not sure about others, but i have my pulsar 220 modified with the big bore + ff exhaust for the last 8000kms and riding my bike every morning brings a big grin on my face. all i want to ask the disgruntled customers is, did Joel shown a cold shoulder to your issues?

An interesting observation Mik.

I wanted put write further however refraining from it as logical answers and replies may be understood otherwise.. it may lead to further flame wars which is not right.. and goes against the purpose of raising an issue at the first place..

Cheers,

Only thing was that sometimes when the engine shuts down at idle, its shuts down with a bang. The last spark fires with wrong timings. This can be a cause. Other than this, when I opened the kit, the insides were lined with carbon - it was running a touch too rich.

No pitting, the piston looked good, only the bore had mild vertical scratches.

The fuel was from the same pump throughout.

Sorry if I have been harsh with my words. The BB kit indeed needs some extra care to fit the piston in the bore.

Forged pistons have a different Piston to wall clearance than your factory piston, Due to different metallurgy and expansion rates, These need to be taken into account and the cyl machined to suit the piston! as each piston is minutely different. Each ring also needs to have its endgaps filed down and measured inside the bore, Depending on the application (drag/circuit/enduro/commuter-daily rider) the endgaps will be larger of closer.
If you have the endgaps too close there is a possibility the ring will expand, press against eachother and gall the cyl wall, extreme cases you can break the ring or sieze the piston.

@Madmik

Do you find this issue with your FZ-S block? I have seen a few post of yours mentioning about starting trouble, so did you ever come across this issue? like the engine will return a bang sound and shut down. It happens with most after market blocks and never on stock block. Before with the RC map I had a little starting trouble and the 165CC block and even the UMA block would return this bang sound and shut down... while now with the new map there aren't any starting/idling issues, but still not sure if that problem was resolved.

I have attached some pics. The block is '5YPOO 135cc' and piston is '5YP ART'. I could not capture very clear pics. However, any inference from the same?

Re: "The Big Bore" - A Story about an R15 getting tuned.

images of 135 cc ....... ??? why ?

Sent from my GT-S5570 using Tapatalk 2

If i may,

this was the same problem we had with the R170, the first map which came along with the RR ECU, turned out to be too rich. We had requested to keep the mapping aggressive as R170 had been built specifically for high speed runs and fun. At first, everything was fine but then the moment the temperatures started dropping here in Mumbai close to 19-23 'C, we ran into trouble with engine giving us slight problems with start ups and then rpms refusing to climb above 7k when on 5th and 6th. At times engine would start and then stop with a bang and sometimes a thick black cloud of smoke would come out. When we opened the spark plug, there was thick gooey deposition on the spark plug, so all the fingers were pointing to rich fueling so we deduced that the mapping was the main culprit besides taking care of other small mechanical problems it already had even before the RC parts were installed (I have covered it extensively on Abhimanyu31's thread).

All changed the moment the new map was tried. It still has slight anomalies to tweak but otherwise now the R170 flies to 120 kmph on 4th gear.. 5th and 6th gear the map fueling is running lean.. once we perfect it it will go even faster.

I suspect that in your case too the fueling may have been the major culprit as the symptoms are pretty similar to what we had faced with our respective build. the pictures shared by you look similar to the pictures i have posted in the respective thread. It is possible that the piston and the rings may have had a manufacturing defect although difficult to point out without seeing the piston in person.

BTW, too much carbon deposition also starts increasing the compression ratio of the engine as the overall area in the cylinder gets smaller due to the layer formed on it. I believe, that's why you were feeling the vibrations and engine feeling rough.

No need to apologise mate.. it was just a misunderstanding and i completely understand your frustration on the same. Perhaps i was too direct with my questions.. Apologies from a habitual blabblering guy.. I believe everything has a cause and effect. We too got in between frustrated with the new build.. But end of the day it was an enriching experience to troubleshoot the problem and then reap the benefits of the R170 whooping other exotics by 4-5 bike length..

That's why i said hot roding is a process of trial and error.. You start learning more about it as the more you get into it..

I feel you should have contacted the tuner/manufacturer to point out your observations and then decide whether it was right or wrong.. You have spent money after all so you deserve a rightful explanation for the same... Completely my opinion, you have absolutely all the rights to decide otherwise.

Cheers,

I did post up a pic of the stock piston in the 200cc/66mm bore as a prank, Got a few bites and some actually thought it was real!!

Anyway when I returned home from work my bike had been delivered to my house after installing my new carb, less than 2weeks prior (I was gone for just over 2weeks) I did have trouble trying to start my engine that night and the next morning. I suspect it may have been bad fuel.
Since then it starts first time.

Though regarding the shutting down with a bang/clunk, I did notice that on both my stock engine and on this engine, Depends on the stroke of the piston and when it shuts down I will get the sound. Doesn't worry me in the least.

My cyl is the yamaha factory cast piece that has been machined to suit a 66mm liner, or the liner itself has been machined to accept a 66mm Piston.

It is a pic of my 165cc block. Joel bores out this block to accept a bigger piston.

When things were fine, my bike revved decently to 9k+ rpm (on 4th & 5th), while touching 12k rpm took a while (on stock cams.) I got average mileage of 30-33kmpl. So, i would like to believe that even though the fueling was a bit rich, it was not off by a huge margin.

But still, yes, compression ratio could have increased too.

I have a simple reason for letting go of this - I don't trust Joel's kit quality after this. I say this because I know how I had ridden the bike - while I touched 9k-10k rpm a couple of times on every ride, I had not abused it in any way. And one more thing - all this time I used fully synthetic engine oil with max 3k kms drain period.

So even though I lose financially, I gain peace of mind. Of course I am sad as well to lose out on the extra grunt.

this may be off topic but i am also facing the issue of bike shutting down sometimes with a loud bang, this happens only when the bike goes over bumps and engine is being revved.
I have joel's ffe only. Could rich fuelling be the culprit? How do i go about correcting this?

I seriously doubt it has anything to do with the FFE or rich fueling.. get the idling checked at the SVC and also the clutch freeplay.. although i will not consider myself to be an expert in this area so i would suggest that you can perhaps get in touch with the ownership thread guys, they will give you better troubleshooting.

Cheers,

Well i am not sure which map you ran your bike in.. but as per my experience with R170.. if a user opts to run the bike on a very aggressive mapping then the map is bit finicky with too much changes in the atmospheric conditions like temperature and major altitude shifts.. It is normal and pretty much same as tuning a carb'd bike on rich setting which then starts coughing or giving out lesser power as the temperature and altitude changes.. So one has to fiddle around a bit to get the tuning set right. If you run a base map then the ECU parameters don't get much affected by the same.

If you were running your ride on rich tuning/aggressive map then yes the map is sensitive to temp and altitude changes.

Anyways, all said and done you have taken a call so i shall not comment on your decision on the same. just posted my opinion.

Cheers,

the idling is at around 1400rpm, i think it may be the clutch...because i find that my clutch is way too sensitive when compared to my friends v2. I dont understand how the clutch could be the culprit though? any specific reason why you would think that could be a problem??

I think it is the Yamaha T/Y 135 cc LC bore which had been sleeved and overbored....