Big Bore Time!!!
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Joined: Aug 2015
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From: Wichita, Ks
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Question for anybody that bought a custom carb from Bill: Did you get a little plastic baggie with writing on the outside and what I'm assuming is a needle jet inside? Because I did, and the writing on the baggie say "P 40 M 140" I'm guessing this means that the Pilot jet is a #40 and the Main jet is #140, but all my tools are at the place where the bike is, and the carbs are sitting next to me. I'm basically trying to determine if those are his recommendations for what I should use, or if the writing means that is what he installed already for me based on what I told him about the aftermarkets on my bike.
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Joined: Mar 2013
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From: Young Harris, GA
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On the rings-the idea is to position the end gaps of adjacent rings so they are NOT stacked on top of each other. You are just trying to make the most circuitous path for gasses to get past the gaps-the rings rotate as the engine runs so it's really not that critical.
I'm still running my oe battery in my '12 and she spins over just fine.
The job is really just unbolt and bolt on new parts-Bill is thorough about checking clearances on bore and ring gap but it's still your responsibility to verify. Just take your time and follow the manual-it's not that hard.
I'm still running my oe battery in my '12 and she spins over just fine.
The job is really just unbolt and bolt on new parts-Bill is thorough about checking clearances on bore and ring gap but it's still your responsibility to verify. Just take your time and follow the manual-it's not that hard.
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Joined: Oct 2013
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Hey guys,
I am following this post for future reference.
I saw that LemonRX asked, but no one seemed to address (or I didn't see it) that one question of whether most are leaving the KACR functional with the big bore kit.
I disabled the KACR when I did the MCM, and am considering the BB331 or BB351 over the winter. I understand that most are NOT running the MCM with big bore, correct?
Thanks in advance!
TC
***BTW, with the MCM and the disabled KACR, the big starts like a dream! Barely a second or two on the start button! (Ah .018 drill through the start jet prior to the mods also) I'd hate to lose that with the big bore...
I am following this post for future reference.
I saw that LemonRX asked, but no one seemed to address (or I didn't see it) that one question of whether most are leaving the KACR functional with the big bore kit.
I disabled the KACR when I did the MCM, and am considering the BB331 or BB351 over the winter. I understand that most are NOT running the MCM with big bore, correct?
Thanks in advance!
TC
***BTW, with the MCM and the disabled KACR, the big starts like a dream! Barely a second or two on the start button! (Ah .018 drill through the start jet prior to the mods also) I'd hate to lose that with the big bore...
Last edited by timc63; Nov 9, 2016 at 05:20 AM. Reason: Addl thought...
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Joined: Jul 2015
Posts: 302
From: Milton Ont Canada
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Hey guys,
I am following this post for future reference.
I saw that LemonRX asked, but no one seemed to address (or I didn't see it) that one question of whether most are leaving the KACR functional with the big bore kit.
I disabled the KACR when I did the MCM, and am considering the BB331 or BB351 over the winter. I understand that most are NOT running the MCM with big bore, correct?
Thanks in advance!
TC
***BTW, with the MCM and the disabled KACR, the big starts like a dream! Barely a second or two on the start button! (Ah .018 drill through the start jet prior to the mods also) I'd hate to lose that with the big bore...
I am following this post for future reference.
I saw that LemonRX asked, but no one seemed to address (or I didn't see it) that one question of whether most are leaving the KACR functional with the big bore kit.
I disabled the KACR when I did the MCM, and am considering the BB331 or BB351 over the winter. I understand that most are NOT running the MCM with big bore, correct?
Thanks in advance!
TC
***BTW, with the MCM and the disabled KACR, the big starts like a dream! Barely a second or two on the start button! (Ah .018 drill through the start jet prior to the mods also) I'd hate to lose that with the big bore...
I think it's Bill Blue that doesn't recommend the MCM with the big bore, but I can't remember exactly why.
My bike starts with maybe 1-2 seconds on the start. Once it's all dialed in, it's runs very well.
Last edited by Dash8; Nov 9, 2016 at 11:49 PM.
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Posts: 4,507
From: SW Idaho
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I didn't remove the KACR, but will likely disable it next time I'm in there.
Dash8, I think you're correct on Bill's concern with the MCM and I thought they were described in the main MCM thread. I also recall a guy, David perhaps, from NY who did the MCM on a big bore and was not impressed with the results and went back to stock. This was before klxter's in depth research and experimentation with jetting, which possibly may have solved David's problems.
Dash8, I think you're correct on Bill's concern with the MCM and I thought they were described in the main MCM thread. I also recall a guy, David perhaps, from NY who did the MCM on a big bore and was not impressed with the results and went back to stock. This was before klxter's in depth research and experimentation with jetting, which possibly may have solved David's problems.
