MPG drop after replacing tensioners?

[Jeffd]

Met a rider who rides an 05 RG with 68000 miles.  He said he had 211's and replaced the tensioners and his mpg went in the toliet.  he said he was getting mid 40's and after replacing the tensioners low 30's.  he said he checked compression and it  is over 200 on each cylinder and they are with in 1 psi of each other.  he bought the bike with 20,000miles and is not sure what it has besides 211's he said it runs strong. He said it is supposed to have been tuned with a SERT but of course he did not get the SERT with the bike so has no idea what map is in the ecm.  What would cause the drop in mpg he said nothing else done and he did the work and he said no oil blowing out the breathers and no loss of power so does not think it can be sumping.

[Admiral Akbar]

Extra drag on the cam shoes is killing the mileage.. 
Max

[Jeffd]

that much?  seems kind of drastic.

[Coyote]

Extra drag on the cam shoes is killing the mileage.. 
Max

[1FSTRK]

Does he have adjustable pushrods?

[smoserx1]

that much?  seems kind of drastic.

Max is pulling your leg and you know it.  your buddy has done something else to screw up his mileage, or he measured wrong.

[Admiral Akbar]

Did he pull the tank?. Might have gotten crud in a fuel injector.. Might be leaking..

Pulled the tank, might have damaged the map sensor?

Max

[Jeffd]

Does he have adjustable pushrods?

Yes and he said he has triple checked them to make sure they were adjusted correctly. 

[Jeffd]

that much?  seems kind of drastic.

Max is pulling your leg and you know it.  your buddy has done something else to screw up his mileage, or he measured wrong.

I know he was.  the guy put in the updated harley tensioner kit so should have 1/2 the drag.

[Jeffd]

Did he pull the tank?. Might have gotten crud in a fuel injector.. Might be leaking..

Pulled the tank, might have damaged the map sensor?

Max

Good question.  I am not sure if he did or not.  I know he has adjustable prs so would not have for that reason.  would a bad map sensor throw a code?  he threw a low battery code and had a fubbared rotor and stator that he replaced a few thousand miles after he did the tensioners.  but the mpg had dropped prior to changing the stator and rotor and right after the tensioner upgrade.

[Admiral Akbar]

Might have pinched an O ring and now it's sumping.. Would be running hotter.. Max

[Admiral Akbar]

If the Map sensor fails I'm not sure if it will throw a code, The DTT wasn't smart enough..At start MAP is high that I think that was the only time it checked.  If the sensor fails where it output 5 volts all the time the system just think that the MAP is high all the time.. On Delphi, it could look at RPM and TPS and think the MAP pressure should be low tho.. From that anomaly  it might throw a code..

Max

[Dennis The Menace]

Dumbass question of the week....did he reinstall the cams correctly?  Then again, who knows.

Told ya it was a dumb question.  Still, I wonder if he got the cams off a bit.  Not real hard to do.

[slypig]

Jeffd.  My man.  You have over 4,000 posts on this site.  You can't really expect us to believe that you are serious with this post.  200 psi compression and a loss of more than 10 MPG.  You must be lost in the black smoke from his exhaust.

Sly

[Jeffd]

Dumbass question of the week....did he reinstall the cams correctly?  Then again, who knows.

Told ya it was a dumb question.  Still, I wonder if he got the cams off a bit.  Not real hard to do.

he double checked the cam alignment and did the compression test and both cylinders are 1 psi ccc from one another so cams should be correct.

[Jeffd]

Might have pinched an O ring and now it's sumping.. Would be running hotter.. Max

that was my intial thought but he said zero loss of power and zero oil out the breathers. He said it runs great just piss poor mpg comprared to what it was.  I will have him check the map sensor and the fuel injectors. 

[Jeffd]

Jeffd.  My man.  You have over 4,000 posts on this site.  You can't really expect us to believe that you are serious with this post.  200 psi compression and a loss of more than 10 MPG.  You must be lost in the black smoke from his exhaust.

