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Hard Starting When Cold


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Hey Viffer Crew.... just a quick question!

 

When my '99 VFR is cold (read: sitting in the garage overnight or sitting long enough to let the engine cool down completely later in the day), the bike is somewhat hard to start. Cranks up and fires but dies immediately on the first try; second try is a little extra power but then cuts out again; on about the third try, it seems to work okay but all my lights, etc. pulse / dim like voltage isn't sufficient. Lights, dash, etc. (all electrics) are a little weak at first, just like the initial RPM struggles.

 

I move the "choke" lever up just a bit to increase the RPM's by 500 or so and after about 60 seconds everything seems to be okay. It idles fine with no weird cuts or sputters anywhere. After the bike has been running for a few mins if I turn it off, it starts right up again.

 

Battery when turned off reads around 12.3-12.5 volts which seems good. When the VFR is running I get 14.2-14.5 pretty consistently even when revving to 5k and beyond. No voltage drops when testing at the terminals.

 

I fixed an inconsistent voltage drop issue initially by installing and direct-wiring a new Rick's stator directly to a new Electrosport R/R I also purchased (I had these two on my last '98 and they proved reliable). I've also replaced the spark plugs with 4 new Denso U27FER9 plugs. The only thing I haven't tried is replacing the battery; but again the voltage doesn't raise any red flags. I also replaced my dirty air filter with a Hiflofiltro unit http://www.hiflofiltro.com/catalogue/filter/HFA1801

 

What could it be? Is it something I'll just have to live with? I've got about 56k on the clock and don't know the last time the valves were adjusted. My airbox and underlying components are squeaky clean.

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28 minutes ago, RedMist said:

I move the "choke" lever up just a bit to increase the RPM's by 500 or so and after about 60 seconds everything seems to be okay.

 

To clarify, do you or do you not apply choke when you 1st start it? Your text implies you used it after the third attempt.

 

If not, there's your answer - use the choke unless the engine is already warm.

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One big problem with owning a 21 year old bike is that the maintenance honeymoon is well and truly over.  5th Gen VFRs are great bikes IF they're kept in good shape as they age.

 

The fuel pressure regulator is 21 years old, how long is it supposed to last?  I didn't wait around to find out when I purchased my '99 5th Gen.

 

Likewise, the fuel filter is 21 years old...

 

And all the rubber seals that hold the fuel injectors are old and hard (they might still look good but after 21 years they're not what they used to be)

 

And what's the mileage?  Is the engine overdue for a valve clearance check and adjustment (as necessary).

 

Have the starter valves been synchronized recently?

 

Your hard-cold-start problem could be due to one particular thing, or it could be due to the interrelated effects of several minor issues.

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29 minutes ago, Lorne said:

 

To clarify, do you or do you not apply choke when you 1st start it? Your text implies you used it after the third attempt.

 

If not, there's your answer - use the choke unless the engine is already warm.

 

Thanks for your question, Lorne. I use choke pretty much after the first crank-over. She's always reliable when she's warmed, but cold starts are a bit of a fuss. And yeah, she's a '99 so any bike this old is going to eventually need some TLC, hence my aforementioned repairs. You would just recommend setting the "choke" (read: idle adjustment lever" a bit when first starting it and then going about my business once it runs for a minute or so?

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17 minutes ago, GreginDenver said:

One big problem with owning a 21 year old bike is that the maintenance honeymoon is well and truly over.  5th Gen VFRs are great bikes IF they're kept in good shape as they age.

 

The fuel pressure regulator is 21 years old, how long is it supposed to last?  I didn't wait around to find out when I purchased my '99 5th Gen.

 

Likewise, the fuel filter is 21 years old...

 

And all the rubber seals that hold the fuel injectors are old and hard (they might still look good but after 21 years they're not what they used to be)

 

And what's the mileage?  Is the engine overdue for a valve clearance check and adjustment (as necessary).

 

Have the starter valves been synchronized recently?

 

Your hard-cold-start problem could be due to one particular thing, or it could be due to the interrelated effects of several minor issues.

 

Hi GreginDenver, thanks for your reply. As mentioned, my bike has around 56k on the clock. I'm sure it's due for an engine valve adjustment, but honestly I'm probably not going to worry about it. There was a bit of ticking on idle but after I recently switched to Motul 300V Full Racing Synthetic, it seems to have quieted down the valve ticking almost completely.

 

I have the PDF of the Honda Shop Manual and have already pulled off a few repairs of my own (pulled the clutch piston and speed sensor for cleaning as well as learned how to replace the plugs). The DID front sprocket and chain need replacing because I think some of the links are starting to skip or kink.

 

How difficult a job is replacing the fuel filter / hoses?