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Joined: Jun 2013
Posts: 3,315
From: North Texas
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David R ran the MCM on his 351 briefly- he wound it up to redline quite a bit - proving that there is no valve-piston clearance issues.
Unfortunately his assessments and opinions are quite difficult to understand - on one he praises the "new power", on another he "diss's it" - He sounded like me when I'm drunk..lol
Also unfortunate is that he ran his 351 with a lid and snorkel AND a hand fashioned quiet tip "stinger" that had the exhaust exiting through a 3/4" copper pipe ! How you jet properly for that is waay beyond my knowledge..lol
Anyway, point is that there is no issue with MCM and the 351 kit - Bill verified that clearances are "as stock" and David R ran it hard with MCM..
Bill will issue a blanket "don't do it" to anyone that contacts him about "fooling" with cam phasing with his kit(s) - and I don't blame him..
Now having said all that - It seems the MCM may "bleed" HP/TRQ a tiny bit more than stock timings above 6.5K. So while a 351(with MCM) would be "stupid" powerful below 6.5k, it looks like it will not "feed it" as well above that compared to stock timings..
There is the fact that we are talking about existing ports, valves, and cam lobes, feeding a 100CC increase in displacement. It is quite possible that they cannot properly "flow and feed" the upper rpm range of a 351 even with stock cam timings - in which case, getting all that crazy TRQ below 6.5k - 7k with MCM may be a "best mod" ...
Unfortunately his assessments and opinions are quite difficult to understand - on one he praises the "new power", on another he "diss's it" - He sounded like me when I'm drunk..lol
Also unfortunate is that he ran his 351 with a lid and snorkel AND a hand fashioned quiet tip "stinger" that had the exhaust exiting through a 3/4" copper pipe ! How you jet properly for that is waay beyond my knowledge..lol
Anyway, point is that there is no issue with MCM and the 351 kit - Bill verified that clearances are "as stock" and David R ran it hard with MCM..
Bill will issue a blanket "don't do it" to anyone that contacts him about "fooling" with cam phasing with his kit(s) - and I don't blame him..
Now having said all that - It seems the MCM may "bleed" HP/TRQ a tiny bit more than stock timings above 6.5K. So while a 351(with MCM) would be "stupid" powerful below 6.5k, it looks like it will not "feed it" as well above that compared to stock timings..
There is the fact that we are talking about existing ports, valves, and cam lobes, feeding a 100CC increase in displacement. It is quite possible that they cannot properly "flow and feed" the upper rpm range of a 351 even with stock cam timings - in which case, getting all that crazy TRQ below 6.5k - 7k with MCM may be a "best mod" ...
Last edited by Klxster; Nov 10, 2016 at 01:33 AM.
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Joined: Jun 2013
Posts: 3,315
From: North Texas
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timc63, if you're near sea level, it would be nice if you would put a DJ144 or K158 main jet, reset the clip to 1N, put the stock spring back on the slide, pull the lid off the airbox, and give us a report - I expect at least same power below 7K with significant increase above.
We have no information regarding running a 351 with the KACR disabled. Obviously, the only concern would be possible over-stressing on the starter. Since starting is usually "instant", a person might not see any strain unless trying to start with stale fuel or a flooded carb..
We have no information regarding running a 351 with the KACR disabled. Obviously, the only concern would be possible over-stressing on the starter. Since starting is usually "instant", a person might not see any strain unless trying to start with stale fuel or a flooded carb..
Last edited by Klxster; Nov 10, 2016 at 01:47 AM.
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From: Wichita, Ks
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timc63 Since there doesn't seem to be anybody that has installed the 351 and disabled the KACR, I will be doing the same and leaving it intact. I'm taking this install time to remove all the smog tubes, just have to make sure I get the other ends plugged.
I got the head and cylinder pulled last night, and I felt bad. My piston had a nice layer of carbon build up on it, and my exhaust valves/valve stem have a nice coating of white stuff. This means that it was running lean, correct? Luckily for me, I had already talked to the local Kawasaki shop about having it ported and polished, 1mm oversized valves installed, and a valve adjustment done. I'm sure the bigger valves won't cause any problems with the 351 right? The indentions in the bigger piston match up with the stock piston, and I haven't heard of any issues with it.
I got the head and cylinder pulled last night, and I felt bad. My piston had a nice layer of carbon build up on it, and my exhaust valves/valve stem have a nice coating of white stuff. This means that it was running lean, correct? Luckily for me, I had already talked to the local Kawasaki shop about having it ported and polished, 1mm oversized valves installed, and a valve adjustment done. I'm sure the bigger valves won't cause any problems with the 351 right? The indentions in the bigger piston match up with the stock piston, and I haven't heard of any issues with it.