Sly

Not my bike and I doubt he is making it up.  not sure of your point.

[Admiral Akbar]

Outer gears could be advance one tooth.. What is the CR need  to be pretty high with 211s..
Max

[wolf_59]

Met a rider who rides an 05 RG with 68000 miles.  He said he had 211's and replaced the tensioners and his mpg went in the toliet.  he said he was getting mid 40's and after replacing the tensioners low 30's. he said he checked compression and it  is over 200 on each cylinder and they are with in 1 psi of each other.   he bought the bike with 20,000miles and is not sure what it has besides 211's he said it runs strong. He said it is supposed to have been tuned with a SERT but of course he did not get the SERT with the bike so has no idea what map is in the ecm.  What would cause the drop in mpg he said nothing else done and he did the work and he said no oil blowing out the breathers and no loss of power so does not think it can be sumping.

Over 200 CCP at your elevation? I would think that would be pretty high compression, possible as suggested timing off, but I'm leaning to the pinched o-ring

[crazylore]

what about the fuel he is using...has anything changed there 

[strokerjlk]

Met a rider who rides an 05 RG with 68000 miles.  He said he had 211's and replaced the tensioners and his mpg went in the toliet.  he said he was getting mid 40's and after replacing the tensioners low 30's. he said he checked compression and it  is over 200 on each cylinder and they are with in 1 psi of each other.   he bought the bike with 20,000miles and is not sure what it has besides 211's he said it runs strong. He said it is supposed to have been tuned with a SERT but of course he did not get the SERT with the bike so has no idea what map is in the ecm.  What would cause the drop in mpg he said nothing else done and he did the work and he said no oil blowing out the breathers and no loss of power so does not think it can be sumping.

Over 200 CCP at your elevation? I would think that would be pretty high compression, possible as suggested timing off, but I'm leaning to the pinched o-ring

10-12 mpg? I never seen sumping cause that much of a loss in mpg though

he said no oil blowing out the breathers and no loss of power so does not think it can be sumping.

has he pulled the plug to see?

[les]

I wonder if he cut the oil pump scavange o-ring and it's wet sumping.

[Jeffd]

if the cam was off by a tooth would he be getting the some CCC in each cylinder?  I thought one would be high and one low.  If the bike was wet sumpingg wouldn't he feel a loss of power?  he said it runs strong and feels same as before powerwise.  He said he has put 48,000 miles on it since he bought it a couple years ago so he seems like he would notice if the power dropped off.  thanks for the info I will pass this along to him.  I have not ridden with him but he stopped by to pick up a windshield and his bike sounded good and no smoke when he rode away and it definely had spunk when he was leaving.

[02roadcling]

that much?  seems kind of drastic.

Max is pulling your leg and you know it.  your buddy has done something else to screw up his mileage, or he measured wrong.

I know he was.  the guy put in the updated harley tensioner kit so should have 1/2 the drag.

And get twice the mileage.

[autoworker]

if the cam was off by a tooth would he be getting the some CCC in each cylinder?  I thought one would be high and one low.

The outer sprockets not being timed correctly would affect both cams/cylinders.

I suspect with 200psi. ccp that is where his problem is.

[Sc00ter]

It's easy enough to check for sumping.  It's worth the few minutes to eliminate the possibility. 

[Jaycee1964]

If it is stock with just the 211's the 200lbs of compression that seems awful high .  I'll bet it had a piston change and or decking of the heads.  I'de dig into it a bit more to be sure what you have.

[Jeffd]

If it is stock with just the 211's the 200lbs of compression that seems awful high .  I'll bet it had a piston change and or decking of the heads.  I'de dig into it a bit more to be sure what you have.

I informed him of this site so hopefully he will check it out.

[rigidthumper]

IIRC, 200PSI was common with 211s on a 95" SE cast hi comp piston, .030 cometic HG, and 82cc chamber build. Sumping would have to be looked at. Overfilled primary can reduce milage a little bit. Time to look at the plugs and see what is happening in the chambers.

