Tomos A35?

T. Clark /
Mar 27, 2001 07:41AM

Hi folks,

I have a question maybe some of you can answer. I have a 1999 Tomos Targa (step through model). My owner's manual says that the engine is an A35. Now I keep seeing postings comparing the A3 and the A5. I've also read somewhere that there is no such thing as an A35 engine (it's either an A3 or A5). What gives? Do I have an A3 or an A5 engine? I don't seem to have any problem with acceleration and the top speed is 30 to 35 miles per hour. I love this bike and can't wait till old man winter goes away(I'm in Canada).

Thanx for the help!

TC

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Re: Tomos A35?

mike /
Mar 27, 2001 05:16PM

its an a5 engine. somone at tomos fucked up.or maybe we did oh well who cares. a35 a5 same thing

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Re: Tomos A35?

Reeperette /
Mar 27, 2001 07:23PM

OK, here goes....

Tomos makes two engines, but was considering making three - this is as near as I can tell, from what is known.

You have the A3 - the older "Bullet" Engine used on the Bullet, Golden Bullet, and Silver Bullet series, it has a hexagonal cylinder, a larger piston, shorter stroke, and the transmission is slightly different - and it produces significantly more power than the A5, for all the A5's hype.

You have the A5 - the newer "Targa" Engine used on the Sprint and the Targa models, it has a square cylinder, a smaller piston, longer stroke, and a smaller transmission of different type - and it produces, for whatever reason, less power than the engine it was supposed to be an "Upgrade" from.

Now, as fer the mysterious "A35" - Apparently Tomos was considering mounting the A3 engine to the A5 transmission, but later decided not to, and went with the full A5 system, but not in time to change the manuals or stickers that went on the mopeds....an "A35" would be the hexagonal cylinder, with large piston and short-stroke, mounted on the A5 transmission assembly, and to my knowledge, none of those were ever, in fact produced.

If you are actually getting 30-35mph out of the A5 (many salesfloor smartasses bend the speedo needle to make em LOOK like they're doin much more than they are...) apparently you've got a good one, and any information that might explain why this is would be helpful - we have about three folks here with stock A5's that are doggin at about 28Mph, one of em in factory-mint condition.

Hope alla that helps some,

-Ree

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Re: Tomos A35?

moped warehouse of New Jersey /
Mar 27, 2001 08:20PM

Ok here is the low down on the A35 engine. It does not exist. When Tomos was revamping the A3 engine they were originally going to use the botttom end of the A3 but that idea was scrapped for the new A-5 engine design. The bore and the stroke of the A5 and the A3 are the same. The only differnce in the bore kits is that the piston on the A3 has a 10mm wristpin and the A-35 piston has a 12 mm wristpin. As for power output the The A5 has the A3 beat. In fact that is why the A5 comes with the restrictive "S" exhaust configuration. The A 3 is capable of higher reves as the running gear is of less mass. And both transmissions are very durable conscidering. The biggest killer of these are the "?" shaped pawl spring used in the trans . It often breaks and with no tensoin on the sprag the trans bangs itself apart. Often times deamaging the outer race of the sprag clutch. (improovement here on the A5 as the outter race is removable and replacable.). Also the earlier A5 had a short intake manifold where as the newer ones have a substantially longer one for ease of carburetor service . Both have different effect throughout the RPM range. Don't get me wrong I like the A3 ; in fact it is my choice for a hoped up tomos but you do want to replace that "?" shaped spring with one from an A5 as it is a heavier guage.

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Re: Tomos A35?

T. Clark /
Mar 27, 2001 08:45PM

Hi folks,

Well let me get this straight. I don't have an "A35" I have an A5?

As far as the speedo being accurate, I've never actually checked if it was.

I guess the only way to check that is to have someone drive along beside me in a car and tell me what their speedo reads compared to mine on the Tomos.

As far as the acceleration, you see I've never been on any other moped other than the Tomos I own so I can't really compare it to anything else.

Well it looks like I'm gonna have to do some tests. I'll let you know what I come up with.

Thanx for the help/advice.

TC

P.S. What do you guy's think of the 1978 Honda Express? I know of one for sale and I was just wonderin' if it's worth buying. Apparently it's in running condition.

thanx

TC

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Re: Tomos A35?

Reeperette /
Mar 28, 2001 01:11AM

>>The bore and the stroke of the A5 and the A3 are the same.<<

Then why does the A3 piston I have come nowhere even close to fitting the hole in the A5 cylinder ?, also, why don't the pistonarms match up when placed side by side ? it's real close, but there's difference, at least to my eyes.

Got both sets in the basement, laid out in pieces on some cloth...if they are supposed to be the same, there's some serious quality control issues here...

Think we can get the direct specs from TOMOS ?

-Ree

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Got the A5 Specs.