 

To your starter valve inquiry, I don't think the starter valves have been checked. I did not ask the guy who I bought the bike from. Overall this '99 is in good shape with only needing moderate maintenance updates. My next job is replacing the rear brake pads and change the fluid with a Mityvac. Gonna use some EBC's as I've heard good things.

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50 minutes ago, RedMist said:

 

Thanks for your question, Lorne. I use choke pretty much after the first crank-over. She's always reliable when she's warmed, but cold starts are a bit of a fuss. And yeah, she's a '99 so any bike this old is going to eventually need some TLC, hence my aforementioned repairs. You would just recommend setting the "choke" (read: idle adjustment lever" a bit when first starting it and then going about my business once it runs for a minute or so?

The choke is designed to be used when the engine is cold - on the 1st attempt, not after one or more attempts.   Later models with the wax unit that replaced the manual choke on '98/'99 FI models does the same as the choke lever and does so on each (and 1st) cold start attempt.  The behavior your describing sounds totally normal for an early 5th gen.  Choke it, hit the starter and after about 30 seconds or a bit more start closing it as the engine warms and needs a bit less rich mixture.  Normally I do that and ride off after 30 secs to 1 min.    From the description it doesn't sound to me like anything's wrong with it - just like my '99. 

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Another thing to be aware of for cold starting is what fuel you are using?

The higher the octane number the less volatile is the fuel, this can certainly have an effect of poor starting in cold conditions. So try using the minimum octane rated fuel suitable for your bike in your country, see if that makes a difference. There is no benefit in running a VFR (except for a 7gen) on higher than required octane fuels. Certainly avoid Ethanol blended fuels IF you can.

 

How old is your battery? Your charging voltage is good but your battery may be down on capacity.

I know I'm repeating myself BUT battery terminal voltage is not a good indication of battery capacity - the battery ability to deliver plenty of cranking amps. You can have your battery properly load tested at any good auto parts store.

 

Agree with Cogswell, strange to be not using the choke on first attempt!

 

I'm not sure of the starting characteristics of a 5th gen. But can assure you my 6th gens and current 8gen virtually start quicker than I can release the starter switch, be it cold or hot!

 

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Thanks everyone for the suggestions! I'll use the idle adjust "choke" and live with the quirkiness. Will certainly be testing and possibly replacing battery soon, too. It's been gross weather lately so it gave me time to do some maintenance items.

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9 hours ago, JimMoore said:

If you can't get a clean start on the choke you need to start contemplating a valve adjustment. I haven't done one on this bike, but I'll be it's a HUGE PITA. 

It actually seems to do fine when "choked" (idle adjusted since the '99 doesn't have an actual "choke" like the 4th gens). A little warbly initially but maintains idle fine upon adjustment. However, regarding valves, would you recommend adjusting the starter valves first before going for the engine valvetrain?

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16 hours ago, Grum said:

I'm not sure of the starting characteristics of a 5th gen. But can assure you my 6th gens and current 8gen virtually start quicker than I can release the starter switch, be it cold or hot!

 

 

Hehe, if I wanted the honeymoon phase, I would have gotten an 8th gen (and spent at least $3500-4000 more than I spent on my '99). However, eventually if I get rid of my 5th gen, an 8th gen might be the way to go since I like the updates to the bodywork more than the 6th gen. How do you like the 8th gen vs. the 5th gen regarding performance, handling, etc? One thing I find hard to give up is the gear-driven cams that they got rid of for the 6th gen. Honda kept complicating the VFR as they increased the generation timeline... while they also increased the weight a bit 😞

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12 minutes ago, RedMist said:

 

Hehe, if I wanted the honeymoon phase, I would have gotten an 8th gen (and spent at least $3500-4000 more than I spent on my '99). However, eventually if I get rid of my 5th gen, an 8th gen might be the way to go since I like the updates to the bodywork more than the 6th gen. How do you like the 8th gen vs. the 5th gen regarding performance, handling, etc? One thing I find hard to give up is the gear-driven cams that they got rid of for the 6th gen. Honda kept complicating the VFR as they increased the generation timeline... while they also increased the weight a bit 😞

Never owned a 5th gen. Love the lighter feel of the 8gen, plus all its added features and better fuel economy.

Funny, I must be one of the odd ones, I've never liked the whine of gear driven cams!

As to your starting issues  I mentioned fuel type, are you running premium high octane fuel? 

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9 minutes ago, Grum said:

Never owned a 5th gen. Love the lighter feel of the 8gen, plus all its added features and better fuel economy.

As to your starting issues  I mentioned fuel type, are you running premium high octane fuel? 

 

Nah, I usually pick the lowest octane rating available since I figure it's not necessary to run 92 in my VFR. However, there is a chance since my Acura takes 92 that I may have filled up with supreme out of habit last time. I'll make sure to specify regular next time and see if it helps!

