My new 1978 SR500

[5twins]

I had an SR for many years. It was my "around town" local bike, that is, until I got my 1st 650. In the end, the SR was just a little too small and under-powered for me (about 6', 200 lbs.). The 650, with about 15 more HP and weighing about 50 lbs more, is just perfect. It rides better because of the increased weight, and has adequate power.

Don't get me wrong, the SR500 was a very nice bike, just a little too small and under-powered for me. They are an enthusiast's bike in my eyes, and have become quite collectable. I was able to sell mine for like 4 times what I paid for it, lol.

Joe Minton also did an article on these, worth the read if you can find it.

 

[Jim]

Joe Minton also did an article on these, worth the read if you can find it.

Here ya go.

 

[atom4488]

Here ya go.

Thanks Jim! An interesting read, of course. I suspect there is lots of tuning data out there as these bikes seem to have a strong motorsports

I had an SR for many years. It was my "around town" local bike, that is, until I got my 1st 650. In the end, the SR was just a little too small and under-powered for me (about 6', 200 lbs.). The 650, with about 15 more HP and weighing about 50 lbs more, is just perfect. It rides better because of the increased weight, and has adequate power.

View attachment 335562

Don't get me wrong, the SR500 was a very nice bike, just a little too small and under-powered for me. They are an enthusiast's bike in my eyes, and have become quite collectable. I was able to sell mine for like 4 times what I paid for it, lol.

Joe Minton also did an article on these, worth the read if you can find it.

That does not mode well... if you rejected the SR as underpowered and too small, then its going to be worse for me as I'm taller by 3" and a bunch heavier too! I find the seat height on the XS too low, in relation to the peg height. My XT on the other hand is a better fit could be taller still. I need to see these bikes and make a judgement call from there.

 

[5twins]

Yes, in stock form, I think they only put out about 30HP. Mine, with a Supertrapp exhaust and K&N airbox filter, maybe was about 35HP. I had the later carb fitted, as Minton recommended, and re-jetted as he instructed. But I think my big issue was gearing it too high. I shouldn't have done that, lol. I've learned from the 650 that a very small change is all that's necessary. I went one tooth up on the front sprocket where I should have gone a couple down on the rear instead. It would still be geared up, just not as much.

 

[jaybar6]

Yes, in stock form, I think they only put out about 30HP. Mine, with a Supertrapp exhaust and K&N airbox filter, maybe was about 35HP. I had the later carb fitted, as Minton recommended, and re-jetted as he instructed. But I think my big issue was gearing it too high. I shouldn't have done that, lol. I've learned from the 650 that a very small change is all that's necessary. I went one tooth up on the front sprocket where I should have gone a couple down on the rear instead. It would still be geared up, just not as much.

This reminds me of this video, with these two raconteurs. Where their hands stopped working with tingling:

 

[Vincenthdfan]

My 1978 TT500 High School do it all bike was a beast back in the day (same motor as the SR500).

I put a Wiseco 10:5 to 1 high compression piston in, White Brothers cam, stiffer valve springs, bigger Mikuni carb and Pro-Tec pipe with Supertrapp on it.

I moto-crossed it on Sundays, flat tracked it on Saturday nights, competition hill climbed it too....man that bike was a ripper!!

 

[5twins]

Yes, there's lots of hop-up parts available. I guess it all depends on how much you're willing to spend, lol. Mine was basically stock with just minor mods on a stock motor. No big bore stuff or bigger carb, just the upgraded oil line for the topend and the basic "pipe and pod" mod (except I had the airbox filter).

 

[Raymond]

My 1978 TT500 High School do it all bike was a beast back in the day (same motor as the SR500).

I put a Wiseco 10:5 to 1 high compression piston in, White Brothers cam, stiffer valve springs, bigger Mikuni carb and Pro-Tec pipe with Supertrapp on it.

I moto-crossed it on Sundays, flat tracked it on Saturday nights, competition hill climbed it too....man that bike was a ripper!!

Mine had similar tuning job. 10.7 to 1 hi-comp piston, can't recall the make, Kenny Harman drag-race cam, radical with huge lift and the exhaust valve open for 420°, strong valve springs, etcetera.

So it was a light, skinny, easy-steering bike which also went pretty well. But long-term the high state of tune gave reliability problems . . .

 

[atom4488]

Mine had similar tuning job. 10.7 to 1 hi-comp piston, can't recall the make, Kenny Harman drag-race cam, radical with huge lift and the exhaust valve open for 420°, strong valve springs, etcetera.

So it was a light, skinny, easy-steering bike which also went pretty well. But long-term the high state of tune gave reliability problems . . .

Love what I am hearing here about tuning these bikes... that's kinda my vision for a build; moderate engine tuning, upgraded suspension, brakes, wheels and tires in an otherwise "restomod" package. There are some exemplary builds out there on the web to draw inspiration from.