Project Dhoom YD 70 Upgrade to 110cc

[N0m1]

Its very impressive & unbelievable too.
Coz my yb100 does 100kmh.

[asjdsm]

bila waja tho ma hero hero nai kahtha na... and jab main kahtha hou ka mujha hero ka carb chaia .. then it means it has some juice..

hero is very good bike..

but one thing it may not be 72cc .. it will be 78cc one ... as these companies try to reduce duties/taxes by under labelling it.. i thnk one mechanic told me that its con rod is same as other 78cc chondas that means its stroke is 49.5mm not 41.4mm of 72cc.. so it may very well be the 86-88cc bike in reality..

m riding a hero rf70 these days.that very bike belongs to my chacha g and its a non abused bike with very clean and sound condition.i use it thrice in a week for 40 kms per day ( home to uni and back and then to office)
top speed i have taken it too is 100kmph.......and i wonder a 72cm3 chonda really goes to 100kmph??????

[gull_s_777]

m riding a hero rf70 these days.that very bike belongs to my chacha g and its a non abused bike with very clean and sound condition.i use it thrice in a week for 40 kms per day ( home to uni and back and then to office)
top speed i have taken it too is 100kmph.......and i wonder a 72cm3 chonda really goes to 100kmph??????

i have seen a 2007 CD70 doing 100kmph with double but never got the chance to match its meter with other bike to rule out meter error....

[asjdsm]

even wearing helmet but visor up .. at 90 my eyes start to leak water ... hahaha .. and its one such horrible speed on this little chonda of mine ..

[N0m1]

^^^LolZ.Naughty guy.Why visor up?

[saadabdulrahim]

This is not a boast but I have a 1997 Honda CD 70. It is with my father since 1999, before that it was with my Khalu.
When we purchased the bike it was clocking 2200 kms. after that my cousin used it till 2009. Never got it tuned in those 9 years but engine oil was changed ever 7-8 months
In 2009, when the bike was handed over to me it was in terrible condition. The engine was all gone.
I used it for 1-2k kms and after that got the engine overhauled.
Running was done by me at the speed of 40-45 max. After completing 1000kms I started to rev the engine higher.
The results were amazing. The bike used to go up till 85 km/hr in 3rd gear and in the 4th gear, all the way up till 115 km/hr.
And yes the speedometer was perfectly alright. Synchronized it with many other bikes and even with cars.
I used that bike for like 3000-4000 kms and after that got a new bike and it was 2008 Honda CD 70.
Now I use the 2008 CD as my daily driver but in the mean time the bike was parked in my garage.
My younger brother started riding the old 1997 CD and now when I ride the old one I don't feel the thrill.
The bike goes till 90 max.
It seems like its engine is losing power.
Can you suggest what can I do to restore it to its lost glory.
Thank you

[asjdsm]

This is not a boast but I have a 1997 Honda CD 70. It is with my father since 1999, before that it was with my Khalu.
When we purchased the bike it was clocking 2200 kms. after that my cousin used it till 2009. Never got it tuned in those 9 years but engine oil was changed ever 7-8 months
In 2009, when the bike was handed over to me it was in terrible condition. The engine was all gone.
I used it for 1-2k kms and after that got the engine overhauled.
Running was done by me at the speed of 40-45 max. After completing 1000kms I started to rev the engine higher.
The results were amazing. The bike used to go up till 85 km/hr in 3rd gear and in the 4th gear, all the way up till 115 km/hr.
And yes the speedometer was perfectly alright. Synchronized it with many other bikes and even with cars.
I used that bike for like 3000-4000 kms and after that got a new bike and it was 2008 Honda CD 70.
Now I use the 2008 CD as my daily driver but in the mean time the bike was parked in my garage.
My younger brother started riding the old 1997 CD and now when I ride the old one I don't feel the thrill.
The bike goes till 90 max.
It seems like its engine is losing power.
Can you suggest what can I do to restore it to its lost glory.
Thank you

i am confused about the last para..
if u say that the 97 model cd70 is doing max 90 and earlier it did 115 and u want it to do that again.. then in my opinion its perfectly right. as cd 100 max is 100km/hr and that is 30 cc more engine power then 70 plus gear ratios advantage..

cd 70 on downhill with rider sleeping on it or in downright position can reach max 97 .. that too some old model .. not these new models..

and 115 on stock rebuilt 70 is difficult in my opinion..
when i just pass 90 my bike feels as its riding on air .. and its another feeling ... offcourse frightening..

waiting for a bit clarification on last para..

