Bad/Worn Combustion Chamber

[Dancallun]

Hi everyone, just got some bad news about my 2011 Busa. Looks like one of the chambers is only testing at 150. I know it could be worse and I still love how the bike rides, but I thought it would be much better since I bought it with only 16k miles.

I was wondering if any engine displacement work would solve this problem? I was looking at these guys:

Carpenter Racing

and was wondering if anyone has any experience with this company or this type of engine work. It sounds like some of the options involve boring out and increasing the chamber size, would this fix a chamber with damaged surface? Also wondering what that would do to gas mileage. Any advice on what to do with this would be appreciated, would like to either upgrade or keep repair costs as low as possible, thanks.

[HayaWakened]

Hi everyone, just got some bad news about my 2011 Busa. Looks like one of the chambers is only testing at 150. I know it could be worse and I still love how the bike rides, but I thought it would be much better since I bought it with only 16k miles.

I was wondering if any engine displacement work would solve this problem? I was looking at these guys:

Carpenter Racing

and was wondering if anyone has any experience with this company or this type of engine work. It sounds like some of the options involve boring out and increasing the chamber size, would this fix a chamber with damaged surface? Also wondering what that would do to gas mileage. Any advice on what to do with this would be appreciated, would like to either upgrade or keep repair costs as low as possible, thanks.

@Boosted Cycle Perf might have some input on this

[CBXRider]

Hi everyone, just got some bad news about my 2011 Busa. Looks like one of the chambers is only testing at 150. I know it could be worse and I still love how the bike rides, but I thought it would be much better since I bought it with only 16k miles.

I was wondering if any engine displacement work would solve this problem? I was looking at these guys:

Carpenter Racing

and was wondering if anyone has any experience with this company or this type of engine work. It sounds like some of the options involve boring out and increasing the chamber size, would this fix a chamber with damaged surface? Also wondering what that would do to gas mileage. Any advice on what to do with this would be appreciated, would like to either upgrade or keep repair costs as low as possible, thanks.

What makes you think boring or honing a cylinder would fix it? Valves or rings could be the culprit.

[Berlin Germany]

@Dancallun
simple question
the 150 at one single cyl only
or at all 4 ?

if at all 4 at around 150
do the compr. test again with full opened throttles.

who can´t breathe can´t compress.

if only at one check at first its valve clearance(s)
and the others in same job too.
16k miles is the standard maintenance intervall

honing / boring the cyl. won´t make sense like wuzza alr. said
the nikasil coated cylinders usually last longer than 100-150k mi.
(months ago an odo was shown here on a pic with over 280k mi)

for checking the ring(s) fill in a drop of motoroil and do the test again.
if the the psi rise with that
a ring might be damaged
or the piston ring groove in the piston is coked - then a piston ring can no longer seal properly and therefore cannot generate good compression.
(and if the oil control ring is coked, a motor literally drinks oil like a camel while drinking)

a busa from 2011 around 10 years old today and only driven 16k miles?
for me, this indicates a lot of short-haul journeys, which can lead to coking.
but to find out, the motor and the head including the cylinder block have to be removed .

do you want to have something like that done (by a shop) calculate a good 12 hours of working time + a few hours for other additional work
and "anorexia" will plague your wallet.

[Boosted Cycle Perf]

Yeah that’s definitely low. I think spec is 190-230psi or right about there.

Theres 3 reasons why you get low compression. First and the most common is a bad head gasket, usually cause by over heating. The other two are leaking from the valves or the piston rings. A leak down test will give you a better idea of where you’re losing compression at.

I have yet to see a stock Busa come to me with low compression because of excessive ring wear. I’ve seen low compression as a result of the bike sitting for years and the rings just get stuck. Fuel treatment and some good beating on it will free them back up.

I’ve had several stock bikes come in over the years with bent valves. Come to find out the owners were “those guys” that free rev the crap out of the bike, and hold it in the rev limiter to show off to the “crew”.

My money is on the head gasket.

[Berlin Germany]

@Boosted Cycle Perf

yep
to be precise it is at 199 – 256 psi and the limit is 142 psi
foundable in the gen2 manual at page 0C-2 Service Data

and yep again - head gasket - but for that he should have mentioned that the water level rises a lot - he didn´t yet

and a leak down test can give a good hint too - if the gasket is bad it would either pump up the water tank or you will hear a hissing at the oil cap / at the mufflers.

but a bent valve? at 16 k mi? man? how often and how hard must the engine be abused?

i stick (full of hope) with my first suspicion - throttle valve(s) not fully open - would be the simplest and cheapest solution

and @Dancallun did not mentioned what values he had at the other cyls.
or if water level rises when engine/water hot
and what mileage the busa today really has.

