englertracing
New member
the del west are titanium valves, coated with chromium nitride 80-100 a piece good stuff. Nascar, f1, and motogp use delwest.
just bought an 8 set of them for an aprillia v twin.
Crf450 common issues????
- Thread starter fastmatt42
- Start date
the del west are titanium valves, coated with chromium nitride 80-100 a piece good stuff. Nascar, f1, and motogp use delwest.
just bought an 8 set of them for an aprillia v twin.
fastmatt42
New member
I have another question. Hope you guys can help. On the exhaust. Do I really need the muffler? Seen guys drill the rivets, cut it all down and rivet it back together to make it shorter. My engine guy says to leave the header pipe from head to muffler pipe alone, but from there back, it doesn't matter. I have the tools and know how to just bend and make a straight pipe off the header and delete the muffler. Anyone else doing this? Ideas? Pics?
DON'T do straight pipe. It makes good power BUT in a VERY narrow band. You give up torque too. Keep exhaust pipe as close to STOCK length as possible. After market pipes might be slightly larger and smoother radius. they will provide better overall performance. As far as a muffler, just a stock lightweight or aftermarket with a good straight through design will work good. You can shorten them to fit in our confines with little to no loss.
ABR #69
Member
As your engine builder said, the header pipe is very important, leave that alone!!
The muffler pipe can be changed and not significantly hurt performance over all, BUT!!! It will in turn change where power is made through the rpm range though. Shorter helps higher rpm, longer helps lower. So depending on the rpm you plan to run at, it will suffer lower power at the other rpm levels. How much depends on pipe design, steps, length and so forth.
The muffler can be shortened "some" with little to no performance loss, but increases sound depending on how short you make it. I might be wrong here, but you can lose top end with it being too short. The muffler I am not quite as sure about how it ultimately effects everything. Effectively the pipe's tuning needs are met where the pipe enters the muffler But, there is more to it than that as well. Also As Jimbo said as long as it's a good flowing pass through muffler, you'll be fine.
PS: There is a lot to tuning an engine and exhaust together.
The muffler pipe can be changed and not significantly hurt performance over all, BUT!!! It will in turn change where power is made through the rpm range though. Shorter helps higher rpm, longer helps lower. So depending on the rpm you plan to run at, it will suffer lower power at the other rpm levels. How much depends on pipe design, steps, length and so forth.
The muffler can be shortened "some" with little to no performance loss, but increases sound depending on how short you make it. I might be wrong here, but you can lose top end with it being too short. The muffler I am not quite as sure about how it ultimately effects everything. Effectively the pipe's tuning needs are met where the pipe enters the muffler But, there is more to it than that as well. Also As Jimbo said as long as it's a good flowing pass through muffler, you'll be fine.
PS: There is a lot to tuning an engine and exhaust together.
For exhaust I would recommend finding a nice aftermarket tuned exhaust system from a TRX450 and use the entire exhaust..this can easily be accomplished by simply cutting it at a welded joint or 2 and rotating to fit the kart and re welding. There is also power to be found in the intake system. Depending on the airbox set-up on the bike you may have to re-jet the carb as well.
fastmatt42
New member
1.How do I get the micron head temp lead hooked up down in the spark plug hole? or do I hook it up differently?
2.Are you guys only running the pull cable connected to the carb? I have pics of connecting the stock bike throttle cable to the kart cable, down on the floor pan. would like to see pics of the hook up at the carb.
3.Can I remove the stock chain protector off the case right in front of the drive gear? any problems with this? I ask because those bolt holes look like the perfect place for me to fab a chain guard and bolt on??
4. where are you guys mounting coil, cdi, and fuel pump???? Please post or send me some pics? I'm going to fab all the brackets for mounting everything. Just would like to do it all once, correctly. Thanks guys
2.Are you guys only running the pull cable connected to the carb? I have pics of connecting the stock bike throttle cable to the kart cable, down on the floor pan. would like to see pics of the hook up at the carb.
3.Can I remove the stock chain protector off the case right in front of the drive gear? any problems with this? I ask because those bolt holes look like the perfect place for me to fab a chain guard and bolt on??
