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Discussion Starter · #1 ·
I’m keen on the DHM inclusive BBK as it seems to be good value considering it includes cam, injector, oil cooler and ECU reflash. (But keeps the original 2v head which I prefer.
has anyone here tried this kit? I heard there have been issues with reliability with bigger BBKs, but has anyone here had issues with theirs when used with 2v heads?
 

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It good if :
inspection of piston before install ... tb parts does have some sloppy parts from time to time.
oil cooler / hd oil pump / are a must
aracer is preferred - can tune and keep a eye on temps and afr

run 110octane if you can - also oil with zinc

change oil often <600miles
 

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Discussion Starter · #5 ·
It good if :
inspection of piston before install ... tb parts does have some sloppy parts from time to time.
oil cooler / hd oil pump / are a must
aracer is preferred - can tune and keep a eye on temps and afr

run 110octane if you can - also oil with zinc

change oil often <600miles
A 5 row oil cooler is included in the kit and I was thinking of going to a higher flow pump once cooler is fitted.
I will look at the Aracer fuel controller. Does it have auto tune function or data log the bikes readings?
If I did go for a bigbore kit I would run 98 octane petrol
 

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Discussion Starter · #6 ·
BBK without an upgraded forged crank is a timebomb. DHM or otherwise. Search the threads.
Ok, I had done a bit of a search around on bigbore kits and no one ever mentioned a crank upgrade. If that is the case I will likely limit the size of the bigbore kit as I didn’t want costs to spiral out of control on this bike
 

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Ok, I had done a bit of a search around on bigbore kits and no one ever mentioned a crank upgrade. If that is the case I will likely limit the size of the bigbore kit as I didn’t want costs to spiral out of control on this bike
IMHO the best value is a complete NEO kit which has everything you need for a cool running, long lasting powerful motor.

You will need a fuel controller. Flash ecu not enough.

Spend some hours in this forum searching through BBK threads and you will likely reach the same conclusion..


 

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IMHO the best value is a complete NEO kit which has everything you need for a cool running, long lasting powerful motor.

You will need a fuel controller. Flash ecu not enough.

Spend some hours in this forum searching through BBK threads and you will likely reach the same conclusion..


Pard, is the Neo kit discontinued? I looked on Kitaco’s website. Unless I missed it, it appears to no longer be listed. I couldn’t find it on Webike either.

Like I said, maybe I missed it. I’ve been really busy and not messing with the Grom much for the last year, so I’m not well informed on what is currently available.

I agree with you that it is the best value. It would be unfortunate if it was no longer available.

To the original poster, I think it would be foolish to install a 186 BBK without replacing the crank and rod with forged parts. They are the weakest links. The additional expense isn’t insignificant, but not huge either. It is quite a bit of work to split the case, though.
 
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Discussion Starter · #9 ·
IMHO the best value is a complete NEO kit which has everything you need for a cool running, long lasting powerful motor.

You will need a fuel controller. Flash ecu not enough.

Spend some hours in this forum searching through BBK threads and you will likely reach the same conclusion..


Thanks for the info and I will follow advice given.
I will start off with pipe, inlet , cam and ECU reflash and will put off the bigbore kit until I’m ready to remove the engine and fit a crank.

I have a turbo GSX1400 build to complete before I tear the grom down.
 

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Pard, is the Neo kit discontinued? I looked on Kitaco’s website. Unless I missed it, it appears to no longer be listed. I couldn’t find it on Webike either.

Like I said, maybe I missed it. I’ve been really busy and not messing with the Grom much for the last year, so I’m not well informed on what is currently available.

I agree with you that it is the best value. It would be unfortunate if it was no longer available.

To the original poster, I think it would be foolish to install a 186 BBK without replacing the crank and rod with forged parts. They are the weakest links. The additional expense isn’t insignificant, but not huge either. It is quite a bit of work to split the case, though.
In stock at Hard Racing.

 

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Pard, is the Neo kit discontinued? I looked on Kitaco’s website. Unless I missed it, it appears to no longer be listed. I couldn’t find it on Webike either.

Like I said, maybe I missed it. I’ve been really busy and not messing with the Grom much for the last year, so I’m not well informed on what is currently available.

