Long Engine Warm Up ‘55-‘69

Post Reply
Posts: 23
Joined: Thu Mar 08, 2018 8:43 am
Location: Lynchburg, VA

Long Engine Warm Up ‘55-‘69

Post by ferrarirobinson »

I have heard from lots of places and people that the ‘55 -‘69 model engines take a long time to warm up. And my ‘57 R60 certainly does take a while to run smoothly. A good while. Of course air temperature determines length of satisfactory smooth running but even 70° and above require a longer warmup period that I think it should be. Is the reputation warranted or to much of a generality. Or, maybe it’s Model specific. Or maybe it’s not true.

If true, what causes this condition. Head design ? Carburetors ? Both ? Am I not holding my tongue correctly during kickstarting and after it fires up .

What’s your opinion ?


Posts: 126
Joined: Sun Aug 12, 2018 5:09 pm
Location: Central Oregon

Re: Long Engine Warm Up ‘55-‘69

Post by FL54 »

My ‘63 R50 is definitely cold blooded. It takes several miles for it to warm up and smooth out. I just accept it as the nature of the beast.
Central Oregon

Posts: 453
Joined: Sun Aug 09, 2015 8:13 pm
Location: Knox, PA. USA

Re: Long Engine Warm Up ‘55-‘69

Post by Daves79x »

My '59 R50 starts instantly with minimal tickling/no choke and you can ride it off immediately. I raised the metering needles one hole in the carbs. For sure not cold-blooded and does not run rich either - plug color is perfect.


User avatar
Posts: 773
Joined: Thu Sep 27, 2012 5:15 pm
Location: Ashfield Ma

Re: Long Engine Warm Up ‘55-‘69

Post by wa1nca »

Yes move the slide needle down to #3 position one hole up from the bottom hole and check that the idle jet is correct size
Note: Like any engine it is not a good to start and drive without some warmup
Tommy Byrnes
54 R51/3 55 R50/Velorex 560 sidecar 64 R27 68 R69US
Ashfield, Ma

User avatar
Posts: 156
Joined: Sat Sep 22, 2018 4:14 pm

Re: Long Engine Warm Up ‘55-‘69

Post by skyler.robbins »

Mine is cold blooded... I let it idle for a couple minutes while getting my helmet on and such.. and it takes a couple miles of driving before it's happy.

User avatar
Posts: 1153
Joined: Fri Oct 27, 2006 3:00 am

Re: Long Engine Warm Up ‘55-‘69

Post by miller6997 »

I live in a warm climate where it almost never drops below freezing. My R69S is ready to go in a couple of minutes. I start it, and by the time I've put on my gear I can be on my way with little or no stumbling.
Jon Miller
'67 R69S
'13 F800GT
Altadena, California

Posts: 458
Joined: Fri Jul 15, 2016 1:53 am

Re: Long Engine Warm Up ‘55-‘69

Post by 312Icarus »

Consider this...you have a pretty massive (thermally) engine system in toto: case/crank cams/jugs/oil etc all of which start at ambient. Gasoline vaporize better as it gets warmer (until such time as it boils!). In order for that gasoline to vaporize the entire thermal mass must get warm enough to allow fuel to vaporize at a rate that it will support the load, without artificially enriching the mixture (choke) Net mixture ratio change significantly with temp, one of the major reasons you don’t see any air cooled cars out there any more. Keeping air cooled engines at constant temps to allow proper lean (read clean) fuel air mixes is near impossible.

So with the vintage boxers (and singles for that matter) the heads and the full intake system needs to get warm. On a cold day, from a cold start getting the heads warm can take a good long while. A short ride at gentle throttle (once the oil is a bit warm) is probably the best way to warm up an engine like this.

If you engine starts we’ll, and gives full power nearly cold, I would guess that it is running too rich once it is fully warm. Plugs can tell that to an extent, as can a exhaust gas temp check...not something that most of us can do.


Post Reply