Topic: Hush's 650 front sprocket experiment

[Retro Rocket]

The rear doesnt effect it as much. And the smallest rear you you can get is 37 teeth.  
1 front will equal 3 rear.

If you can work out how many teeth you need to have on the rear it will work, there are plenty of places that make sprockets to suit.
There is a gearing calculator on this site somewhere....

[scunny]

there may be some confusion(mine) on front sprocket size, I will have to recount but probably 16, damn, ageing is a bugger.

[Hush]

OK well if you already have a 16T I'll hang onto it Larry, I would highly reccommend replacing with the 17T though as the effect is just amazing, I'm back in love with my bike again.

[mjstone]

Stock front for my 500 is 17 tooth and rear is 34 tooth.  Makes it real easy - 2:1.   With a 17 front and a 37 rear you would have 2.17:1 ratio.

MJ

[cb650]

The rear doesnt effect it as much. And the smallest rear you you can get is 37 teeth.   
1 front will equal 3 rear.

If you can work out how many teeth you need to have on the rear it will work, there are plenty of places that make sprockets to suit.
There is a gearing calculator on this site somewhere....

Yes you can have anything special made if you want to pay for it. I was talking without a special order.   The one I ordered was listed in DK's catalog.  Its for a 70's yamaha 750 twin but has the same bolt pattern.

[manjisann]

Interesting post Hush    I may have to try this as I'm hoping to do a lot of cruising this summer and next (assuming the bike agrees  ) Wonder if this would help my MPG, especially with my non stock carb setup.

Brandon

[nancy]

The sprocket change by just 1 tooth makes a serious difference. My CB750 is fine - highway and city. I can sit in 4th gear crusing inner city and drop to 2nd to turn slow at intersection and it has enough revs on to pull away with power.
But my new Triumph Sprint is geared differnet with a 19t front sprocket, That makes the bike go like a ballistic loco on the highway, but in the city with a pillion on, it is awful. Have to ride the clutch and pour on the throttle to get off from a stop and if I want to do a slow 20kph turn or go round a bout, even in 1st, it is pulling too much and about to stall unless I ride the clutch into the turn! It needs an 18t front sprocket...it's on order.
Regards
Mark

[Hush]

Brandon where ya been boy?
Cheers Mark, you intersted in doing a leg on the SOHC4 Relay later in the year?

[nancy]

Hush
Yes and no. Depends on whether  I still have a SOHC at that time. I'm doing phase last of my restore and having guards rechromed. After that the missus is suggesting I upend it onto someone else and concentrate on owning just one bottomles money pit - but I'll be very sad and forlorn and she may decide not to forsake me and let me keep them both. So...yes in principle.
BUT I know ZIP of this event in our country. Saw the details of the USA event and did wonder what was to happen to make it a WORLD event. I assumed it was USA and Europe maybe. SO will be nice to be involved.
Regards
Mark

[manjisann]

I've been about. Mostly just been busy with work and school and work, and the occasional bit of woodworking   Now that it's back to riding season I was thinking about my SOHC4 fam and figured I'd drop by and say hi!  I'm hoping to do some serious touring on the bike and if this $18 part can help her run a bit happier and maybe eek out another mpg or two, even better

Brandon

[dave500]

Stock front for my 500 is 17 tooth and rear is 34 tooth.  Makes it real easy - 2:1.   With a 17 front and a 37 rear you would have 2.17:1 ratio.

MJ

i tried a 37 rear with the 17 front on a 500 and its like youve lost 5th gear,you get a lower first and lose top gear,accelleration seemed the same but you run out of gears sooner.

[mjstone]

I agree, dave500.  I was trying to point out that the ratio is still closer to 2:1 as cb650 was saying 3:1.  When I looked for replacement sprockets for my 500 I found lots of 37 tooth, but held out for a 34 tooth.  I'm very satisfied by the stock setup on my 500 and didn't want to change a thing.

MJ

[dave500]

we used to gear our two stroke dirt bikes way down,lucky to hit 90 kays(55 mph)flat out,we used to ride in real tight trails though,creek crossings and steep inclines,the stock gearing just didnt suit in that application,a super low crawl gear is handy on a two stroke!i dont think you can go up on the front sprocket on 500s because of the clutch rod,or less on the rear as its about the same size as the hub anyway,the 550 and 650 give you a bit more flexibility that way?