Ronkens Honda MT project

My name is Henrik and I live in a little town near Gothenburg in Sweden.
This bike started out as a day to day Honda MT5, restricted and boring to drive.
Well, things do happen in five years
This is the newest part of the project, with a new engine being built.





Info on the bike:
Honda MT5 from 1990
Stock rear shocks
Lowered front shocks
Homemade clip-on style steering handle
Tomaselli throttle grip
Derbi senda radiator
Reich waterpump


Setup 75cc engine:
Airsal 48mm EBS/EBE cylinder, slightly tuned
Honda MB5 enginecase, casereed konverterad
Honda CR80 reedvalve
Honda CR80 crankshaft (41,4mm stroke)
Koso PWK 32mm carb
Homemade intake manifold
Homemade exhaust pipe
6-speed CR80 gearbox
5-plate clutch
HPI 2005 universal ignition

Fuel: Ethanol E85 and Castrol R40 oil


UPDATE 10/08 07

A new engine is being born

A friend of mine had a Derbi Senda cylinder he didn't use.
After my cylinder broke down on my last engine he said that I should use his Derbi cylinder.
A couple of days later he came back with the cylinder and an empty MB5 engine casing I could use.
A lot of problems was to be solved, one of them the placement och the reedvalve.

Some days of work and the MB5 engine had become a casereed engine
Over to the cylinder porting!




UPDATE 28/10 07

Finally the cylinder porting was done.
I have to finish up the outside of the cylinder, don't look nice with all that welded material...

Sadly the nicasil plating isn't in its best shape, hope it will hold for a while though.
I also drilled up the studholes to accept M8 cylinder studs, like it better like that.






UPDATE 9/12 07

I have worked a little with the engine case now, but it is a lot of work left to be done






UPDATE 2/1 08

Have worked some more with the engine case, whats left now is final touch to the porting, make some threads and then the engine case is almost finished.

A friend lent me his Koso PWK 32 that I'm gonna try first.










UPDATE 11/1 08

The porting of the case is done and all threds are tapped.
I have also finished up the cylinders outside a bit and polished the combustion chamber and piston dome.










UPDATE 18/1 08

Sprayed the engine with black paint, it will go nice with the rest of the bike, when i decide to clean it
Made some adjustments to the reedvalve as well, hope it will flow a little better now.
Up next is making an intake manifold.







UPDATE 2/2 08

Made some further adjustments to the reedvalve and made an intake manifold.








UPDATE 23/2 08

Engine is bolted together complete with reedvalve and intake.
Have also made an exhaust flang.








UPDATE 2/3 08

Have made a front mounting piece for the engine to be mounted in the frame.
Have also got myself a waterpump and started to make the exhaust.
First exhaust that I oxy/acetylene weld so the wels are far from nice...








UPDATE 12/3 08

Have made a bit more on the exhaust and I am staring to learn the welding process, but it's a long way to go...
I have also got myself a water temperature meter and a friend gave me a new throttle grip.




One of the more successful welds






UPDATE 23/3 08

Exhaust and silencer is finished, have also got an old derbi senda radiator from a friend, that should work nice










UPDATE 4/4 08

The cooling system is done and the engine started, nice to see it alive
Though I have a problem with the clutch, it won't disengage fully som I have trouble shifting gears.
Looked it over without finding anything wrong, wierd...










UPDATE 12/4 08

Made the first testrun with the bike yesterday.
Was a bit worried for the cylinder but it seems to be fine.
Runs very rich at the moment, gonna tune the carb and ignition settings better some day.

Still having trouble with the clutch, wounder that the heck is wrong with it...

[ame="http://www.youtube.com/watch?v=oR0lTRv5Zmc"]YouTube - Ronkens Mt75 first testrun[/ame]


UPDATE 11/6 08

A couple of days ago i lowered the forks and shortened their stroke, as a result they got harder
I also rebuilt the front brake and got a shorter brakewire, 35 cm shorter, fits a litte better

I'm waiting for my new airsal 48mm cylinders to arrive, hope they arrive soon...