 

Anyone who lives in the Seattle area can find a filling station in Issaquah that doesn't use Ethanol in their gas. It's the only fuel depot that I have found within 50 miles of my house that doesn't add Ethanol to their holding tanks. I always make it a point to use the gas in my car; and the point of riding a bike is to go the "long way around" 🙂 So it's my priority to shop for the good stuff:

 

https://grangesupply.com/

 

I wish the corn juice wasn't as prevalent everywhere else, but it is what it is...

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Starter valve synch. Note this link for getting correct valve offset. Has a huge effect on idle and small throttle opening.

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1 hour ago, Grum said:

Starter valve synch would be first to check before engine valves. Note this link for getting correct valve offset. Has a huge effect on idle and small throttle opening.

 

I was looking at some feedback from various sources, and I stumbled across this device:


https://thedigisync.com/

 

While it seems to be a bit expensive for a one-time adjustment, it may be handy to have for future needs. What do you think? I know on the VFR, there is one valve that is set in place as a reference.... I think the second from left is the reference valve (the one that doesn't have a screw). I know that something like this would have been handy to have on my old V45 Sabre! That thing NEVER wanted to start and I was always terrified of digging in and synching FOUR CARBURETORS!

 

BTW, thanks Grum for being one of the more helpful members on this great forum 🙂

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18 hours ago, Grum said:

Another thing to be aware of for cold starting is what fuel you are using?

The higher the octane number the less volatile is the fuel, this can certainly have an effect of poor starting in cold conditions. So try using the minimum octane rated fuel suitable for your bike in your country, see if that makes a difference. There is no benefit in running a VFR (except for a 7gen) on higher than required octane fuels. Certainly avoid Ethanol blended fuels IF you can.

 

How old is your battery? Your charging voltage is good but your battery may be down on capacity.

I know I'm repeating myself BUT battery terminal voltage is not a good indication of battery capacity - the battery ability to deliver plenty of cranking amps. You can have your battery properly load tested at any good auto parts store.

 

Agree with Cogswell, strange to be not using the choke on first attempt!

 

I'm not sure of the starting characteristics of a 5th gen. But can assure you my 6th gens and current 8gen virtually start quicker than I can release the starter switch, be it cold or hot!

 

So higher octane gas is less volatile than lower octane? Didn't know that. I guess I assumed the higher the octane, the better it burns but that's too simplistic. I do try to avoid ethanol blends as my old carbeurated Suzuki 750's carbs had to be replaced after only 2 years from using ethanol blends. 

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6 minutes ago, interceptor69 said:

So higher octane gas is less volatile than lower octane? Didn't know that. I guess I assumed the higher the octane, the better it burns but that's too simplistic. I do try to avoid ethanol blends as my old carbeurated Suzuki 750's carbs had to be replaced after only 2 years from using ethanol blends. 

 

Hi interceptor, try this website to see if it provides accurate mapping for your area regarding ethanol-free filling stations. That's how I originally found the one in my area, many years ago now. All the powersports guys take their equipment there. Quite often when I'm filling up, there's always a boat, or a couple motorcyclists, or a guy filling gas cans. They know the secret to better mileage is to skip the corn juice and use the good stuff 🙂

 

LINK -- https://www.pure-gas.org/

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5 hours ago, interceptor69 said:

So higher octane gas is less volatile than lower octane? Didn't know that. I guess I assumed the higher the octane, the better it burns but that's too simplistic. I do try to avoid ethanol blends as my old carbeurated Suzuki 750's carbs had to be replaced after only 2 years from using ethanol blends. 

Standard unleaded here in Australia is 91ron which the VFR is designed for. Premiums are 95 and 98ron non ethanol and due to the additives to increase octane has the effect of lowering volatility. Ethanol blended fuels are also available here, largely E10. Believe your standard fuel 87aki is equivalent to our 91ron.

In general increasing ethanol content increases octane rating but decreases volatility as well.

The greater the volatility the better for cold starting.

There are known issues with cars that don't require premium fuels that do suffer badly from cold starting on premium fuels. Have heard the same with some bikes as well and going back to standard rated fuel for the bike has helped cold starting.

Cheers.

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5 hours ago, interceptor69 said:

So higher octane gas is less volatile than lower octane? Didn't know that. I guess I assumed the higher the octane, the better it burns but that's too simplistic.

