Kawasaki GTO 125, Time to Time Small Repairs/Cleaning

[aximaxim]

from where in karachi?
bro kindly tell me the name place n cont # if u have

Courtesy Xulfiqar
MICRO FINE ELECTROPLATING B-16/A-9,Eastern Film Studio Compound Manghopir Road 37065220 Karachi

Courtesy capsat
few electroplating chrome shops are located at hiranand street off murad khan road opposite zooligical garden in Karachi, red is street am referring to, yellow goes to makki masjid & garden police hq. pink goes to nishtar road & at corner is (illegal) hydrant

Im hoping either of the facilities will be able to help...... if not check this thread out...... maybe it has some more facilities listed:
https://www.pakwheels.com/forums/bikes-3-wheelers/234775-hard-chrome-wheres-best-chrome-plating-facility-your-town

[Danish_Naseem]

there was one in eastern studio compound across from Pakistan Beverages (pepsi) in SITE, there were a few other small operations too near the old philips bulb factory near to the highway that goes to hub. The rechroming buildup of the front shock rods a long time ago cost me Rs 4500/- but they were honestly better than the yamaha factory finish. Reason to do that was - the rods available in spares (used parts) were worn out according to me - shock repair shops would claim them perfect and use thick gear oil in them.

thanx alot @xulfiqar bro

[Danish_Naseem]

Courtesy Xulfiqar
MICRO FINE ELECTROPLATING B-16/A-9,Eastern Film Studio Compound Manghopir Road 37065220 Karachi

Courtesy capsat
few electroplating chrome shops are located at hiranand street off murad khan road opposite zooligical garden in Karachi, red is street am referring to, yellow goes to makki masjid & garden police hq. pink goes to nishtar road & at corner is (illegal) hydrant

Im hoping either of the facilities will be able to help...... if not check this thread out...... maybe it has some more facilities listed:
https://www.pakwheels.com/forums/bikes-3-wheelers/234775-hard-chrome-wheres-best-chrome-plating-facility-your-town

Thanx alot @aximaxim bro fr the detail
cheers

[msabbasi]

the primary reason for such cylinder failure is a compound problem

1 the machine folks cold press the liner which leaves a lot of room for error (some use epoxy which is death spelled differently for two strokes)

2 the ports are completely messed up, their angles, timing, etc are completely thrown off as they just drill them and leave them alone - e.g. transfer ports on modern japanese 2 strokes are pointed backwards and shallow to enable the mixture to collide into each other at the opposite end of the exhaust port - this is then pulled by the exhaust port (scavenging) - the reason to create this loop is to ensure a full charge is able to be delivered in the cylinder and the exhaust expansion tuning along with the exhaust port timing will ram back this mixture causing the required supercharging we need or the boost port in some engine which is pointed a the cylinder vertical edge - they point it horizontally forwards which completely upsets the swirling effect during compression (I need not explain this to you as you know fluid dynamics far better than me)

That is exactly why I suggested Nadeem Sb to take a good cylinder barrel to the lath shop so that the ports could be machined in the exact shape and location in the new sleeve.

Nadeem Sb. says that the re-lined cylinder offers poor performance he did not say anything about a loose liner syndrome so I am guessing the fit is good but the ports are off.

[Xulfiqar]

That is exactly why I suggested Nadeem Sb to take a good cylinder barrel to the lath shop so that the ports could be machined in the exact shape and location in the new sleeve.

Nadeem Sb. says that the re-lined cylinder offers poor performance he did not say anything about a loose liner syndrome so I am guessing the fit is good but the ports are off.

That is a tall order itself

[msabbasi]

That is a tall order itself

Indeed. It would be nice to buy an original cylinder barrel but as you know the problem in Pakistan with older out of production bikes and cars is that it is near impossible to find parts for them. Unlike overseas where it is easy to find originals parts or near original reproduction items.

[basic]

Zero Performance means less power, more and irregular noise, less pickup.

Re sleeving was done in end 2003. So I don't remember correctly other irregularities .

and after re sleeving fail, got new one(Made in Japan), which is fitted at the moment, so your idea is good to take original with the bad one to machine a near match quality.

