TRX250R.ORG
Workshop => Engine and Bottom End => Topic started by: TRXDAN on April 25, 2016, 12:37:31 PM
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have a question. but heres my set up first.its a 350 cylinder 78.5mm bore with a 5mil stroker crank trx11 porting and trx11 pipe. i'm looking for a tad bit more power. i am currently running a stock ignition, is that hurting me? also whats the most timing i can run on it?
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Step #1 is the ignition. Looking for more anywhere else at this time will still be being held back from its potential by the ignition.
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What are my options...cr250 ignition? Or?..id still like to have my light if possible
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The cr ignition is a HUGE upgrade!!! Well worth the money. Some companies claim to rewind the stator for lights or you will have to go with a battery setup
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guess ill be looking for a cr ignition. will i gain anything from advancing the time as well?
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I got a cr ignition to try on mine as well TRXDAN, I also do some night duning so keeping the headlight was a necessity. Ill be going with the battery set up that Grande mentioned earlier. Led light bars dont draw as much juice as the halogen setups. With a good battery I should be able to get a few nights of riding on one charge. Ive heard that the rewound stators are not very reliable (dont know to the validity of that.) Due to the oilfield picking back up I havent had a whole lot of free time to install the cr and hook the light bar directly to the battery. Ill let you know how it goes, should be getting to it pretty quick. Also, this is just my experience, my friend and I had more problems than good messing with the timing on a factory trx ignition. May work for others, but our setups didnt like it.
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Do you have timing adjust plate, give it 4-6 degrees of timing,have it reported, custom cut dome .. Race gas with proper compression
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I got a cr ignition to try on mine as well TRXDAN, I also do some night duning so keeping the headlight was a necessity. Ill be going with the battery set up that Grande mentioned earlier. Led light bars dont draw as much juice as the halogen setups. With a good battery I should be able to get a few nights of riding on one charge. Ive heard that the rewound stators are not very reliable (dont know to the validity of that.) Due to the oilfield picking back up I havent had a whole lot of free time to install the cr and hook the light bar directly to the battery. Ill let you know how it goes, should be getting to it pretty quick. Also, this is just my experience, my friend and I had more problems than good messing with the timing on a factory trx ignition. May work for others, but our setups didnt like it.
thanks for the info turkey ill be looking forward to the updates
Do you have timing adjust plate, give it 4-6 degrees of timing,have it reported, custom cut dome .. Race gas with proper compression
no plate yet i will be ordering soon. as far as custom dome yes. unsure of cc's but it cannot run on pump gas i built it for only race gas.
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is this an older esr cylinder or a newer one... made within the past 2 years? reason i ask is the older style esr cylinders that eddie did for stroker cranks did not have the port timing adjusted correctly and can tend to be a bit down on power.
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is this an older esr cylinder or a newer one... made within the past 2 years? reason i ask is the older style esr cylinders that eddie did for stroker cranks did not have the port timing adjusted correctly and can tend to be a bit down on power.
cylinder was bought in 2013. it runs very hard it runs side by side with 4 mil drag ported banshees. i have videos on youtube of it too....but to me the bike pulls hard on bottom end but seems to not rev out and pull in higher rpm. almost feels like a cr500.
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well being a drag port and a drag pipe, it should be quite the opposite........ there may be more to the problem then just "needing more power"
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well being a drag port and a drag pipe, it should be quite the opposite........ there may be more to the problem then just "needing more power"
when i got the cylinder bored for the first time the guy said it was out of squar really bad. really didn't understand what he meant.
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i bought this motor from a guy it had low hours but he could not get it to run properly. when i got it, it would detonate a lot and blew quit a few head o rings before it finally had a light seizure and thats when i rebuilt it. but since then its ran great no more detonation/pinging or blowing orings.
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i bought this motor from a guy it had low hours but he could not get it to run properly. when i got it, it would detonate a lot and blew quit a few head o rings before it finally had a light seizure and thats when i rebuilt it. but since then its ran great no more detonation/pinging or blowing orings.
Is the TRX 11 pipe a center mount or out of frame silencer?
Are you using it for 300 ft drags only or other types of riding where you are at wide open throttle for more that 5 seconds at a time?
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Is the TRX 11 pipe a center mount or out of frame silencer?
Are you using it for 300 ft drags only or other types of riding where you are at wide open throttle for more that 5 seconds at a time?
center mount With silencer. Its a hill shooter its about a 5 second run. Start from first and end up in high 4th at the end of the hill.
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it doesn't feel like it's running out of fuel but if you stay in one gear too long and there's no power it seems to peek out until you shift to the next gear and it pulls hard again. So the shifts are coming on pretty quick. I'll post a video and you'll be able to hear my 250 over the banshee and you could hear how fast I go to the gears.
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https://youtu.be/hEGglOLvYi8
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gearing?
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13 42. I just put a 14 up front i havnt tried it yet
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Have you enlarged the stinger on the end of the TRX11???....I run almost exactly the same setup as you and it made a difference.....But I also run a CR ignition...
