86 vfr 700 extremely hard to start under 70 deg.

Hello,
Basically the title says it all. It's an 86 700, and if the temp drops below 70 it is a pain to start even with full choke It can take ten minutes before I can get it to run. Once I get it running and up to operating temp I have no issues. Any ideas or help would be greatly appreciated.
Thanks,
Eddie

 

Have a look at your sparkplugs, check that gap is about .032"

Consider replacing them, how many miles have they been in use?

Your carbs may be partially clogged, and SeaFoam might help.......

a well tuned bike like yours should start easily without choke unless temp is below about 50F.

 

Thanks I will pull it apart tomorrow I have not had a chance to really check it out. I was thinking it may be plugs also but since I am more informed about automobile repair I figured I would get some opinions from people who are more comfortable on the motorcycle repair side. I appreciate your reply and I will keep you updated.:biggrin:

 

Sparkplugs in bikes need much more frequent replacement than in cars....


While you're in there a compression test would be a good idea since low compression makes starting difficult.

 

that helps me a bit to thanks for making this post eddie

 

Well I changed the plugs today they were actually fairly new but I have seen even new plugs out of the box have bad resistance readings in the past so I changed them anyway, and I also fixed an exhaust leak I did not know about.
Unfortunately it still did not solve the problem. When I pulled the plugs they were a little wet so I'm leaning toward a carb issue as I believe that they are seeping gas into the cylinder as the bike cools down making it that much harder to start with the cold weather. I did not even think of a compression test due to the bike running flawlessly at normal operating temps., but I will check it out next Sunday which is again my only day off this week. I have rebuilt quite a few carbs on automobiles but have never done one on a bike, if anyone else on here is familiar with automobile carbs would these be similar in difficulty to a quadrajet, or would you say maybe an standard edelbrock carb. Just wondering what I'm getting into. Thanks again:smile:

 

IT'S unlikely that carbs are seeping gas since they have zero fuel pressure when pump isn't running.....

Did the plugs all look the same?

How long have you had the bike ?

 

link.....hope it helps.

http://vfrworld.com/forums/mechanics-garage/22449-cleaning-carbs.html#post170019:biggrin:

 

I have had the bike for a few months and have put about 900 to 1000 miles on it. The plugs all looked the same except the plug with the exhaust leak at the cylinder head it had a little less carbon buildup probably due to higher cylinder temps from the exhaust leak I'm lucky I did not burn a valve. I was thinking the same thing about the carbs not seeping because of the fact that they do not have pressure after you shut the power off but its the only thing I can think of because there is definitely fuel going in the cylinder some how because the plugs were wet after sitting overnight the first time I pulled them to start checking the problem out. I really appreciate your help, it really does help to have someone to bounce ideas off of for me. I wonder if the carbs may have had a different set of jets installed and its just running rich enough that when I shut it down it does not burn all of the fuel in the cylinders? I'm going to keep digging until I find this problem I really should have looked this bike over better when I bought it I have also found that the previous owner put silicone on the radiator cap the keep it on:crazy:, he told me when I bought it the motor was changed to a newer 750, nope looks to be the original 700. but it's my fault for not checking it out. Whoa I am rambling now so I will end this one for the night thanks again all:smile:

 

TRY using LESS choke when starting: you could possibly be flooding the plugs with excess enrichment.

begin with using only about 1/4 choke and gradually increase if it doesn't start, and keep the throttle closed while cranking

 

i was gonna say ..make sure the choke is connected.....

 

Have you confirmed spark at low temps?
what about fuel pressure?

 

IS the choke cable still connected? I know it sounds retarded to ask , but I had similar problems it would start when it was really warm out but not wehen it was cool.... the PO disconnected the choke cable from the bracket and all it did was slide the housing back and forth...

 

IF Crusty is correct, the choke lever will be very easy to move and have practically no resistance.

 

lmao, how funny...I have this same problem, and the choke cable IS my cure. I'm not sure if it's disconnected or broken, but either way, the choke lever does nothing when moved. I knew when I got the bike that the cable was bad, but rarely use a choke anyways, but i'll be damned if i don't actually need it on this bike in the cold, so I've already planned to tear it down this weekend and find out where the problem is.

 

I"ll send you a consulting bill.......................:biggrin::biggrin::biggrin::biggrin:

 

No my choke is hooked up, I do not think it would start for me at all if it wasn't I tried the 1/4 choke today it was still a pain even @ a little over 60 deg. but like I said before once it starts and runs for about a minute you would never know that there was a problem at all. Thanks again to everyone who is helping out.:thumbsup:

 

This may be a dumb question but the casting on the side of the engine that says 699 cm3 means it is a 700 not a 750. I am being told that it is a 750 but that makes no sense to me. sorry for the dumb question I just want to be sure.:thumbsup:

 

its a 700 thats what mine says.....what does your title say?

 

It says its a 700 on the title, but I was told the engine was swapped for a 750. I later looked at the casting and decided it was in fact a 700 but someone told me today it was a 750 I just wanted to make sure I was not missing something I appreciate the answer. Ok I'm leaning very hard towards the carbs now I took the airfilter housing off and started it and I noticed as you hit the throttle the fuel coming from the needles are more of a broken spray instead of a even mist, does this sound like it could be it? If so I will be pulling them and doing a cleaning following a thread posted earlier in this post. Thanks again everyone.