Because don't have proper knowledge, will take the operating temperature of the block in slow moving traffic.

Then will see at what temperature we should press the new sleeve.

will this be ok or should I do some other method.

I am not clear about your comment regarding "zero performance". Do you mean that when this barrel is fitted, the bike has poor acceleration? if that is the case then it is not a mater of metallurgy but more to do with workmanship of the place where this job was done. If the diameter is not correct (too big) or the ports in the walls of the sleeve are not correct, both will result in poor performance. If the ports are too high, as the piston travels down during the power stroke, the combustion gasses will exhaust before completely expanding against the piston. Also if the intake port is not in the right place, it is possible the correct amount of oil/air/fuel mixture is not entering into the combustion chamber therefore the engine is being starved of the explosive mixture.

If you were experiencing a loose cylinder/sleeve fit then you might have heard a knocking sound during cold start caused by the sleeve sliding up and down with the piston. However that is very rare so the subject of shrink fitting can be set aside.

If I were in your place, I'd give the bad cylinder + the piston you intend to use with this cylinder + a good original non-sleeved cylinder to a reputable machinist and get him to re-sleeve your bad cylinder. He will use the piston you give him to work out the final bore size of the new sleeve and use the non sleeved cylinder to work out the exact shape and location of the ports to be machined in the new sleeve.

[basic]

Yes, compound problem.

All your description, Ah! local machinist don't bother about it.

the primary reason for such cylinder failure is a compound problem

1 the machine folks cold press the liner which leaves a lot of room for error (some use epoxy which is death spelled differently for two strokes)

2 the ports are completely messed up, their angles, timing, etc are completely thrown off as they just drill them and leave them alone - e.g. transfer ports on modern japanese 2 strokes are pointed backwards and shallow to enable the mixture to collide into each other at the opposite end of the exhaust port - this is then pulled by the exhaust port (scavenging) - the reason to create this loop is to ensure a full charge is able to be delivered in the cylinder and the exhaust expansion tuning along with the exhaust port timing will ram back this mixture causing the required supercharging we need or the boost port in some engine which is pointed a the cylinder vertical edge - they point it horizontally forwards which completely upsets the swirling effect during compression (I need not explain this to you as you know fluid dynamics far better than me)

[msabbasi]

Zero Performance means less power, more and irregular noise, less pickup.

Re sleeving was done in end 2003. So I don't remember correctly other irregularities .

and after re sleeving fail, got new one(Made in Japan), which is fitted at the moment, so your idea is good to take original with the bad one to machine a near match quality.

Because don't have proper knowledge, will take the operating temperature of the block in slow moving traffic.

Then will see at what temperature we should press the new sleeve.

will this be ok or should I do some other method.

The text book method is to do a shrink fit. Dry ice (solid Carbon Dioxide) is usually used to cool the sleeve and dropped on the cylinder and allowed to warm up and get secured in place. Having said that, the "local"l method is to keep one or two thou interference and hammer the new sleeve into the cylinder. You will be very fortunate to find such a shop that will do a shrink fit for you. When I was working in the industry we used to use liquid Nitrogen for fitting our compressor sleeves.

[Xulfiqar]

I think an approx 180C oven bake and a nitrogen bathed sleeve will drop in without issue, it would be ideal to rough in the angle of the ports with a dremel tool before all this action.

Finish the ports after the sleeve is installed.

nadeem sb, The avenue of port finishing is addictive, it changes the driveability of the engine and you can even tune the engine to have a specific powerband by porting the engine correctly. Some minor refinish of the ports (remove factory slop) results in quite a lot of power increase.

[aximaxim]

The text book method is to do a shrink fit. Dry ice (solid Carbon Dioxide) is usually used to cool the sleeve and dropped on the cylinder and allowed to warm up and get secured in place. Having said that, the "local"l method is to keep one or two thou interference and hammer the new sleeve into the cylinder. You will be very fortunate to find such a shop that will do a shrink fit for you. When I was working in the industry we used to use liquid Nitrogen for fitting our compressor sleeves.