4. where are you guys mounting coil, cdi, and fuel pump???? Please post or send me some pics? I'm going to fab all the brackets for mounting everything. Just would like to do it all once, correctly. Thanks guys
Justin Westerfeld
Member
1. CHT is not something you need to know. Water temp is however. Engine needs to operate between 150 and 180 degrees water temp. You will need to buy a new sensor for your Michron.
2. I only ever ran the one throttle cable. Use the OEM cable to connect to the carb. Cut the other end, strip and use a brass Farrel to crimp on and thread into std 1/8" npt kart hook up. This will work if your throttle hook up is under the steering column. If you are up front like the umax you will need a split linkage in the floor pan like the Kwik link for the animal engine.
3. I always made my own chain guard in place of the plastic guard.
4. CDI and coil mount easily on the seat. You will need to make a little hanger. Ignition doesn't like engine vibration. I always mount on the seat with a rubber gromet. The fuel pump will mount easily on a piece of aluminum flat bar (1/4" x 1") on the rear motor mount bolt.
Good luck.
2. I only ever ran the one throttle cable. Use the OEM cable to connect to the carb. Cut the other end, strip and use a brass Farrel to crimp on and thread into std 1/8" npt kart hook up. This will work if your throttle hook up is under the steering column. If you are up front like the umax you will need a split linkage in the floor pan like the Kwik link for the animal engine.
3. I always made my own chain guard in place of the plastic guard.
4. CDI and coil mount easily on the seat. You will need to make a little hanger. Ignition doesn't like engine vibration. I always mount on the seat with a rubber gromet. The fuel pump will mount easily on a piece of aluminum flat bar (1/4" x 1") on the rear motor mount bolt.
Good luck.
alvin l nunley
Site Supporter
I'm confused, (I know I know, so what's new) but I'm wondering, how do you make good power and give up torque? Maybe my confusion is caused by you saying, "makes good power". Do you mean horsepower? Horsepower is a calculation, torque x RPM / 5252.1. If you give up torque, (less) you give up horsepower.
TS Motorsports
Member
mike grady said it best, "horsepower is nothing more than a mathematical figure, torque is the only measurable thing in the equation"
fastmatt42
New member
Thank you Justin!
Taft Racing
Member
That's if you want to take Mike Grady's word for anything lol. Allot of multimillion dollar race engine builders spend those millions in pursuit of a mathematical figure. Just saying. Why do the Japanese manufactures chose to use a 62mm stroke 450 to create x power output vs the speedway 500cc engines using 80mm stroke. ? What exactly is the purpose of using such different bore stroke combinations if there's no such thing as HP vs torque?
I don't care what math says. Its what my butt cheeks tell me on the track that matters. I ran a straight pipe and a full exhaust. While the straight pipe rattled your ear drums, it didn't seem to pull real hard outta the turn. Half way down the straight, it would kinda hit like a 2 stroke and rev very quickly but only for about 1500 rpm or so. So it made very narrow power at a peaky rpm then would just go flat. On the other hand, with a full exhaust, the motor seemed to pull harder off the turn for longer. It seemed like a much more linear power curve and it pulled all the way to the rev limiter. This was on my crf250r. I couldn't tell you actual numbers from a Dyno but I know how it felt and what was faster on the track.
Are you talking about the case saver? Leave it on there. It'll save your cases if the chain ever breaks.........
So....just do it the Japanese way, and you'll be on top of the race engine world.
That, by the way, is the illogic called a circular argument.
A circular argument goes like this: "The Japs are the fastest". We do it the way the Japs do it. Therefore we are the fastest also.
You see the problem with this argument?? The problem is that the argument does not address the engineering factors that go into a
fast/faster engine. It just cites the Japanese way of doing things, with the assumption that there (their) way is the ultimate.
That, by the way, is the illogic called a circular argument.
A circular argument goes like this: "The Japs are the fastest". We do it the way the Japs do it. Therefore we are the fastest also.
You see the problem with this argument?? The problem is that the argument does not address the engineering factors that go into a
fast/faster engine. It just cites the Japanese way of doing things, with the assumption that there (their) way is the ultimate.