have to give that a shot...

 

Get the other valve adjusted properly. One big mistake you made was to bring it to a shop that has no clue on how to work on a 30 year old bike.
You need to do this stuff yourself because the mechanics of today do not know.
You still have a few things to do yet..... Once you get that valve taken care of then you need to sync the carbs and do a color tune.
All 3 of these things work together.
You will get it. You just have to do it all.

 

Ok, it's likely that you made one mistake trusting your carbs to a shop. There is almost NO WAY anyone can clean the carbs properly without charging an arm and a leg. To properly clean the carbs, you need to remove EVERY part, FLUSH every passage, jet, well, emulsion tube with carb cleaner, and even run a thin wire through to break up caked on gunk. Then it's a good idea to replace all of the rubber (unless this cleaning followed a full rebuild, the rubber is likely dry, cracked, and will cause air leaks).

I cleaned a set of hitachis on a bike that sat for 6 months after an accident, but had been fully rebuilt, and it took about 3 hours. However, cleaning and rebuilding my turbo seca carbs (on a bike that has been sitting for 25 years) is taking me closer to 10 hours.

What condition was this bike in when you got it? How long had it been sitting? Also, check to make sure the shop didn't mess up something simple, like installing the jets in the wrong spot (both fuel and air jets).

 

Bike was in great condition when I got it, ran fine, great even. My problems started after I adjusted the valves...
Not sure how long it sat, but it fired right up before. The carbs had no varnish/gunk when I opened them up. I didn't clean them to marine standards, but they were clean.

I trust the shop as much as one can trust a shop... I've dealt with them before with good results. Also, I've had the bike running since cleaning/having the carbs cleaned.

My current situation started when I couldn't get the carbs to sync...I took them off, verified float levels, set mix screws at 2 1/2 turns out, reinstalled, and now it won't start. Thats the main reason I suspect pilot screws.

I don't doubt you when you say I will have to overhaul the carbs, I just think it should be able to run, or at least start.

All that aside...After sitting on the charger for a few hours it ALMOST fires the first time, then just cranks forever. Not sure of that means anything...

 

Well you can't get the number 4 mixture screw out, so unless you're extremely lucky, 4th's pilot passages are not clogged at all, and it's set to the perfect mixture setting, you're going to have issues starting/idling.

Did you take out, and flush the pilot passages, enrichment passages, and enrichment well (at the bottom of the float bowl)? It's not impossible to gunk things up worse if you don't do a full tear down (especially in that enrichment well).

You said it's a new battery, but have you ever run it down? Can you test it? Have you properly gapped the plugs? Checked for spark? Are your bowls full of fuel (did you put it on PRI for a few minutes to fill the bowls)?

Also, 2.5 turns might be a little too lean. Try backing them out a bit (3-3.5 turns).

Again, check the jets! If they aren't put in the right places, the thing basically can't run right. They all look the same except for a tiny number printed 2 or 3 times, and all have the same thread.

You said it lacked power? I say, it wasn't running right! You can spend ETERNITY chasing carb gremlins, or you can do it once and do it right. Multiple problems can overlap and mask each other.

 

Thanks Manbot and DuoDs! Everyone else too!

Turned the Pilot Mix Screws out to 3 and got it to fire, but I'm having the same issues...

Revs to 5,000 rpm when I start it with choke on, RPM's DECREASE if I give it any gas..

If I shut the choke off RPM's fall so low it dies unless I play with the idle adjustment...idles with choke halfway, but dies if I touch the throttle.

Plugs looked ok, definitely rich...
Will do colortune later tonight/tomorrow...At least it fired up!


I have an unrelated question... How noisy is the valve train on these things?? I'm hearing a clicking type noise, increases with RPM's... Maybe cam chain guide?
Maybe that's just what it sounds like when 19 of 20 valves aren't extremely tight

 

did you swap the throttle cable and chock cable?

 

Both are in the correct spots. Today I got it to idle with no choke, just dies when I give it gas; WOT or gradually...

Used the colortune, seemed to be getting blue flame in all cylinders... Is it normal to get alot of arcing from the adaptor when doing the test?

 

Yeah, you'll get quite a zap from it too (like 10kV). try to position it so it doesn't touch any other metal.

Did you check your pilot/main air/fuel jets? If you accidentally swap just one of those pairs in the carb, it won't function properly (especially when you open the throttle).

 

Just for shiggles;

Go back and double check not only the valve clearances but your CAM TIMING. It will run, albeit poorly, with one cam a tooth off. And frustrate the crap out of any carb-tuning efforts.

 

Found that out the fun way :?

I have nto taken the carbs off, but I will double check everything when I do...

I have been wondering about the timing, I thought I got it right when I put the cams back in, but the instructions were a bit unclear and I didn't secure the sprockets to the chain when I pulled the cams so it is a possibility.

How would I go about using a timing light on this thing? The timing mark doesn't match up with where it should on the pick-up, I.E. when my lobes are pointed away from the valves, the "T" is not where it should be... I know others have come across this.

 

A timing light is for ignition timing. I'm talking CAM timing; the adjustment you broke when you removed the camshafts.

The "T" mark is only going to line up "where it should" when the #1 PISTON is at TDC on a compression stroke; you can't go by cam lobe position this isn't an old Ford V-8. The valves won't be open but the lobes won't be straight up either.

You need to check the CAM timing; the "T" mark, the dots/arrows on the cam shafts, and the cam caps all have to line up as specified in the manual.

 

Fitz I think you might be on to something...

I thought I had it all together correctly, but this is the deepest I've dug into a motorcycle so it's quite possible I made a mistake...

When I recheck the valves should I measure them with the timing mark ("T") lined up with the mark on the pick-up coil, or should I have the cams pointed 180* from the valves?