Two Two Stroke Questions

[ClareQuilty]

Well gentlemen I just bought another old two-stroke - a cute little Honda 'Smile', which is very soft riding and light, but has a lot of power. It seems in great shape, and the girl who sold it to me said 'I even changed that white stuff in here <pointing at the engine>, which was all burned up'. Anyone have any idea what she could have been talking about? Could it be that lubricating oil (not the two stroke oil) that one does seem to have even in two stroke motors? I wonder if it was in pretty bad shape to be 'white' and 'all burned up'.

Secondly, my old Honda Tena - which is still soldiering on well - has a 'catylizing system', and it is labeled 'Honda HECs'. Now, another Tena I have has none of that on it, and is about twice as powerful, responsive, and generally runs better. So I'm wondering if anyone is familiar with this 'catalizing system' from older Honda two-strokes? Is there a way I could have it removed, so that the bike could run better/stronger?

[Leckyman]

For the 1st point; Is this bike water cooled? If so, it sounds like the water pump seal has gone, so you are getting water in the gearbox oil (makes it white).

You'll need to get the seal replaced & flush the engine oil (gunk) out.

On the 2nd point; Never had a tena so don't know, sorry.

[H2oDunc]

I would hazard a guess that the guy means he gave the bike a de-coke. With two strokes you tend to get a build up on the cylinder head. Whitish in colour.

[BigBikeBKK]

Have you checked your turbo encabulator?

[ClareQuilty]

No need to be facetious, guys. Its just a catalytic converter, I guess located somewhere in the exhaust. And I'm just asking if I can take it off. (a Tena is just a standard little old time 2-stroke, about 105 or 110 CC, air cooled. The Smile has I believe the exact same engine.).

I think the question about catalytic converters is not specific to this model, but the answer would be the same for pretty much all bikes - either you can or cannot remove it.

[seedy]

No problem removing cats. On two strokes, always check jetting after any change in the air flow - intake or exhaust. A quick read from a new plug will tell you if you need to increase jet size or needle position to allow for mods which allow more free-breathing.

[ClareQuilty]

No problem removing cats. On two strokes, always check jetting after any change in the air flow - intake or exhaust. A quick read from a new plug will tell you if you need to increase jet size or needle position to allow for mods which allow more free-breathing.

Wow, thanks so much for your comment Seedy. Do you think that such carburetor modifications would be within the capability of the local bike mechanics? Although I love the bike, it is a 5,000 baht 105cc little thing hardly worth major expense (not to mention I'm a very broke mofo).

[seedy]

I am not familiar with your model of bike, but if the carb top removes - unscrews -, there should be a needle which fits into the carb slide, which is attached to the throttle cable.. Most have a number of grooves machined into the top of the needle. If your spark plug reading indicates that the engine is running lean - plug color should be a chocolate brown, not white or light tan - then remove the small circlip and place it in a lover groove. This will raise the needle, which will allow more fuel, which will richen the mixture. Easy to do - you can do this yourself. The needle takes care of throttle openings from 1/4 to 3/4 - the main jet takes care of full throttle. Is the carb a Mikuni ??

[VocalNeal]

Seedy,

I don't want to start a p###ing war but if you are not familiar with the bike how can you say removing the cat is either not a problem or possible. As with the NSR 150 SP it is part of the expansion chamber, cutting open the chamber and removing it may change the characteristics of the pipe.

Better if Clair was to purchase and install a pipe from an earlier? or not cat model.

[Kf6vci]

Re #1, I found many confuse something and use hot for cold or white for black. Black carbon deposits would be my guess. And I would stick with fully synthetic oil!! Hope she will run for years to come... Fancy an old Kawa GTO myself

Chris

[jbeck]

why try to maintain 3 similar bikes? It's also 3 times as expensive to do so.

I would sell all three and buy a decent honda dash if you like that style.

It also depends on how 'nice' you want them to look, run, I guess.

In my experience none of these bikes are taken care of and whatever you buy you'll need to change a lot of stuff if you want a 'nice' bike.

Most people, even mechanics, don't know what they're doing, e.g. a Honda mechanic at a dealer got brake fluid all over my brake pads when bleeding the brake system.

Now they need to be replaced at my time and expense..

You cannot remove the cat, but you may be able to buy an aftermarket pipe for about 3000 baht which will make a huge difference.