UPDATE 19/6 08

I got two new Airsal 48mm cylinders from my sponsor yesterday.
The cylinders dosn't have any nicasil, should be a little better to weld on i think.
Today i have planned the porting a bit, hope it will turn out good in the end

Cool conversion, that's what I call a tuning. Top work

Nice projekt--a lot of work.

Do you have made tests between E85 and normal ROZ 98 gasoline?

What´s the diffrence of the ignition setting and mainjet bore?

David (D.N.): Sorry, no performance measures between the two fuels.
I started running on E85 för about 3 years now cause I had huge temperature problems on my engine at that time with BF98.
I knew that the fuel would keep the engine cooler and it helped.
But I think around 5 % higher performance output would't be a too optimistic expectation.

The fuel burns slower so larger spark lead is required, how much, well, just try and see, but some 10 degrees more I think would do good on must engines.
More fuel is needed, around 40% more fuel, but also here you will need to tune every engine differenly.

One thing with alcohol is that tends do give you larger margins in you tuning.
On my last engine I had a "field" of about 5-8 degrees of sparkadvance before I noticed any performance drop when advancing the ignition further.
Think I had about 45 degrees sparklead at low rpm and around 15 att max-hp rpm.

But atleast on my engine I would need a steeper slope in the ignition curve after max-tourqe rpm, the fuel needs quite high sparklead on low rpm to perform good, but not that much more on high rpm.
This gives me too much sparklead at high rpm which causes the engine to drop off power shortly after max-hp rpm .
But I guess you tune scooters so that woun't make much difference then cause you probably don't rely that much on overrev...

These extra margins also applies the carburation, the engine is not that picky on mainjet sizes, it will run good on quite a lot of different sizes whereas on gasoline a couple of sizes larger and the engine is robbed of much power...

Nice project Henrik! Runs pretty good on the movieclips

great work on tuning, i like the custom pipe as well.....any other plans for it??

respect,good work,sound strong on videoclips,love the custom pipe......any plans or its for joyride?

Big B NRG:Thanks
Hope the cylinder don't break on me before I can get it tuned in

The bike is just a fun-to-ride bike.
Here in Sweden we haven't any regulated sprint races yet, just small meetings here and there
But it is mostly i a hobby bike, something to tune and ride now and then...

I have had plans for some time now to drive the engine on a nitro/methanol mixture, hope I can begin testing soon but first I got to tune it to run good...

what does the combustion chamber polishing do?does it improve performance?

atauskas said:

what does the combustion chamber polishing do?does it improve performance?

Click to expand...

Not much I think, I had some time to kill

But anyway, in theory, shiny surfaces won't attract or radiate as much energy (heat) as a "non shining surface".
It probably isn't even a measureable difference, but if I can keep just a tad more energy (heat) inside the combustion chamber instead of "leaking" out to the coolant liquid then I'm happy...
Think of it as a poor mans heat-shield, probably not very effective, but still...

Another thing is that it will not collect any soot or carbon deposits (for the short times I run it befor tearing it down again) but rather probably have an almost constant layer of oil, further more blocking heat transfer and keeping the heat inside the cylinder.

Good to see that i am not the only one adjusting and tuning an old Honda MT5! I think that you carburettor is just to much for this setup. An original Keihin 28mm from a CR85 will do the job good, and I think even better than the KOSO 32mm. If you keep this carb, fit a smaller fuel-jet, the fuel-mixture sounds too rich.

Your ignition seems to stand a little too early, what is the pre-ignition time now?

Although, I have much respect for your engine conversion to a casereed engine! I have chosen the "easy" way: a fully tuned LC NSR engine.

And why did you chose for an Airsal cylinder? They are not so good quality

Keep up the good work!!! :W

hkbisde said:

Good to see that i am not the only one adjusting and tuning an old Honda MT5! I think that you carburettor is just to much for this setup. An original Keihin 28mm from a CR85 will do the job good, and I think even better than the KOSO 32mm. If you keep this carb, fit a smaller fuel-jet, the fuel-mixture sounds too rich.

