Topic: Patina Hyena - 550/650 674cc Hybrid Cafe Build

[DaveBarbier]

The tank baffle is an interesting idea. I could easily slit the tank and slide in a perforated "wall".

In the immortal words of "W", you misunderestimate that undertaking.

Haha

Really though? Doesn't seem that hard

[DaveBarbier]

Something like this?

Interesting. With a reverse image search that comes up as Pete Thompson's 650. Is he a member? The article says it has CR29's. I guess they fit with the stock 650 tank and petcock. Or maybe some modification was done...

Thanks for that picture Cam, I haven't seen a 650 with CRs before...maybe I just haven't looked, haha.

[SOHC4 Cafe Racer Fan]

My CMR tank has internal baffles to control fuel sloshing/movement.  I'm just wondering if I'll need to relocate the petcock.

[DaveBarbier]

Yeah I see what you're saying. It's easy when you spend zero time thing about something, haha.

[DaveBarbier]

My CMR tank has internal baffles to control fuel sloshing/movement.  I'm just wondering if I'll need to relocate the petcock.

I wish I could help, but with a custom tank I'd have no idea where your petcock will land. I'd bet you won't be able to go in between the carbs and head though. There's not much room, unfortunately.

[DaveBarbier]

Ok, well it looks like Golan won't work for me It's far shorter than stock but it's a lot wider especially with the lever. The stock petcock is thinner which makes it able to be snugged up against the carbs more.

I'm going to return it back to Revzilla unless someone wants to buy it and a 22mm bung. If so, let me know by tomorrow afternoon.

Bought it for $100 and the bung for $13. I'd sell both for like $95 shipped.

[bwaller]

I don't think you'd have much problem with fuel starvation and a rear mounted petcock. I've never used foam but I know people that do. In case it is an issue this could be a solution.

[DaveBarbier]

I don't think you'd have much problem with fuel starvation and a rear mounted petcock. I've never used foam but I know people that do. In case it is an issue this could be a solution.

What the hell? I've never heard of that before, that's pretty interesting. Obviously I'm sure the foam is fuel/ethanol safe. Yeah, could be a solution if I have an issue.

Thanks Brent

[DaveBarbier]

I keep going back and forth. I'm now really considering eliminating reserve and just having a nipple off the existing 16mm bung of the tank with an inline valve. I'm trying to find a fitting that's M16x1.5 with a 90° elbow. Anyone know a place that sells these?

This way I won't have to cut or weld the tank at all. It'll be a much simpler solution.

[DaveBarbier]

Like this?
https://www.zoro.com/hatec-fitting-compression-elbow-m16x15-wnw04hs/i/G9725983/?gclid=CJH2iIPRztICFZiCswodSZgMGQ

Kind of, but almost $20 for a small fitting is crazy. Also I'd want a nipple on one end for a hose. Not really keen on having a whole plumbing system to connect a rubber hose.

I'm actually thinking of just welding a washer to the base of an m16 nut and then welding a 90° barb on the end of that. I could drop a viton flat washer in the nut to seal it against the bung.

[SF]

Hate to add more work for ya and not sure if you mentioned before but are you putting in a inline fuel filter?


Sent from my iPhone using Tapatalk

[bwaller]

That's what you'll need to do, make something up. Check with funjimmy though, I think he uses an inline valve.

I made up a 90 degree brass  barbed fitting when I first used a 400f tank but I can't find it and I'm not sure what size the 400 tank bung was.

[DaveBarbier]

Hate to add more work for ya and not sure if you mentioned before but are you putting in a inline fuel filter?


Sent from my iPhone using Tapatalk

I can use the existing tank filter that presses into the bung. Thanks for looking out

[bwaller]

I hope Jim doesn't mind!

http://forums.sohc4.net/index.php/topic,27159.225.html

[DaveBarbier]

Thanks for that post Brent, I looked through it but decided that I wanted to get it done that day. I ended up welding the petcock behind the carbs. My welds aren't pretty but no one will see it and it's air tight (checking with soapy water and lightly pressurizing the tank)



When doing research for welding on a used gas tank I see a lot of people freaking out about it. Some say never do it, some say it'll take your fingers off when it explodes...but if you use a little precaution it can be fine. I had the tank empty for a week in prep for the welding, then I stuck my shop vac in it and blew air inside for about an hour. Taped a bottle of propane on a stick and put the flame directly into the cap hole and didn't even get a little "swoosh" of the unburnt gasses. You definitely want to do this so if there are gasses they'll all be purged.

Are the people who say it's dangerous trying to weld a newly drained tank with all holes plugged?

[SOHC4 Cafe Racer Fan]

Nice fix Dave.

[bwaller]

Well done.

I agree Dave, take precautions but it can be done. I brazed two holes in the bottom of a tank in a 69 GMC 1/2 ton (rear cab mounting bolts were pointed and the tank was behind the seat) The first time I played a flame to it it blew across the yard. I then learned about the vacuum and exhausting fumes trick. 

[DaveBarbier]

Thanks guys. Yeah brazing would be nice. You can see the original bung was brazed. I don't have the knowhow for that. Would have looked a lot cleaner

[DaveBarbier]

Yeah I was thinking about filling it with my 75/25, but just ended up doing it empty with all holes open. I definitely want to try brazing sometime. Maybe I'll get some of that wire and mess around. Thanks

[DaveBarbier]

So now I'm thinking of sprockets and chain. Don, Gennaro and Cam, you guys decide yet?

Found this info from MiGhost over at hondacb650.com

79-81 Standard 16\40
82 Standard 17\39
80-81 Custom 16\39
82 SC Nighthawk 17\38

I have an '82 motor and it makes sense that the gearing changed as it did for lower RPMs at highway speeds because the later 650's are a more cruiser style. I'm thinking I want to go with 16/40 to match the peppier earlier models.

Thoughts?

I also think I want to go with an o-ring chain just for easier maintenance. The 650 comes stock with an o-ring chain so there's no risk of wearing out the case.

[Camrector]

Dave what rear tire you running? My rear tire is an 18in, so I decided on just using stock 550 sprockets 17/37. I wanted to have lower rpms at higher speed though to make better use of the cams power. It's not to drastic of a change.

[DaveBarbier]

My rear is 18 also. Which cam are you using again? Yoshi or megacycle? To best mesh with the cam I'd think trial and error is the way to go. Anyone you know have experience with similar setups?

Unless anyone advises against it I might just try what I said above and report back.

[bwaller]

Just checking 1st & top gears quickly it seems the 650 gearbox nor primary ratios changed through the years so Honda just changed final ratios to appeal to the buying public??

The primary ratio is different from the 550 so that bikes final gearing will be tall, (2.176:1 - lower revs) compared to (2.5:1 - higher revs) for the 16/40...shorter. A 13% difference so pretty substantial.

You're both using the opposite ends of the gearing listed, and I'm not saying that's a bad thing, only that you'll be able to compare realistic notes. 

[DaveBarbier]

My thinking is purely logic and assumptions without actual numbers to back it up. But I'm thinking that the early 650 was just a bigger brother to the 550. Pretty much the same bike and same purpose (small commuter bike that's quick and light) but with more power. Customers wanted to use that power for more highway riding especially as the form changed to a cruiser style so Honda also adjusted the sprockets. So my thoughts are that I want to get back to a "quick" bike like the earlier years which would be similar to the 550.

My only question is if the early 650 had too extreme of a gear ratio to begin with, even more than the 550, and Honda adjusted the sprockets to get back to what the 550 feels like in the later years.

I really just want a bike that feels like my 550 but much faster.

[bwaller]

You're going to get that.