Apart from a sprocket change is their anything available engine wise (cam) that I can do to provide me with a little more low end torque?
I have a 1970 that I use around the homestead for odd jobs and would like a little more low end grunt.
Ron
Apart from a sprocket change is their anything available engine wise (cam) that I can do to provide me with a little more low end torque?
I have a 1970 that I use around the homestead for odd jobs and would like a little more low end grunt.
Ron
That would depend greatly on your budget and how far you wanna go.
There have been some pretty serious upgrades done on those over the years.
I was born and raised on Venus & I may be here a while.....
What are you trying to pull, I have always been pretty impressed with what the little 90s could do. Are your clutches maybe slipping? I never had one of the US 90s but don't they have a Hi-Lo gearbox?
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1985 250r
1985 200s
1984 200x
bandito x2
1979 atc70
Trikefest 2012,13,14,15
Other than changing the sprockets to a numerically higher gear ratio, the only way to obtain an appreciable increase in low end power is to increase the engines displacement with a big bore kit. Simply increasing the compression with a high compression piston will increase the low end power a little but if you increase it enough, you then need to run race fuel etc, and changing the cam to a "torque" cam (if one is even available) would only slightly increase low end power.
So, all I want is a little, more so for hills and such, it just seems like I can only pull in first gear in low range. So getting from one place to another takes a little time. Most times I am just dragging around a wagon and use it to haul wood, brush tools etc.
I’ve thought about clutch slippage, but it doesn’t feel like it as the engine just loads up and won’t move the trike. It runs great unloaded with just me on it. It’s timed correctly, carb rebuilt, new plug and air filter. Basically it’s tuned as well as it can be, starts first pull. Perhaps it just needs the too end done, I do get a puff of blue out of the exhaust once and a while. That said finding US90 pistons and clutch parts isn’t really easy. I see plenty of CT90 parts, do they interchange?
In your particular case, even if you have a significant amount of compression loss from worn rings etc, a new top end will still not increase low end power by an appreciable amount. You prey much need to either install a big bore kit or live with it the way it is....unless you add a nitrous bottle.
Sounds like a big bore kit is in order then. I see 54mm pistons available, but no cylinders is it safe to assume I can bore the standard cylinder to 54MM? What about exhaust and carb? Can I get by with a re-jet to get the most out of it or should I get a 110 carb? I would prefer not to change the exhaust as it took me forever to find the correct one.
Or maybe buy a 125m.
How about a pic of this 90 Ron?
Last edited by DAM shop; 03-11-2019 at 07:08 PM. Reason: Because I can
90 nickolson Bored and Stroked "The Good"
Big Bore 110 Pauter frame "The Bad"
90 Bored and Stroked “vey’s frame” "The Ugly"
110 JSC frame Bored and Stroked
flat track build. “Shop trike”
1974 original 90 X 2
1974 Original 70.
I was thinking if you put some rubber on the trailer wheels you may not require as much low end to pull it around.
90 nickolson Bored and Stroked "The Good"
Big Bore 110 Pauter frame "The Bad"
90 Bored and Stroked “vey’s frame” "The Ugly"
110 JSC frame Bored and Stroked
flat track build. “Shop trike”
1974 original 90 X 2
1974 Original 70.
It’s supposed to be Parrot green I assume. I didn’t paint it. It came to me that way. The rest of the joke went over my head.
Yes, rubber would be good, they roll just fine on the grass probably with less rolling resistance on the thin steel than with rubber. Glad I could provide you with some humor.
ATC’s aren’t super common around here and the ones that do pop up need some serious work. So if I am going to spend money might as well do it with what I have.
Ron
If you wanted to split the cases I have a stroker crank I would sell
90 nickolson Bored and Stroked "The Good"
Big Bore 110 Pauter frame "The Bad"
90 Bored and Stroked “vey’s frame” "The Ugly"
110 JSC frame Bored and Stroked
flat track build. “Shop trike”
1974 original 90 X 2
1974 Original 70.