Your ignition seems to stand a little too early, what is the pre-ignition time now?

Although, I have much respect for your engine conversion to a casereed engine! I have chosen the "easy" way: a fully tuned LC NSR engine.

Keep up the good work!!! :W

Click to expand...

Yeah, we are a dying breed I guess, although in sweden there are a couple of guys who tune good ol' Hondas

I will try a Keihin 28mm PWK as well, to see which one is best suited for my engine.
But if I get the engine to run good on this carb I see no reson to change to a smaller.

And yep, it is running very rich now, as a safety precaution.
New engine, new carb and a fuel that demands quite much fuel, would be sad to start out lean the first thing I do...
So I took a 2,0mm yet, thought first about testing without any yet (2,4mm emulsion tube) and tried that as well with terrible result, wouldn't even reach the powerband
I'm gonna try a litte smaller yet tomorrow I hope, and then a litte smaller and a little smaller until it runs good, better safe than sorry

About the ignition setting I actually think the opposite.
The ignition is set as recomended to 3,5mm BTDC, on my last engine I had to advance the ignition fully on the stator with a 4mm BTDC base setting to get best performance.
Since the engine burns ethanol I will need a larger spark advance than engines burning gasoline, how much more depends, but a good 10-15 degrees more shouldn't be far from the mark.

So I will rejet the carb until the engine runs pretty smooth and then experimenting with the spark advance.
After that is done I can begine testing with tighter squish clearance, running on 1mm now...

Very nice bike, runs pretty good when is come into the powerband. You should try to set your neadle leaner. And keep this mainjet.

Tom.#86 said:

Very nice bike, runs pretty good when is come into the powerband. You should try to set your neadle leaner. And keep this mainjet.

Click to expand...

Well, that's the thing with alcohol, it can run pretty smooth/good even on quite rich mixtures, just be down on power...
That makes it a little trickier than gasoline to tune in, cause gasoline says stop quite fast when it is lean or rich, you have much larger margines before that happens on alcohol.

The downside is that lean mixtures is really dangerous on alcohol, dangerous on gasoline aswell, but maybe more dangerous on alcohol cause it is harder to notice, you have to be pretty far on the lean side before the engine bogs when opening the throttle wide open.
On gasoline that would happen pretty fast if you are on the lean side.

I've learned that after some seized pistons so nowadays i start out awfully rich, and going leaner untill i won't notice any difference in power.

The needle needs to be leaner aswell, that i am aware of, that too is set very rich for the same reason.


About the bike now, i am having a real trouble stopping an oil leak from, it seems like, the clutch cover.
I've noticed that all my gaskets have been torn partially apart at the place where it leaks.
Now i've tried a softer gasket material, hope that will do the trick, although i doubt it...

i love the sound of 2t engine...

I agree with satanasso, the sound is verry nice when you shift the gears
i hope u will add more video's soon..

Nice you liked the sound

More videos will come, when the bike is up and running again.
Some week ago i seized the piston which took away some nicasil.
It seized cause the bore got warped/distorted due to the heat expansion when I welded it.
I knew about the problem and knew that it would need reboring and plating to be good again, just wanted to see if and how well it performed in the state it was.

Anyhow, it occured when i dropped down yet another mainjet sizes, and probably just a tad too small cause i noticed a small power decrese.

Before this occured I had a larger jet (smaller than that on the video though), leaner needle setting and a couple of degrees more spark advance.
It ran really good then, sad that you wont know when you've got a good carb tune till you go slightly lean
But on the other hand, driving with a warped cylinder bore can't be good...

Now I am thinking about either a new cylinder or rebore and plate this to 50mm bore.
I think the o-ring would get too k reboring would be best, but then i've got to weld the o-ring seat and take up a new to a larger ring.close to the bore otherwise...

hoi

hey nice moped dude
And nice music
Hc4life

A little update, lowered forks.

kevintjeuh_nl: Thanks

nice mt5 !
i can't stop looking at the sound of your bike when you shift *D
absolutely amazing !
keep the updates comming i'm very curious !

Btw what song is that in your little clip ?