exactly, that's what i said in previous page.

I just highlighted that karizma's pin to top height is the same...

guys guys.........i hope we are confusing him too much.......

see as far as modding the engine ur peace will be in battle field.......until u have a reach of good info & helping hands..........

i have tried these sort of things & my happiness was lost totally......

hence the best thing is keep & maintain the bike or just sell it......

to maintain buy rite spare......for ur bike get the flame bore & piston kit which should fit very well.........

u cannot alter the stroke w/o touching the crank....DO NOT DO IT

True where sticking to stock spec., is possible, it is the best desicion to take.

Oversize Piston


Dear Nanotechnology
I was just looking for pistons having stroke 53.5 with oversize bore and here is what I found
A new bike launched by TVS in Indonesia TVS Tormax
Its bore x stroke is 59.5 x 53.5 which equals 148.7 cc(5 mm oversize than Victor GLX and exactly same height)
But is there any way that its pistons are made available.Because since it is a newly launched bike(few days back it is launched) I doubt that its pistons will not be available in indonesia also.
Hoping that TVS launches a 150 cc bike in India with bore x stroke same like tormax then I think that I can directly fit its block on my bike without doing any reboring.

You cannot guarantee that any bike which has the same stroke will have a block which will be a direct fit.

The bolts as well as the block geometry, the timing chain tensioner and groove, all of these should be a perfect match to think about the entire block swap.

On the other hand, (PSR please read this) if there's a bike which has a longer stroke, its more likely for it to have a shorter piston so that the piston doesn't hit its crank compared to the piston of a shorter stroke bike.

So to speak, i think if we fit a short stroke piston (like CBZ's) to a bike with a longer stroke, its more likely to hit the crank in that case, as the piston height might be more since its short stroke, its not needed to make shorter piston for those blocks.

Pankaj, i still suggest you to go for fiero's piston, its very very likely for it to fit perfectly, and it will be easily available too.

A OEM +1 size piston (or whatever its called) for a fiero will have a bore of 57.5mm, will give you a 3mm extra, hence it will be a decent increase in compression with minor head enlargement work (may or may not be needed), this is far better than a 59.5mm piston of a difficult to source Indonesian tvs.

you'll save a lot of money too, as you might not need to go for a new block.

Its not rocket science buddy, its easy and can be done by any lathe guy.

If your looking for awesome increase in power, only then go for 5mm or more, but then you'll need more head work to be done.

But i strongly suggest, go for Fiero's piston.

Reboring

Thanks NanoTechnology
I settled down for going after fiero's piston
But one question from where can I get Mahle's Piston.
For your bike which make of piston are you using Sam/Mahle?
because I met the best reborer in Pune(Bhamburda Mechanical works near Shivajinagar opp SSPMS school) but he tells me to buy a piston and bring it at the time of reboring.
Some reborers are having pistons with them but they are not known for their quality works.
because in Pune only Sam pistons are available and the person who will do reboring is not suggesting Sam pistons.He tells that Sam pistons give problems within a year itself hence he recommended Mahle.He also told that even if it is 5 mm oversize,he will put sleeving and do reboring


Thanks and Regards
Pankaj

replies in bold...

Dear Nanotechnology,
In pune I am getting one 0.25 mm oversize piston of Suzuki Fiero.
The piston Manufacturer is SAM KRG

Will it be fine to go for that Piston?

Regards
Pankaj

I have no idea about different manufacturers at all.

Last time i bought a +1 sized piston for fiero, it was from the official dealer.

This time i am using again an OEM block and piston kit of rtr 180.

So i cannot comment on it....

So you have put RTR 180 block-piston kit
So did you put only piston of rtr 180 into fiero block with sleeving/reboring or directly fitted the block-piston of rtr on your fiero?
Did it required change in crankcase or the cranck is of Fiero
Also did you changed/upjetted the carburettor since you are using 180 cc engine on a carb which is meant for 150 cc.

Because I checked the dimensions of Fiero FX block piston kit and I found that it doesnt fit on my GLX crank case.Hence I have to do sleeving on GLX block and rebore to fit fiero piston in it.
There are some possibilities of RTR 160 block piston fitting on my bike but only one mechanic is able to do it but cost is around 10000 to 15000.I told him that I will source him an RTR block-piston set and just fit it instead of my 125 cc block.But he refused.He is saying that along with RTR 160 block,he will put different valves,do head shaving/polishing for good performance plus he will put a Yamaha RX100/Shogun carb.But all these other things I dont need.
I have already upjetted my carburettor with a Bullet 350 main jet no 90 and I can easily touch 115 kmph top speed with my 125 cc bike and also mileage around 65 kmpl on highways.My bike's pickup has dropped a little but top speed has increased from 100 kph earlier before upjetting to 115 kph present.

