Question about 2002 Yamaha V-Max

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My 1989 vmax has poor compression on the rear 2 cylinders.

This loss in compression happened over a period of 50 miles or so of intermittent riding. A standard comp. test showed 125-135on front 2 cyl. and 80 or so on rear 2 cyl. I attempted a leak down test but did not have proper tools to be accurate... It pops occasionally through the carbs and sometimes exaust. This all started with a slight miss at light throttle/cruise and progressed to no power and resulting comp. loss. I strongly suspect poor valve seal. Bike has stage 7 and kerker pipe and could easily be over revved. I suspect the previous owner of this. My question is if valves were bent from hitting pistons due tue excessive rpm why would only the rear 2 cyl. be affected and why would the problem get worse over time? I have purchased rebuilt assembled heads to install but would like to make sure before removing the engine for repair...Thanks for any help very much,Nik

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You can rule out poor piston rings by doing another compression test, this time with a teaspoon or two of oil in the cylinder. Oil will help seal a piston ring (raising compression temporarily), but will have no effect on valves. I would suggest burnt valves rather than bent. That might explain why only the back two cylinders, they run a little hotter. Under normal circumstances (stock exhaust, sane driving) not hot enough to make a difference but if your previous owner was a clown who knows?

Good luck Nik, those bikes are a lot of fun and pretty reliable when done right.

Posted on Jan 15, 2009


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1989 vmax 1200 back firing at low idle

Hi, Michael and the usual suspects are:
1. Severely discharged or a damaged battery, should have 12.5 volts or better and be able to pass a load test if necessary.
2. Check battery terminals for damage or corrosion, check the battery cables at "BOTH" ends for loose, corroded, or broken connectors, "INSIDE" and outside the cable harness, perform connector wiggle test and check cables with an ohmmeter if necessary.
3. Faulty main circuit breaker and or connections.
4. Faulty ignition coil and or connections.
5. Faulty spark plug, oil or gas fouled, wrong heat range or service type, wrong gap, loose in the cylinder head, broken electrode or insulator.
6. Faulty spark plug cables, leaking or broken, internal damage check for spark leakage in the dark.
7. Faulty ignition module, switch, CKP, MAP, CMP, sensor and or any connector in the ignition circuit could have corroded, loose, or broken pins/sockets
8. Burnt exhaust valve or air leak in the exhaust system.
For more information about your issue and valuable "FREE" downloads that you will need please click on the links below. Good luck and have a nice day.
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if your loosing compression it could be dirty valve guides or valves. could also be poor rings or a loose timing chain. have the compression checked when its happening.

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I have a mitsubishi galant 2001 and has 181k miles that currently has a misfire in cylinder 2 i had a full tune up two weeks prior and had my catalytic converter replaced a week before that,. The misfire...

check that the plug leads are not touching each other causing the misfire on that cylinder. Use lead separators to achieve this.. To turn off the engine it has to be backfiring through the inlet manifold and burning incoming fuel. This will not show up on a scan as it is a mechanical problem and not electronic. I think it may be an idea to have a compression test done to check for valve and valve seat insert problem on no 2 cyl

Jul 09, 2014 | Cars & Trucks

1 Answer


which engine? there are many.
can be 50 things
300 means random misfire on all cylinders.
it really means all cylinder have weak HP, weak power, weak combustion energy levels !

The ecu actually measures crankshaft acceleration rates (geekspeak)
in lay terms this means (btw 300s never lie, it's REAL misfire)
there is one exception a loose timing belt or cam chain. can trip 300s.

in no order ever.

1: bad spark to all cyl.
2: low compression to all cylinders (cam timing off, melted CAT)
3: bad fueling to all. (EGR stuck wide open , engine stalls?)

but can be 50 things, so its best not to GUE$$
what we do is conduct simple tests.
first is do the 60,000 mile tuneup. do that its cheap, and works in most cases.
1: tuneup time.sparks and filters both. fuel and air.
2: compression test, and vacuum tests. at WOT,. both. ask for data.
3: check cam timing. if compression fails on all cyl.
4: i scan the ECU looking at fuel trim and closed loop working, ask.

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1 Answer

2003 harley softail will not start

Did you pull any error codes (Diagnostic Trouble Codes)?

1. Remove right side saddlebag and side cover if so equipped. Remove protective plug from data link connector. Other models will be under the seat.