I agree with you that it is the best value. It would be unfortunate if it was no longer available.

To the original poster, I think it would be foolish to install a 186 BBK without replacing the crank and rod with forged parts. They are the weakest links. The additional expense isn’t insignificant, but not huge either. It is quite a bit of work to split the case, though.
I just put a TB parts 186cc BBK, koso throttle body, koso intake manifold, TB cam, 150 injector, TB oil cooler, Kitaco clutch cover also paired with a Dyno Jet power vision 3 tuner. I didn’t spend the $800+ on the crank and rod. I was reading that they are good as long as your not into like the 20HP or more mark. Would you be concerned in your honest opinion if I was around 16-18hp on stock crank. PLUS I think the higher RPM’s are what kill the stock crank and rod. They don’t like to go 10k or more RPMs I feel like that’s what kills them is the guys who try to raise the rev limiter way too high on the stock rod and crank. ANYBODY HAVE ANY OPINIONS ON THIS??
 

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Thanks for the info and I will follow advice given.
I will start off with pipe, inlet , cam and ECU reflash and will put off the bigbore kit until I’m ready to remove the engine and fit a crank.

I have a turbo GSX1400 build to complete before I tear the grom down.
I think what kills the stock crank and rod is the high RMP’s people push these little bikes to. Keep it under 10k RMP and the stock crank and rod should be fine with the original 2v head. Once these bikes get 10-12k rpm the cranks blow out easy. Maybe I’m wrong but that’s what I’ve read and I have a 186cc bbk with a stock crank and rod
 

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I just put a TB parts 186cc BBK, koso throttle body, koso intake manifold, TB cam, 150 injector, TB oil cooler, Kitaco clutch cover also paired with a Dyno Jet power vision 3 tuner. I didn’t spend the $800+ on the crank and rod. I was reading that they are good as long as your not into like the 20HP or more mark. Would you be concerned in your honest opinion if I was around 16-18hp on stock crank. PLUS I think the higher RPM’s are what kill the stock crank and rod. They don’t like to go 10k or more RPMs I feel like that’s what kills them is the guys who try to raise the rev limiter way too high on the stock rod and crank. ANYBODY HAVE ANY OPINIONS ON THIS??
I think what kills the stock crank and rod is the high RMP’s people push these little bikes to. Keep it under 10k RMP and the stock crank and rod should be fine with the original 2v head. Once these bikes get 10-12k rpm the cranks blow out easy. Maybe I’m wrong but that’s what I’ve read and I have a 186cc bbk with a stock crank and rod
Stock crank is designed for 9 hp.

Many failures with have been reported just by bumping up the power a little bit even if the RPM range is kept in the green. I stay below 9K even with my NEO.

Hard to know what percentage of engines fail, but they sure do.

The cost for replacing the entire engine and starting from scratch far exceeds the cost of upgrading your crank now.

Even if you stay below 9K, the additional power you will be producing exceeds the design goals of the stock moving parts. Risk goes up for failure.

My experience here:

 

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Looking at dyno charts from bikes with similar modifications to mine, I estimate my bike is making around 12hp. My rev limiter is set at 10,000rpms. That’s about all I feel comfortable with on the stock crank and rod. I still plan to back cut (taper bore) my throttle body and do some head port matching. That will add minimal additional power output.

I’m still running stock compression and stock valve springs. Higher compression produces more heat (although I do have a Kitaco 3-Row oil cooler installed). I’d say it also stresses the crank and rod even more. While unrelated, I’ve also wondered if stiffer valve springs are putting more wear and tear on cam chain tensioner wheels (maybe?).

My bike regular sees 10,000rpms. Could it fail? Absolutely. I’m not terribly worried about it though. Every other part has been upgraded to something stronger. Without a doubt, it’s weakest links are the crank and rod.

Some people are making much more horsepower and still using the stock crank and rod. In my opinion, it is only a matter of time before the crank or rod fails.

There doesn’t seem to be any rhyme or reason to some of the crank failures. The bikes making big power come as no surprise, but I’m told, that stock bikes have failed too. All the ones I’ve seen failed at the flywheel.
 
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