[phillybuilt]

Badass build! Looking great so far!

 

[nema741]

She’s a runner! Got it all wired up, all lights and controls function as they should! Took it for a ride up the road .. wow oh wow... cannot wait to finish up my exhaust and final mount of radiator. I zip tied it in place for the test ride. Still have to put plastics back on. Cluster is final mounted. Just modified grom bracket a bit. I gotta figure out how to upload videos

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[3sexy5u]

Holy crapoli! That thing must be a fuggin beast

 

[nema741]

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[nema741]

Ok well I finally figured out how to share videos, of course I uploaded the one in the dark lol. If I get a chance to do more work on it tonight i'll most likely have the plastics back on. Good news, my wiring conversion table that I made was a success! Everything matched up and worked as it should. I will be finalizing it mostly today. Adding things that I "found" along the way. Once it's completed i'll send it out as a PDF so just hit me up if your interested in my guide. In it I cover wiring the grom's Bazzaz over to the CBR, Wiring all Grom controls, headlights, turnsignals, brake lights over to the CBR harness. I should note, that I have not permanently wired the rear turn signals or license plate light as of yet. I did connect them and test them, but realizing now that I am going to end up with a undertail exhaust I will probably get a integrated tail light. So I Opted not to finish these as of yet.

 

[maz_636]

I'll take a copy of that PDF when its ready pretty please mate :big smile: Im searching ebay every day for a crash damaged 250 to use as a doner bike !

 

[funcoland]

Ok well I finally figured out how to share videos, of course I uploaded the one in the dark lol. If I get a chance to do more work on it tonight i'll most likely have the plastics back on. Good news, my wiring conversion table that I made was a success! Everything matched up and worked as it should. I will be finalizing it mostly today. Adding things that I "found" along the way. Once it's completed i'll send it out as a PDF so just hit me up if your interested in my guide. In it I cover wiring the grom's Bazzaz over to the CBR, Wiring all Grom controls, headlights, turnsignals, brake lights over to the CBR harness. I should note, that I have not permanently wired the rear turn signals or license plate light as of yet. I did connect them and test them, but realizing now that I am going to end up with a undertail exhaust I will probably get a integrated tail light. So I Opted not to finish these as of yet.

Wow, that's really awesome man. Congratulations on the build! That didn't really take long at all. It seems like the most work was basically in just hooking all the wires up in the right spots.

I too will take a copy of the PDF please!
Also, do you know if there's anything different between wiring a 300 vs 250?

 

[funcoland]

I'll take a copy of that PDF when its ready pretty please mate :big smile: Im searching ebay every day for a crash damaged 250 to use as a doner bike !

Have you tried contacting salvage yards?

 

[nema741]

Wow, that's really awesome man. Congratulations on the build! That didn't really take long at all. It seems like the most work was basically in just hooking all the wires up in the right spots.

I too will take a copy of the PDF please!
Also, do you know if there's anything different between wiring a 300 vs 250?

From what I have researched the wiring is all the same with the exception of the "clusters". The 300 harness uses the same cluster plug as the grom does, so you can use either the grom cluster or cbr300 or koso DB-03. I used the cbr 250 harness and cluster. I slightly modified the groms mount to accept the 250 cluster. It has the same 3 bolt mount, but they are spaced a bit further apart, with a slight mod to it got the rear 2 bolts holding the cluster which is perfect.

So far I have probably 8 hours invested, about 1 1/2 hours to strip my grom down from original form; approx. 4 hours with electrical wiring (this can be reduced greatly if you get the CBR left/right hand controls) and about 2 1/2 hours to mount the new engine, header, radiator, install new sprocket, cut the new chain to size, etc.. I did most of my work over the course of 3 separate evenings; not to mention I have 3 kids which my 8 year old helped me with strip down the bike, my 2 year old helped me hide my 12mm, ratchets, etc. The 5 year old was in constant need of ice cream, food or bandaids.

I spent ALOT of time doing research. It was amazing just how "little" was out there as "concrete" information. Countless forums, facebook groups etc. Thankfully for a few people that helped out with little tid bits here and there. If you plan the swap right and have decent mechanical abilities it would not be difficult to perform this swap in one day assuming you have all the right materials and can fabricate brackets, exhaust..

Random thought on wiring before I forget; The headlight.. If you get the "headlight" portion of wire harness from a CBR you can use that plug to wire all of your groms plugs to and then plug it right into the CBR harness. This made it easy for me; I have pics of all the harness plugs that I modified. Throughout the week I'll get them uploaded.

If you want the PDF "how to" send me a PM with your email address. I will be cleaning it up more and more this week but I don't mind sending out what I currently have to get you started on your research.

 

[CiscoSanJose]

Thanks for the write up and sharing your information. I guess now you'll be running a 6 speed, water cooled, reliable transplant conversion grom, so called in my mind Franklin-grom, such as Frankenstein.