2. To activate the diagnostic feature,follow these steps.
a. Create diagnostic test wire or use a female spade clip which will bridge the two terminals perfectly.
b. Install diagnostic test wire/clip across Terminals 1 and 2 on the data link connector, they are marked.
c. Turn Ignition/Light Key Switch to IGNITION and wait approximately 10 seconds (4 seconds lamp ON, 6 seconds lamp OFF) for check engine lamp to start flashing.

3. All trouble codes are sent out as a series of flashes. To retrieve the first digit of the trouble code simply observe the number of times the lamp flashes.
a. The lamp will then flash one or more times to indicate the first digit of the trouble code.
b. The length of time the lamp is illuminated and the length of time in which it is off are each about 0.5 second in duration.

4. The second digit follows:
a. Following the transmission of the first digit, there is a 1.2 second pause in which the lamp is off.
b. The lamp will then flash one or more times to indicate the second digit of the trouble code. Count the number of times the lamp flashes to retrieve the second digit.

5. If more than one trouble code is sent:
a. Following transmission of the second digit of the first code, there is a 3 second pause in which the lamp is off.
b. Once all codes have been sent, the data string is repeated. When you have recorded the same trouble code twice, it is an indication that the transmission has been restarted and that all trouble codes have been retrieved.

IMPORTANT NOTE ..If diagnostic test wire is installed across Pins 1 and 2 on connector in lieu of a Scanalyzer, the ECM is placed in a diagnostic test mode and the engine will start. The test wire must be removed from the data connector and the ignition switch turned OFF or the check engine lamp will continue to flash codes. A historic trouble code resides in the memory of the ECM until the code is cleared by use of the Scanalyzer or a total of 50 trips has elapsed. A "trip" consists of a start and run cycle, the run cycle lasting at least 30 seconds. After the 50 trip retention period, the trouble code is automatically erased from memory (that is, assuming no subsequent faults of the same type are detected in that period). The numbers after the 'historic' or 'current' is the speedo code number, but without the electrical diagnostics manual you're not going to know what they mean.

