Ok ... after a frustrating day of getting nowhere and swearing a blood oath to burn Haynes Manual Headquarters to the ground, I figure I'll ask the real world experts ...

I am restoring an F3 from a very untidy state. Its going well but I am stuck and its to do with the rats nest of hoses and pipes that connect to the carburettor.

On the carbs is a central heater tube pipe that connects carbs 2 and 3. (Pic attached - stolen not mine)

So questions:

1) These unions are in a 'V' shape, you can see in this picture that there are other hoses attached to the other halves of the 'V's. I need to know exactly where they go (not a california model)

2) I know that there are two heater tube pipes that come off the water pump. The lower one routes up to the thermostatic valve .. but to where from there?

3) The left hand water pump heater pipe ... where does that go?

4) This leaves me with two additional connections to work out. One is under the thermostat just to the right of the 'right hand V connection', the other is just below the left hand 'V' connection and comes out of the engine at 90 degrees as opposed to the downward orienttion of the 'V's.

I have Haynes Manual and I have the original Honda workshop manual (which has been excellent so far and ****s on Haynes) .. but ... neither have a clear explanation of this or pictures in any section on coolant, fueling or engine. Incredibly frustrating.

So in short ... its the left and right hand of the 'V' unions that I am unsure of, the one under the thermostat itself and the one under the left hand V. If someone can tell me where all those tubes route id greatly appreciate it. I must have found 20 threads on this in various different forums and not found one reply that actually solves the answer or gives an 'idiot proof / well worded' explanation.

Thanks
John

 

@CBR469 Take a look at the OEM manual on the opening page of the Cooling Section, Chapter 6. Look closely at the Arrow Heads. They are matching pairs as to where they go, and you can draw a straight line from one to the other (based on where they point and arrowhead design). You should be able to figure out where each one goes. This one goes from the Thermostat Housing to the Thermostatic Valve.

 

lol thanks man, i scoured that very image repeatedly along with others, it doesnt actually help at all .. BUT, i just found an old video of the engine when i took it out of the bike which does show exactly how they route ... well ... how they were routed on my bike anyway, but it ran sweet before so i guess it's correct. In fact, the manual is so badly worded that it suggests something very different. Equally, there are so many threads and questions on this i think its fair to say that the OEMmanual (which btw is arguably the best manual i;ve ever used) is actually way short of clear on this topic.

 

unless you're in a cold climate or ride in really low / sub zero C' conditions my vote is delete them and block the ends on the thermostat and waterpump, save on weight and clutter. carb heater hoses and bridges on the carb are prone to getting blocked up with foosty coolant/corrosion too. seen a few that were all blocked up.

they're part of the heat management circuit that help keep temps isolated to engine and carb until the thermostat opens and allows full flow round the rad. with these hoses deleted it will still isolate temp to aid warmup but not put it through the carb. really its an emmisions thing and to help prevent carb icing, arguably it harms performance with heat but it's going to be negligable either way

trying to recall exactly how they route but cant remember fully, i'll have a look at mine later if it's any use.

 

Cheers mate. Pretty sure I've got it worked out now. Unfortunately the fuel joint on the right hand side of the carb had a hair line crack in it and shattered when i pushed the fuel hose back on. There were signs of a fuel leak around that area (golden no 3 & 4 carbs) so all in all not a bad thing. Just got a carb refurb kit through the post today (waiting on the fuel joint still) so they are coming off again and I'll do a complete refurb on them. Videoing the whole restoration so I'll put some links up on a new thread when I'm done with it all. Here is where I am at so far ...
And yeah ... the front wheel is in the wrong way round, I know lol

 

good stuff man, they absolutely deserve to be saved, total 90s gem had a quick look anyway and for what it's worth i reckon the long hose from bottom right of the waterpump goes to the carb 4 and the hose from the bottom of the thermo housing goes through the mounted brass valve to carb 1. that's how mine was routed before i blanked them anyhoo. make sure all the carb heater hoses / carb ports are clear, they seem to be really prone to choking up and it's easily missed.