No cold compression

[Hawk54]

 :dash2:OK, the "Orange Whip" from Oregon has stumbled into a small problem, no compression when engine is cold. Now I spent the last few weeks trying to get this barn find to start. New battery, starter, plugs etc. I even rebuilt the carbs. Of course I ignored the basic check, the compression check. After starting the bike with starter fluid and running it for a little bit -- I thought I had it licked - nope! Surprise Surprise, it would not start cold, it tried to, but to no avail. I had a mechanic friend check it and he said, no compression when cold, but 180-190 when hot. Now I am not going use starter fluid every-time I want to go for a ride on the bike. So the mechanic suggested a ring replacement rebuild. When the bike ran, it ran good, with a little blue smoke coming out, the transmission shifted really well, actually every thing is fine --except starting. So, people of great wisdom, that means all of you out there in FJ land, where do I go from here. Yes I have some mechanical background, mostly on European bikes, and single Japanese bikes. I did not see any ring sets on RPM and I did not get a reply from Randy when I asked for parts. So without begging ( I am of course ) as none of you live out here in Oregon, can you advise.

Thanks
LH

[Mark Olson]

Hi LH ,  The fj likes full choke when cold to start and no throttle twist . There are 4 small hoses attached to the carbs that are choke air vents , check that these are not plugged with dirt .  As for the compression dealio , You may be dealing with stuck rings that expand with pistons when hot giving you the difference in compression numbers.

Most common fix is to ride the hell out of the fj, with lots of full throttle acceleration past 7k and deceleration from 7k ... This will most times free up the rings and stop the smoking . If in your case this does not help you will have to ring it.

When contacting RPM ... it is best to send a separate e-mail as the one on his web page has a linking problem and he can't receive it. Parts can be ordered from the site with no problems though .

try this one. randy@rpmracingca.com  it works. 

[Hawk54]

Thanks Mark, I was wondering if I rode the bike hard if it would help. It did sit for 8 years. I am also wondering, I do not know if the valves were ever checked by the previous owner. Could tight valves cause this too? If so, what are the clearances on the intake and exhaust, I assume cold. I guess a good long hard ride is always good for the sole, maybe the bike too . I will let you know what I find on Monday.

Thanks,
LH

[fj1289]

LH,
IS it hard to start cold but runs okay after it does start?  Does it idle?  Does it do OK pulling away from a stop?

When you rebuilt the carbs, how much time and pain did you go through with the small jets and passages for the idle circuit?  Most people who get one of these bikes that have been sitting for a while THINK they cleaned them really well the first or second time...I think three times is probably average.  These carbs are very well known for gunking up the pilot (idle) circuits when they sit for a while.  A full disassembly and ultrasonic cleaning seem to be the best way to resurrect the carbs.

Good luck!  And let us know how it gets on

[red]

OK, the "Orange Whip" from Oregon has stumbled into a small problem, no compression when engine is cold. I had a mechanic friend check it and he said, no compression when cold, but 180-190 when hot.  Thanks
LH

LH,

Yamaha makes a product called Ring-Free, which some have tried, with varying levels of success.  I'd need to see that stuff fail, before I actually tore into the engine.  Yamaha dealers should have it, and Amazon.com does have it, also.  'Way cheaper than a ring job.       

Cheers,
Red

[Hawk54]

 :hi:Thanks riders , I will try Ring Free when I take it this weekend, good idea! As to the carbs, yes I really cleaned them -- followed the files section on here for rebuild, but that does not mean I did not screw up. It does idle when hot, and pulls away from stopping rather well. So I think I'll do the Ring Free treatment, then ride the wind out of it and see what happens when it is cold. I am thinking I should check the valves, what are your thoughts? Now where did I put my leathers -- gotta have them to go fast -- don't ya

Thanks,

LH

[Mark Olson]

Valves on the fj get tighter when hot .

cold settings are intake .004-.006 or .11mm-.15mm
                       exhaust .006-.008 or .16mm-.20mm

best if in the middle of the range as too tight will burn valves.

If you are hearing a lot of valve train noise when hot you are probably ok .. when the engine gets quiet that's when valves are tight .

