So close to starting...help it's driving me nuts!

Hi there,

I'm working on a new to me 3rd gen project bike.



The bike is rough but I have had it running twice - for periods of about 10 seconds each time...then it dies and won't start again!

I have checked all of the obvious things:

- plugs have good spark and wires are connected
- Fuel pump is sending gas to motor
- carbs are clean - slow jets / pilot jet blown out and adjusted to 2 1/4 turns - varnish removed - floats clean
- compression seems ok

I've tried choke, no choke, throttle open, throttle closed, ether direct down the venturis - still nothing. it seems to be closest to working when there's no throttle or choke applied. It will give out a massive back fire every so often.

I'm cranking the bike off of my car battery so it turns over beautifully and you can tell it's soooo close to starting....but it just won't quite catch!. it's infuriating. I've pulled and cleaned the carbs 4 times! If i hadn't heard it running i would have given up long ago - but now it's all i can think about....and I'm completely out of ideas.

Please tell me what I'm missing - I'm open to all ideas.

 

The pilot screws seem a little far out. Also, is there an inline fuel filter that you haven't replaced yet? Also as a dummy check, is the valve on the bottom of the gas tank open? These would be the things that I would check again and they are pretty simple too. By the way, what year is your 3rd gen? I can double check my manual to see what the pilot screw settings should be. And is there anything special about the carbs, are they jetted differently than stock?

 

Thanks for the ideas - yes I have checked most of these and I think they are all good. The bike is a 1990 Canadian model - I found 2 1/4 in my manual.

One thing i might have overlooked is the jet that is circled in the picture below. I believe it's the starter jet and it should not be removed for cleaning. I did some research online and found a test to confirm if they are plugged (attach a piece of clear tube and spray carb cleaner in and watch it drop). i tested this and the carb cleaner does not drop at all. I have tried sticking a thin piece of wire in them and none go further than 1/4 inch. They are all plugged solid.

I also sprayed compressed air in to them at 55psi - and nothing moved.

Does anyone know if these can be removed and cleaned - or if there is a more effective way of cleaning them?

Thanks

 

Ok - so I have taken a video to show how close it is to starting and to hopefully get some good diagnosis around what the problem might be.

I was able to clean out all the starter jets but that didn't solve it.

[video=youtube;2OXIt4IgO10]http://www.youtube.com/watch?v=2OXIt4IgO10&feature=mfu_in_order[/video]


let me know what you think

 

I was here for a long time. You think you've cleaned those carbs, you really do. They look clean, blow air through them, but they aren't clean enough. My answer is still clogged carbs, but almost there. While they are off I would also make sure they are bench synced as close as you can get.

 

Cannot be removed, I also suffered through this. If you got the liquid to drop, make sure its at the same rate as the others. You might have just barely gotten through the grime, and are not letting enough through. Thats what your video sounds like.

 

Pine-Sol

I've said this again. Take the carbs off take apart ,but not the housing holding the carbs to the top fixture. bowls off, jets out . Rubber-maid Binni with 7 pine-sol in the bin immerse the carbs, 5-8 hours . Wash with water, blow the water out,(immerse the jets as well ,use 1.5 lit pop plastic cut in half.) reassemble, reset the carb floats reset the jets.. my 2 cents.


Pine-Sol is a degreaser and eats the goo in the carbs..

Smells good to. capture the used Pine-Sol, so it can be used again or clean your bathroom..

 

One of the benefits of all this "tinkering" is that I can remove and replace the carb rack in well under 5 minutes - including hooking-up throttle and choke cables. The first time it took me about 2 hours just to get the carbs-off and another 2 hours to get them on again!

I will do the full soak down this weekend and hope that will fix it. I haven't been able to do a compression test as my comp-tester doesn't have a fitting small enough for the VFR plug hole. The couple of times it ran for around 10 seconds - it purred like a kitten so I had assumed compression was ok. I don't know anything about th histroy of the bike. It doesn't appear to have had the heads removed (no evidence on nuts) but I think it's a fair question - the timing seems to be off slightly to me. Is there an easy way to check the timing on these bikes?

Thanks for the replies - I will keep you posted.

 

Have you tried fresh, clean sparkplugs ??

A quick plug inspection after the engine dies might give you more clues about what's going on.

 

No - I didn't buy fresh plugs. Mainly because they all seemed to have a strong spark - plus I din't want to drop $70 without knowing it would fix it. I cleaned the exisitng plugs quite well - but i guess you nwever know for sure if that's the root cause - that might be a later step.

When i pull them from the motor after it dies, they have a light layer of gas on them and a little dark oil - but they're not dripping wet or covered in oil.

 

I have read all posts but i didn't see fresh gas, also once i had a cracked ceramic coating around the ground electrode cause almost the same problem

 

I was here last weekend. Here's what I did - YMMV of course - to get it going. 1.) pull carbs and triple check that all jets are clean using a bit of wire 2.) Pull plugs and clean with spray can of carb cleaner 3.) Spray carb cleaner directly into the air funnels for about two or three seconds per funnel, then crack the throttle to open up the butterflies and let the cleaner in 4.) crank and crank and crank until it catches. If it dies after this you have a fuel delivery problem. In my case, the fuel hose was kinked under the tank by the petcock causing a lean condition (which resulted in backfiring very much like what you have here).

EDIT: Avoid pine-sol like the plague. I tried that crap on a spare carb set and it a.) didn't help at all and b.) left a white crusty film on everything which made them much worse.

EDIT 2: just saw your post about your plugs - your problem sounds identical to mine; my plugs were coming out the same way.I'm looking forward to hearing back that it's working now...

 

Uh-Oh - I hope you're wrong about the Pinesol!



I've already stripped the carbs and have everything soaking in Pinesol. I read a few posts that said it's fine for everything but magnesium.

I happened to have a stack of small pinesol bottles in the house - so i was more than pleased to use them.

BTW, when i came home from work tonight I tried firing-up the bike and it actually ran for a couple of minutes. i ended-up turning it off. But when I tried to fire it up shortly after - it wouldn't go!.

What would have changed that allows the bike to start after sitting for 18 hours?

I'm completely obsessed with getting this thing going. It's taking over my life!

 

Just be certain to rinse everything off very well, you'll (probably) be okay. The only thought I'm having on your random start-up is that fuel was able to seep through whatever blockages you've got while it was sitting and that was what you were burning off. I'm far from an expert on this however - mine is still not fully operational, though I hope to be riding by Sunday.

 

So, I agree that "clean" is easier said than done. New jets are pretty inexpensive if you're not satisfied with idle quality or throttle response once you get it running. What I'm thinking, due to the short duration of run and, especially, the backfire you mention is that you're actually overfueling due to poor needle and seat seal...check those rascals out beneath (above) the pivot point on the floats...bet you'll fix it. Good luck.

 

Are your float levels correct?

 

Right, needle and seat, pull and clean, reinstall and try again. Cam timing may certainly be problematic but, other than that, if you've sprayed "ether directly down the venturis", you have effectively ruled out the aforementioned possibility that "old fuel which has seeped past a blockage is being burnt off" but not the possibility that you are flooding the bike, a much greater liklihood especially if anyone has ever "rodded" the jets.