tomos engine questions a3 / a35

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tomos engine questions a3 / a35

Postby hotwheels » Wed Dec 31, 2003 5:18 pm

I have an 84 silver bullet, with an 13 engine. it has a biturbo, its jetted. Iv heard the a3 is one of the best engines tomos made, and it does run great. I like the heavy duty "real clutches" not cork like the a35, and the more solid connecting rod. The only drawback is id like to do a reed kit in a 70cc. Can an a35 engine be fitted with the a3's crank, connecting rod, and clutch assembly?
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re: tomos engine questions a3 / a35

Postby hotwheels » Wed Dec 31, 2003 5:27 pm

O ya another question If i stick with an a3 engine, id like to put a 15mm or 16mm dellorto carb. Does a piston ported engine need a special intake manifold? I am thinking of fabricating a manifold
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re: tomos engine questions a3 / a35

Postby Kenneth_Bailey » Wed Dec 31, 2003 5:42 pm

the only kit I was able to get on my a3 silver bullet was a non reedvalved athena kit with a piston with a 10mm wristpin. And it didn't work too well. I think the stroke was too different. There's not much you can do as far as kitting an a3. I think the best best is trying to change the bearing in the crank to a 12mm needle bearing and putting an airsal or parma kit for an a-35 on it.
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re: tomos engine questions a3 / a35

Postby hotwheels » Wed Dec 31, 2003 6:03 pm

an a35 kit can fit the a35 studs, if i change the crank and bearings?
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re: tomos engine questions a3 / a35

Postby Kenneth_Bailey » Wed Dec 31, 2003 7:53 pm

do they have different stud locations?
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re: tomos engine questions a3 / a35

Postby hotwheels » Thu Jan 01, 2004 9:56 am

Its good to know that the cylinder stud locations are the same. Im thinking od going with an airsal kit. I read an online manual , for the part you are describing its called a gudgeon pin or the beaing or bushing? Is the difference between the 10mm and 12mm bearings in the diameter or the width? Also how is the bushing inside the connecting rod? Om gonna try to get a picture. thanks
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Re: re: tomos engine questions a3 / a35

Postby andypooh » Thu Jan 01, 2004 5:16 pm

KC Trike wrote:A3 is 10mm
A3N is 12mm
A5(A35) is 12mm
A3SP = ??

Tomos is weird, eh ?
-T


yeah, youre not kidding T..... but just to mess things up even more, my A3N engine has a 10mm wristpin. but i see where youre coming from on the bushing..... it would prob be easy enough to push the old one out and get a machine shop to produce a brass bush to the correct outer dimensions but with a 12mm inner diameter. ormaybe just fit an A35 bush??
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re: tomos engine questions a3 / a35

Postby donp » Fri Jan 02, 2004 8:19 am

i'm not a machinist so to me it would make more sense to order the a35 bushing and install it. for the couple bucks it would cost to buy the a35 bushing versus the machine shop cost to make one (which they are not going to do cheaply due to setup time just for one 12mm bushing) or the time it would take to drill and ream one yourself. if your gonna do it yourself, why not just ream the 10mm bushing out? or is it a needle bearing? i havent pulled either of my 3 tomos engines apart just yet.
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re: tomos engine questions a3 / a35

Postby andypooh » Fri Jan 02, 2004 12:45 pm

DonP, its just a plain brass bush with bevelled edges. also has 2 small oil holes
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re: tomos engine questions a3 / a35

Postby hotwheels » Fri Jan 02, 2004 10:21 pm

Im gonna take the head off tomorrow when i get hom form work. What is the best way to get the bushing out of the rod?
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re: tomos engine questions a3 / a35

Postby Kenneth_Bailey » Sat Jan 03, 2004 12:16 am

i think you have to press or drill it out.
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