Topic: CB750A w/side car

[scottly]

Hey Neal, the trike is looking good! I have to ask how fast your maximum intended cruising speed will be? If less than 80 MPH, you may be able to simply change sprockets to get that G-force rush.    

[notn]

Scottly...well as I grow older I have slowed down a bunch.  In reality it needs to do 65 comfortably for freeway stuff but most all my riding is backroad (pavement) and it will cruise at 60 with no problem except when hitting any grade and it realy strains it, remember me in power wheelchair, and trike are 1500 pounds.  What is interesting is back in 2000 or so I had a 650 yamaha with wheelchair sidecar (all controls were on the sidecar) and at 50 mph it felt like you were doing 75-80.  I thought the trike would be different but it isn't, it feels like your going way faster than you are. on my website there are some u-tube links to some rides (2 videos) it even looks slow there but speedo is right on with my riding partners.  I put an old "SUN" tach on it and not sure how accurate it is (set at 4cyl with diodes ) but at 3 grand its right at 60mph give or tak a few as speedo bounces a little right there.

[raymond10078]

3,000 RPM at 60 MPH is geared way low.  Stock (and not considering torque converter slippage) 60 MPH will net you about 4500 RPM.

What sprockets are you running?  If your tach is accurate, you would gain a LOT of acceleration by a simple sprocket change.

[notn]

Kandrtech..well you say its geared way low (3000 @ 60mph) then say stock it should run around 4 grand that would be geared high wouldn't it? However you ask about sprockets. Well it is a trike not a sidecar so there is a jackshaft involved from primary-jackshaft-secondary- drive sprocket.  we tried to keep the ratio all the same from jackshaft to drive sprocket (16 tooth) and rear sprocket is whatever was stock on 750a in 1977.  I counted it once but didn't write it down and have 5 inches snow in shop door.  We do have an issue with the sprockets were using, they are not made for what we are using them fo as with 1000 miles the jackshaft sprockets are wearing the teeth way fast, need to find a hardened sprocket as the primary and rear sprockets are doing fine.  Lots of trial and error stuff here but learning as we go.  I appreciate all your input
neal

[raymond10078]

Stock on a 77 is 15 front and 42 rear, 630 chain.

I would bet that your Tach is off.  Any chance of that? 

[notn]

It wouldn't supprise me if the tach was wrong, it is a modified Sun Super Tach from the 70's era set on 4 cyln with diode's in line.  If I can find the tach gears out of a "K" valve cover I can put stock tach on it as I see on the "76" motor I got tore apart in the shop that the cam has the gear on it but no gears in valve cover. 

[raymond10078]

I've seen those gear sets on ebay for $20 or so.

[scottly]

I think I have the tach drive gears; I'll check when I get home this weekend. PM me with your mailing address, Neil.

[scottly]

I do indeed have the tach drive parts, Neal.

[notn]

Scottly...did my "PM" make it to you..hope I did it right
Neal (NOTN) do want the gears tho

[scottly]

Got your PM, and replied Neil. If you look near the top of the screen, the "my messages" part will show the number of un-read messages you have received.
I haven't had a chance to mail the gears yet, due to my current work schedule...