what octane gas are you using 87 or 91 or higher

use 91 octane or higher and change your spark plug to a better heat range

change your oil and use regular dino oil instead of full syntactic oil, remove oil spinner cover and clean and check for any filings or metal in the oil spinner and also the oil screen that is below the oil spinner.

good luck and ride safe

 

I use 95 octane fuel, and i have installed a CPR7EA-9 (NGK)

but , i think, the oil is not the problem...

 

You might have to disassemble the cyclinder/head and check everything to see if there is any problems.

Recheck your cam timing marker with the flywheel marker and make sure everything is lined up to spec.

Make sure your cam tighter spring is in. Some Grom owners will forget to put the spring back in when doing oil change and remove the wrong Nut instead of the oil nut they accidentally remove the cam chain spring nut.

 

Why would oil effect anything?

OP are you using any tuning ecu? PCV , bazzaz?

Whats a tuning manifold?

 

Hi RacerX,

No. I don't use a ECU-Tuner like barrar etc...

THX

 

Hi.

i have checked everything.

Cam timing is O -> T

The cam tighter spring is OK.

Thanks for the ideas!

 

Your A/F should be around 13:1 to 14:1 depending on RPM.

Your stock ECU will not work quit well with the mods unless for one like some other Grom builder/mod have done was to remove/plug the O2 sensor and ground/gnd the O2 sensor wire plus running some type of piggyback ECU adjustment system PCV etc

Best price for PCV
http://www.hardracing.com/13-14 Bikes/14 GROM.htm

Some read up on ECU/02 sensor and possible problem you are having
http://www.hondagrom.net/forums/13-grom-performance/3113-o2-sensor-grom-piggyback-tuners-6.html

http://www.hondagrom.net/forums/att...chments/10299d1398818010-grom-ecu-cel-o2-sensor-issues-finally-resolved-wb1.jpg

 

thanks for the ECU info, but i will not install a ECU. Here in Germany is it not allowed.

 

Why not? It the German government a bunch of NAaaaaeevvermind.

 

They wont know..


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well you better look for some higher octane gas, because w/o an ecu to richen up the fuel mixture, you are going to destroy your cyl. head.

 

make a video so we can hear this noise

 

Sounds like your getting detonation. With out a fuel controller your going to run that bike extremely lean and burn it up. Atleast get the bigger injector so that the stock computer can try and keep up with the 155 kit.

 

Well, thats not too true with the ECU in Germany. As you can get an additional control unit for E-85 street legal here, it amy be possible to get an A/E corrector too or another ECU.
If that doesn't work, try the ultimate102 at ARAL ;p
(schreib mir ne PM wenn ich mal meinen Kollegen fragen soll, der hat sich mit sowas mal beschäftigt, aber ich denke schon dass man sowas eingetragen kriegt )

 

Hi!
Thanks for the Infos! Today i will make a video with the "knocking"
And thats with the ECU is right, but you use a ECU with a speciale parts certificate... bla bla bla... this is in Germany a extreme effort to use a ECU official... and it costs a lot of...

Br,

Benny

 

Hi Gavin Davis fitted one of these kits too and had BIG issues. His posts are on this site somewhere. From memory - the piston was hitting the spark plug - he ended up fitting washers under spark plug and making a new head gasket. Even after all that he melted a Pistona dn ended up taking the kit off and going back to the 125cc. He recently had a bottom end problem after 20,000 miles on the bike - most done at 125. Look up his posts - unless they changed the kit from faddy bikes - then I assume you have the same issues.

 

Hi Simon,

I had the same "spark plug" problem, i have fix it with "fitting washers" too...

thx

 

Did you measure the piston rings? maybe they are a bit too small/loose on the hot engine. Otherwise it could be a porlbem with the injected gas as it doesn't burn completly. I'm using this spark plug on mine...way better with it ...but I'm not too sure wether a iridium spark plug will fix your problem.

 

No, i have measure nothing...

here is a video with the knocking:

the engine was not very hot, if the engine is extremely hot, then is the knocking louder

THX

 

oh thought it was knocking on each rotation. hmm... sounds more like anything loose. When you installed the bore kit, did the copper plate match up with the cylinder? And does it happen in a specific gear?

 

Honestly if it were my bike and i heard that noise i would open it back up. the video is too short to really figure something out.

 

Does it knock when the engine is first started (cold) ?

 

Hi,

if the engine is cold, then is everything ok... just with a hot engine i can hear knocking, but just if i drive with 1000 r/min...

thx

 

Its because you use the stock head gasket your supposed to use the thicker head gasket

 

Hi!
Now i have checked the spark plug (the plug has run 80 km)...

i think it´s shows not good, or ?!?


Br,

Benny

 

Let me know if you've solved the problem. I hear the same knocking sound from my intake area when at idle. It goes away after about 2.5k rpms. This too after a bbk install.


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Yes... i will report, if i had solve this problem...

This weekend i will change the head gasket...

br,

Benny