WTF is this Engine I have????

[SpecOps13]

I know it's an 89 VMax Engine but lately I've been wondering what's inside making it tick... It has an irritating knock at idle. Sounds almost like a spark knock. When running and warmed up, it's way faster than my 94. The 94 seems to be running perfect.

I thought catching up with my buddies R1 in second gear was a fluke. He had 6 extra teeth on his rear sprocket at the time. If he hadn't, he told me I probably would have blown past him...He's an accomplished rider too. Kyle took a ride on this bike one time when it was running on 3 cylinders and felt it was ran fine.:ummm::ummm::ummm:


I re-ran a compression check and followed Kyle's guiding thoughts. I ran the check with the throttle wide open. My readings ranged from 220-230 lbs. To me that seems quite high...

I run fuel anywhere from 87 to 93 octane, depends on what Non Ethanol is available. I got the thought yesterday to buy some 108 octane booster and see if the knock quiets down. If it does, I'll have somewhat of an answer... Somebody, been into this motor and done some work....

We'll See..:confused2:

 

[one2dmax]

The compression is way high. Could be carboned up creating higher compression.

Sean

 

[gennro]

Would have to be a ton of carbon buildup in each cylinder. Also to be 220 to 230 psi each. I betting someone put some higher compression pistons in. But for that to be extremely useful some bigger cams would be needed.

 

[SpecOps13]

I've got so many Garage Projects going on I almost forgot to mix some 108 in. It was the last thing I did before I came in. I mixed enough for a full tank then topped it off.

I started the bike and let it run at a high idle on choke. Initially, it sounded like the normal Rock Tumbler that it's been since I got it. I let it run long enough to pull it off choke. By then it had pulled fuel from the tank. That's when I noticed it was notably quieter. Still got the valve train noise but more to the level of my 94. Revs quicker too if that makes sense.

I shut it down and fired it right back up again several times. Starts really easy when it's warm up. It hadn't been doing that before. Always been a scary proposition to shut it down and then try to fire it right back up. It turned really slooooow when it hadn't cooled for a few minutes.... Battery always read 12.7 when I checked it and I've soldered every connection dealing with power.

I feel like somebody drove over me with a big truck right now so a rides going to have to wait...:bang head:


It would amaze me if there's any carbon build up. I haven't cut this bike much slack since it's been running on all cylinders. It's seen well over 100 on a few dozen occasions...

 

[gennro]

Yeah sounds like you may have a built engine. I doubt carbon has built that evenly between each cylinder for it to have that even of a compression between cylinders. I would definitely check your plugs though.

 

[SeaTownV-Max]

looking forward to finding out more about this mystery!

 

[alorio1]

:th_favorites24:I'm interested in this thread also........

 

[[email protected]]

Drive to Kyles house and pull the heads.

Lets take bets!

Then post pics and specs.....

 

[tugla]

might be worth using a different compression gauge to see if it was faulty or not.

 

[dannymax]

PCW stamps numbers on the rear of the engine case, below the rear headers....maybe you 'caught the brass ring' and got a PCW motor??? :confused2:

Compression does sound way high tho.

 

[maleko89]

Same situation as my '99. All my compression readings 205-216 PSI. About 133 rwhp.

 

[SpecOps13]

I'll look for PCW Numbers. Kyle's got too much going on to be pulling my motor apart. I'm looking to do it on a dyno. best way to find out if it's out of the ordinary. BTW, my 94 measured 150 - 160 lbs with the same compression gauge....:worthy:

This bike feels like it has way more balls down low in the RPM Range than my 94.:confused2:

I had a 1970 Olds Cutlass that I bought with the understanding it was a 350 CID. As I started tuning it and realized it was a 455 CID, 13.5 to 1 pistons, Turbo Hydro 455 designation tranny and a few other things. Engine was stamped with a serial number of 12. It turned out to be quite a car. I made it 90 miles from Orlando to St. Pete very late one night in 53 minutes. That's a pretty good average speed considering some of it was in town driving on both ends...


Dave