[saadabdulrahim]

I mean to say that my 1997 CD70 is losing power and goes till 90 kms max. previously it used to do go uptill 115 km/h.
The only thing I've changed is the chain and sprocket set. I'm using atlas honda engine oil(oil change every month) + tuning after every 3 months. The bike runs not more than 500-700 kms per month.

[asjdsm]

well in my opinion u are already getting more then enough speed for this bike ..

however make sure its properly tuned.. use good filter.adjust tappets properly.make sure there is no leak b/w carb and engine any where... clean and adjust plug.adjust chain. and ensure both wheels are free to rotate.

[user-xxx]

So a new united 100 cc cylinder and a suzuki 110 cc piston together.....or head, valve etc? or yeh bolt to bolt fit ho jai ga road prince 70 per yah alteration kerwani pera gi?

70cc > 110cc than how will you amend your motorcycle papers ? han .
that thing will become illeagel.
Thanks.

[asjdsm]

there is no inscription on either the cylinder or the cylinder head or the carburetor that is written in papers or documents...

70cc > 110cc than how will you amend your motorcycle papers ? han .
that thing will become illeagel.
Thanks.

[user-xxx]

there are same cc on papers and cylinder ie . 70cc . and some other specifications like bear axel weights . number of passengers to carry.etc

if we upgrade 70cc to 110cc than the papers should also be amended or otherwise illegitimate.

what people think they can put 200cc in their 50 cc ?

[asjdsm]

ider mistry ko nai patha hotha udar toolay ko kia patha hoga ka ya kitnay cc ka ha .. hahahaha .. just grind the cc written on it .. if you are that much concerned ..

i havent done so and no tulla has said anything .. even itp guys .

technically its illegal ..
the papers do quote cc's of engine but from the manafacturer and tax viewpoint not from consumer viewpoint..

in my opinion its the way one handles bikes thats more of concern then whatever cc is it souped up to ..

have your own way man ..

there are same cc on papers and cylinder ie . 70cc . and some other specifications like bear axel weights . number of passengers to carry.etc

if we upgrade 70cc to 110cc than the papers should also be amended or otherwise illegitimate.

what people think they can put 200cc in their 50 cc ?

[user-xxx]

asjdsm bro jab bhhi mujy challan kartay han mudguards ki wajah se tab , hamasahah engine pe ghor se dekhtay han buri nazro se .....
trafic walay bhi and police walay bhi ....... shaid yahi dekhtay han mery to khayal se ky , engine bara to nahi laga ?

anyways we will find other ways ....

[asjdsm]

hahah

jis na mud guard utharya hothay hain unki tho wo ........... gharzay aik aik cheez check karthay hain .. par meri tara shareef altered bike rider jo hamlet pahna hotha ha and bike looks proper uski tho lift hi nai kartha tulllllllllay

so to avoid them make your bike in good shape .

asjdsm bro jab bhhi mujy challan kartay han mudguards ki wajah se tab , hamasahah engine pe ghor se dekhtay han buri nazro se .....
trafic walay bhi and police walay bhi ....... shaid yahi dekhtay han mery to khayal se ky , engine bara to nahi laga ?

anyways we will find other ways ....

[vickytulla]

Good work asjdsm! so I am not alone Finnaly!!! .....

In Lahore their is an Undercover 125 (use to be a 72cc E22 shareef bachon wali bike) which has already smoked sprinter, CD100s, junoons, pridors, shridor, burgers, sandwiches .... soon it will be taking on GD110 too.. it gets head to head with CGs and storms but lacks top speed due to low gear ratio but in short strips its heated acceleration is unmatchable..