Most carbs do NOT have adjustable needles (even the NSR 150SP) you'll have to change the main jet, slow jet, and adjust the air screw which will be very difficult (impossible) to do properly (to get it jetted properly) if you haven't done it before. A mechanic will change the jets for you, but won't spend the time to keep test driving it and changing them and trying different ones until they're correct..

Good luck.

[jbeck]

I would hazard a guess that the guy means he gave the bike a de-coke. With two strokes you tend to get a build up on the cylinder head. Whitish in colour.

White would mean it's running way too lean. It should be a dark carbon build up. Top of the piston, too. Mostly on the exhaust side (front of the bike) of both.

[ClareQuilty]

why try to maintain 3 similar bikes? It's also 3 times as expensive to do so.

I would sell all three and buy a decent honda dash if you like that style.

Well, the reason is that those are the ones that have popped up for sale over the last few years - I've never seen a Dash for sale around here, much less a decent one. All these kinds of bikes seem to be very rare to find for sale nowadays.

You cannot remove the cat, but you may be able to buy an aftermarket pipe for about 3000 baht which will make a huge difference.

Most carbs do NOT have adjustable needles (even the NSR 150SP) you'll have to change the main jet, slow jet, and adjust the air screw which will be very difficult (impossible) to do properly (to get it jetted properly) if you haven't done it before. A mechanic will change the jets for you, but won't spend the time to keep test driving it and changing them and trying different ones until they're correct..

If I'm understanding correctly, getting the new (aftermarket) exhaust pipe would eliminate the catalytic converter, right? Regarding the carburetor issue, wouldn't it be possible to just replace the entire carburetor with one from a non-catalytic Tena (with the same engine)? I have no idea how much that would cost, but it seems to me then you would have the exact set-up of a non-catalytic Tena - no cat in the exhaust, and the 'correct' carburetor for that setup..

[FTB]

Jetting in Thailand is a little known art. A scant few know anything about it and how to do it properly. Secondly a variety of different size jets to do the tuning with are vey difficult to come by over here. i would never rely on the local scooter shop to tune my carb as i've seen such horriffic methods as drilling out the main jet with a manual drill etc. .

Best bet is to ride the thing as is and not go abouyt fettling with the bikes jetting unless you know what you are doing. i've been jetting my own bikes and i have a decent idea what to do but it takes an awful lot of time and patience to get it right.

An FYI as Jbeck stated if you have an NSR150SP and want to richen the non adjustable needle you can accomplish this by shimming up the needle with a small washer to gain a richer needle position.

As H20Duc stated the deposit removal could be carbon build up however i find preventative maintenance on bikes over here not done too often and would have a tough time believing a person that own one of these older two strokes is going to the trouble of de-coking the combustion chamber. Nice if she did though:) . If its a white build up though i would have expected the piston to melt a long time ago since as Jbeck stated it would be running too lean.

Water may have gotten into the motor oil which would of turned it a dirty white milkshake color.

Best of luck with your two smoke:) .

[VocalNeal]

....Best bet is to ride the thing as is and not go abouyt fettling with the bikes jetting unless you know what you are doing. ................ it takes an awful lot of time and patience to get it right.....

..and many people think that MotoGP switched from 250 two-stroke to 600 four-stroke for environmental reasons.

[dave_boo]

..and many people think that MotoGP switched from 250 two-stroke to 600 four-stroke for environmental reasons.

That and the fact that few of the lessons learned recently from the 250 2T class could be applied to production motorcycles....

[VocalNeal]

..and many people think that MotoGP switched from 250 two-stroke to 600 four-stroke for environmental reasons.

That and the fact that few of the lessons learned recently from the 250 2T class could be applied to production motorcycles....

I'm sure they can learn lots it's only the power plant that was 2T.

[dave_boo]

..and many people think that MotoGP switched from 250 two-stroke to 600 four-stroke for environmental reasons.

That and the fact that few of the lessons learned recently from the 250 2T class could be applied to production motorcycles....

I'm sure they can learn lots it's only the power plant that was 2T.

Forget part of my post?

[VocalNeal]

..and many people think that MotoGP switched from 250 two-stroke to 600 four-stroke for environmental reasons.

That and the fact that few of the lessons learned recently from the 250 2T class could be applied to production motorcycles....

I'm sure they can learn lots it's only the power plant that was 2T.

Forget part of my post?

No. did not forget. Moto2 bike are not "production" bikes I think you are confusing them with Superbikes or technically as they are 600cc with Supersport

[dave_boo]

Forget part of my post?

