Wassell Engine

[chuck]

I recently picked up a Wassell Trials and it has the large radial head and cylinder that is on the MX bike. The engine is a 126/6B. What is the smaller cylinder and head that you see on most Wassells?

Thanks,

Chuck,


72 125 Six Days
74 250 Hare Scrambles
72 Wassel
74 125 Honda Elsinore
73 250 Honda Elsinore
74 175 Yamaha TY

[Dennis Jones]

Chuck, the 6B is the correct motor for your bike, they all came from England with them. When they got to Ohio the new style 6B motors were pulled out to use elsewhere and replaced with old iron barrel motors.

If you want it to be correct use the 6B. If you want to ride trials with it find a 5A motor to put in it.

Dennis Jones

[chuck]

Dennis,

Does the 5A refer to just the cylinder and head or is it the entire motor?

thanks,

Chuck,


72 125 Six Days
74 250 Hare Scrambles
72 Wassel
74 125 Honda Elsinore
73 250 Honda Elsinore
74 175 Yamaha TY

[Dennis Jones]

Chuck, The 5A  motor is a different bottom end. It is a 5 speed and the crank wheels on the crankshaft are larger diameter. These motors make better low end power than the pipey 6B. I think top ends can be interchanged but I have never tried it.

If you do change motors or top ends you will have to get a different header pipe or modify the one you have.

Dennis Jones

[chuck]

Dennis,

Thanks for the info. How difficult will it to be to ride trials with the 6B motor. I am a beginner at Trials. I've ridden two AHRMA trials events on the beginner line with a Yamaha TY175. Didn't find it too difficult. However, with the peaky 6B motor I can imagine it being more of a challenge.

Any ideas on where to pick up a 5A motor?

Thanks,

Chuck,


72 125 Six Days
74 250 Hare Scrambles
72 Wassel
74 125 Honda Elsinore
73 250 Honda Elsinore
74 175 Yamaha TY

[Dennis Jones]

The 6B is not to bad to ride. Get it tuned so it runs nice and crisp and get it geared good and low and it should work fine for you.

I rode one riding the 2 line for at least 3 seasons and won an AHRMA championship in 2001 on it. The biggest handicap I found would be a move where you would be coming off a tight turn and imediatly have to do a steep climb, it is just hard to get it to pick up. If I had 3' to get going I could climb almost anything.

The 5A will pull like a tractor down low and that just makes it easier to ride. I do kinda miss the hit sometimes though.

Dennis Jones

[Lew Mayer]

Try to get a 24MM Bing and retard the timing a little may help too.

Lew Mayer

[TGTech]

I'm never been an observed trials guy, but I have lots of experience with the Sachs engines, so I'd like to make some suggestions for the trials experience.

My choice for the engine type, would be the 5A engine because the crankshaft is a larger diameter, and that will provide more rotating mass on the crank compared to the 6B crank, which is smaller in diameter.

The aluminum cylinders on the 6B engines, were ported for more RPM, which lost some of the engine's bottom end. The cast iron cylinders had a better bottom end and if you added some compression to the head, that would help pull off the bottom end.

A 22mm carb would also help the bottom end, because the air speed through the carb, would help the bottom end of the performance as well.

Using the 6 speed transmission, would give you a little more gear opportunity, so that would be the way I'd go.  

Setting the ignition timing at about 3.2 mm will also help the bottom end as well, but if you put the compression up, you may have to move the timing back a little because of the heat that will be created with the combination of the timing and compression.

Dane

[Lew Mayer]

Actually, Dane, I back my timing up farther than that. I figured a 24mm Bing is hard enough to find. I don't think I've ever seen a 22mm but I'd like to.

Lew Mayer

[Dennis Jones]

A six speed 5A motor would be cool but in AHRMA trials you really only use 1st and 2nd gear. Some guys will not shift in a section for anything. How do 1st and 2nd gears compare between the two motors.

I remember one real muddy trials I tried to enter a section in 4th on the 6B bike to try to run up a muddy hill. I'm glad I didn't make it as the few that did crashed hard on the trip back down.

Dennis Jones

[chuck]

Thanks for the info. Since I have no aspirations of becoming Sammy Miller, I think I will try the 6B motor with the 24 Bing and your other recomendations.

Thanks,

Chuck,


72 125 Six Days
74 250 Hare Scrambles
72 Wassel
74 125 Honda Elsinore
73 250 Honda Elsinore
74 175 Yamaha TY

[brian kirby]

I know they were not mentioned but small Mikuni carbs in 22-24-26mm range are readily available. Since a trials bike is not all about top end HP and throttle response is critical one of those might be a better choice than a Bing.

Brian

'73 Berkshire

[john durrill]

Dennis,
5 speed  counter shaft gear's
1st 46 teeth
2nd 41
3rd 37
4th 33
5th 31
6 speed
1st 46
2nd 41
3rd 39
4th 36
5th 33
6th 31
Hope this helps
Of all the folks we have on the board Dane is probably the best source for info on a Sachs A/B 5/6 engine. I would take his advice to heart.
I had a 68 Sachs Cross country Iron barrel and rode it for half a year in the woods. Great power for slow going even though it was hoter cylinder than the stock military or enduro type cylinder. The first CMF Pentons we got in 72 were 6A engines
I rode the 100 / 125 ( motor size depended on what we were riding at the time . Just swapped top ends on the same engine ) 6A for 2 years and the wife rode it for one more year after that.
 Found every thing dead on Dane posted in my limited experience.
 A  6/A 125 with the stock military or enduro Iron cylinder and the right carb 22 or 24 mm would be the cats meow for trials for a Sachs engine. Only thing better suited would be a 152 kit on the above setup.
 A 100 cc Iron barrel and head and talk to Rick G about a 152 piston on the 6A bottom end would be a very good tool.
 That would get you the best bike possible without a lot of machine work i think.

John D.

[john durrill]

Brian,
 you know if you get an adapter made up to slip over the spigot , the Rat Pack guys could be a source for the small Mikunis. They came on the Ace 100's. Bet they would work out good for this.
 John D.

[brian kirby]

John, Mikunis are available new in 16, 18, 20, 22, and 26mm sizes in the small bodies. Bings make more HP, but the real strong point of the Mikuni is crisp throttle response which seems like the ideal setup for trials. AT-1 Yamahas came with 24mm Mikunis too and are plentiful and easy to find on eBay.

Brian

'73 Berkshire