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Discussion Starter #1 (Edited)
Since I've been running or using the Takegawa 181-4v BBK kit for a couple of years I came to the conclusion "which is my second post on the subject" that the piston should be made by JE or Wiseco and the exhaust valve stem or even the intake valve stem should have a little more thickness in them.

300F degree is not your friend to the piston shelves that hold the piston rings or even the valve stem.

I did notice on the 5 axis heads for the Takegawa 181-4v the company has cut into the valve stem guide and to me that will be your weak point if you are going to use your Takegawa 4v grom for a daily rider.

Yes 4v takegawa engine make really good power but with the issues I mention above you are going to be constantly changing out the piston, maybe the cylinder and maybe the heads.

As for ECM to control the A/F for these engines I believe the Aracer unit is a good choice, stand alone ECU seems to make it a little EZ for adjusting the right A/F for power an also for cooling down the piston tops at high speed running.

Even with a external oil cooler and good dia hose for the return lines, it is critical that you monitor your head temps, cylinder temps and oil temps and know when to back down on the RPM when your engine temps goes up pass 250F esp on the heads. External fan could be your friend for flowing air over the head or cylinder.

So far for me the Takegawa 181-4v is the best BBK kit followed by the Koso 170-4v BBK kit.

Food for thought those fingers for the valve adjustment are bullet proof and I have yet to have one fail on me with all the crazy testing and high speed run that I do.

One weak point on the takegawa head is the circular clip that holds in the cam, I had one come off and spin into the flywheel housing and get all bent up and caused problem to the charging circuit. Not sure how the clip came loose.

The other item to make sure you torque correctly is your cam chain guide bolt that is mounted on the out side channel of the cylinder wall, this bolt supports the rubber wheel cam guide and the bolt can spin loose and cause all kinds of pain on your engine and your wallet and that is why I made this post my bolt got loose spun off and the rubber wheel got loose and it got chewed up by the cam sprocket which produced little tiny rubber trash which plugged up my oil strainer on my engine which starved my engine of clean cooler oil causing piston failure due to the temps quickly rising to 300F.
 

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Speaking of pistons shelves, here's what my Koso 170 piston looked like during my teardown. Luckily I have a spare.

I did not gap my rings, lesson learned. Cylinder thankfully looks OK.

 

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Discussion Starter #3
Oh I did notice on both of my spare Takegawa 4v heads I did a light test thru the intake port and also the exhaust port and these heads are one's that went thru a lot of high speed runs or high heat range and I noticed that the exhaust valves seem to warp just enough to let a little light thru, so it looks like possible stem warp-age or valve lapping might need to be done or better yet replace the exhaust valve or get a complete set of intake and exhaust valves and replace the ones that are on the head. These valves are not cheap esp 4 valve set.
 

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Discussion Starter #4 (Edited)
Speaking of pistons shelves, here's what my Koso 170 piston looked like during my teardown. Luckily I have a spare.

I did not gap my rings, lesson learned. Cylinder thankfully looks OK.

I did the ring gap check and recheck and I think it is just the type of material used on the piston and the amount of heat being created by high RPM and also not having the correct A/F at the higher range such as having A/F at 11.9-12.3 range to cool down the piston tops.

Oh also even if your cylinder might look good with no scaring or scratches, I learned from BrianS who built my first BBK kit 170cc-2V that the cylinder can get out of round from the heat that was created from failure so it would be wise to check the spec of roundness with a micrometer or some type of gauge so you can see how out of round the cylinder might be or how out of spec it is to give you a good compression seal.

here is a proper way to check your cylinder to see if it's with in tolerance for a Takegawa 181 cylinder
inspection of Cylinder
Check the inside of cylinder for wear and damage.
Measure the internal diameters of the cylinder bore at 6 positions; at the piston pin angle and at the right angle to it (X-Y) each at upper, middle and lower parts of the cylinder bore.
Treat the largest value as its internal diameter.
If larger than 59.03mm, replace it.

 

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GSX Grom: 115mph - 13 something on the 1/4 mile - thousands of miles - no problems with the Takegawa piston, valves or head, and no, he's not ''lucky''.
Your piston could be made from Kryptonite by the Lord himself and you'd still have the exact same problems.
With the failure rate you have I just don't understand why you don't turn to a pro to assemble and tune it, it would have saved you thousands of $$$$ and you'd be riding instead of wrenching. I understand you like to wrench on it, I do to but I like to try to make it better, not to fix it because it broke down again.

I also don't understand how you come to the conclusion, with all the problems you've had with the Take 4 valve, without messing with the Koso 4 valve, that the Take is the better kit.
 

