84 vf700 with low compression

[John365]

I have low compression in all four cylinders, been told I have 3 options 1) rebuild it. anyone have a rough price on parts and list. 2)replace the engine.where can I find one. 3) FOR SALE: 1984 vfr700 13168 miles w/low compression $1000.00 ... $500. for the bike $500. for the rebuit carbs.

[eddievalleytrailer]

How low is low?

[John365]

#1 84, 130 with tsp of oil. #2 110, #3 95, #4 85. this one keeps fouling plugs

[masonv45]

You need to do a leakdown test to determine exactly where the bike is leaking.

If it's just a headgasket, the gasket is about $36 and you can do the labor.

You should have about 150 on a cold motor.

[kinome79]

Don't you have to remove the engine from the frame to remove the heads? I think you have to on the '92.

[loopsandlogic]

Originally Posted by masonv45

You need to do a leakdown test to determine exactly where the bike is leaking.

If it's just a headgasket, the gasket is about $36 and you can do the labor.

You should have about 150 on a cold motor.

When you say a rebuild, do you mean, New pistons and rings, valves seals plus a regrind.....You need to be more specific of what you think or know that needs rebuilding.

Sounds like to me, that your valves are seating properly.

I've never seen a bike that needed new pistons and rings at 13k on the clock, especially a Honda!

Unless it's been raced really hard by the PO.

ll

[derstuka]

Originally Posted by loopsandlogic

When you say a rebuild, do you mean, New pistons and rings, valves seals plus a regrind.....You need to be more specific of what you think or know that needs rebuilding.

Sounds like to me, that your valves are seating properly.

I've never seen a bike that needed new pistons and rings at 13k on the clock, especially a Honda!

Unless it's been raced really hard by the PO.

ll

Curious....I don't see where that you think he mentioned a "rebuild." He was just talking about installing a new head gasket, which is by no means a rebuild. A leakdown test would be a good idea though.

[masonv45]

Originally Posted by kinome79

Don't you have to remove the engine from the frame to remove the heads? I think you have to on the '92.

You only have to remove the engine for the rear head on a VF700F.

[squirrelman]

sell the bike for parts and use the rebuild money on a newer bike.....

[John365]

thanks for all the replies. rebuild it? yes. hopefully rings only, bore out and o/s pistons too if I have to when I get into it. gaskets, valve seals, timing chain and sprockets,etc. the bike is in pretty good shape....other than that.

[eddievalleytrailer]

Originally Posted by masonv45

You only have to remove the engine for the rear head on a VF700F.

Hey Mason, Nice new Avatar!!!!

[JamieDaugherty]

Originally Posted by John365

thanks for all the replies. rebuild it? yes. hopefully rings only, bore out and o/s pistons too if I have to when I get into it. gaskets, valve seals, timing chain and sprockets, etc. the bike is in pretty good shape....other than that.

More than likely it's something to do with the valves. The valve seats take a beating on motorcycles and require reconditioning after a while. The rings could be losing their seal also, and it could be a combination of several things. From the readings given I'd say that it needs a full rebuild. The cost is tough to say because you could run into a situation where some of the parts are not available anymore. For example, some of the colors of main bearings are discontinued.

With that said - I think it's a good idea to give it a shot. There are VF700/750 engines on eBay quite often, so if you found out that you could not rebuild it you would always have a backup plan. I wouldn't give up on it so quickly.

Where are you located? I've got quite a few VF700/VF750 spares including engines and I might be able to help.

[John365]

thanks Jamie, Im in coventry ct. the cost of shipping and engine may be less than a rebuild. please let me know how much.

[JamieDaugherty]

Originally Posted by John365

thanks Jamie, Im in coventry ct. the cost of shipping and engine may be less than a rebuild. please let me know how much.

Engines can be shipped using BAX Global for around $100. They will even deliver to your house, which is handy.

[DKC'sVFR]

I recently did a cold compression test on several bikes including a VF500 and my dead cold VFR 700. I also did a ninja 500 and 250. The ninja,( warm) 500 had one cylinder at 180 psi and the other at 90. I'd say this bike had a valve or head gasket problem. Hard to believe one cylinder would wear out rings while the other still pumps like new. The ninja 250 was only 2 years old but it was used hard daily and the owner never adjusted anything. It had 140/130. The '84 VF 500 had been warmed up and it pumped 155/165/155/160. We called it good but we were looking for 180 X 4, after testing the ninja 500. The VFR 700 had been sitting for months and it pumped 150 X 4. I still wanted 180, but bought it anyway. And finally, the factory manual suggests 190 psi +/- 10%, at least I think thats what I saw. I'll check it after I send this off. I have really enjoyed this discussion of compression/leakdown testing. But, what is desirable compression for a Vf engine?

[John365]

Originally Posted by DKC'sVFR

I recently did a cold compression test on several bikes including a VF500 and my dead cold VFR 700. I also did a ninja 500 and 250. The ninja,( warm) 500 had one cylinder at 180 psi and the other at 90. I'd say this bike had a valve or head gasket problem. Hard to believe one cylinder would wear out rings while the other still pumps like new. The ninja 250 was only 2 years old but it was used hard daily and the owner never adjusted anything. It had 140/130. The '84 VF 500 had been warmed up and it pumped 155/165/155/160. We called it good but we were looking for 180 X 4, after testing the ninja 500. The VFR 700 had been sitting for months and it pumped 150 X 4. I still wanted 180, but bought it anyway. And finally, the factory manual suggests 190 psi +/- 10%, at least I think thats what I saw. I'll check it after I send this off. I have really enjoyed this discussion of compression/leakdown testing. But, what is desirable compression for a Vf engine?

before I get into anything big Ill have to do a leakdown test. the clymer manual says 147 - 213 psi

[John365]

Originally Posted by JamieDaugherty

Engines can be shipped using BAX Global for around $100. They will even deliver to your house, which is handy.

how much for the engine itself

[Alaskan]

I replaced the front head gasket on my 1984 VF750F. It wasn't a lot of fun, but it's doable. The valve timing was the worst part. Oh, and getting the carbs back on wasn't fun either.