Honda FT500 Starting from cold.

[david2520]

Hello, 

 

I have recently bought a Honda FT500 single cylinder 1982 from the USA.

My experience with motorcycles is mostly twins and 4 cylinder machines during the 80's and not singles.

I'm a little out of date with DIY motorcycle mechanics so any help would be appreciated.

 

It's an electric start with no kick start option available.

The bike is on the road here in the UK and very runs well when started and ridden.

However I'm havening some issue with getting the bike to start from cold.

Cold is when the outside weather temperature is between 10-20 deg C here in the UK summer time. 

When I electric start the bike from cold it might take 3 to 7 seconds before the engine bursts into life.

I have tried various choke and throttle positions during the cold start to find a best start position but with little change.

I have been using the bike 1 to 3 times a week for about 20-30 mile journeys and travelled about 700 miles to date.

When the engine is warm it starts straight away no issue.

Tick over when warm is about 800 RPM according the the rev counter.

 

The carb has been cleaned a few times, the petrol tank is clean, the bike has no modifications other than a new non vacuumed petrol tap, new E5 fuel that flows freely to the carburettor, Battery OK (correct type, charging, holding charge and cold start loading), valve/rocket gaps are correct, new ignition plug, new air filter and new engine oil and filter have been fitted.

I estimate the bike has not done no more than 25K miles from new and the engine has never been opened.

The carburettor butterfly choke valve opens and closes fully. 

When I turn the fuel on I leave on for about 5 to 10 seconds before I press the electric start button.

I cut the original HT lead both ends to get a better connections in the original coil and original ignition cap (both screw type connection).

The carb has been setup as the Honda Factory Service manual.

My question is does anyone know if the USA model had a different fuel jetting or carburettor to the UK model?

and if so do you know the type/specification?

I seem to remember USA were particular to environmental emissions in the 80's and/or is the environment/air is different in the USA (hotter, drier?).

Any other related thoughts would be appreciated.

 

Thank you, David Jones.

Edited October 5, 2023 by david2520
Clarification

[RideWithStyles]

Looks very nice.

Cold 10-20c now you're sounding like a southerner!!!

 

800rpm idle for a single seem very low to me, tou could try 1100 at least.

Wife's 125 single is HOT idle 1500 +-100 but cold is up to 1800-2000+ and the ktm i had before was 1500-1800 hot and cold somewhere around the same as old bike.

the usa versions of pretty much all bikes were purely Californian emissions so more to do with recycling air back to the air box or restricting exhaust.

engine oils grades make a difference too.

[Bianco2564]

Check you haven't got a big voltage drop (12v side) at the coil when you first crank it, it takes a lot of effort to get a big single turning.

Or a weak coil .On my ancient Honda 125, that became difficult to start, I replaced the coil and it transformed it.

[david2520]

Hello Ridewithstyles and Bianco2464,

 

Thank you both for the replies.

 

My current engine oil is Motul 5100 10W40 (standard issue) what grade do you suggest I could change it to? 

 

Regards, David

 

 

[RideWithStyles]

I wouldn't change the oil just yet until sorting out the main starting issue first, the thinner oil will help the engine from cold but wont solve the actual problem.

if the idle is too low the fuel with choke still wont be enough. If after trying to start taking a look at the spark plug, is it wet/oily, dry white/brown? May give some clue.

if the jet pilots are ok the other might be; 
Air leaking from carburetor joint or vacuum hose joint, 

leaking from joint between starter body and carb.

Air leaking from carb joint or vacuum hose joint.

Improperly working starter (enricher) plunger (Choke).

or a tiny hole/nick in a pipe somewhere.