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sounds like the clip wasnt seated right and the bolt wasnt tight enough. or the threads were worn out due to the massive number of motor teardowns. no issues on my koso as of yet. I might need to rering as it has a ton of miles on it, but still kicking. I also ported my head and smoothed the guide down in the ports. no problems. you just have to debur the edges and do it correctly.
 

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sounds like the clip wasnt seated right and the bolt wasnt tight enough. or the threads were worn out due to the massive number of motor teardowns. no issues on my koso as of yet. I might need to rering as it has a ton of miles on it, but still kicking. I also ported my head and smoothed the guide down in the ports. no problems. you just have to debur the edges and do it correctly.
I was just sharing me experience of what happened when I didn't gap the rings - potentially this is cause.

Deburring the rings after gapping, do I just hit it with some 1000 grit after filing?
 

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I was replying to ciscos post. yeah yours looks like typical gap closed up and snapped rings. it happens. at least you didnt lunch the cyl.
 

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Discussion Starter #9 (Edited)
GSX Grom: 115mph - 13 something on the 1/4 mile - thousands of miles - no problems with the Takegawa piston, valves or head, and no, he's not ''lucky''.
Your piston could be made from Kryptonite by the Lord himself and you'd still have the exact same problems.
With the failure rate you have I just don't understand why you don't turn to a pro to assemble and tune it, it would have saved you thousands of $$$$ and you'd be riding instead of wrenching. I understand you like to wrench on it, I do to but I like to try to make it better, not to fix it because it broke down again.

I also don't understand how you come to the conclusion, with all the problems you've had with the Take 4 valve, without messing with the Koso 4 valve, that the Take is the better kit.
I'm not the only one having problems, I'm the only one posting the good and bad when I do my testing, I know for a fact there is a lot of BBK that have blown up but they don't post their results on a forum like this. I post what I experience with my builds, plus most of these other people have real race mechanic like GSX who is a world known Hayabusa racer who has professional mechanic that builds his engine.

Others on here post their fast times or 100mph runs but they will not post how many blown engines they had before getting there just the good runs or if they are using race fuel etc.

You don't understand cause you are French, we Americans do it different and we like to do it our way, if something goes wrong we fix it. No need to explain to you. Just remember you are on the internet and not all news are real or fake news or posting.

Be Hawaiian and have some Aloha in you.

 

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Cisco I understand. I've had a few engines that I've torn down just to tear into. No problems with them, I was just bored and wanted to get in there and check things out.

However, there is a point that I would just go and have someone else do it if I was continuing to have problems with something that I can't figure out. Knock on wood I haven't gotten to that point yet, but I've been damn close.
 

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I'm the only one posting the good and bad when I do my testing
Seriously? Maybe you need to pay a little more attention to what others are posting on this forum. Plenty of useful advice, nice builds and dramatic failures.
Sharing a fuck up and saying ''Look at what I did, that's stupid! Don't do it'' and learning from it is very positive, both for you and others.
Killing yet another engine and blaming parts again is useless, you can do it 500 times it's still useless to others.


You don't understand cause you are French, we Americans do it different and we like to do it our way, if something goes wrong we fix it. No need to explain to you. Just remember you are on the internet and not all news are real or fake news or posting.
It's just what you say, it's the internet. ''Location: South East France'' doesn't mean I'm a crazy french froggie. Curious as to what you would say if I posted my american birth certificate on here? lol

Still curious about your statement, why is the Take kit better?
 

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Seriously? Maybe you need to pay a little more attention to what others are posting on this forum. Plenty of useful advice, nice builds and dramatic failures.
Sharing a fuck up and saying ''Look at what I did, that's stupid! Don't do it'' and learning from it is very positive, both for you and others.
Killing yet another engine and blaming parts again is useless, you can do it 500 times it's still useless to others.



It's just what you say, it's the internet. ''Location: South East France'' doesn't mean I'm a crazy french froggie. Curious as to what you would say if I posted my american birth certificate on here? lol

Still curious about your statement, why is the Take kit better?
David don't bother wasting your time... He's living the melting pistons matrix... He took the blue pill...

Enviat des del meu LG-H870 usant Tapatalk
 

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i must not be an american.... because my bbk hasn't blown up. Makes perfect sense.
 