The gas companies pitch that the higher the octane the better it burns

The rule is don't buy more octane than you need. Octane is one formula
in the alkane series of hydrocarbons. Made up of 8 carbon atoms
singled bonded together with 18 hydrogen atoms connected. Although
octane is a simple organic compound, it was some what expensive to
Crack and supply in large quantities. so todays gas has no real
octane. What we use is an octane rating system. The properties of this
formula is that it burns slow when ignited; therefore it does not
detonate or knock during heavy loading of the engine. Knocking is an
explosive combustion of part of the fuel/air cylinder charge, after
burning begins. What the ear hears is the shock waves of the normal
flame pattern colliding with the detonated fuel/air mixture. Engine
temperature will begin a steady rise and micro particles of the piston
will eaten away. Looking at a piston that suffered knocking it looks
as if the surface as been pitted by sand blasted When the cooling
system Maxim heat capacity is reached, beyond that,around 300 F, metal
to metal contact damage has probably occurred. The oil companies used
the next lowered alkane formula Heptane which can be refined in large
quantities. Heptane's big drawback is that it burns too fast when
ignited and would knock continuously under load. To slow done the
burning process additives are added instead of deadly lead. Back in
the 60s lead was added to the formula about 1 grams per gallon like
leaded premium, Union Oil 76 which had an octane rating of 98 with
only about 1 gram of lead per gallon. If you have an old 427
Hemispherical combustion chamber engine you add lead and reach a 3
gram per gallon , or about a 100 octane rating. High performance
engines like the VFR employ pentroof shaped combustion chamber. This
shape promotes rapid flame patterns, all in right direction, so the
killer knock is restricted to light knocking at sea level under sever
loading. Most of us can get great service from unleaded regular or
about 87 octane rating...

 

Things to check for that would effect cold starting are:

 

1) coke cable adjustment... too loose or too tight effects range...

 

2) unobstructed idle air tubes... pinched rubber tubes from the air box restrict
idle air... the result is a lean mixture that doesn't support 100% combustion...

 

3) throttle body butterflies... any air that bleeds past the butterflies kills

vacuum needed to draw in the correct rate of fuel... the result is a lean mixture
that doesn't support 100% combustion...

 

If evreything is right you should be able to use full choke... no throttle... hit start and it fires up and idles...

 

 

 

 

 

gallery_3131_51_651212.jpg

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8 hours ago, interceptor69 said:

So higher octane gas is less volatile than lower octane? Didn't know that. I guess I assumed the higher the octane, the better it burns but that's too simplistic. I do try to avoid ethanol blends as my old carbeurated Suzuki 750's carbs had to be replaced after only 2 years from using ethanol blends. 

It's actually not. RVP - Reid Vapour Pressure (volatility) of high-octane fuel is same as low-octane. This is property that can be tailored completely independently from AKI - anti-knock index. RVP is adjusted between summer and winter seasons (this is done to both ethanol and non-ethanol fuels):

 

summer 87 & 91-oct = 7.8 RVP

winter 87 & 91-oct = 9.0 RVP

 

Higher volatility blend is used in winter for easier starting and results in less unburnt petrol being dumped out tailpipe. Lower-volatility blend doesn't evaporate as easily. The liquid petrol doesn't ignite and goes out tailpipe in liquid form. The higher volatility of both 87 & 91-oct winter petrol vapourises much easier and less liquid is easier to ignite. The difference in ease of ignition has nothing to do with octane (which is still same), but ease of vapourisation (liquid petrol actually doesn't ignite). AKI - anti-knock index (octane rating) is still same as summer blend regardless of volatility.

 

I wrote up an article many decades ago for PorscheFans board on octane. It's been copied numerous times without credit, typos and all! 🙂

https://members.rennlist.com/951_racerx/Fuel-WhatsOctane.html

http://www.offroaders.com/technical/whats-octane/

https://www.fordescape.org/threads/regular-or-premium-fuel.212/post-826794

 

The "volatility" part, which isn't really volatility, but rather resistance to forming radical-akyl groups when combustion starts under high-load/high-pressure conditions (WOT). These akyls are extremely temperature & shock sensitive and they cause multiple flame-fronts to start in combustion-chamber. Resulting in high-pressure spots when multiple wave-fronts collide and causes unstable combustion. This detonation/knock/pinging can shatter rings, and melt holes into pistons. These akyls do not form in low-load/cold-start/idle conditions, so octane-rating is irrelevant then.

 

BTW - pre-ignition is completely different phenomenon altogether. Engines don't survive 1-additional RPM of rotation after pre-ignition.

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13 hours ago, RedMist said:

It actually seems to do fine when "choked" (idle adjusted since the '99 doesn't have an actual "choke" like the 4th gens). A little warbly initially but maintains idle fine upon adjustment. However, regarding valves, would you recommend adjusting the starter valves first before going for the engine valvetrain?

I'm not sure about that, but I do know that hard starting is an indication of tight valves. 

 

I'll also second the other poster. Mine starts at first touch of the start button.

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