Still Baffeled

[rhinoevans]

If some of you remember an earlier post on my 2002 Pitbul. Very poor DYNO (70 HP) and a very small main jet (62) to get the right a/f ratio. Started some troubleshooting.

1. Sent carb to xXx and had a complete upgrade kit and Bob checked it out and said the carb was good, except for some valve blowby on the carb. He did fix a cracked a/f mixture screw problem. Obviously someone had over tightened it. When I got the bike it had a 70 main and was still running RICH.

2. Compression and leak down on the motor last week. All numbers good. I was convinced it was a valve problem despite the fact that the bike run great cept for the loss of 20-30 ponies.

3. Installing a 600 as we speak (at the dealer). Should know more later on that. My mechanic thinks it all about the cam, so that is why we went for the 600. However, I still find it hard to believe that what ever cam is in the bike will call for a 62 main jet. I also think that the small main explains the loss of HP.

4. Pull the V&H exhaust. All looked good. Did look black and sooty from the rich condition.

5. Bike runs good, so timmng is OK.


WHAT ELSE SHOULD / CAN I check on this adventure to find 30 HP and get the correct main jet (74-76)??? :bang: :bang:

 

[Daddycool]

taking a stab here... could you have a worn lobe on the old cam?

 

[Loafington]

What are you running for an air filter system?

 

[01Mastiff]

On my 2001 Mastiff I changed from the original hooker pipes to Samson. I don't know what the HP was originally, but after that change I had Speed tune and do a dyno run on it and it came up only 74 hp (also had K&N air filter). Think they used a conservative cam back then. It was enough for me and it runs great so I am leaving well enough alone and telling people it has more hp (like I used to tell people I had a lot more sex than I did when I was married...no point in subjecting yourself to cruel remarks of others).

 

[rhinoevans]

On my 2001 Mastiff I changed from the original hooker pipes to Samson. I don't know what the HP was originally, but after that change I had Speed tune and do a dyno run on it and it came up only 74 hp (also had K&N air filter). Think they used a conservative cam back then. It was enough for me and it runs great so I am leaving well enough alone and telling people it has more hp (like I used to tell people I had a lot more sex than I did when I was married...no point in subjecting yourself to cruel remarks of others).

What was you main jet size?

S&S teardrop air intake with K&N filter

 

[scubaman15]

On my 2001 Mastiff I changed from the original hooker pipes to Samson. I don't know what the HP was originally, but after that change I had Speed tune and do a dyno run on it and it came up only 74 hp (also had K&N air filter). Think they used a conservative cam back then. It was enough for me and it runs great so I am leaving well enough alone and telling people it has more hp (like I used to tell people I had a lot more sex than I did when I was married...no point in subjecting yourself to cruel remarks of others).

Now THAT is funny!!!!!!!!:lol: :lol: :lol: :lol: :lol: :lol:

 

[lee]

are you absolutely sure you lost 30hp - that is a hell of a lot for a 100hp motor - you say it still runs great but after losing nearly 1/3rd of the power I wouldn't expect to hear you say that.

If you have lost that much you must have a pretty major issue getting air in and back out again but the exact reason I don't know

 

[Loafington]

It has a 107 right?

 

[rhinoevans]

It has a 107 right?

Yes a 107

 

[Loafington]

Compression's good, cam is good, exhaust is good, intake is good. Is your ignition shithouse or something?

 

[lee]

is your clutch ok too? could it be slipping?

 

[Loafington]

I thought the same until I saw about the dirty pipes and shit.

 

[Loafington]

Where in the power range does the power fall off, is it midrange? Where the power falls off will be a good indicator where the problem could lie.

 

[lee]

good point - may have to wait until the cam is done to know more

 

[Gas Man]

What type of dyno was it?

 

[rhinoevans]

What type of dyno was it?

I do not recall, and I am on the road in CA. What bothers me the most is the main jet size of 62. Not really concerned about HP, because I think what ever would fix the main jet size problem would solve the HP issue. Maybe not 100 HP, but definetly more than 70.

Also just picked up the S&S single bore tuned intake, and will be installing it as soon as the cam is in.

 

[Loafington]

I wouldn’t be too concerned with the actual jet size, meaning the number stamped on it. I would be more concerned with getting the air/fuel ratio correct for where ever you are. Altitude, air temperature, and relative humidity at the time of set up, have a lot to do with what jet size you ultimately end up with, so don't worry about the number that is on the jet, jet it to get it running right. My jet sizes are different than someone who does their set up at 2000 ft or even higher. Make sure you have all the basics figured out too. Make sure you do not have an underlying problem that could be causing your rich condition and low dyno numbers.

Engines are just air pumps. Getting the air/fuel ratio dialed in plays a huge part in obtaining peak performance. Sometimes we sacrifice performance for looks. Finding one that gives both can be a challenge.

 

[rhinoevans]

I wouldn’t be too concerned with the actual jet size, meaning the number stamped on it. I would be more concerned with getting the air/fuel ratio correct for where ever you are. Altitude, air temperature, and relative humidity at the time of set up, have a lot to do with what jet size you ultimately end up with, so don't worry about the number that is on the jet, jet it to get it running right. My jet sizes are different than someone who does their set up at 2000 ft or even higher. Make sure you have all the basics figured out too. Make sure you do not have an underlying problem that could be causing your rich condition and low dyno numbers.

Engines are just air pumps. Getting the air/fuel ratio dialed in plays a huge part in obtaining peak performance. Sometimes we sacrifice performance for looks. Finding one that gives both can be a challenge.

I am trying to find out if their is an underlying problem, with no success. Every thing seems normal. Do you think that at 2500msl on a standard day that a 107 with stock cam (520) and no major mods (V&H pipes and K&N filter) would DYNO at 70 with a 62 main jet? Carb OK, pipes OK, timing OK, and I guess with a good compression and leak down test, the rings and valves are OK. What else is there?

 

[lee]

what V&H pipes do you have? If the BR's 2 into 2 that is not a performance exhaust - do you still have the stock baffles in them? and 2500msl will make a bit of a difference too

 

[rhinoevans]

what V&H pipes do you have? If the BR's 2 into 2 that is not a performance exhaust - do you still have the stock baffles in them? and 2500msl will make a bit of a difference too

Big Shots I think. Basic 2 into 2 with baffels.