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Yes Klx678, I know I've got quite a bit to clean up. I've bought several cans of degreaser, brake clean, and lots of shop towels in preparation for this.
Dash8, I've been through the good write-ups several times over (I have a few of them open in other tabs and browsers right now) as well as going through Mr DuhFactor's playlist on youtube when he did his big bore kit. Hopefully I don't have to make a Thanksgiving day run to a machine shop. As far as rings go, mine were already set on the piston when I picked it up, and if I remember correctly they need to be positioned to where the openings are spaced evenly apart around the circumference, yes?
2007 Green Machine, I bought a new battery last year when the Ballistic battery in it went bad. It's just a boring Everstart Powersport AGM from Walmart, but I haven't had any problems with it, even when the bike has sat for months without being on a trickle charger. Question for you, when you did your big bore kit did you leave the KACR connected? I know disconnecting it while it's still a 250 seemed to make it start easier for others, but I'm not sure if it would be the same way with the 351.
outrecording, I have been making very detailed sketches and notes when I take these things apart now. I usually have a camera that I devote solely to one project and take pictures of everything, then go through them backwards to reassemble, but I forgot it when I started so I'm going old school. I also have a GIANT drip pan (like a cookie sheet but bigger) that I have been laying parts and pieces on very meticulously. Had issues when I had to replace my shift star so I'm very careful now.
Back to Dash8, I'll definitely keep a EarthX battery in mind if this AGM one starts cranking slow....also contemplating a kick-starter for fun.
CONTINUED: So far I've had to make a store run to get the proper sized tool to remove the head bolts. I couldn't find what size it was online, so I got there and had to stop. Made it to Lowe's before they closed today and picked up a 8mm Hex with a 3/8" drive attachment so I can just hook it up to my torque wrench to bust them loose.
Still haven't been able to find torque specs for head bolts or cam girdle bolts though. Help?
Dash8, I've been through the good write-ups several times over (I have a few of them open in other tabs and browsers right now) as well as going through Mr DuhFactor's playlist on youtube when he did his big bore kit. Hopefully I don't have to make a Thanksgiving day run to a machine shop. As far as rings go, mine were already set on the piston when I picked it up, and if I remember correctly they need to be positioned to where the openings are spaced evenly apart around the circumference, yes?
2007 Green Machine, I bought a new battery last year when the Ballistic battery in it went bad. It's just a boring Everstart Powersport AGM from Walmart, but I haven't had any problems with it, even when the bike has sat for months without being on a trickle charger. Question for you, when you did your big bore kit did you leave the KACR connected? I know disconnecting it while it's still a 250 seemed to make it start easier for others, but I'm not sure if it would be the same way with the 351.
outrecording, I have been making very detailed sketches and notes when I take these things apart now. I usually have a camera that I devote solely to one project and take pictures of everything, then go through them backwards to reassemble, but I forgot it when I started so I'm going old school. I also have a GIANT drip pan (like a cookie sheet but bigger) that I have been laying parts and pieces on very meticulously. Had issues when I had to replace my shift star so I'm very careful now.
Back to Dash8, I'll definitely keep a EarthX battery in mind if this AGM one starts cranking slow....also contemplating a kick-starter for fun.
CONTINUED: So far I've had to make a store run to get the proper sized tool to remove the head bolts. I couldn't find what size it was online, so I got there and had to stop. Made it to Lowe's before they closed today and picked up a 8mm Hex with a 3/8" drive attachment so I can just hook it up to my torque wrench to bust them loose.
Still haven't been able to find torque specs for head bolts or cam girdle bolts though. Help?
I did mine in the bike... You can keep a lot of the bolts in their respective covers, to save on bags. just make sure you have a torque wrench and take your time... Mine took a good few attempts to start and had me worried at first. But once she fired up, she ran like a champ... Also did the pumper carb at the same time. So my job was more complicated. (removed one of the throttle cables) and had to rejet the pumper to get it right.
Last edited by TheDoc46; Nov 10, 2016 at 08:16 PM.
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Joined: Feb 2011
Posts: 164
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Question for anybody that bought a custom carb from Bill: Did you get a little plastic baggie with writing on the outside and what I'm assuming is a needle jet inside? Because I did, and the writing on the baggie say "P 40 M 140" I'm guessing this means that the Pilot jet is a #40 and the Main jet is #140, but all my tools are at the place where the bike is, and the carbs are sitting next to me. I'm basically trying to determine if those are his recommendations for what I should use, or if the writing means that is what he installed already for me based on what I told him about the aftermarkets on my bike.
Also don't forget to pull your plug every few hundred to get a reading to make sure you're not lean.