[jellyrug]

Yeah that’s definitely low. I think spec is 190-230psi or right about there.

Theres 3 reasons why you get low compression. First and the most common is a bad head gasket, usually cause by over heating. The other two are leaking from the valves or the piston rings. A leak down test will give you a better idea of where you’re losing compression at.

I have yet to see a stock Busa come to me with low compression because of excessive ring wear. I’ve seen low compression as a result of the bike sitting for years and the rings just get stuck. Fuel treatment and some good beating on it will free them back up.

I’ve had several stock bikes come in over the years with bent valves. Come to find out the owners were “those guys” that free rev the crap out of the bike, and hold it in the rev limiter to show off to the “crew”.

My money is on the head gasket.

Blown head gasket, first signs are almost always water content in the oil and/or discoloration of the coolant. Never needed a compression test to diagnose a blown gasket.

[Dancallun]

What makes you think boring or honing a cylinder would fix it? Valves or rings could be the culprit

What makes you think boring or honing a cylinder would fix it? Valves or rings could be the culprit.

Damn sorry I thought I put it in there but must have accidentally deleted it. It is the chamber wall that's the problem, that's what the mechanic told me and I trust him.

[bigoltool]

Leak down testers are super cheap, or even free to rent at auto parts stores. Just need a compressor. I have a set of simple screw in fittings I bought decades ago for exactly this purpose. A compression test should just be the first step before you start tearing down your motor.

[Dancallun]

@Dancallun
simple question
the 150 at one single cyl only
or at all 4 ?

if at all 4 at around 150
do the compr. test again with full opened throttles.

who can´t breathe can´t compress.

if only at one check at first its valve clearance(s)
and the others in same job too.
16k miles is the standard maintenance intervall

honing / boring the cyl. won´t make sense like wuzza alr. said
the nikasil coated cylinders usually last longer than 100-150k mi.
(months ago an odo was shown here on a pic with over 280k mi)

for checking the ring(s) fill in a drop of motoroil and do the test again.
if the the psi rise with that
a ring might be damaged
or the piston ring groove in the piston is coked - then a piston ring can no longer seal properly and therefore cannot generate good compression.
(and if the oil control ring is coked, a motor literally drinks oil like a camel while drinking)

a busa from 2011 around 10 years old today and only driven 16k miles?
for me, this indicates a lot of short-haul journeys, which can lead to coking.
but to find out, the motor and the head including the cylinder block have to be removed .

do you want to have something like that done (by a shop) calculate a good 12 hours of working time + a few hours for other additional work
and "anorexia" will plague your wallet.

Yes it's only one cylinder, it's at a shop and they said the chamber wall is bad. I only talked to them briefly but it sounded like you can't repair it because it's part of the block. These engines have some kind of upper and lower block though right?

[Dancallun]

What makes you think boring or honing a cylinder would fix it? Valves or rings could be the culprit.

It's the chamber wall, mechanic said there is no easy fix. It's not the gasket, rings, pistons.

[Dancallun]

Just to add an update, sorry I wasn't more specific in my original post. The bike is at a mechanic shop now and they specialize in sport bikes. They said the chamber wall is bad and it's not gaskets, rings or anything that can be replaced. The compression is only bad in one cylinder, the rest are at 220-223

[Dancallun]

Yeah that’s definitely low. I think spec is 190-230psi or right about there.

Theres 3 reasons why you get low compression. First and the most common is a bad head gasket, usually cause by over heating. The other two are leaking from the valves or the piston rings. A leak down test will give you a better idea of where you’re losing compression at.

I have yet to see a stock Busa come to me with low compression because of excessive ring wear. I’ve seen low compression as a result of the bike sitting for years and the rings just get stuck. Fuel treatment and some good beating on it will free them back up.

I’ve had several stock bikes come in over the years with bent valves. Come to find out the owners were “those guys” that free rev the crap out of the bike, and hold it in the rev limiter to show off to the “crew”.

My money is on the head gasket.

Yeah it's the chamber wall that's bad unfortunately. The shop I bought it from was shady and the more I dig into this bike and have the mechanic look at it the more I can see the previous owner mistreated this bike. I know the Busa is super tough and reliable, honestly I still want to get a few more and style/build them for different purposes. They're so cool looking and fit me perfectly for handling, power etc. I know the 2021 is a let down but I do like the body and new exhaust and still want to get one.
It's my fault too though on this bike, the air filter was disgusting and I should have checked it when I got the bike, maybe it cause some damage idk. Place I got it from was supposed to be a maintenance place too. Motorcycle City in Lemon Grove CA, I'm taking my good reviews down.