No. did not forget. Moto2 bike are not "production" bikes I think you are confusing them with Superbikes or technically as they are 600cc with Supersport

And that's my point. No manufacturer was learning anything that could be translated into their production bikes. Yes they are still learning about 2T, but for that size engine on production bikes there are few, if any, things that were being carried from the race track to the sales floor.

[VocalNeal]

Forget part of my post?

No. did not forget. Moto2 bike are not "production" bikes I think you are confusing them with Superbikes or technically as they are 600cc with Supersport

And that's my point. No manufacturer was learning anything that could be translated into their production bikes. Yes they are still learning about 2T, but for that size engine on production bikes there are few, if any, things that were being carried from the race track to the sales floor.

Well technically from Moto2 none of the big 4 manufacturers are learning anything except maybe Honda the engine suppler.

From a sales floor perspective it is the name on the side that gets people into the showroom, as you know. Which is what killed 250 GP as there were not that many different bikes.

I haven't been keeping up that much to see if lap times are going down now the class is 600cc. I suppose the next move will be to make 125 into 400 which will make the bikes heavier.

Interestingly 2T outboards are making a comeback in the 45hp and lower ranges. Not new ones but the used ones. There are quite a lot of old boats with small engines and it is impossible to replce them with 4T as the transom will not hold the weight and the power is down on the 2T mode.

Edited September 2, 2010 by VocalNeal

[jbeck]

Moto 2- a far cry from a Honda smile!

the last few posts COMPLETELY OFF TOPIC/Thread, why not start a new one - for the benefit of everyone interested in and subscrribed to the OP question.

Everyone (who sets it up) gets an email about a new post - but now they have nothing to do (or provide help) with the original post.

Annoying.

You sign up for one thing, you get something else - usually in the form of a debate/argument as well.

Moto 2 discussion/debate/argument does not belong here.

thanks

jbeck

[dave_boo]

Moto 2- a far cry from a Honda smile!

the last few posts COMPLETELY OFF TOPIC/Thread, why not start a new one - for the benefit of everyone interested in and subscrribed to the OP question.

Everyone (who sets it up) gets an email about a new post - but now they have nothing to do (or provide help) with the original post.

Annoying.

You sign up for one thing, you get something else - usually in the form of a debate/argument as well.

Moto 2 discussion/debate/argument does not belong here.

thanks

jbeck

I'm sure that your email contains this:

If you have configured in your control panel to receive immediate topic reply notifications, you may receive an

email for each reply made to this topic. Otherwise, only 1 email is sent per board visit for each subscribed topic.

This is to limit the amount of mail that is sent to your inbox.

Rather than complaining about the organic nature of a public place why do you not take steps to 'protect' your sanity?

[jbeck]

Moto 2- a far cry from a Honda smile!

the last few posts COMPLETELY OFF TOPIC/Thread, why not start a new one - for the benefit of everyone interested in and subscrribed to the OP question.

Everyone (who sets it up) gets an email about a new post - but now they have nothing to do (or provide help) with the original post.

Annoying.

You sign up for one thing, you get something else - usually in the form of a debate/argument as well.

Moto 2 discussion/debate/argument does not belong here.

thanks

jbeck

I'm sure that your email contains this:

If you have configured in your control panel to receive immediate topic reply notifications, you may receive an

email for each reply made to this topic. Otherwise, only 1 email is sent per board visit for each subscribed topic.

This is to limit the amount of mail that is sent to your inbox.

Rather than complaining about the organic nature of a public place why do you not take steps to 'protect' your sanity?

yeah, of course, i set it that way. I want to be notified when an new on-topic post is made. That's the point, right?

your way, I'd still have to read a bunch of off-topic posts.

i'm complaining about the misuse of the organic nature - a nature that allows the creation of new threads - it's so obvious....

Instead of telling me how to set my preferences, why not just stay on topic or start a new one, it's easy enough, and to your benefit, "leverages" the "organic" nature (i.e. forum paradigm) ?

the recent posts are SO FAR removed from the OP...

anyhow, thanks for the advice,

case closed

[VocalNeal]

Rather than complaining about the organic nature of a public place why do you not take steps to 'protect' your sanity?

What he said

As if the turbo encabulator had anything to do with the OP.

Jbeck,

Is your avatar and MC21 or an NC30/35? It is too small to tell. 'course it might not be a Honda at all.

Edited September 3, 2010 by VocalNeal