Speedzilla Forums banner

1 - 20 of 212 Posts

·
Registered
Joined
·
876 Posts
Discussion Starter #1 (Edited)
OK, this is a 2002 RC51 SP2 engine rebuild and the steps that went into it.

My engine has about 1.5 seasons of racing on it so we figured it was time for a freshening up. Also next season, I'm going to be playing with the experts so a little more HP would be nice. It would have been nice for this previous season but that's life.

First things first, drain your coolant and oil. Remove the bodywork, exhaust, radiators, rear wheel, shock, and swing arm. Also you will need to remove the airbox, throttle body, and all electrical connections. I have a bike lift so the front wheel was held in place by the clamp. We were then able to rotate the frame up off the engine which was on top of couple of small scissor jacks. Be careful, a RC engine is pretty heavy. It helps to have a couple of buddies around.

(Side note) While your shock is out, now would be a good time to send it out for a rebuild. I expect mine back in a couple of days from Traxxion.

Make sure you have a nice area to work in and be able to store all the parts from your engine. It might be apart for a little while before it's back together, waiting on parts etc. etc.

You might want to figure out ahead of time what you are planning on doing to the engine before you take it out. My plans include removing any of the quieting gears, port the heads & valve job, hi compression pistons, under cut the transmission, and any other little thing to hep make some HP. Also looking at the HRC RC51 service manual, they show a few spots to port in the engine cases. I'm going to do that also.

I'll be updating this as we go along. I'll also add pics when possible.
 

·
you're not Irish...
Joined
·
845 Posts
You know I've heard people talk about removing the quieting gears but never asked why. It doesn't make more HP, does it? is this just for effects? good thread start. can't wait to see how it goes...:twocents
 

·
TOP GUN Instructor
Joined
·
5,717 Posts
Dan, those Q Gears have a pretty good amount of weight to them, that is why, to get rid of spinning Weight.. IF I was racing my RC51.... I'd Do It but for 90% street use and 10%: EVEN 50/50 Track Day useage or whatever it is... I'll pass on that mod. as I like the gear whine!

Hey Chuck, I'm really looking forward to this, as I know of only one other guy here that did a similar "hop up" but he doesn't come around here hardly anymore and has Never answered my request about his RC51 Engine build up...:(

Anyway, According to my Honda Service Manual: says the Engine weights in at 155.4lbs or 70.5kg dry weight...

Peace Jeff
 

·
Registered
Joined
·
1,259 Posts
I was going to ask the same thing, gpz can you tell us more about this HRC service manual? If its real HRC could you possibly PM me some of that info as im going to do an engire rebuild soon. Im sure some of that info would be helpful for me as well. Thanks
 

·
Registered
Joined
·
876 Posts
Discussion Starter #6
I've bought the HRC RC51 service manual from Thousand Oaks. It is not the regular service manual. I don't know if you can still get it from them. In one of my other threads with pics, you can see it sitting on my workbench. It is the book with the bright yellow cover.
 

·
Registered
Joined
·
1,259 Posts
Is it possible you could probably post some relavent data for any of us doing an engine rebuild?
 

·
Registered
Joined
·
876 Posts
Discussion Starter #8
OK, I've got it in front of me and it is the HRC 2000-VTR1000 SP-1 Owner's Manual and Parts List.

The Thousand Oaks part # is VTR1000SP1-00
 

·
VTR1000SP1
Joined
·
50 Posts
OK, I've got it in front of me and it is the HRC 2000-VTR1000 SP-1 Owner's Manual and Parts List.

The Thousand Oaks part # is VTR1000SP1-00
Hi there,
I got my engine apart for this winter. (maintenance and mods too)
Read your info and I was about to ask the same as the guys above :)
Could you possibly describe what they suggest to port ?
they show a few spots to port in the engine cases. I'm going to do that also.
As for "Thousand Oaks"; what is it ? an online book shop ? or a Honda dealership ?

Thanks a million !
 

·
Registered
Joined
·
876 Posts
Discussion Starter #13
This is grinding the primary drive gear. I am not going to be reinstalling the quieting sub gear or springs so we ground the gear down to 12mm as per Thorston. In looking at the HRC parts sheet, they do not install the quieting sub gear either.
 

Attachments

·
Senior Member
Joined
·
750 Posts
To those of you that PM'd me, please accept my apologies for not being able to send this file. It is quite a large file and my ISP won't allow anything more than 10MB to be sent.

So, having said that, I will be arrangeing a special download address, which i will provide over the next couple of days.
If this is still a problem for some of you, i can burn copies of this manual to cd and mail them.

I hope this helps.
Cheers.
 

·
Registered
Joined
·
1,259 Posts
Nice! thanks Mondial

Also GPZ the grinding of that gear is that the remaning quieting gears that your talking about? Ive removed the ones from the cams but i know there are a couple more are those the ones in the pics.
 

·
Registered
Joined
·
876 Posts
Discussion Starter #18
There are another set in the cam gear train. You have to cut them out since you can't disassemble the gears from the housing.

I've included a pic.

Nice! thanks Mondial

Also GPZ the grinding of that gear is that the remaning quieting gears that your talking about? Ive removed the ones from the cams but i know there are a couple more are those the ones in the pics.
 

Attachments

·
Registered
Joined
·
601 Posts
There are another set in the cam gear train. You have to cut them out since you can't disassemble the gears from the housing.

I've included a pic.
Are you going to be running standard cams in this engine after you have rebuilt it?

If so and you have done the Q gears on the cams, what have you done with the oil way on the cams? Welded them up or something? I say this because when I did this mod last winter, I think this seized my cams resulting in bent inlet valves on the front head......
 

·
Registered
Joined
·
876 Posts
Discussion Starter #20
Yes, we are going to be running the standard cams and removing the Q gears. We've had a discussion about this and we aren't sure how we are going to proceed.

You seem to be the only one that we know of who's had an issue with removing the Q gears. I removed them from my old engine and it did over 50 dyno runs without incident. That enfgine did pop down at Barber but it dropped a valve and the cams still looked great.

I'm afraid that if we weld the holes shut that we might cause a different issue with the oiling system.

Are you going to be running standard cams in this engine after you have rebuilt it?

If so and you have done the Q gears on the cams, what have you done with the oil way on the cams? Welded them up or something? I say this because when I did this mod last winter, I think this seized my cams resulting in bent inlet valves on the front head......
 
1 - 20 of 212 Posts
Top