[rbabos]

So, it runs strong, no pinging, no increased heat , no carry over to the breather. Just about rules out anything mechanical, doesn't it?
I vote botched mpg checks, or inconsistancies on how they were done. One tooth out on cam timing can have a major effect on the tuning and how it runs. I'm not reading any problems like that.
Ron

[Jeffd]

So, it runs strong, no pinging, no increased heat , no carry over to the breather. Just about rules out anything mechanical, doesn't it?
I vote botched mpg checks, or inconsistancies on how they were done. One tooth out on cam timing can have a major effect on the tuning and how it runs. I'm not reading any problems like that.
Ron

that was my thoughts on mechanical thinkgs.   His mileage dropped over 3000  miles ago and he has to fill up every day vs every other day before. He does over 100 miles a day round trip so not the math.

[rbabos]

So, it runs strong, no pinging, no increased heat , no carry over to the breather. Just about rules out anything mechanical, doesn't it?
I vote botched mpg checks, or inconsistancies on how they were done. One tooth out on cam timing can have a major effect on the tuning and how it runs. I'm not reading any problems like that.
Ron

that was my thoughts on mechanical thinkgs.   His mileage dropped over 3000  miles ago and he has to fill up every day vs every other day before. He does over 100 miles a day round trip so not the math.

Interesting. This might not even be related to the tensioner change. Could be just that a sensor happen to crap out at the same time. I'd go with the head temp and iat based on the going rich. Codes are not always thrown on these as long as they function to some extent.
Ron

[flash]

 hello i just joined this forum after jeff told me about it.        it is my bike he posted about, so i will give more info.  i bought the bike used with 24,000 or so miles on it. i had put about 35,000 miles on it before the cam chain tensioners problem. so i know what kind of gas mileage the bike got in  normal riding conditions. one of the posts thinks i may not know how to check gas mileage, so here is how i do it. fill up and reset trip meter. ride till i need gas, fill up again divide miles traveled by gallons of gas used, and i use a calculator to do the math.  the first clue the mileage had dropped was the low fuel light coming on at 147 miles. it used to come on around 190 or so unless i was traveling above 90 mph for most of the tank.  more info on the bike setup 95ci kit se211 cams se air cleaner se slip on mufflers and was tuned with the race tuner but i did not get what i need with the bike to have it retuned.        to answer a few questions from the posts i did not remove the gas tank, it has adjustable pushrods so was no need to.  i have also considered this may be unrelated to the camplate upgrade.     i changed my oil a few days ago and i drained the case from the sump plug. i got 5.5 oz. of oil ot of the case. is that enough for this to point to wet sumping? i know the crankcase dose not have much oil in it but dont know how much should come ot when drained. before i changed the oil i rode 50 miles so it would be good and warm. i am going to change the fuel filter and see if that could be it. i hate to just throw parts at this thing but am not sure where to look next. thank you for all the replies and for any help.

[Admiral Akbar]

i have also considered this may be unrelated to the camplate upgrade.

Thought you only replaced tensioners.. What else was replaced?

Max

[flash]

replaced the cam bearings in the case. lifters, and installed the se upgrade kit that is a new cam plate with hyd tensioners and the new oil pump that comes in the kit. secondary cam chain , new bearings in the camplate. primary cam chain and sprockets  which were part of the camplate upgrade kit were installed as well.   

[Sc00ter]