1 Current 53 ECM flash error
2 Historic 53 ECM flash error
3 Current 54 ECM EEPROM error
4 Historic 54 ECM EEPROM error
5 Current 63 ECM serial data low
6 Current 63 ECM serial data open/high
7 Current 63 TSSM serial data low
8 Current 63 TSSM serial data open/high
9 Current 61 Loss of TSM/TSSM serial data
10 Current 14 Loss of all ECM serial data (state of health)10 24 Loss of vehicle speed10 33 Loss of vehicle inhibit motion10 43 Loss of powertrain security status
11 Current 33 System relay contacts open
12 Current 33 System relay coil high/shorted
13 Current 33 System relay coil open/low
14 Current 33 System relay contacts closed
15 Current 99 Incorrect password
16 Current 99 Missing password
17 Current 41 CKP sensor intermittent
18 Current 41 CKP sensor synch error
19 Current 11 TP sensor open/low
20 Current 11 TP sensor high
21 Current 12 MAP sensoropen/low
22 Current 12 MAP sensorhigh
23 Current 14 ET sensor voltage low
24 Current 14 ET sensor open/high
25 Current 15 IAT sensorvoltage low
26 Current 15 IAT sensoropen/high
27 Current 24 Front ignition coilopen/low
28 Current 25 Rear ignition coil open/low
29 Current 24 Front ignition coilhigh/shorted
30 Current 25 Rear ignition coilhigh/shorted
31 Current 24 Front cylinder combustion intermittent
32 Current 25 Rear cylinder combustion intermittent
33 Current 23 Front injector open/low
34 Current 32 Rear injector open/low
35 Current 23 Front injector high
36 Current 32 Rear injector high
37 Current 16 Battery voltage low
38 Current 16 Battery voltage high
39 Current 43 VSS sensor low
40 Current 43 VSS sensor high
41 Current N/A (no speedo code for this) Check engine light open/low NO CHECK ENGINE LAMP AT KEY ON or CHECK ENGINE LAMP ON CONTINUOUSLY
42 Current N/A (no speedo code for this) Check engine light high NO CHECK ENGINE LAMP AT KEY ON
43 Current 35 Tachometer low
44 Current 35 Tachometer high
45 Current 25 Rear cylinder no combustion
46 Current 24 Front cylinder no combustion
47 Current 34 Loss of idle speed control IDLE AIR CONTROL
48 Current 35 Accelerometer fault
49 Current 34 Starter output high
50 Current 25 Ignition enable output high
51 Current 21 Left turn output fault
52 Current 22 Right turn output fault
53 Current 11 Battery voltage high
54 Current 31 Alarm output low
55 Current 32 Alarm output high
56 Current 41 Ignition switchopen/low
57 Historic 63 ECM serial data low
58 Historic 63 ECM serial data open/high
59 Historic 63 TSSM serial data low
60 Historic 63 TSSM serial data open/high
61 Historic 61 Loss of TSM/TSSM serial data
62 Historic 14 Loss of all ECM serial data (state of health)
63 Historic 33 System relay contacts open
64 Historic 33 System relay coil high/shorted
65 Historic 33 System relay coil open/low
66 Historic 33 System relay contacts closed
67 Historic 99 Incorrect password
68 Historic 99 Missing password
69 Historic 41 CKP sensor intermittent
70 Historic 41 CKP sensor synch error
71 Historic 11 TP sensor open/low
72 Historic 11 TP sensor high
73 Historic 12 MAP sensor open/low
74 Historic 12 MAP sensorhigh
75 Historic 14 ET sensor voltage low
76 Historic 14 ET sensor open/high
77 Historic 15 IAT sensorvoltage low
78 Historic 15 IAT sensoropen/high
79 Historic 24 Front ignition coilopen/low
80 Historic 25 Rear ignition coilopen/low
81 Historic 24 Front ignition coilhigh/shorted
82 Historic 25 Rear ignition coilhigh/shorted
83 Historic 24 Front cylinder combustion intermittent
84 Historic 25 Rear cylinder combustion intermittent
85 Historic 23 Front injector open/low
86 Historic 32 Rear injector open/low
87 Historic 23 Front injector high
88 Historic 32 Rear injector high
89 Historic 16 Battery voltage low
90 Historic 16 Battery voltage high
91 Historic 43 VSS sensor low
92 Historic 43 VSS sensor high
94 Historic N/A Check engine light high NO CHECK ENGINE LAMP AT KEY ON
95 Historic 35 Tachometer low
96 Historic 35 Tachometer high
97 Historic 25 Rear cylinder no combustion
98 Historic 24 Front cylinder no combustion
99 Historic 34 Loss of idle speed control
100 Historic 35 Accelerometer fault
101 Historic 34 Starter output high
102 Historic 25 Ignition enable output high
103 Historic 21 Left turn output fault
104 Historic 22 Right turn output fault
105 Historic 11 Battery voltage high
106 Historic 31 Alarm output low
107 Historic 32 Alarm output high
108 Historic 41 Ignition switch open/low

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1 Answer

Cylinder #1 continues to Misfire

What DTC code(s) are you getting?
You performed a compression test on cylinder #1; did you test cylinder #2?
Compare the readings, if there is a significant difference in compression readings between the two, you may have a bad head gasket, a bad valve, etc.
The bottom line, the problem is internal to the engine.

Dec 09, 2013 | 2002 Buick LeSabre

1 Answer

What is the Compression supposed to be for a 1987 Toyota Pick up 22R with carb, 4 cyl.???

A new engine would be about 180 psi for each cylinder. As the miles add up and wear occurs, compression will get lower. The important thing is that compression is even and balanced-lowest compression reading should be within 75% of the highest cylinder's compression. Some Toyota engines had a minimum allowable compression of about 135 psi, but if compression is balanced, you could have average compression as low as 125 psi and engine would still run good, some loss of power but still acceptable, and oil consumption would not be that bad.
If cylinder compression is below 120 psi as an average, you should be looking into a rebuild event-rings and valves need attention. If any cylinder is below 100 psi, it may not even fire, certainly will produce no power, and could be a head gasket failure, very worn rings, or valve problems.
Remember the important thing is to find compression readings that are very close to each other. I have an '87 Sentra with 75,000 miles(true!)-lowest comp. is 160, highest is 165 psi-runs great, good power. Also a '79 Datsun pickup (with god only knows how many miles-about 200,000 maybe). Compression is about 125-135 psi, fairly well balanced-noticeable loss of power, very little oil burning, still runs fair to good-dependable, at least.
That should give you an idea of what to look for. Good luck.

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