1974 Alsport Trisport RTS 340 SL Restore / Rebuild thread

Rebuild the walbro or get a different carb

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Ok so I have decided to finally create my own thread instead of hijacking the few trisport threads going now.

So to kick things off I want to say that I'm not going to restore this as an original trike, the parts are just way to few and far between to even think about going all original, not to mention how much they cost :blink:

I'm trying to upload more pics but I've run out of room in my picture manager daelio so if anyone knows what I'm suppose to be doing here to upload more pics that info would be awesome:D

So here is the trike in all its glory, or leaves, however you would prefer it. As you can or cant see its extremely neglected and rusty.

Once I got the trike home I realized its much more rusty and missing much more then I originally thought. A little bit of buyers remorse was setting in as well haha. Either way this was my findings:

Front wheel assembly including axle was trashed and seized with rust
-One of the rear disc brake assemblies was missing
-One of the two header exhuast pipes were missing
-Both exhaust expansion chambers are missing
-Both of the heim joints for the wheel stabilizers need replacing. Below the worst one is pictured as it actually broke loading it from all the years of rust penetration.
-Missing U joint and U joint cup from one side. I've found the correct parts at tractor supply and am patiently waiting for them to come in :D

The engine looks to be in good shape but for the time being will not turn over ( I haven't spent any time trying to free this up but I have taken a few minutes each day to spray lubricant in the cylinders and through the carb in hopes that helps ) I also pictured the engine tag and it is an original 340 kohler so that was a nice suprise.






I have started the rust removal process via my handy wire wheel attachment and surpisingly that is going very very well. I'm going to tackly most of the rust with the grinder and wire wheel and then roll the trike to my neihboors for a quick visit with his media blaster to get the really tough spots ironed out.

If there are any OldMiniBikes tripsort experts out there I am trying to figure out a few things:

Jackshaft bearings ( size dimension type and availability )
Axle bearings ( Same as ^^^^ )

Front axle and wheel assembly. Thinking that an 5/8" standard mini bike 10" axle might do the trick with some home made spacers. I really would like to use a dirtbike wheel with a disc brake but they all use metric axles that are much to narrow for use with the trisport.

I have decided to scrap the one rear disc brake caliper that I do have because it looks really rough and a new oem caliper costs around 170 bucks :censure:
I did see a few aftermarket options but of course suggestions are always accepted :D

My immediate plan is to get all the bearings replaced and get the trike rolling again. Once I get the trike rolling and mechanically sound I am going to finish the chassis off by taking everything back off I just put on ( lol ) and coating the whole trike with POR15.

Once the chassis is done I'll turn my attention to the kohler and replacing all the original wiring and accents like turn signals and brake lights etc etc etc.

Guys please continue to follow this thread as I try and resurrect the beast and advise me on all the ignorant decisions I'll surely be making.

Well I'm no expert,but I've been down this road with my Tri Sports. I have 2 - TS 150's and a TS 130 completed and getting ready to do another. And one thing I've learned most parts are available...you just have to dig ! Several/many/a lot are just plain Jane parts you can locate at Industrial supply shops,bearing companies,go kart shop,TSC ect. Ect. So don't worry too much.
Next there are people and places that carry specific Alsport parts. Try Rt21 trading and another is Mark Saxon of vintage trike group. He manufactures all the body parts and carries several odd ball items too. Well for SL's .
The other advice I can offer is HOARD parts when you find them !! I have. I've bought parts 2 years ago that I didn't need and just used them this week end. It'll all come together and we're all here to help.:thumbsup:
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Well I was a Tri-Sport dealer back in the day. I have had many of the different models through out the last 45 years. For parts I have a friend that you might want to contact his name is Robert Grace and he lives in West Miffen, PA I will send you his phone number in a private message. Robert knows every thing about the Tri-Sports.



Well-Known Member
Mini bike bearings 5/8 I.D. and 1 3/8 O.D. can be swap out with with 12mm 15mm I.D.'s and 35mm O.D. Perfect match between mini cycles and modern "pit bike" . So what im saying is you can use 10" metric disk wheel and slap some 5/8's I.D. 1 3/8 O.D. in there and perfect match! :thumbsup:
I good working front brake is very nice to have as the Tri-Sport 2 shoe brake was not very effective with that heavy of a machine much less a rider like me that out weighs the trike LOL. I needed new tires that were DOT approved for my Street legal so I bought new 10 inch wheels with a street tire. I had lots of issues with the Borg Warner brakes and with the higher speeds and gearing I ended up going to 10 inch diameter disc and used Draglite II dual piston calipers. and they worked great. But I got stupid and sold the machine something I do regret.

Well my real problem for the front wheel is that I need it all. But I see what your saying. I can use a minibike axle with a pitbike 10" disc brake wheel without any issues. ?? I think that's what your getting at anyways lol.

Steve how much did those wilwood brakes run you and how did you mount them to the existing mounting pad?
To tell the truth I don't remember but I had a lot more money back then or at least I thought I did LOL I would take a look a some of the Go Kart brakes like Martin sells they have some with floating mounts that make it easy. WJustice did a good job on his trike by using the Kelsey Hayes mounts and they are a good brake. I still have a NOS Kelsey Hayes handle bar mounted master cylinder for sale.

If I could provide people a free ride on a good running Tri-Sport during their project they would see new light as they are such a fun ride.
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Well a member on here has struck a deal with me on 4 nos shocks as well as a good running Rockwell 340 complete with clutch and a few seat pads and head rest.

With any luck the Rockwell will slide right in and run like a top :)

Still have to straighten out the rear brakes....u joint...heim joints...and front wheel and brake setup...

Oh and do the old ignitions from these require a custom cut key or will any Trisport key work? Mine didn't come with the key....naturally lol.
Could one of you experienced alsport rts guys give me a link to the bearings I would need to buy for the jackshaft and the axle bearings for the trisport. I've found plenty of decently priced bearings on the OldMiniBikes warehouse here but unsure of what I exactly need.
I want to go ahead and get the bearings ordered so when I start pulling parts I can replace them once the frame is coated.
I also saw that they have a 1/2" bore 40 chain idler sprocket on here ( I'm assuming that correct )??

Thanks guys.


Well-Known Member
Bearing are standard. J/S are 3/4 insect bearing like used in a pillow block. Axles are 1 x 2. I used ones with an external snap ring for placement. 53" will be too short. Get the 90" one. You have to go forward to the steeribg head then back under the seat and over the engine. 40 chain is correct but the used 3/4 j/s. I used mcp brake parts but they are NOT cheap. Good stuff but pricy. I just got some to redo my TS with. I custom made my brake mounts but styled them after the stock type.
wjustice not to be a pain but I'm a bearing idiot. For some reason I've never either taken the time or just really understood all the bearing types. Are the bearings your talking about available through OldMiniBikes warehouse? If they are it would be a huge life saver if you could link them so I know I'm getting the correct bearings.

I will look for a 90' cable and hopefully they have one. Seems that everything is marketed towards the mini bikes with the shorter cables.

Thanks again I really appreciate all the help.
Was re reading your post and not sure i'm getting everything you were trying to say lol. Were you asking about an axle size in there somewhere? I know the axles are 1" and i believe the jackshaft is 3/4" . I can check both tonight if thats what you were asking.

Thanks for your patience lol.