Reminds me of the Ferrari's two robots the Romeo and the Juliet
Romeo and Juliet assemble valves and guides through thermal interference. The valves are cooled in liquid nitrogen. The robots then insert the valve into the cylinder head. Finally, the valve and guide are dipped into cold water, generating a thermal shock that makes the two pieces indivisible. A match made in heaven.

Much like the real world Romeo does all the heavy lifting; he picks up two machined cylinder heads and, using compressed air, warms them up to 160 degrees centigrade. While hes doing that, little more than an arms length away, Juliet picks up what look like small aluminium rings and, one by one, dips them into liquid nitrogen to cool them to minus 100 degrees centigrade. She then stacks the supercooled rings on small poles, ready for insertion.
So when Romeo and Juliet finally come together, head and valve seat do likewise. When contact is made, the holes in the cylinder head contract and the valve seats expand. And forthwith the two are together forever, the aluminium forming a stronger, more accurate bond than you could ever hope to achieve by welding aluminium (which is notoriously difficult to do) or bonding it (which tends not to work too well with components that get so hot).

[Xulfiqar]

I think you missed one word - "SEAT"

the valve seats are installed as interference fit - the valve guides are phosphor bronze and the valves themselves are free floating in them.

[basic]

Today got oil pump from Lahore for Rs. 1400.

Shall replace within few days.

[basic]

Took temperature of cylinder after few kms in slow traffic, cylinder block 105 C and head area 90 C.

Discussing with tech people for re sleeving.

[Xulfiqar]

105C is very normal temperature, the reason two strokes are hotter on the barrel is the exhaust port

[abdul_basit007]

Sir...Sorry forget your name..
I am working on Kawasaki GTO 110 and GTO 100...
GTO 100 is ready to assemble with all new parts but dont have enough time.
Whereas GTO 110 was standing at my Khaloo's House for more than 10years.
I took it last week and cleaned its carburetor.
The bike is started but making issuse in idle....
Need to abt its spark plug i.e, Plug Size (21mm or 16mm?)
Also need to know the position of idle valve screw in carburetor?
Thanks!

[Xulfiqar]

Sir...Sorry forget your name..
I am working on Kawasaki GTO 110 and GTO 100...
GTO 100 is ready to assemble with all new parts but dont have enough time.
Whereas GTO 110 was standing at my Khaloo's House for more than 10years.
I took it last week and cleaned its carburetor.
The bike is started but making issuse in idle....
Need to abt its spark plug i.e, Plug Size (21mm or 16mm?)
Also need to know the position of idle valve screw in carburetor?
Thanks!

the spark plug you need is B8ES, which has a 21mm hex fitting (bara waala or yamaha wala plug pana). the gap should be 0.8mm

the idle mix is very finicky to setup - make sure you have a 17.5 idle jet in the carby and its clean, also make sure its air emulsification passage is clean too. Get a carburettor cover gasket so you dont get air leaks. The idle mix screw is set to 1.5 or 2 turns at max and to test it your engine should "4 stroke" just above idle and then smooth out as it goes into mid rpm. It should pull cleanly from idle to mid range if you sweep it open.

[abdul_basit007]

the spark plug you need is B8ES, which has a 21mm hex fitting (bara waala or yamaha wala plug pana). the gap should be 0.8mm

the idle mix is very finicky to setup - make sure you have a 17.5 idle jet in the carby and its clean, also make sure its air emulsification passage is clean too. Get a carburettor cover gasket so you dont get air leaks. The idle mix screw is set to 1.5 or 2 turns at max and to test it your engine should "4 stroke" just above idle and then smooth out as it goes into mid rpm. It should pull cleanly from idle to mid range if you sweep it open.

Xulfi bhai thanks for the brief account on spark plug but didnt get yur idle related point....
I cleaned all the jets and check them by passing air through it....Carbi inlet venturi has a very minor port in bottom and its cleaned too and i though that it is the idle port.....
Where as if u see the carbi from the venturi side you see a flat small screw and on its left its has a port as well
Should i turn that screw 2 turns after tighten it up to max?

[basic]

After about six months

[basic]

More dissolved plastic