Do you know what the stock HP is on your 250 grom and what will be the weight of your grom once you have all the pieces put together and gas and oil added.

Great work and Ride safe.

 

[crakerjac]

Curious how checking/changing oil will be with the swap. I imagine the sight window is now inaccurate since the motor is leaned forward. Also, how do you get all the oil out of the motor while changing it? Lift the front wheel 10" off the ground? Not trying to be a dcik, just trying to figure out the mechanics of it all.

 

[nema741]

Thanks for the write up and sharing your information. I guess now you'll be running a 6 speed, water cooled, reliable transplant conversion grom, so called in my mind Franklin-grom, such as Frankenstein.

Do you know what the stock HP is on your 250 grom and what will be the weight of your grom once you have all the pieces put together and gas and oil added.

Great work and Ride safe.

Once I finalize the exhaust and radiator, button all the plastics up I will be taking it over to the dyno. According to what I have read the stock CBR250 is approx. 24HP and 13 lb.ft of torque. I'll also stop over to the local scrap yard and put it on the scale to give you the final numbers on weight! I am definitely looking forward to the 6spd, liquid cooled for sure! Just taking it down the road yesterday the gearing felt so much better. I will say one thing that caught me by surprise though was the deceleration with the steady garage chimera chain "rollers" I had completely forgot about it until I came up to the stop sign!!!! At first I was like WTF was that!! When the chain becomes slacked using engine breaking it makes like a "Spinner" noise while it rides on the rollers. It def got my attention quick because it was one of the "test rides" when your listening for every little sound to make sure it's all good..

 

[nema741]

Curious how checking/changing oil will be with the swap. I imagine the sight window is now inaccurate since the motor is leaned forward. Also, how do you get all the oil out of the motor while changing it? Lift the front wheel 10" off the ground? Not trying to be a dcik, just trying to figure out the mechanics of it all.

Funny you mention it, yesterday as I got the bike ready to fire up I needed to change the oil and filter, I did exactly that. I put the front tire up on a wooden block, and added the 1.6quarts of oil. I only put it on the block for draining purposes to make sure I got everything out. Other wise the "fill" process is straight forward and you put 1.6q in after a oil/filter change.

 

[pwr2wh8]

since you are coming fresh off a 170 4v, what's you take between the two? i've been gathering 4v parts on my end as that was what i was doing next, but a swap is definitely appealing. most of all, how does it ride? i love now nimble the grom is in the canyons and kart tracks.

 

[3sexy5u]

since you are coming fresh off a 170 4v, what's you take between the two? i've been gathering 4v parts on my end as that was what i was doing next, but a swap is definitely appealing. most of all, how does it ride? i love now nimble the grom is in the canyons and kart tracks.

Weight was a big factor when I was considering a swap. I wanted more power, but didn't want to ruin the nimble handling of the grom.

I wonder how the stock suspension is going to handle the extra weight. I feel like a fork kit is a must if you do an engine swap.

 

[MSXi]

Awesome review!

Hows the clearance at the throttle body intake? According to steadygarage theres no space at all for any kind of air filter. Can you confirm that? Is there at least space for a hose to mount an air filter somewhere else?

Thanks Mike

 

[nema741]

Awesome review!

Hows the clearance at the throttle body intake? According to steadygarage theres no space at all for any kind of air filter. Can you confirm that? Is there at least space for a hose to mount an air filter somewhere else?

Thanks Mike

Mike,

The throttle body ends very close to where the side plastics bolt up. Some individuals are running a screen with like panty hose over it which does block a lot especially since it's hidden behind the plastics. Others have put a hole in the side of the plastics to hook a filter up and it sticks out of the side about 3", this is probably the method I plan to go with. I have a pic of another guys bike that has it completed let me find it and i'll post it.

Opus/Pwr2w8,

When I went for my first ride (it wasn't very far yet, still have some things to button up before I make a maiden voyage) The weight is obviously noticeable but I didn't feel limited to throwing it around. I will give a more accurate review once I am able to go grind around on it.

Update: Yesterday I finished wiring up the Grom's Bazzaz unit to the CBR. Piece of cake! Absolutely no need to waste money on another tuner for the CBR when a piggy back system is just performing a "function" and it really doesn't matter which bike it goes on. All it needs is to be able to see the Injectr, TPS, CKPS, Speed Sensor, Neutral Switch, +12V and a ground. The only thing I had to modify on the groms Bazzaz harness was the "injector plugs".. One thing I did notice that was different on the grom vs cbr was the injector pulse wire (pink) that comes from the ECU and goes to the injector plug was on the "left" side of the groms injector plug, and the CBR had the "pink" ECU wire going to the "right" on the cbr injector plug. The Bazzaz unit gets connected into the bikes harness plug, and then the Bazzaz has another plug that goes into your injector (this is so the unit can control what the injector does) All I had to do was to make sure I supplied the Bazzaz system the same way the grom did. I cut the CBR injector plug off, and used the groms harness injector plug which helped ensure the Bazzaz was supplied with the correct "pink" pulse wire. Then on the Bazzaz "injector" plug, I cut this off and wired up my CBR injector plug; but this is where I had to "swap" the wires so the signal wire would goto the correct (left) side of the injector and perform the same functions it did on the grom.

