[steevensi]

Hello Roflhat,

I just made an impulsive buy and I got a 1980 A100, which is pretty similar to yours. I really like it.
I see that you have worked a lot on it and I have a technical question you might be able to answer.

The muffler leaks and it needs to be repaired so it can pass inspection. It should be easy the remove, however I'm stuck. I removed the uper bolts and the 2 lower bolts. I also loosen the @[email protected] that hold the muffler and the front pipe together. I should be able to remove it but I just can't... it moves but I don't have enough space to get the braket out of the bolts and out of the front pipe at the same time. Is there a trick??? Do we have to remove the front pipe?

I would appreciate if you could let me know if you found a way to remove the muffler without removing the front pipe.

Cheers

 

[Roflhat]

Hi,

sorry not been on here in a while, I removed the muffler when changing the piston, I remember it was a bit of a mission but can't remember exact details on how I got it off.
Hope you get/got it off!

cheers

 

[Roflhat]

Back at home for a few days so I decided to have a go at the bike while I'm waiting for a rebuilt crankshaft for my outboard.
Wouldn't start so after going through the usual process, fuel, spark etc. It turned out to be a bad plug. Replaced it with a similar one I found in the shed while I ordered a new one. Started and ran absolutely beautifully, took it for a short ride and all is well.


Removed the oil tank - I'll just put oil in the fuel - and removed the battery. Also removed the mirrors and rear light, which I'll hopefully replace with a smaller one. I'll probably sell the mirrors + light unit if anyone is interested.

Couple other things done, out of the 4 bolts which hold the handlebars one of the holes had no thread, so I had to tap it to take an M10 bolt.

Still looking for a fuel tank! There's a couple on eBay but they must be from different years, not sure if they will fit but they're not identical.

 

[Rizingson]

Not trying to be a buzz killer, but you must run the injection pump on Suzuki 2 strokes (unlike many other manufactures models) or you'll lose the left crank bearing in short order. It's normal to run 40-1 pre-mix in the tank only long enough to insure that the pump is primed and working. Instructions for start up of a dry pump can be found in the shop manual.
Just hate to see your hard work go to waste.
Here's a schematic of the pump operation.

 

[Roflhat]

Ah ok, thanks for that. I'll have a go at that today

 

[Roflhat]

So today I got to the oil pump, had to take off the gear lever, side casing, chain, to get to it. Took it apart and it looked as new, drained all the old oil from it, made sure it wasn't seized and flushed it out with carb cleaner before bleeding the new oil through. I've re-installed the oil tank put fresh oil in it, fair bit of snow out today so no much testing, I've marked the oil level so I see if it drops. Still running premix in the meantime. Also fitted the new light, which I got for free. Made a bracket for it from an old alloy radar reflector mount. Not too pretty but it works!
Also cut a chunk from the rear mudguard, looks a wee bit less dorky now I think.
Before:


After:


Really rocking the rat look

 

[Roflhat]

Anyone know where I could get a seat like this? Or even better tips on making one? If I could harder foam and maybe use the material from the existing seat over it.

 

[Roflhat]

Ordered a new tank from eBay, £42.50, which brings the total so far to £194.35.
It's not identical, I think from a newer model but should fit.


Spent this morning modifying the seat. Took it off and marked 20mm all the way around, the borrowed an electric carving knife and set to it. Looked a bit rough after this so then tidied it up using a powerfile.


Overall probably just over 20mm taken off all around. Put the cover back on and used to rivets to hold it in place.
Here's before and after:


Hard to picture how it will look with the tank in place but hopefully alright

 

[Roflhat]

Does anyone know if there is a performance gain to be had from changing to a K & N style filter? The stock part looks quite restrictive. Also thinking about skimming the head

 

[Easy Rider]

Does anyone know if there is a performance gain to be had from changing to a K & N style filter?

In general, NO. Not without a complete rebuild to go along with it.
Without other changes to compensate for the decreased restriction, it is likely to run worse and not better.

A pretty good test is to run it for a bit with the air filter completely off.......not in dusty conditions of course.

