Sprockets Sprockets

[Tripleking]

I want to lower my overall gearing on my 71 T250. Should I change the front and/or rear sprocket? If so, what size. My T250 does not have great pick up off idle and it has difficulty climbing hills at low speeds. It pulls Very well from 4,000 RPM and up, but I have to slip the clutch like crazy climbing my driveway and it cruises at 55 MPH at 5,500 RPM in 4th! Heck, I have six gears. I would like to use them.

[LexPaul]

The cheapest easy fix is to drop to 13T or 14T on your front sprocket, but only if your manual showed these as an option. You don't want to get to far from spec on the front as you may end up with clatter and a worn place as your chain is rubbing something it's not supposed too. As far as the rear sprocket, I went from a 33 to a 36 on my T500 and it helped but I wanted a little bit more off the line, so now I am going 40T. I had to buy a chain with more links for this, so keep that in mind when you're making changes. Last thought I have, be aware that as you get quicker off the line, your going to lose some top speed. This was not a huge issue for me because I rarely run my T500 over about 65mph anyway and very little at that speed. I'm sorta a back road 40ish mph kinda guy. Good luck. LexPaul

[jabcb]

Per a Cycle World review of the T250R, “strong power is available from the six-ported cylinders beginning at just under 4000 rpm and continuing right up to almost 8000 rpm.”
Max speed in gears is:
71.4 @ 8k rpm in 4th
82.5 @ 8k rpm in 5th
90.3 @ 8k rpm in 6th

That works out to 49 mph @ 5.5k rpm in 4th

You have 55 mph @ 5.5k rpm in 4th.
Some of the difference could be gauge error. (Results with these 40 year old gauges does vary.)
Some could be because a PO changed the gearing to reduce vibration.

As LexPaul said, check with a parts manual to see what gearing options were available.
Also check you current sprockets to see where you are starting from.

If you don’t have a printed parts manual, check out the local Suzuki dealership websites.
Some have online parts manuals going back to the late 60s.

[Tripleking]

Lex, it is getting time I replaced the old chain anyway. What I want is to get into the power band more quicky and make it easier to move when outside the power band.

Jabcb, my Speedo is quite accurate surprisingly. I checked it with a GPS app that is dead on with my 2007 Dodge Dakota Speedo and the T250 clock is also dead on. The engine is out of a 73 GT250. DK if the previous owner used the GT250 or T250 front gear. Not even sure if there were any sprocket or gearbox ratio differences between the two. I did do a crank up rebuild on the engine with a 1mm oversize bore, but the gear box is stock.