Reeperette /
Mar 28, 2001 01:21AM

TOMOS A5 ENGINE SPECS

Engine versions: 49/40/25 km/h

Additional equipment: pre-mix pump, catalyzed exhaust, pedals

Basic technical specifications (49 km/h version)

Engine: single cylinder, two stroke, air cooled

Bore x stroke: 38 x 43 mm

Piston displacement: 49 cc

Compression ratio: 9.1:1

Power output: 1.8 kW/5200 min-1

Torque: 3.7 Nm/4000 min-1

Carburetor: Dell'orto SHA 14-12 P w. reed valve

Gearbox: 2-speed automatic with two centrifugal clutches

Gearbox oil/quantity: ATF Dextron III/220 cc

Transmission ratios: Gear ratio 1 st speed (66/17) i = 3.8823

Gear ratio 2 nd speed (53/24) i = 2.2083

Gearbox ratio 1 st speed (3.88 72/11) i = 25.4117

Gearbox ratio 2 nd speed (2.20 72/11) i = 14.4545

Chain transmission ratio (24/26) i = 0.9230

Total transmission ratio 1 st speed (25.41 24/26) i = 23.4570

Total transmission ratio 2 nd speed (14.45 24/26) i = 13.3426

Ignition: electronic 12V/80W (12V/50W)

Spark plug: Bosch W 4A2/Champion L82/NGK HS

Spark plug gap: 0.5 mm

Mixture: gasoline and two stroke oil (2%)

Consumption: 1.8 l/100 km

Starting: kick starter

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Where the Difference is.

Reeperette /
Mar 28, 2001 01:28AM

Ah, there we are...apparently the A3's I have been using have been, according to TOMOS, "Oversize"...the A3 Pistons I got are 38.50mm and shorter than the one that came out of the A5....no reliable data on the pistonarm, tho.

Thanx to Moped Junkyard for the picture attachment here, which does show some differences...but apparently there are indeed supposed to be the same bore.

And these specs conflict with the ones in the Manual presented with the 'ped, too...in which case (if these are right) more work needs be done....since one calls for a 0.28" Gap and the other for 0.50", et cetera.

No logical reason this 'ped should be toppin out at a max of 28mph however, so we will see what can be done about it with the (hopefully) correct engine specs.

-Ree

PISTONS.jpg
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Re: Where the Difference is.

moped warehouse of New Jersey /
Mar 28, 2001 02:56AM

You have to take into account that the measurement you need is the stroke not the lengthe of the rod. All the more confusing when doing a visual comparrison because of the different upper connecting rod hole diameter. Also as far as the piston height differences you have to take into account that the piston on the A3 is a standard piston port design and the lenght of the intake skirt section has an affect on the port timing and volume. There are 4 A3 pistons available; one for the 1.5 hp and a shorter skirt piston for the 2 Hp model .. Both are available in the 38.5 oversize. The A35 engine being a piston port reed valve uses the 2 slots on the intake side of the piston skirt to regulate port timing and volume.

Chris

the Moped WareHouse

www.mopedwarehouse.com

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Re: Where the Difference is.

moped warehouse of New Jersey /
Mar 28, 2001 02:56AM

You have to take into account that the measurement you need is the stroke not the lengthe of the rod. All the more confusing when doing a visual comparrison because of the different upper connecting rod hole diameter. Also as far as the piston height differences you have to take into account that the piston on the A3 is a standard piston port design and the lenght of the intake skirt section has an affect on the port timing and volume. There are 4 A3 pistons available; one for the 1.5 hp and a shorter skirt piston for the 2 Hp model .. Both are available in the 38.5 oversize. The A35 engine being a piston port reed valve uses the 2 slots on the intake side of the piston skirt to regulate port timing and volume.

Chris

the Moped WareHouse

www.mopedwarehouse.com

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Re: Tomos A35?

moped warehouse of New Jersey /
Mar 28, 2001 03:07AM

I have all of the specs on both engines at the shop. I'll try and post them tomorrow.

Chris

www.mopedwarehouse.com

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Re: Tomos A35?

Reeperette /
Mar 28, 2001 03:02PM

Thanks a bunch Chris...right now that would help quite a bit, I think.

-Ree

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Re: Tomos A35?

twowheelers /
Mar 28, 2001 05:09PM

Tomos A35= A3 frame + A5 engine

Apparently somewhere somehow someone titled the engine of this moped an "A35", whereas it's actually an A5.

Tomos also produces A45 moped versions for the Scandinavian market, which are based on an A4 single seater frame and the same A5 engine (detuned to 1 kW alias 25 km/h).

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Re: Tomos A35?

moped warehouse of New Jersey /
Mar 29, 2001 02:33AM

I got all of the info. Scanner was not workign tonight though.(garbage). I'll send it in from the shop tomorrow.

Chris

the Moped Warehouse

www.mopedwarehouse.com

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