hello i just joined this forum after jeff told me about it.        it is my bike he posted about, so i will give more info.  i bought the bike used with 24,000 or so miles on it. i had put about 35,000 miles on it before the cam chain tensioners problem. so i know what kind of gas mileage the bike got in  normal riding conditions. one of the posts thinks i may not know how to check gas mileage, so here is how i do it. fill up and reset trip meter. ride till i need gas, fill up again divide miles traveled by gallons of gas used, and i use a calculator to do the math.  the first clue the mileage had dropped was the low fuel light coming on at 147 miles. it used to come on around 190 or so unless i was traveling above 90 mph for most of the tank.  more info on the bike setup 95ci kit se211 cams se air cleaner se slip on mufflers and was tuned with the race tuner but i did not get what i need with the bike to have it retuned.        to answer a few questions from the posts i did not remove the gas tank, it has adjustable pushrods so was no need to.  i have also considered this may be unrelated to the camplate upgrade.     i changed my oil a few days ago and i drained the case from the sump plug. i got 5.5 oz. of oil ot of the case. is that enough for this to point to wet sumping? i know the crankcase dose not have much oil in it but dont know how much should come ot when drained. before i changed the oil i rode 50 miles so it would be good and warm. i am going to change the fuel filter and see if that could be it. i hate to just throw parts at this thing but am not sure where to look next. thank you for all the replies and for any help.

2/3 oz. would be ideal, but 5.5 oz. in the crankcase is not excessive...

[wholehog]

Just for shits and grins...what was the before and after gas mileage?

[flash]

Just for shits and grins...what was the before and after gas mileage?

depending on how fast i rode 40-46 before and 31-36 after .  before i never got under 40 in 35,000 miles or so. after i have not got better than 36 in about 4,500 miles

[pappy42]

I hate a mystery!  Can't wait for the ending where the guru solves the problem.

[wholehog]

was tuned with the race tuner but i did not get what i need with the bike to have it retuned.   

even if you dont have the sert dongle, you can read the sensors with any one else's sert -- you just cant tune it.....

[barny7655]

When talking gas milage i would first go to the pump and check delivery pressure , id check air cleaner or infection, restrictions, 3rd check out the exaust system isnt blocked, and make sure the service centre you get fuel from hasnt changed supplier to a ethonol blend other than what you have been using , try a different pump gas ,make sure the bike when riding along will not pull up when in neutral  to brake drag , primary chain etc ,any air leaks aroung throttle body,sensors O rings okay , good luck , cheers Barny

[coastie56]

My fuel mileage recently dropped and my stage 2 95 would cough under hard decel,occasionally if the tank was half filled. I have read many posts with same complaints that were eventually found to be a hole in fuel line in tank. Going on reserve too soon was also my first clue. It is easy to do a basic check. Take the fuel cap off, and while you have your ear to the filler turn on the ign switch. You will hear the fuel pump pressurize than stop. When it stops it should be dead silent as it is holding 55 lbs pressure. On mine, I could hear a faint pissing/splashing noise. The pinhole in the line was allmost too small too see with my 55 year old Mark 2 eyeballs. I caught it right when it started, within a couple weeks. I was in the local dealership buying the parts so I checked a couple of their used bikes on the floor. Their parts guys were stunned and irritated when I pointed out the same noise on two other bikes, probably traded in because they couldn't diagnose the trouble! I bet this is more common than people know and I found out that my line rubbed through where it was contacting the TOP of my gas tank because they were all built too long from the factory. The updated part is an inch or so shorter.

[pappy42]

My fuel mileage recently dropped and my stage 2 95 would cough under hard decel,occasionally if the tank was half filled. I have read many posts with same complaints that were eventually found to be a hole in fuel line in tank. Going on reserve too soon was also my first clue. It is easy to do a basic check. Take the fuel cap off, and while you have your ear to the filler turn on the ign switch. You will hear the fuel pump pressurize than stop. When it stops it should be dead silent as it is holding 55 lbs pressure. On mine, I could hear a faint pissing/splashing noise. The pinhole in the line was allmost too small too see with my 55 year old Mark 2 eyeballs. I caught it right when it started, within a couple weeks. I was in the local dealership buying the parts so I checked a couple of their used bikes on the floor. Their parts guys were stunned and irritated when I pointed out the same noise on two other bikes, probably traded in because they couldn't diagnose the trouble! I bet this is more common than people know and I found out that my line rubbed through where it was contacting the TOP of my gas tank because they were all built too long from the factory. The updated part is an inch or so shorter.

