New1978 atc90 is kinda doggy

[ctbale]

Got a box stock 78 atc90 that is totally original, even the guy I got it from was orig. Anyway, went thru it, advancer is good, valves, carb, points, timing chain, its all set. I have a few ct90s and when was riding this after going thru it, and before I put the compression gage on it, it was running like it had 60 or 80 psi, so I was surprised to see the 125 today. So I guess its how these stock 90s are? Is there anything simple I can do to get a little more pull? It struggles with 3H and forget 4H I weight 210. I think I read cl90 or sl90 cams will help? I have a few ct90 cams? Anyway, thanks,

Chuck
Anchorage Alaska

PS, I have the tire pressure pretty low so that might be most of it. And that stock snorkle seemed kinda restrictive, pulled it, no change.

[Vealmonkey]

I didn't see you mention anything about checking wheel bearings, rear brake, chain tension or condition or making sure the clutch was properly adjusted. If you have done all these things and you are still looking for more power, you have to figure out how much you want to spend. If you are on a budget, then the first thing I would look into is an atc110 carb and intake and a better breathing filter and a better exhaust. A new DG exhaust is probably your best bet. It will be louder than stock, but not real bad. Stay away from the cobra exhaust. I'm not sure about the jardine exhausts. A sl90 or cl90 cam is a good swap as well. The original performance cams were sl90 and cl90 cams and then companies started making true performance cams. You can always change rear sprockets for a small increase in power. These are about the simplest ideas. After these, you are talking larger bore pistons, stroker cranks, machining the engine cases and all sorts of other things. Unless you are looking to start doing alot of work and spending alot more money, you would possibly be better off with a larger displacement trike, like an atc185s. Best of luck with whatever you decide to do and keep us posted. Don't forget to get a few pictures on here as well.

[ezmoney1979]

Good point Vealmonkey. After I rebuilt my rear brake, adjusted chain, and put the proper air in my tires, my US90 came to life- before that I thought there was something wrong (low comp).

[fabiodriven]

You've already answered part of it. Inflate the tires before you do anything. That will make a big difference. Checking out all the bearings and brakes and what not are very important as well.

[ctbale]

Dang, you guys are good! Yup, two days ago pulled the chain cover off and brake drum off and cleaned it all, lubed/adjusted the chain, and greased splines and brake pivot shaft. It looks like I was the first one in there since new. Bearings are good too. brakes are at 75% plus. Adjusted the clutch 2 or 3 times since I got it. Vealmonkey, you just reminded me I have a atc110 motor thats good, with carb. (from my old ct90 obsession period) I think its an early one though with points. Now I am thinking put that in there with the DG pipe. Damit! I think I am getting a new obsession! The bike is mostly used to walk the dog. Well he walks, my lazy ass rides. :p Any ideas on how to fix this crack? I was thinking a scarf patch from below, dont want to paint the fender right now, just stop it from cracking more. Thanks for everyones help, you guys sure know your 3 wheelers!!!!!!

[coolpool]

Nice 90 BTW. If you drill a small (1/16th) hole at the end of the crack that should stop it from further progress. It works for plastic; not at all familiar with fibreglass but I would try it.

[Vealmonkey]

Tires look a little overinflated now. LOL About the only way to fix fiberglass is to drill the ends of the crack with a small hole. Grind out the crack some and get to fiberglassing. You might want to use one of those heatlamps to help cure your fiberglass up there.

[ctbale]

been looking, where do I find a dg pipe? ebay and bikebadit none there

[Vealmonkey]

You should be able to buy direct from DG off of their website.

[Pafrig]

Was that on craigslist a little while ago listed as "20 miles south of anchorage"? it looks real nice for what the guy was asking!

[ctbale]

got it out in sutton back in july, there was one for $300 on CL sunday, maybe a 77? (was at work :mad: ) , was there for about 4 hrs. Oh, BTW, thanks coolpool, you have a nice collection there yourself. No luck on DG's website, will keep lookin.

[ctbale]

damit! I found the pipe on DGs web site, thats going to hurt the pocket book thats for sure!!

[Shorty]

damit! I found the pipe on DGs web site, thats going to hurt the pocket book thats for sure!!

Find a old school cheap pipe like a super trapp,bannisan,pk,etc

[Pafrig]

i sort of made a dg pipe... i took an aluminum baseball bat, chopped off the handle about 4 inches back from where the bat started to taper. then, i cut the end of the taperd half off and scooped out all the foam packing and stuff. next, I adapted the handle side of the tapered part to fit on a 1 inch-ish pipe that i made a custom header and whatnot out of. then, i thew the handle on the lathe and opened up hand part of it, so it was clear all the way through. then i cut a hole in the part that i cut off of the taperd part earlier that was the size of the handle's od, and welded it in so that the majority of the handle would be inside the taperd end when i slapped it all together. then, i welded the two parts together and threw it on. worked great on my 90, but restricted the flow too much on a 200. its kind of loud, but could problay be quieter if a bunch of holes were drilled in the handle part, or if the handle part were made out of schedule 10 or something haha.

[ctbale]

i sort of made a dg pipe... i took an aluminum baseball bat, chopped off the handle about 4 inches back from where the bat started to taper. then, i cut the end of the taperd half off and scooped out all the foam packing and stuff. next, I adapted the handle side of the tapered part to fit on a 1 inch-ish pipe that i made a custom header and whatnot out of. then, i thew the handle on the lathe and opened up hand part of it, so it was clear all the way through. then i cut a hole in the part that i cut off of the taperd part earlier that was the size of the handle's od, and welded it in so that the majority of the handle would be inside the taperd end when i slapped it all together. then, i welded the two parts together and threw it on. worked great on my 90, but restricted the flow too much on a 200. its kind of loud, but could problay be quieter if a bunch of holes were drilled in the handle part, or if the handle part were made out of schedule 10 or something haha.

damm, thats some serious tooling you did! I sure wish I got that $300 90 on sunday, it was kind of a beater, but good back up machine for parts, shoot just the tires ... you know how shipping up here is. That DG pipe cost $12 to ship ... but not here ... its $45 shipping!

[Pafrig]

yeah, it was nice.... but I just cant bring myself to spend over 200 bucks on something like a 90.. btw, If you ever need 90 parts, i got a handfull laying around.

[swifty]

nice 90 looks to have survived well, you have no top end power or low power because your tires are swelled up to almost double there original size!! put some new smaller tires on it they will realy wake it up its just too over geared with those huge balloonies especialy if your 210 lbs and a header pipe i like cobras myself there cheap and sound good kinda loud think like $119 bucks new or $50 used on ebay