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Hi everybody, I am new here and am desperate to get my bike going faster and would be grateful for any info on my bike. i have a 1974 Suzuki TS185 Sierra. Its an enduro it is geared to ride on trails up hills and what not. I only use it on the streets. Im not too concerned about keeping it original i have already painted it because the original paint job was rusted and looked horrible. So i have a few questions about the gearing do i need to change both the front and back sprockets and also do i have to shorten chain i would assume i have to get sprockets with less teeth so i would need to shorten my chain. Also is it necessary to change my tires to road tires instead of the knobby off road tires it has? i want to be able to cruise at 55 mph and at the most go 65 without having the rpm's being so high. right now i can barely cruise at 35. I am a newbie to this so please any info would be appreciated i hate having cars and trucks ride my ass! its just too dangerous i want to be able to ziip out of a bad situation when needed. anyways thanks for any help guys! -joey
 

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First, if you're only concerned about riding on the street and you want to make more street rideable, you can DECREASE the number of teeth on the rear sprocket. This will lower the RPM in top gear so the top speed will rise along with lower engine vibrations. However, the bike will not be as "quick" off the line.

A rule of thumb is that each tooth reduction will lower the RPM by about 500 RPM. Keep in mind this is a loose guideline and will be dependent upon the transmission gearing.

You could also INCREASE the front sprocket to lower the RPM but you might have clearance and/or chain binding problems.
My suggestion is to lower the rear sprocket one tooth at a time until you find what you are looking for.

Street tires instead of knobby tires will give you a smoother ride with better grip on cornering and stopping due to the higher patch contact.
 

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The easy way is to put on a larger front sprocket. I have a TC185 and have on order a 13 and 14 tooth (stock is 12 tooth) I calculate about 400 rpm reduction in rpm at 50mph for each. 5500 rpm at 50 mph at present so will see which one works the best. The tc185 has a dual range transmission so it will still work offroad. I ordered the sprocket from dennis kirk. Less then 10 bucks each.
 

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Well the sprockets came in and I had to machine the splines to fit my TC185. The 14 was too big, had to grind some clearance on the shift shaft. Tried the 14 and it would be good if used on long highway runs, 5th was like overdrive. The 13 worked out just right for short runs around the neighborhood. I had to make a 50 thou spacer to put behind the sprocket for chain clearance.
 

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Wondering if anyone knows about the 1974 suzuki 125 I'm really new to this bike scene how would I go about fixing a spark plug lead that has just snapped at the end are they easy to replace or can I join a new onto the end of the existing any info would really help
 
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