@ pankaj

Dude, fiero and rtr has almost the same engine.
atleast the block and piston kit of apache 150 rtr 180/160 and fiero are all the same.
Fiero and apache 150 is exactly the same engine with a different gearbox.

if you cannot attach a fiero's block-piston kit, you won't be able to attach rtr's either.

one thing where the block and piston has an upper hand (instead of over-boring and sleeving) is the hardened nickel-silicon coating over OEM cylinder kits which gives the piston a good life reducing wear and tear.

rest everything is the same, now in my case i was lucky enough that rtr 180's engine geometry, as well as the stroke length was EXACTLY the same, hence i went for it, it was just a bolt on job.

i am using a BS29 carb with 112.5 main jet, slightly ported inlet and outlet ports, TCI ignition and a different exhaust.

Do not go for different block kits as you might not find any matching your current setup exactly.
That mech is robbing you.
Just get your head matched to the new bore, with a dip of 0.5mm, keep your ports stock, keep the up-jetted carb as it is.

plonk in a fiero's piston (with or without a new sleeve) and keep everything else stock.
You won't get greater speeds, but the time required to reach that speed will reduce to a great margin.
Torque will increase.

I got one Fiero piston of 0.5 mm oversize from SAM KRG so it is 57.5 mm in width
I checked its size with GLX 125 piston
GLX piston is around 2 mm longer than Fiero piston but the position of pin which is attached to the con rod is exactly at same position hence no problem regarding size.Fiero piston is a good match for GLX 125
But one problem I am seeing that is

The pin which connects the Con Rod and piston.
Fiero pin is little bit big in diameter than the GLX one
Because so far I know,the Hole on Con Rod must be sufficient for a piston to move freely.The only doubt I am having that the pin may somehow fit in con rod which might create problems in free movement of piston.
Does it make any difference
Because rubbing the pin on lathe and making it little bit thin will not do since this pin will not fit the fiero piston then.
Currently this is the only problem which I am facing.
I am just collecting the info from all of you because these rebore persons and mechanics will always try to avoid work at crunch moment(when the engine is opened) and nothing can be done other than accepting their solutions and hence it is better to approach them with some solution in mind.

Thanks and regards
Pankaj

Does that pin (bigger in diameter) fit your existing con-rod ??

well, this is an important thing, if it doesn't fit well, you might have to go for a different piston having the pin diameter which is an exact fit, or get the con-rod's diameter enlarged to match the new pin.

however i wouldn't recommend playing with con-rod...

Its good that the piston is smaller in length, frees off from a lot of doubts we had earlier of it hitting the base...

does the lathe guy insist on going for a new sleeve ??

Do not forget to have a 0.3 mm dip in the head (the area that matches the bore), your head as well as bore diameter should be same in order to get 100% stock reliability.

tell me how much diameter difference is there between the two pins ?

Here is one picture attached
The left pin is of GLX and the right one of Fiero
Fiero's pin is marginally big than that of GLX

I think it should fit in con rod of glx
because so far I remember last time when the engine was opened,the con rod is having much more diameter but all I will know after opening the engine
But confirmed I dont know about con rod diameter

One thing I can do is I can check with TVS spare parts/service center and try to source a con rod and I will match Fiero's pin with Con rod.
If it suits then I think it will not have any problem
The Lathe guy told that he can do boring above 1 mm also and he told that it is better to put a sleeve and then plonk the piston because on that block I already rebored by 1 mm.
Let me put in short
2 years back,I rebored the piston by 1 mm but it didnt worked and in 6 months,I changed to standard block piston kit
Hence now I am having the block which is already rebored by 1 mm
Hence lathe guy recommends sleeving

It's not that simple is it?no one who is knowledgeable in lathe work or knows a thing or two about engines will bore by 1mm on stock sleeve.The result of doing such over-bore is already experienced by you.It won't perform or last long,because sleeve would have become too thin.
Instead of worrying so much and doing research on piston pin,piston height,stroke etc,you haven't even thought of sleeve quality.
Pay attention to sleeve quality and the kind of work the lathe is known for.Putting a sleeve properly is not a simple work,if not done properly,it'll cause lot of vibrations and ruin all the reciprocating parts.
Then, are you sure the crank can take the load?

Any lathe will bore and put a sleeve,but very few are skilled enough to do it properly.The quality of work will be known only when the performance is checked and when the bore is opened up again after 2k or so kms.
Here the sleeves put by any lathe on bikes for racing purpose won't even last more than 1k and will start leaking compression within a few hard drag race sessions or track sessions and it's not about the coating a stock sleeve comes with.A properly done re-bore,that is the coating will be gone after the re-bore will actually last longer than a stock bore.
Think about it.