I suggest getting a manual for maint issues . I think there is a spot in the files section to download one.

good luck.

[movenon]

As per Mark, check your valves and check the TQ on the head bolts also as the bike is new to you check the cam timing just because.  When you say no compression when cold, all cylinders, what are your readings cold?   Mine was down to 120 PSI and started "ok", a lot better now after fresh rings. 

Some of the early FJ's reportedly had head gasket problems.  Mark or one of the older heads can probably elaborate.  I only mention that because of your hot compression reading and you stating no compression when cold. ? Numbers please .
George

[simi_ed]

:hi:Thanks riders , I will try Ring Free when I take it this weekend, good idea! As to the carbs, yes I really cleaned them -- followed the files section on here for rebuild, but that does not mean I did not screw up. It does idle when hot, and pulls away from stopping rather well. So I think I'll do the Ring Free treatment, then ride the wind out of it and see what happens when it is cold. I am thinking I should check the valves, what are your thoughts? Now where did I put my leathers -- gotta have them to go fast -- don't ya

Thanks,

LH

LH, I think I would reconsider.  A "new to you" bike that is having starting issues?  I'd get to the bottom before I "ride the wind out of it and see what happens when it is cold".  You might end up burning a valve or 3! I recommend check the valve clearances before any more riding.  You don't know the entire pedigree of this bike, and may discover something that requires immediate attention. 

Trust me, you don't want to burn a valve or worse!  Your new bike may end up as someone else's barn find in another 20 years. 

Ed

[FJmonkey]

One of the first things I did with my '89 was check the valves. 7 of them were tight, not real bad but tight is never good.

[aviationfred]

My 2 cents are as follows.....

Make sure your valves are adjusted properly.
New spark plugs
Verify that the plug wires are transferring good voltage to the plugs.
Verify the coils are good.
Verify the carbs are 100% clean.

The next suggestion is something I have done and it had worked well. It is a chemical additive that unseats your rings and cleans compression and oil rings. The product that I used is BG Purge.

Remove all 4 plugs
Pour approximately equal amounts of BG Purge into the spark plug holes. Allow to soak for a minimum of 4 hours up to overnight. Put a towel/shop rags over the plug holes and bump the motor on or two revolutions. Drain your oil and change your filter. Once done, pour a teaspoon amount of fresh engine I'll into each plug hole. Repeat the engine bump process with NO plugs installed. Now install the plugs and plug wires. It may take a few try's to start. Make sure the garage door is open or the bike is outside. Once started, it will smoke like nothing you have ever seen. Should clear up in about 5 minutes.now your rings will reseat themselves over the next 300-600 miles and compression should be better.

[ribbert]

:dash2:OK, the "Orange Whip" from Oregon has stumbled into a small problem, no compression when engine is cold............Surprise Surprise, it would not start cold, it tried to, but to no avail. I had a mechanic friend check it and he said, no compression when cold, but 180-190 when hot............Yes I have some mechanical background, mostly on European bikes, and single Japanese bikes.

Thanks
LH

Something doesn't sound right with all this info. It has enough compression to start and run. The hot comp readings seem too high and stuck rings are something you hear about a lot more than you ever find. Why has your mechanic not given you exact comp readings, which is the norm when a test is done?
Ring Free is more of a regular preventative treatment than a single dose fix.

Don't forget, it was being ridden up until it was parked and there are only certain things that time alone will affect.

Not saying it isn't something oddball or major, but eliminate the simple stuff first. For example, if the choke is not working it would behave as you describe. Have you checked the plugs to see it they are wet after an attempted start?

You'll have no problem working on the FJ if you have experience on European and Jap singles, they're the same.

Noel

[Firehawk068]

I'm with Noel on this one.
It sounds like a fuel issue to me.

If it has 180-190 psi, hot compression, there is absolutely no possible way that it can have zero cold compression.

You have already proved that it will start and run on starting fluid. You have to have compression, and spark for that to happen.

Your best bet is to pull the carbs, clean them extra-good. Pay really close attention to the choke circuits.
As with most motorcycles that sit for any length of time, especially with modern fuel, you'll have gummed-up fuel passages.

I would also advise against using starting fluid for any length of time, to keep an engine running.