| Author | Message | ||
     Titusand |
2004 Blast, 19,500 miles. Replaced boot at 9,000 miles. Mods: Vance and Hines exhaust, K&N, carb adjusted. New behavior: won't go faster than 85 and engine is doing some missing starting about 65 or 70. Air filter is clean, plug and wire and good. Below that speed, it runs fine. | ||
| Gearheaderiko |
What’s the carb jetted at? | ||
| Titusand |
I do not remember, the carb jetting was done 15,000 miles ago, but I used the most recommended sizes per this website. What I have described is new behavior. | ||
| Titusand |
Found it: Jardine exhaust, 45/175 jetting | ||
| Gearheaderiko |
So it ran fine with this set up and there was nothing you just modified and this coincidently started afterwords? Seriously anything. Obvious first answer is to check the boot. | ||
| Gearheaderiko |
Plug, wire are tight and the spark plug nipple is tight? Loose spark plug nipples are notorious for this symptom. | ||
| Gearheaderiko |
It will do 30mph in first gear? No issues? | ||
| Titusand |
Small update: I installed a new plug wire (original was on it and it didn't click on anymore) and I tried running it with air filter off, and neither improved the top speed beyond 83mph. Next to the boot | ||
| Titusand |
It will hit 34mph in first, where it hits the rev limiter, and it will hit the rev limiter in every gear, except 5th, and it won't budge past 82- HOWEVER- the engine begins to miss just before the rev limiter in every gear, and power declines, but the bike can muscle its way up to the rev limiter in 1-4th gears at of course lower speed. At 82 it begins to miss and it will not go faster than that. | ||
| Titusand |
I have now changed the boot (old was fine, but I had a new one), put on a Superboot clamp, new plug, new wire, also tried 89 gas instead of 87- no changes. Perfectly consistently in every gear, it will start missing right around 5700 RPM, and do so till red line, below that it runs perfectly normal. Any hints? | ||
| Titusand |
I found quote from an earlier post. Maybe I should switch to 175, as perhaps the engine is not getting enough fuel with a 170 at the upper RPMs? Mods shouldn't make you go slower. Check your main jet. If it's a 170, go to a 175. If it's already a 175, shim the needle. Jetting isn't that hard. 45 is good. It's going to be a 170, 175 or 180 main jet. The needle is going to be 0-3 shims, but 2 is almost always spot on. You're going to fall in that range. There is more you CAN do, and it does take lots more time (and obsession) but we need to find out why you're not hitting Redline first. | ||
| Gearheaderiko |
Try a 175 or 180-jets are cheap. Its the middle of summer and I wouldn’t run anything but premium gas. At this point, don’t cheap out on gas, it CAN make a big difference. To push past 80mph you’ll need all the horsepower you can get, so that’s where any weak link will pop up. Incorrect plug gap, wrong air filter (commonly wrong Outerwears filter), loose plug wire, clogged fuel lines, bad ignition module...... Modules can do many wacky things. If it’s beginning to miss in every gear at 5700 rpm, you’re not going to get much past 80. Very hard to diagnose unless you have a good one to install. Other things that mimic a bad module or vise versa: Fuel flow, electronics not properly connecting, worn valves springs or sticky guides, carb malfunction, bad coil, bad gas, loose timing cup, loose module, bad ground, altitude. Weird unusual problems can cause wacky things to happen, but you have to start with the common problems first. My thoughts: 175 jet Premium gas Change the module. The fact that it misses at the same point in every gear leads me to a bad module. | ||
| Titusand |
New plug and 175 jet on their way! My interest in my P3 has been recently rejuvenated after riding a 1200 Sportster. I need to drive a lot for work and this is my transportation. It is for me, a tool. I rarely take it out for a pleasure trip and as such as a piece of transportation in the city and the 10-20 mile stretches in the countryside I drive, I find it superior to the HD. | ||
| Titusand |
Premium gas made a noticeable difference. I noticed in an earlier post, from a long time ago, very near the time of the upgrade, I posted 175, so that is what it is, I am sure, but no shimming either. | ||
| Titusand |
Turns out - compression is only 80lbs. | ||
| Gearheaderiko |
Bad rings or valves? That’s certainly your problem though. |
