Rebuild Advice

[rcbailey56]

Alright, it's time to pull the engine (1300 from an '87) out of one of my parts bikes and rebuild it.

 

I have a set of VMAX heads, complete with cams, buckets, springs and shims that I want to have machined/reconditioned.

 

Is there any reason the heads from the VMAX won't fit on the 1300? Is there any reason to not use them? Any pitfalls you know of?

 

From what I can understand, I would be getting a little better volumetric efficiency and a higher compression ratio.

 

I look forward to hearing any discussion on the subject.

 

Thanks,

[bongobobny]

Putting Vmax heads on a 1300 is considered an upgrade to the VMax crowd...

[GaryZ]

I have installed Vmax cams and springs in my '87 Venture engine

The Vmax heads are pretty much a direct bolt-on. The pretty parts might need mods to look right (side covers).

 

Using the Vmax heads would bring 1mm larger valves to the party (intakes are 29mm vs 30mm, exhaust are 23mm vs 24mm) and some people are convinced the smaller valve stems improve airflow.

 

The 10.5:1 compression for the 1st Gen Vmax is the same as the 1st Gen Venture (1200 & 1300).

 

The Vmax heads on a 1300 Gen 1 should get you about 120HP at the crank. To make more power you will need to use the Vmax carbs and open up the exhaust. These carbs with the v-boost manifolds are taller than the VR set up and will interfere with the fake gas tank that covers the battery and air box. I have a 2-barrel version of a Q-jet carb and one day I hope to make a manifold and bolt it on my beast.

 

My question before starting this project was; Will I lose torque at lower RPM? The answer is no, and my recently acquired '92 VR shows me torque is about the same until the Vmax cams start making music . . .

 

My biggest headache has been the carbs. I have been trying to make my '85 carbs work and have not been very successful. I installed Vmax needles and saw some improvement. Each time I get the carbs working OK they gum up again. I try to run only 100% gas, but, exposure to E10 over the years has deteriorated the seals. A rebuild with newer seals will probably help a lot.

 

I say go-for-it

Edited October 14, 2014 by GaryZ

[rcbailey56]

Thank you guys. I'll get started soon. I love this part. WooHoo!

 

My biggest headache has been the carbs. I have been trying to make my '85 carbs work and have not been very successful. I installed Vmax needles and saw some improvement.

 

Gary,

 

Is it just gumming up or are you having problems with performance?

Edited October 15, 2014 by rcbailey56

[rcbailey56]

The bike the rebuilt engine is going to be put in is an '87 Venture Std and the engine that is in that bike already has the v-boost setup. The previous owner installed it. To get around the headroom issue, he cut out a place in the cover just big enough for the top of the air box to poke through. So, it looks like a small hood scoop sticking up in your lap.

 

This bike is going to be an experimental bike for me. Rebuild a 1300 motor, machine VMAX heads (to be milled down about .040). I'm going back with either a VMAX or an FJR final drive. Pulling all the fairing off, bags off too. Modify side panels (still looking for inspiration on this one). Going back with windshield only and a modified dash. Raise the seat height for the driver (extra padding). Hopefully, that will give a little more leg room. Maybe by spring/summer at the latest, I'll have a nice cruiser.

 

Thanks again for the replies.

[GaryZ]

Thank you guys. I'll get started soon. I love this part. WooHoo!

 

 

 

Gary,

 

Is it just gumming up or are you having problems with performance?

 

 

Carbs keep gumming up jets, weeping fuel, etc.

I have had low-speed jets gum up a couple of times, once had a high-speed jet clog, and two different carbs have suddenly started weeping from the float bowl. Oh, and one stuck float!

 

I fix one problem and another pops up if the bike sits longer than a couple of weeks.

I know, it should never sit. But, life happens.

 

I really want to build a single carb manifold for this two barrel Q-jet off of a '80s Camaro . . . Maybe this winter

 

In the mean time I am racking up miles on my '92 VR

[GaryZ]

The bike the rebuilt engine is going to be put in is an '87 Venture Std and the engine that is in that bike already has the v-boost setup. The previous owner installed it. To get around the headroom issue, he cut out a place in the cover just big enough for the top of the air box to poke through. So, it looks like a small hood scoop sticking up in your lap.

 

This bike is going to be an experimental bike for me. Rebuild a 1300 motor, machine VMAX heads (to be milled down about .040). I'm going back with either a VMAX or an FJR final drive. Pulling all the fairing off, bags off too. Modify side panels (still looking for inspiration on this one). Going back with windshield only and a modified dash. Raise the seat height for the driver (extra padding). Hopefully, that will give a little more leg room. Maybe by spring/summer at the latest, I'll have a nice cruiser.

 

Thanks again for the replies.

 

This is my kind of project!

Please keep us in the loop as you progress

[videoarizona]

 

I really want to build a single carb manifold for this two barrel Q-jet off of a '80s Camaro . . . Maybe this winter

 

 

 

 

Oh my...this will be interesting! Lots of pics!!!

david

[rcbailey56]

Gary,

Where do you store your bike for the extended periods you're not riding? If it's too warm the gas will not hold up.

[GaryZ]

Gary,

Where do you store your bike for the extended periods you're not riding? If it's too warm the gas will not hold up.

 

The '85 VR was usually parked in the garage with my '99 Ninja.

No problems with the Ninja . . .

[dingy]

Rebuild a 1300 motor, machine VMAX heads (to be milled down about .040).

 

Machining the heads will give a much lower compression gain than if the block head surface were to be machined.

Block is harder to machine though. Mainly due to the middle drive output casting area creates interference issue when mounted in milling machine.

I have had 2 blocks milled. Cost was $160 each.

Gary

[rcbailey56]

Thanks Dingy,

 

I knew machining the block would change the ratio, however, I was thinking it would effectively lower the compression ratio, but if you say it is the best bang for the buck, I certainly want to consider it.

 

Based on what I find when I get into it, I may well have to machine both block and heads in order to get perfectly true surfaces.

[rcbailey56]

The '85 VR was usually parked in the garage with my '99 Ninja.

No problems with the Ninja . . .

 

Well, in that case, I guess it's not the temperature. One thing I did when I was getting my '92 VR roadworthy was rebuild the carbs, sync them and then while working on wheel bearing and brakes and meters, the bike sat up for a few months. When I got it back on the road, it didn't run very well. It would hang up at 2500 rpms, wouldn't run without choke until it was hot.

 

I pulled the carbs and cleaned the jets. Still didn't run very well, couldn't sync. What I ended up doing was putting in about 1/2 can of Berrymans carb and fuel injector cleaner in a tank of regular gas. After driving that tank out, it ran a little better, so I did it again. I made sure I was giving it time at all throttle positions. Now after running it hard on the Interstate, it only needs a little choke and not for long, I have been able to sync it and it runs pretty good.

 

Don't know if this will help you, but I wish you well in whatever you choose to do.