I bought an AJS 370 Stormer ('70's 2-stroke) from a guy who doesn't know it's background,been in a shed for over 30 years, and all I have for reference material so far is the owner's manual. It recommends a 20:1 premix of Castrol R40 , and has a warning about not mixing castor oil and mineral oil. Is there a way to tell if the bike has been running on castor oil, and if it has what are the problems associated with switching to mineral oil? Is a special cleaning of engine internals required if changing to a 2-stroke mineral oil?
Yes, if you don't know the maintenance history of the bike, nor how long it has sat still, good practice suggests replacing the mains and seals. While it's down that far, you would be cleaning every thing anyway, right?
When I was younger, and riding dirt MUCH more often, I had gotten to the point of knowing what ratio to run, dependant on the type of riding I was going to be doing; If plonking around in the woods, or difficult terrain, where I was not riding at WOT all the time, 3 oz. per gallon. If I was out in the wide open desert, with LOTS of country to travel accross, lots of WOT time, then 3.5 oz. to a gallon. This was with dino oils....
I have no experience with synthetics. You will need to speak with others who do, then you might get a fair close answer to ratios.... Often, the last I knew about ratios for 'modern' dirt bikes, the factory recommendation was 32:1, which is about 4 oz. a gallon? The old saw was "a little smoke is right", but with the EPA getting into their act, no smoke almost became mandatory.... I often see new 2-strokers making no smoke, and they live quite a long while! Myself, I want to see a little smoke, lets me know I have enough in the pre-mix! Brett P.S. A 410 Stormer is rarer yet....
Thanks for the replies guys. You're probably right about the bearings & seals;but everything seems tight, and I'm tempted to remove the carb & pipe to give the crankcase,cyl.,primary case & gearbox a good flush with kerosene (coal oil) and see what I've got before I tear it right down. Do you think this would remove the bean oil and allow running on mineral oil, or does that require the total teardown? I'm also wondering about the gas tank being safe w/ ethanol gas, can't tell if it's fiberglass or molded plastic of some sort, anyone know for sure? I don't want to put a lining in it if it isn't req'd. Tiger, it's the only Ayjay I've seen in Canada outside of a magazine, do you see them in Aus.?
There are a few Starmaker engined bikes in Western Canada in trials and scrambles. One chap in this area has been scrambling a stormer in vintage events and may still be and I hear of at least one rider on the mainland riding trials on one. Cheers, Wilf.
Koob. I have an original Stormer workshop manual. It includes 250, 370 and 410. My brother Gordo found it for me when I acquired a 1965 NOS never run Starmaker Trials engine with which I was going to put together a trials bike but have gone the C15 route and I'll now offer up the engine. I'll have to keep the w/s manual to go with the engine but, if you like, I'll photocopy the manual and mail it to you. Send me your mailing adress and I'll get it to you soon as I get out. I'm just recovering from some surgery and it may be a week. Cheers, Wilf.
I think Tiger is right. Two stroke engines rely on the main bearing seals and yours could be hard as rocks. This manual will help you get there. When I got this engine, there was at least one very good supply of parts in England. Cheers, Wilf