3aj,3tb,4pt
 

hello everyone

thanks to all for the knowledge accumulated here. i am trying to build an overlander from a 3aj, 3tb and a 4pt that i have collected over the last year. i am basing the bike around the 3aj. originally i was going to use the motor and wiring from the 4pt but it seems the gearbox in that is the worst of the lot.....
the best gearbox is the 3tb. so my question is: are the ignitions the same on a 3tb as a 3aj, hence influencing which bikes wiring i choose to use.....
my second question is: which set of carbs(or combination thereof) should i use with an arrow exhaust and 3aj airbox. there seems to be small differences between each pair which add to my confusion.....
my third question is: what is the best gearing compromise for off road and highway. i would like to be able to cruise at 70 and still be able to hoist the front in 1st and 2nd off the throttle.

thanks in advance and apologies if these questions have already been answered.

cheers

point75
ps trying to do all this as cheap as possible
pps will want to sell left over bits once bike is finished. email if you need anything

Hmmm...
I can't help with anything but the gearing question. In order to do 1st and 2nd gear power wheelies and cruise comfortably at 70 m.p.h. you'll need to buy yet antoher engine, maybe a really new, cutting edge one that has been designed in the last 20 years.
But seriously , 15/42 seems like a pretty good all around gearing on my u.s. model 1989 xt600. I think Klaus recommends 15/40 for 3ajs and earlier but I think that is due to reducing 5th gear wear? So it might not be needed to go this low on a later engine, due to stronger 5th gear. I would go with 15/42 if you are using a newer gearbox.
HTH,
Nate

thanks nate

what would the engine be spinning at in fifth at 70 with this combination.
i know a tenere is not going to be a fast bike off road. but then again i'm not a very quick rider.
my dr350 suzuki is quicker than i am off road, but i still enjoy the childish pursuit of wheelying over small obstacles

what is the smallest front sprocket that would fit (to be changed from a 15 when needed)?

also one of the bikes has a wiseco 636 kit fitted. would it be unwise to use this on an overland bike? has anyone any experience of this piston?

thanks

point75

Hi point75,
I have never heard of anyone doing a long trip or even alot of miles with the oversize piston. Could be good, but it seems most likely to be less reliable than the original. You could do compression tests and use whichever one has the best compression.
Front sprocket- I have heard elsewhere on this forum that it is bad to use anything smaller than a 14 tooth front, due to the angle that the chain is forced to bend at.
As I recall my xt is at a bit over 5,200 rpm at 70mph, and it does power wheelies well, but mainly in first gear.
Hope this helps,
Nate

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BLAME PATAGONIA

oops,
according to the post "tenere 34l tips" klaus says to go with 14/ 40 for old xts and 14/ 45 for newer ones. I would follow his advice, although your engine is going to be stressed at 70 m.p.h. with the first gearing.
Nate

thanks again nate,

i was thinking of doubling the base gasket to lower the compression a touch and use the wiseco. but this is me thinking on my own and i'm no mechanic. mainly worried about it stressing the crank and gears. will probably go with the 4pt piston, barrell and top as it has the least miles.

so what gearing do you have on your bike?

cheers
point75

I have 15/42 and am actually at a bit less than 5,000 rpm at 70 mph. So really if you went with 15/42 or so, you could just bring along a 14 tooth front sprocket for long off road sections.
Best of Luck,
Nate

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BLAME PATAGONIA

will do. any suggustions on brands. up untill now i have always bought DID chains which seem good.

nate, my plan is to be in the southwest USA, with my XT, this summer. do you have any recommended rides or know of any groups doing ride outs. i dont really have any firm destinations as yet, so it might be nice to string together some rides with people who know the land.
i plan to fly into florida and then head west. perhaps spending several weeks in your neck of the woods before heading south towards mexico and then central america.

do you have an equivalent of the trail riders fellowship?
what kind of restrictions are there on riding on government land and how do you know who owns what? what maps should i get?

cheers

point 75

point75,
D.I.D. x-ring gold chains are what chris scott reccomends, paired with o.e.m. sprockets. In my experience o.e.m. yamaha sprockets last about 15,000 miles on an xt600, without oiling the chain. Chains (though I've never used anything as expensive as the D.I.D.) tend to last around 5 to 10,000.
IMHO the area around Flagstaff has the best dual sport riding in the country, the options are almost endless and the terrain ranges from desert to alpine in just a few hours of trail riding. Riding off road in the national forest (government land) is generally not allowed, but there are many minor forest service roads that cross the national forest which are rarely maintained and perfect for dual sports and almost all of the national forest (except for a few small tourist areas) is free to ride through and camp in. Most of the land is owned by the government, alot of the rest is Indian reservations. It doesn't really matter too much who owns what, signs will be present if there is restricted access.
There are alot of trail riding groups out here, check out advrider.com look for south west regional forums.
When you are in Flagstaff we should go for a ride. Also if you have a chance you should head down to Copper Canyon, there is an almost all dirt route (again see advrider.com) from the border to Creel that sounds incredible.
Good Luck,
Nate

thanks nate,

i will check out advrider. it would be great to go for a ride. i will email when in us. i'm looking at maps at the moment and getting very excited.

cheers

point75

My bro Fish has 30,000k so far (UK to Goa, India on his rtw.) DID X ring, 15/45 JTS sprockets ( M&P ) and an oiler.

Should have said could do with changing now.New c/s £88 from M&P in the UK.