I am looking at the MB Black death 5500 for my 1854 Excel. I don't run all out for speed by any means, just want an efficient motor with power (occasionally) when needed.

Q: Which modifications adversely affect reliability the most and why?

I am NOT a tinkerer, however my dealer says the BD series maintains stock cam and pistons, so is reliable.
Are BPS SS valves, rockers and twin Mikunis going to make this thing really tempermental?

What do ya'll think?

Only thing I can say wit certainty is dat every motor I know of dat went "BOOM" had a Mikuni carb on it. And I do not know of any modded motors wit a stock carb to go "BOOM". I am not sayin da Mikuni is da reason, dis is just an observation of mine. Da main thing is don't raise your compression or your RPM's too high. Wit da new CDI engines RPM's being to high may be a thing of da past, but you never know, anything manmade can fail.

Single carb (BD4500) will be easier to adjust/maintain- IMO (I run the equivalent of it with a little extra)

The head work and exhaust on that motor are a proven recipe that are not affecting reliability.

I have a BD 5500 and would get the BD 4500 if I had to do it again. Mine was running way too rich on one cylinder and lean on the other. I have since adjusted everything and it's running great but I can't imagine the extra carb making all that much difference. It does suck more gas though and I only have 11 hours on it so I can comment on longevity but I'll let you know at the end of this duck season.

Team Camo, I'm believing it! makes a lot of sense. I am not a tinkerer...sounds like the 4500 is a better bet for me.

So, the SS valves and stuf is not so much an issue?

I'm also wondering what real HP ya get from the BD 4500 & 5500 as the website says these numbers are NOT HP indicators? Not that I care a lot as I'm good with my present PD-36, just want newer and perhaps a bit more power if I run a full load.

I was just fixing to say that QC, i think you like the motor alot more with a stage 1. You'll get the power you are looking for!

BJ, you know alot more than me bout these engines, and I believe if can happen. I just didn't know of any.

I kinda been thinking about a mikuni..... Just been unsure about that as of yet.

all of 'em are over-rated!

Mods are kinda like liquer,gambling, drugs, and whores. Der all fun in moderation, you just got to know when to stop.

I would say a mikuni setup would go boom faster because of there being no rev limiter( thats if you didnt install one) But it swings both ways I guess.

granted u lose the govener but the mikuini is tunable right with the rev limiter installed ur ok

Re: adding Stage one to existing PD...I think with the amount of hours I suspect is on this motor (200 +/-) I would prefer a new motor anyways. Also, I have a MB dealer/friend fairly close.

all of them do, some one way some the other. One piece ss valves add life, decking heads and larger carbs shorten life. Any thing that allows you to carry a given load faster or a heavier load the same speed is either doing it by compression (additional torque) or rpm (gearchange or additional hp through more flow and cam timing)

One adds wear one adds strain neither is good for the life of a engine.

JD

yes you would and don't doubt me on this craig because i did stay at a holiday inn suite and im feeling pretty good.

Besides having no rev limiter (by the operators choice) with a MIkuni carb the only other reason one may see more motors that have went BOOM is because the motor is making more power. More power usually equates to running WFO all the time are carrying as much sh*t as possible at WFO therefore putting more load and strain on the engine. There is a difference in a motor turning 4000 rpms light loaded and 4000 rpms with it's tounge hanging out.

At 120 hours I lost my Cam shaft. If bent a push rod. 36 HP- PD
Purcahsed 10/08 broke Jan of 2011 Just out of warranty.
So I am getting a new one installed.

I hope the new one last longer than the stock.

I am getting a high TQ version installed by a guy who works on racing go-carts and mowers.

He told B/S was having cam shaft issues.

i currently have a gtr with stage one :mikuni,heads,cam,and exhaust. next time it will have stock carb. no adjustments and no headache. burnt motor up once bc of it

I mean you guys must be running the piss out of ya'lls motors to be having all these problems! This is the first thread i have seen where people are complaining about the Mukuni's burning their motors up.

How many adjustments are u having to make on your mikuni that make it that much of a hassle?

I had 2 stage 3's go boom both times was the connector rod's which was after market . My current motor has stock rods in it. As for how one runs their motors people who ride around all the time with 2 people and a icechest they will last forever my rig is always loaded down to the gill they don't last long under pressure