2 strove v 4 stroke , pro and cons

[Neill_k]

As title suggests Im wondering from experience some of use have had from riding both 2 stroke and 4 stroke bikes what use think the advantages and disadvantages of both are. is one more user friendly , cheaper to run etc etc.

Edited January 1, 2019 by Neill_k
Spelling mistakes

[Intotrials]

I find the four stroke's in general heavier.

I owned a 300 gas gas and a 4rt and depending on my mood would ride which ever I fancied that day. I ended up selling the 4rt. Don't get me wrong it was a lovely machine, well built extremely reliable and very smooth. But in competition especially when I got tired I found it more of an hand full compared to the gasser. I also was more confident firing up a big step on the 2 stroke compared to the 4 stroke. When things were going wrong I found the 4 stroke to be a bit more of a maul. 

This is just my personal experience, obviously the 4rt's are awesome machines in the right hands (Bou, Fuji...). I think it just comes down to personal preference. But I have seen many riders go back to a 2 stroke after riding a 4 stroke for many years. 

As far a advantages and disadvantages I can't really see much in it. Trials bikes these days are pretty much as good as each other (especially for the average rider) I would say the only slight advantage a 4 stroke has over the 2 stroke is that they tend to be better on the road & no need to pre mix the fuel, oh and the 4rt is a very well built machine. The 2 stroke advantages are, the engines are less complicated (less moving parts), they feel lighter and in my experience they are easier to recover if you lose grip. The 4rt would grip really well until it lost grip then it (for me at least) was difficult to recover.     

Edited January 1, 2019 by Intotrials

[konrad]

That's a bit like asking, "What's the best religion" isn't it?  I'll try to be objective.  I can't disagree with anything written above, but will add... I've always loved the challenge of tuning 2T engines, but can't get away from the fact they are very dirty (environmentally).  A 4T is going to get better fuel economy and emit far fewer unburned hydrocarbons than a 2T.

I'll also state up-front that the vast majority of my motorcycles have been built in the land of the rising sun and I'm relatively new to trials (6 years).  The Japanese have an attention to detail second to none.  So, my acquaintance with the quality control (or lack thereof) of modern trials bikes came as quite a rude surprise.

When I think 4T trials, I only think HRC Montesa.  I have ridden two of them, one very old and one very new for about an hour each.  Neither instantly made me a better rider. (I also rode a 4T Sherco that was very difficult to start but probably had setup/maintenance issues.)

Some 4T pros: Really great service manual -- download one and see for yourself.  Auto-decompressor makes them easy to kick.  Can buy one from a Honda dealer.

Some 4T cons: Higher initial cost.  Heavy, but maybe not really objectionable until you have to drag one out of a ravine.  I've heard owners complain about expensive parts.

In the end, I'll stick with 2Ts until the Japanese produce a usable electric (are you listening Yamaha?).

P.S. I really wanted to love the 4RT.

Edited January 1, 2019 by konrad
Added P.S.

[mcman56]

I recently changed from a Beta 300 2T to a Beta 300 4T and really like the change.  It took me a while to get used to it but it takes me time to get used to any new bike.  My riding skills are probably average.  At my level it is still about doing things with throttle more than clutch.  The 4t is slightly heavier but I can't say that it affects anything.  The 4t has more engine braking but I can't say that it is a pro or a con.  Mine is a 2016 and I bought the oil pump upgrade that is said to reduce engine braking but after getting used to it, I think I actually like the engine braking so have not installed.        

Pros

1. It is very very quiet
2. The 4t has more off idle power in that initial blip.  This is good in coming right up to a large log. 
3. The 4t has less power at higher revs so you can be less precise with the throttle.  It feels kind of fluffy.  The 2t 300 produced a lot of power once wound up which could get away from you and was really no use to an average rider like me anyway.
4. The 4t power comes on softer, more like a push than a hit.  I find it less tiring to ride and it beats me up less so I am riding more.   I think everything happens a little slower so I'm also in better control 
5. The 4t is very easy to kick.  It takes a long slow kick with not much force.
6. It gets better traction and seems able to regain traction easier if you do start to slip.  
7. No mixing of oil or cleaning of oily exhausts.
8. It is hard to explain but it is more fun to ride, like a Reflex.  Maybe it is the quiet smooth power.

Cons

1. That strong power on the initial blip tends to push the front end when doing full lock turns.  To compensate, I changed my style to hold throttle steady and just use clutch in those situations.
2. Full lock turns do seem a little harder.  It could be a higher center of gravity due to the taller engine or maybe the geometry is a little different.   
3. The clutch is probably a little less progressive.
4. It only has 5 gears so feels like it is missing 6th.  For trials it is fine but if you want to do high speed road it could be a limitation.  The gears are nicely spaced, not like the old Shercos that seemed to be missing 4th gear. 
5. Occasionally, after being dropped or stalled in some odd manner, it can take a number of kicks to get it going.
6. It has 3 oil filters.  One is changed out and two are cleaned.  It is actually quite easy and quick to do.
7. The carb is much more difficult to get out.  Instead of a 5 or 10 minute jet change, it is probably more like a 45 minute or hour change....still not horrible.
8. Valve adjustments are a lot of work.  You come very close to pulling the engine to get it to rotate down and get access.  The recommended interval is 60 hours so it does not have to be done often.  

[nzralphy]

My Beta4T has a lot more character and is more fun to ride over the Beta 2T. For me it balances better and has a LOT more traction at all revs (and it constantly amazes my mates) I'll not go back to a 2T.

Canyou do your own maintenance? You need to factor in the valve adjustments $$ by a mechanic.

The 4T is quieter and is SUPER easy to start. You never need to rev n 'clean out' the engine like a 2T.

The 4T loves to rev - good for hills 

The first time you ride the 4Tyou will instantly feel and you'll notice approx 3kg heavier engine. After 1-2hrs you won't notice it as you adapt.

Edited January 2, 2019 by nzralphy