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Have you enlarged the stinger on the end of the TRX11???....I run almost exactly the same setup as you and it made a difference.....But I also run a CR ignition...
what did you do to enlarge it?
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13 42. I just put a 14 up front i havnt tried it yet
13/42 is about the same as 12/39 which is pretty low gearing. 12/39 is whats on my wife's R for slower tight woods riding. Maybe try a 39 or 38 rear along with the 14 front.
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In the video it sounds like you are over-revving it on the last part of the hill. I would take one to two teeth off of the rear sprocket and see if that will keep it running closer to your peak power. I think that one tooth on the engine will be too big of a change
Advancing the timing will make it come into the power at a lower RPM but will usually make it not rev as high.
Your run on the hill was about 7 seconds long. On my dyno a TRX 11 CM becomes too restricted when the time at full throttle is more than about 3 seconds and making 60 HP or more. Full throttle for 5 seconds or more at 55 plus HP the TRX 11 CM becomes too restricted by its stinger and silencer.
The out of frame TRX 11 pipe and silencer builds more back pressure and heat in a shorter time and lower power levels.
The power, pipe temperature and time at full throttle determines the optimum restriction for any given pipe.
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In the video it sounds like you are over-revving it on the last part of the hill. I would take one to two teeth off of the rear sprocket and see if that will keep it running closer to your peak power. I think that one tooth on the engine will be too big of a change
Advancing the timing will make it come into the power at a lower RPM but will usually make it not rev as high.
Your run on the hill was about 7 seconds long. On my dyno a TRX 11 CM becomes too restricted when the time at full throttle is more than about 3 seconds and making 60 HP or more. Full throttle for 5 seconds or more at 55 plus HP the TRX 11 CM becomes too restricted by its stinger and silencer.
The out of frame TRX 11 pipe and silencer builds more back pressure and heat in a shorter time and lower power levels.
The power, pipe temperature and time at full throttle determines the optimum restriction for any given pipe.
In the video i hit 4th gear thats when the clutch was slipping making it sound like i was over revving it.
Would you recommend another pipe Jerry?
Yesterday i notice something about my pipe. When i rev it up the pipe moves like it has a lot of pressure being built up.do you get what im saying?.its mounted correctly and have good springs at the head pipe to cylinder.
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trx11 and zeplins have been used on some fast 370 at the dunes drag strip successfully with no problems for over 20 years.
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trx11 and zeplins have been used on some fast 370 at the dunes drag strip successfully with no problems for over 20 years.
you're right etccb. maybe its just me thinking too much about this whole thing.
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In the video i hit 4th gear thats when the clutch was slipping making it sound like i was over revving it.
Would you recommend another pipe Jerry?
Yesterday i notice something about my pipe. When i rev it up the pipe moves like it has a lot of pressure being built up.do you get what im saying?.its mounted correctly and have good springs at the head pipe to cylinder.
Fix the clutch before making any changes. You cannot evaluate anything accurately with the clutch slipping.
Pipes move off of the flange due to pressure and or vibration. You cannot evaluate the optimum pipe pressure by watching the pipe move on the flange. When the pipe moves on the flange it is due to insufficient spring tension and or the pipe being improperly mounted not too much back pressure.
Adjusting pipe pressure is an experimental process that is best monitored and optimized by instrumentation and an experienced person using a dyno. Optimum back pressure is not the same for all engines and pipes!
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Fix the clutch before making any changes. You cannot evaluate anything accurately with the clutch slipping.
Pipes move off of the flange due to pressure and or vibration. You cannot evaluate the optimum pipe pressure by watching the pipe move on the flange. When the pipe moves on the flange it is due to insufficient spring tension and or the pipe being improperly mounted not too much back pressure.
Adjusting pipe pressure is an experimental process that is best monitored and optimized by instrumentation and an experienced person using a dyno. Optimum back pressure is not the same for all engines and pipes!
its been fixed Jerry, i put a new clutch kit in i not too long ago and has not slipped since.
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trx11 and zeplins have been used on some fast 370 at the dunes drag strip successfully with no problems for over 20 years.
The problem is not how long the guys have been using these pipes. The problem is, guys are getting more power from these cylinders than they were 25 years ago using these same pipes. As the power goes up, the back pressure increases. My testing is showing that some guys engines are reaching this critical pressure level and is causing detonation and in severe cases a reduction in power as compared to the same pipes that have the restriction optimized for the type of riding.
The same engine and pipe restriction optimized for 300 ft drags will require a smaller restriction than the same engine with the pipe restriction optimized to race up a sand hill like TRXDAN was on in his video.
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now that make sense about making more power now day. what do you recommend Jerry?
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trxdan your R looks like it runs pretty hard judging from the video, for me theres no replacement for displacement , but you can get the best of out what you got with more porting , dome and ignition. maybe have jerry make you a pipe
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trxdan your R looks like it runs pretty hard judging from the video, for me theres no replacement for displacement , but you can get the best of out what you got with more porting , dome and ignition. maybe have jerry make you a pipe
It does run pretty hard fast350r..is it possible to get more porting out of it?
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Yeah were is your exhaust port set at ?