 

[Roflhat]

In general, NO. Not without a complete rebuild to go along with it.
Without other changes to compensate for the decreased restriction, it is likely to run worse and not better.

A pretty good test is to run it for a bit with the air filter completely off.......not in dusty conditions of course.

OK, thanks.
I was thinking about taking a bit off the head for more compression and a K & N filter.

 

[Easy Rider]

I was thinking about taking a bit off the head for more compression

This is a 2-stroke, right ?
If so, I think you should be glad that it runs at all and not mess with it. :mrgreen:

Sorry, couldn't resist.

But.....if it was that simple to make the engine run a bit better......why do you think that wasn't done in it's original design ???

There likely was a good reason.
At the top of my guess list would be that there isn't enough clearance in the combustion chamber to do that without parts crashing into each other.

 

[Aussie Steve]

Skimming the head was an old trick to increase the compression and thus the power....very limited increases are usually achieved...it is usually necessary to experiment with the expansion chamber shape and length too.

Back in the day they used to do this... polishing a flowing the ports is also an option but it it best to remember the A100 was designed to be a reliable cheap form of transport that gave good fuel economy. There is nothing stopping you other than you have only one machine with limited spare parts availability and doing any or all of the aforementioned may end up ruining a bike that was designed for a specific purpose.

Good luck

 

[Roflhat]

I've done some 2 stroke tuning before, with 3-cyl tohatsu and yamaha outboards. Skimming the head raises the compression, the downside being you need to run higher octane fuel. As the Suzuki was designed to be sold worldwide in the 70's, I'd guess it would run on any old sludge. It was the same on the outboards, you can take 1mm from the head and get a noticeable gain in power.

I'd think a similar thing for the air filter, it's likely more restrictive but can operate in very dusty conditions, whereas if you're putting clean air into the engine you could increase the flow by chaning the filter. Bigger jets in the carb may be neccessary, more air = more fuel.

The biggest gains would be from a properly designed expansion chamber, but they're £££!

 

[Aussie Steve]

The bottom end will need to be in excellent condition too...also the main bearing seals...lose compression there and its a full stripdown...having said that two strokes are easy to work on.

 

[Roflhat]

The bottom end will need to be in excellent condition too...also the main bearing seals...lose compression there and its a full stripdown...having said that two strokes are easy to work on.

Yeh, I figure I'll give it a go. If I have to rebuild it that's fine by me

 

[Roflhat]

Had the bike out for a spin over the weekend, I've fitted an inline fuel filter and a new fuel tap. Bike started second kick after sitting for 5 months and first kick every time after that.

Thinking about changing the tires to slightly chunkier ones as most of the use is off road, anyone have any experience with this? There's not a lot of room for wider tread, even the thinnest offroad tires I've seen would be pretty close to hitting the frame. Was thinking a 100/100 would maybe fit on the back, and maybe even a push bike offroad tire on the front, 2.175" wide (standard is 2.50")

 

[Roflhat]

Bought a new tyre for the rear, its a 3.00x18 Duro bought from Oponeo. Took a while to fit it as the old inner tube kept bursting so eventually I replaced that too. Both the chain adjusters snapped during removal so I've had to improvise new ones.
Bike looks pretty smart with the new tyre on it

Also found that the banjo for one of the oil feeds in with the carb had completely shattered, was just a plastic job so I bought a brass replacement and fitted it. The oil in the oil tank is slowly going down which is good as it means oil is getting through. Might still run a bit of oil in the fuel just to be on the safe side, it runs fine with it anyway.

Replaced the spark plug too, engine wasn't starting so well. Back to running sweet now!

Might get another Duro tyre for the front yet

 

[Aussie Steve]

Just dont overdo it with the oil too much will foul the plug and cause rapid carbon build up. Having said that two stoke's being so easy to work on would mean a 'de-coke' wouldnt be too hard.

 

[Roflhat]

Yeh think it's definitely getting too much oil at the moment, lots of smoke! Going to use straight petrol in the tank now I'm satisfied it's getting oil.
Had some minor rubbing issues with the tire, only when going over very bumpy ground 2up, not really a problem.