[Dancallun]

@Boosted Cycle Perf

yep
to be precise it is at 199 – 256 psi and the limit is 142 psi
foundable in the gen2 manual at page 0C-2 Service Data

and yep again - head gasket - but for that he should have mentioned that the water level rises a lot - he didn´t yet

and a leak down test can give a good hint too - if the gasket is bad it would either pump up the water tank or you will hear a hissing at the oil cap / at the mufflers.

but a bent valve? at 16 k mi? man? how often and how hard must the engine be abused?

i stick (full of hope) with my first suspicion - throttle valve(s) not fully open - would be the simplest and cheapest solution

and @Dancallun did not mentioned what values he had at the other cyls.
or if water level rises when engine/water hot
and what mileage the busa today really has.

It's definitely the chamber wall that's what the shop said, the others are at 220-223. What do you mean the limit is 142? You're not supposed to ride it with compression lower than 142?

[Dancallun]

Leak down testers are super cheap, or even free to rent at auto parts stores. Just need a compressor. I have a set of simple screw in fittings I bought decades ago for exactly this purpose. A compression test should just be the first step before you start tearing down your motor.

Thank you, a compression test is what they did at the shop. He said they used oil to test it too (idk how that works), not sure if the throttle was open but I'm guessing it was since the other cylinders tested over 220. He told me it's no easy fix, that they were hoping it was a gasket or ring or something but it's not

[bigoltool]

Thank you, a compression test is what they did at the shop. He said they used oil to test it too (idk how that works), not sure if the throttle was open but I'm guessing it was since the other cylinders tested over 220. He told me it's no easy fix, that they were hoping it was a gasket or ring or something but it's not

The oil will bump it temporarily as it gets around the rings... If the rings are the problem. Applying air pressure via a leak down tester, or simple fitting as I described will allow you to isolate the problem, whether it's rings, a gasket, a valve etc.

[Bumblebee]

Doesn't sound like an inexpensive repair....the good thing is the Hayabusa engine is able to be repaired unlike other brands...

[jellyrug]

It's the chamber wall, mechanic said there is no easy fix. It's not the gasket, rings, pistons.

After 20 years, I still have work at learning American English. What is a chamber wall?

If you have scoring of the cylinder bore on only one cylinder, it is unlikely that the rest is OK. Time to pull her apart.

[Dancallun]

Thank you, chamber wall is probably called the cylinder wall (first pic seems to call it a chamber wall, 2nd calls it cylinder wall). They didn't specifically say it had scoring just that it was an uneven surface and compression was low in only one cylinder. I don't have the means to pull it apart right now, I moved in with my father to help him start a business and it turned out to be a huge mistake, place is a mess and he loses my tools. Moving out in a few months will at least have a safe place for my tools. Do you think it's a terrible idea to ride it as is? I mean it's still fast for me and I haven't lost a race to any of thes cocky street racers yet lol. I'm still considering increasing the displacement of the engine, is that not done by boring out the cylinder walls to be bigger?

[Berlin Germany]

@Dancallun

a nikasil coated chamber (no one calls it that way) cylinder wall shall be scratched?

can´t be - nikasil is nearly as hard as diamonds the cyls are good for more than 150 000 mi !!!

ask the so called specalists for a camera pic of the scratch
they should have such a pic because they only can say so if they have a special endoscope camera that fits through the spark hole into the cylinder
if they can´t show you that pic flee that shop with your bike
they wanna robb you by a huge fine

what cost estimate did they make?

as we say here - they ly in the moment they open their mouth

so my recom. was to
go somewhere who has the endoscope and look inside
if there is really in deed a scratch (what i can´t believe)
go to ebay and buy a used cylinderblock and its pistons (all under 50 000 mi are good and usable) where the seller says seriously that he had measured all the cyl. and the pistons in 1/100 of a millimeter !!!
ask the seller for pics of his cyl.-block and its pistons
and if both are better than then limit (see manual)
both are in good conds.
after getting the cyl/pitons join your suzuki dealer and get a set of piston rings for all 4 pistons
plus the head gasket and the "foot" gasket

the rest of the job is best described in the manual (gen2)
only prerequisite is that you have the correct tools (torque 4-20 & 20-80 Nm, metric ratchet, etc.) and a good knowledge of "screwing/wrenching" a motor and bike.

then the job won´t bring anorexia to your wallet