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Yeah were is your exhaust port set at ?
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Not sure. How do i go about finding out? Degree wheel? Or measuring the port height?
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I think you should send your quad over to Jerry Hall and let him go through it. With his experience and that dyno, I bet he could get that thing dialed in, no problem.
Road trip!!
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Eddie trx11 port is pretty generic , now if you pay eddie to really port that cylinder like one of his own motor then it will rip , or send to any other reputable builder . Pete at hybrid , matt shearer , nate mccoy , HPR here in phoenix .
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(http://forums.trx250r.org/vbulletin_imports/1637_7656_2017-04-18_1501.jpg)
i know its super hard to see.but from the bottom it goes grey to a small strip of white to gray then light tan to a dark brown on top..basically i am lean at WOT RIGHT?
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(http://forums.trx250r.org/vbulletin_imports/1637_7656_2017-04-18_2437.jpg)
i know its super hard to see.but from the bottom it goes grey to a small strip of white to gray then light tan to a dark brown on top..basically i am lean at WOT RIGHT?
The spark plug CANNOT tell you if your engine is rich or lean. A spark plug cannot tell you if your engine is developing max power. The only thing that a spark plug can tell you is the temperature that the spark plug is operating at.
A spark plug cannot tell you the air fuel ratio, neither can an O2 sensor tell you A/F ratio of what JUST HAPPENED IN THE COMBUSTION CHAMBER IN A TWO STROKE ENGINE. There is a very popular dyno manufacture that is trying to train new dyno operators on how to use an 02 sensors for tuning two strokes. A two stroke will fool an 02 sensor because of the short circuiting and the over scavenged mixture that passes through a two stroke engine and escapes the combustion process.
I can raise the coolant temperature (spark plug base temperature) and guys who read plugs for mixture will say it is leaner. I can lower the coolant temp and spark plug reading guys will say it is rich. I can run the same plug and jetting an make 2 seconds dyno runs and guys will say it is rich. I can run the same plug and jetting and make a 15 to 20 second dyno run and guys will say it is lean. I can run one heat range colder than what the engine needs for the load the engine is experiencing and guys will say it is rich. Again the spark plug can only show you the temperature that it HAS reached and how much time the spark plug has on it since it was installed.
The spark plug pictured above has had two of the key areas removed that will give a vague indication of the combustion temperatures the spark plug has been exposed to. The tip of the above spark plug pictured above is not operating at a high enough temperature to keep the deposits burned off. It could be the result of too cold of a heat range for the length of time the throttle is held wide open. The dark plug tip could be the result of head temperatures that are too cold for the heat range of the plug. It could be the result of running around a few minutes at partial throttle since the engine has had a few wide open passes through the gears. It could be rich but you will know that it is rich enough to darken the tip because it will be misfiring. If the tip is dark on only one side, the dark side of the spark plug will face the carb carburetor side of the engine when installed.
Peak combustion temperatures are in the 3000 to 5000 deg range in a two stroke engine. A spark plug will usually cause pre ignition when any part of it reaches temperatures around 1400 deg F or higher.
A spark plug can help reveal if mild detonation has been occurring. Microscopic pepper like specks will accumulate on the porcelain cone that surrounds the center electrode. A magnifying glass must be used to see these small specks. Severe detonation is easy to spot because the spark plug may have the ground strap burned off or the porcelain cone will be covered with molten aluminum or you engine just quit because it has a hole in the center of the piston or the piston seized.
It is unfortunate that there are a lot of guys that are trying to read spark plug readings to tune their engines for max performance based upon the misinformation than has become rampant based upon spark plug dissection or mutilation.
Tuning an engine is not rocket science. Tune it so that it runs right and monitor the spark plug for indication of detonation. If you make a jetting change and cannot feel a difference or see a difference on the dyno or a drag race, you are at max power as long as the engine is not experiencing ANY detonation. Most engine will have about a one to three jet spread where the engine makes the same peak power. Poorly developed engines will have a much narrower range of jets where max power occurs and where the engine burns up or the power suffers because it is rich.
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Wow really good info. Should i go down to a 7 series plug?
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Wow really good info. Should i go down to a 7 series plug?
Only if you are going to run it at full throttle for a few seconds at a time. I would not worry about trying to get rid of the dark colored spark plug tip by changing heat ranges. I would richen it up a couple of jets and put in a new 8 series plug if you are going to continue running it like you were in the video. The new plug will stay white for a while if you run it hard and then it will eventually start getting some color after many runs up the hill.
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Only if you are going to run it at full throttle for a few seconds at a time. I would not worry about trying to get rid of the dark colored spark plug tip by changing heat ranges. I would richen it up a couple of jets and put in a new 8 series plug if you are going to continue running it like you were in the video. The new plug will stay white for a while if you run it hard and then it will eventually start getting some color after many runs up the hill.
Ok thanks Jerry for your knowledge. Did you get my message. I might of wrote it in the wrong messanger i think.
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Ok thanks Jerry for your knowledge. Did you get my message. I might of wrote it in the wrong messanger i think.
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No I did not get a PM