Ok now that I've probably lost you and your confused on what I was trying to say, anyhow I hooked up the computer to the Bazzaz, checked the diagnostics and calibrated the TPS open / shut points. I had a huge score, another guy I met through the planning process of this swap hooked me up with his Bazzaz fuel map for a cbr250 in the grom.. This was huge! It saved me a lot of leg work for now, I uploaded the fuel map and tested the Bazzaz out. Fired the bike up and WOW it idles perfectly and rev's out very smooth. The bike sounds great. Cannot wait to finish up this damn exhaust and radiator. It's tough getting time to do all this with 3 kids and camping season lol!

 

[nema741]

All in all, I Probably didn't have to worry about "swapping" those injector wires when I wired in the Bazzaz injector plugs because a injector is merely a solenoid that opens and close, they still function regardless of which side sees + / - dc voltage. My big concern was just keeping everything consistent and match up to the way it was done at factory.

 

[CiscoSanJose]

Nice follow up and write up, speaking about camping my neighbor's kids took off this weekend for camping down near Monterey where the Super Bike races are being held this weekend so they will be running into a lot of motorcycles on the road and a lot of craziness. The mini moto club of Monterey holds a big mini-bike run and they all end up at Cannery Row where all the super bike gather after Saturdays qualifying races at Laguna Seca.

Can't wait for the shake down ride when all is put together, Ride safe

 

[nema741]

Alright guys, clocked 60 miles on the bike over the weekend and about 25 miles on the way to work this morning. You know that feeling when you first got your grom? Yeah that's how I feel right now. Absolutely LOVE this swap!!! While it did add weight to the bike, it makes the front end feel more "stable". You can certainly feel that the bike has extra weight but I don't feel like it negatively effects it at all. I'm sure some may say the bike doesn't feel as "nimble" but i'm still able to throw it around with ease. I do have the ND4SPDBH fork mod and I definitely feel like this is a must have with this swap. I'm still running stock fork oil, but will probably be changing that out soon. The torque of this motor is just awesome! It was so peaceful riding into work this morning and the motor just pulled me along so effortlessly. My old build Koso 170 4v setup was peppy, but man did it always have to be rev'd out high in the RPMS to produce the power. The 6 speed transmission is just soooooooo smooth, not to mention the clutch action is great! Unlike the grom's clutch engagement lol. Liquid cooled.... wow so nice not having to watch my temp gage anymore. I really like the CBR 250 cluster with the analog RPM gage.

Wheelies are super easy with this setup!! I also was able to utilize my Yoshi RS-9 slip on for now. I have yet to finalize the mount with it, I have a temp system in place as I was just too impatient to wait another few days to ride the bike (I knew with camping & kids this weekend that I wasn't going to get any work done on the bike; so a temp mount was my only hope). I still have to find a suitable place to put my licenese plate at. Right now it's zip tied to the right rear set which has it sit just behind the shock. I wish I could get away with the vertical plate mount here. I know several people that get away with it and haven't been pulled over, but I really don't feel like taking the chance. Especially since I don't have the rear turn signals on yet... Going with the integrated tail light to ease this part.

So Ill be going by the local scrap yard to put the bike on the scale and see what she weighs now then i'll report back. The weather looks great all week so i'll keep you posted as I keep clocking away miles and update my reviews. I seriously don't think my review is going to net anything negative unless I have some sort of mechanical failure lol.. Oh wait. I did have one issue. First run out I was out riding ear to ear smiles, on my way back home the bike started to cut out, and shut off a few times on me. I instantly figured it was a wiring issue because the bike was running absolutely perfect up until that point. It would restart and go fine, then randomly want to shut down. After I got home and inspected everything I realized the main "ground pack" bolt under the rear seat was loose!!! After tightening it and restarting it was very clear that was my issue.

My thoughts on the previous build Koso 170 BBK; If I had to do all this over again I would NEVER purchase a BBK, Kitaco Cover, etc, etc, etc. The CBR motor is everything I was looking for. The only application I can think of that the CBR swap might not fair well would be as a stunt bike since it does add that weight and stunt bikes don't need all the power.

Now what are you waiting for? Get on facebook marketplace, craigslist, ebay, you name it! Start looking for your swap!! I believe the best deals you will find is searching for a private seller that has a wrecked bike sitting in their garage that they just want to get rid of. Otherwise if you goto ebay for a motor you will probably pay a bit more. A donor bike is the way to go as you can save a lot of time in wiring.