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Do you have any wear on the little plate that retains the rocker arm shafts? The exhaust rocker shaft dug in so far it broke a piece off the plate. I got a replacement from minimob racing. The old one seems to be some kind of stainless steel, it's slightly magnetic. The replacement part is a little thicker, the magnet sticks to it more and it has a part number etched on it. I'm not sure what caused it. I don't have an oil cooler, maybe it's getting too hot and seizing on to the shaft. I also had my straight up pump installed wrong. Sometimes it would feel like I was hitting the rear brake during a wheelie but I wasn't. I'm also on the stock fuel line. Not sure if that could be a problem or not.
 

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Discussion Starter #16
Seems like the Takegawa piston problem has been solved. I added a little more gap for the top piston ring from .28 to about .30 and increased the gap on the second ring from .31/.32 to about .33/.34, I'm also using VPracing Octanium booster of 7-8 cap full per gas fill up. I also switch over to full synthetic 10/40 Amsoil, and another thing was when I did a repair replacement of the Takegawa 181-4v piston and smothered the piston pin with assembly grease and did the same to the connecting rod and piston pin hole. I also did the same thing after I ported the intake and exhaust port by smothering the rocker arm pin with assembly grease.
 

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Since I've been running or using the Takegawa 181-4v BBK kit for a couple of years I came to the conclusion "which is my second post on the subject" that the piston should be made by JE or Wiseco and the exhaust valve stem or even the intake valve stem should have a little more thickness in them.

300F degree is not your friend to the piston shelves that hold the piston rings or even the valve stem.

I did notice on the 5 axis heads for the Takegawa 181-4v the company has cut into the valve stem guide and to me that will be your weak point if you are going to use your Takegawa 4v grom for a daily rider.

Yes 4v takegawa engine make really good power but with the issues I mention above you are going to be constantly changing out the piston, maybe the cylinder and maybe the heads.

As for ECM to control the A/F for these engines I believe the Aracer unit is a good choice, stand alone ECU seems to make it a little EZ for adjusting the right A/F for power an also for cooling down the piston tops at high speed running.

Even with a external oil cooler and good dia hose for the return lines, it is critical that you monitor your head temps, cylinder temps and oil temps and know when to back down on the RPM when your engine temps goes up pass 250F esp on the heads. External fan could be your friend for flowing air over the head or cylinder.

So far for me the Takegawa 181-4v is the best BBK kit followed by the Koso 170-4v BBK kit.

Food for thought those fingers for the valve adjustment are bullet proof and I have yet to have one fail on me with all the crazy testing and high speed run that I do.

One weak point on the takegawa head is the circular clip that holds in the cam, I had one come off and spin into the flywheel housing and get all bent up and caused problem to the charging circuit. Not sure how the clip came loose.

The other item to make sure you torque correctly is your cam chain guide bolt that is mounted on the out side channel of the cylinder wall, this bolt supports the rubber wheel cam guide and the bolt can spin loose and cause all kinds of pain on your engine and your wallet and that is why I made this post my bolt got loose spun off and the rubber wheel got loose and it got chewed up by the cam sprocket which produced little tiny rubber trash which plugged up my oil strainer on my engine which starved my engine of clean cooler oil causing piston failure due to the temps quickly rising to 300F.

Hello CiscoSanJose,

I'm almost done installing my Take 4v kit and had concerns like you with the circlip holding the cam. I pushed a good amount of force on the cam but I still feel like the circlip may come loose. Doesn't feel there's a ton of tension against the groove and can easily slide it out with a small pick. DO you think centrifugal force makes it tighter if engine is running? Is yours pretty snug?

Thanks..
 

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Hello CiscoSanJose,

I'm almost done installing my Take 4v kit and had concerns like you with the circlip holding the cam. I pushed a good amount of force on the cam but I still feel like the circlip may come loose. Doesn't feel there's a ton of tension against the groove and can easily slide it out with a small pick. DO you think centrifugal force makes it tighter if engine is running? Is yours pretty snug?

Thanks..
There are no heavy side forces to the cam. That ring just holds it in place.

You've got forces from the valves/rockers and the cam chain/sprocket. No major side loading.

Make sure the groove the circlip rides in is clear and install it.

Also make sure your bearing journals are clear so the cam is fully seated.
 

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There are no heavy side forces to the cam. That ring just holds it in place.

You've got forces from the valves/rockers and the cam chain/sprocket. No major side loading.

Make sure the groove the circlip rides in is clear and install it.

Also make sure your bearing journals are clear so the cam is fully seated.
Thank you. I was just worried since the circlip barely has tension that it may come dislodge from the groove with a hard bump or something.

You're right, I forgot that the circlip won't be spinning. wth was I thinking, kind of thought of the whole bearing spinning.
 
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