Top speed acheived so far. 106 under best circumstances.. still under evolution, will make a seprate thread once I am done with every thing.

The difference of stock Piston with new Cylinder

124CC compressor chamber

a side view of how wide the Cylinder looks.. engine looks smaller then head Cylinder. LOL!

My This project was influenced after @FC works... thanks FC.

[asjdsm]

awesome Vicky2Law (finaly i can say your name from my heart .. earlier it wasnt suitable interpretation )

yes @FC is no doubt an inspiration to all of us ..

i have been riding it and have good pick and power .... but the only thing bugging me is that i cannot find a piston that fits stock 13mm con rod and gives me some 9+ CR ..

i have found one piston of max100 but thats 54mm dia and 13mm wristpin .. but that is very high if deck to deck comparision is made with stock 52.4mm piston that comes in 110cc engines.

currently in my opinion i am getting 8.66:1 CR .. or may be less then it ..

i am looking forward for your project .. and i will post two new findings of mine .. which i hope you would have already found and solved if not would help you somehow..

yes its engine look obsenely big compared to the crankcase ..

[vickytulla]

their are lots of salvaged 125, 150 110 engines of quad bikes in bilal ganj and the trend of modifying E22 is quite in these days...

awesome Vicky2Law (finaly i can say your name from my heart .. earlier it wasnt suitable interpretation )

yes @FC is no doubt an inspiration to all of us ..

yea after he showed whats the Karachi guys are doing with there 70s and 125s I was totally comited to do it one day ...

right now two of my friends funded projects are keeping me in a loop thats why I have been unable to find time to continue further ...
these are what my friends are dreaming about ...

A rotten ages dead CD175

BEFORE

AFTER (STILL UNDER PROGRESS)

waiting for the parts like tanky tappa to arrive from paint Job to continue..

have to keep equilibrium between Job + Hobby + home Life = VERY hard.

[vickytulla]

i have been riding it and have good pick and power .... but the only thing bugging me is that i cannot find a piston that fits stock 13mm con rod and gives me some 9+ CR ..

9+ CR means ? compression ? I haven't measured it so far ... relied to much on my mechanic he is awesome... lol so I have to worry less... I guess you have only swapped the cylender,piston + head only and not the crank/weight ? is that the case ? I hope you are not facing vibrations but I doubt it must not be reving upto 10k RPM becuase the wieght below on crank and the piston size would not be in harmony ?

which bikes clutch box did you used ? I am using qinqi100's clutch-box set with final reduction sprocket of stock125ccquad bike .. forgot how many tooth it had..

i have found one piston of max100 but thats 54mm dia and 13mm wristpin .. but that is very high if deck to deck comparision is made with stock 52.4mm piston that comes in 110cc engines.

currently in my opinion i am getting 8.66:1 CR .. or may be less then it ..

I dont know how it is working in your case because even a 100cc piston needs a increased weight on crank down below .. the head you are using is a bearings based head or uses a Bush based cam in it ? becuase 100cc above need a bearing up there for free flow movement of cam and more lubrication (as heard from mechnic)

i am looking forward for your project .. and i will post two new findings of mine .. which i hope you would have already found and solved if not would help you somehow..

two main problems I faced so far were the gear box and the carb... even a qinqi, junoon, and sprinter carb didnt did well with jets re done junoon carb did some but not in stock so I had to put a CG125 own Carb which worked finaly with a carb to chamber Bend rebored becuase the stock bend is very narrow and doesn't lets the piston to suck properly.

secondly 4th gear is eaten up to fastly .. I am using the final drive sprocket of 15 + 36 right now..

yes its engine look obsenely big compared to the crankcase ..

while assembling the eninge the two crank cases were not joining together becuase of a huge weight of 125cc ... so had to tool Collars from the crack cases to adjust it in...

[asjdsm]

you pretty much solved the issues ..
do make sure that the holes/bores of the carb bend pipes are in perfect harmony with carb and the head .. and not offset ..

and your assumptions are also correct about my bike ..