OK, you baffled me here (not hard to do).  How did this leaking line lower your fuel mileage if it was leaking inside the tank?  I'm really not trying to be a smart alec; but I'm not following.

[Admiral Akbar]

I doubt leaking in the tank would do anything but let the motor run lean.Seems like that would increase gas mileage not cut mileage..   I'd look at the plugs. They should be nice and white. If not I'd look for leaking injector.. Going from 40-45 to 31-36 is a pretty radical drop. It might take putting the bike on the dyno to see if any issue can be diagnosed... Squeaking out  over 200 psi CCP could mean the outer chain is off 1 tooth but you it's not hard to get that much with higher compression pistons like Wisecos.  If the new outer chain and sprockets had some problem they could cause a change in performance but you would think that a new chain would advance the cams ever so slightly and not make much difference on the mileage..

Max

[coastie56]

A fuel pressure leak on the pressurized side of the oil pump lowered my mileage by 4 to 5 mpg, from41-42, to 36-37. It loses pressure to the injectors (the hoses are pressurized to 55 lbs per the manual) and causes the bike to stumble, and cough when the fuel level is lower than the pinhole, ie., when you brake hard and the gas flows to the front of the tank thereby sucking air intermittantly. Interestingly under most riding if the tank is full or nearly so, the bike seems to run fine. Yes i understand that it would seem that a lean condition would seem to cause it to get better gas mileage but in years of reading and tuning I have yet to see a twin cam run better in any way with a leaking fuel line. I have seen MANY people suddenly lose gas mileage and endlessly adjust power commanders and dfos and then discover that adjusting them richer was a band aid solution. If the cam was really off by a tooth it would run like crap. Anyway, it takes about 5 seconds to check and the cost is nothing.

[Admiral Akbar]

The above makes sense but it seems to me that the motor needs to be lean enough that it can't run efficiently.. In that case the motor runs like crap and the rider feels it.. Heck, a smogged bike can run bad and get a lousy mileage compared to a better tuned bike.

Is it the case above?  If the motor runs well, I'd say, "no"  Especially with a 200 ccp. There would be little balls of piston all over the plugs. Flip side with a high CCP, the motor could burn kerosene.. Too much fuel might appear as the slightest sogginess. No miss. Again you'll see it in the plugs.. I agree about cam timing.. One part of the power band will change with the cam off. Rider will feel it..

Max

[wurk_truk]

was tuned with the race tuner but i did not get what i need with the bike to have it retuned.   

even if you dont have the sert dongle, you can read the sensors with any one else's sert -- you just cant tune it.....

Jeff's TTS Datamaster will work for this, too.

[1FSTRK]

 

[slypig]

this is helpful

[1FSTRK]

I was just wondering if they have made any progress on this. It is has been a real head scratcher and I am curious to see if it can be figured out.

[slypig]

I was just wondering if they have made any progress on this. It is has been a real head scratcher and I am curious to see if it can be figured out.

Gotcha.  on me

[flash]

an update on this problem. on 9/5  even though i did not think the motor was wet sumping i pulled the oil pump and replaced th oring on the spigot. the old oring looked fine no tears i could find. while in the camchest i checked out the cam timing they were in correct.  at the same time i replaced the following  fuel filter, plug wires, plugs, as i thought it may be an unrelated problem causing this drop in mileage.  i have only rode it about a thousand miles but my mileage seems to be back to what it was before the drop. back and forth to work i have been getting 43-45 mpg running at 75 to 80 mphand have got as much as 47 on one tank. since i did more than one thing at the same time not sure what was wrong but i am back to being able to ride to and from work for two days before i need gas. i just hope winter is a long way off

[1FSTRK]

It would be interesting to see how much oil you get from the flywheel compartment now.

[hogpipes1]

If u still have the wires & plugs , back step  with the old plugs  for a tank of gas , then the wires. after all the time and work   you  put into it . if me i'd have to know  just to sleep good.

[tqjunkie]

was wondering if you are still getting 200 psi cranking pressure after putting it back together?