Help me build a RELIABLE HIGH MID-RANGE ORIENTED HP XR650L engine


11 replies to this topic
  • machman

Posted November 01, 2006 - 07:56 AM

#1

Hey guys,

I've spent countless hours on this board searching for "the" answer on how to approach this. I should also say, don't tell me to sell and by an XRR. I don't want to.

I've got a lightly modified (pipe, drilled carb, jets, etc) '93 XRL with 20,000kms on it. My goal is to end up making as much reliable power as possible. However, since I'm not running Baja, I'd like that in the mid-range. I do a couple trips per year but mostly just around town. I'd like to be able to get 30,000kms on these mods before I need to worry.

Additionally, I do have some money to spend, but I'm not willing to spend $200 more for a carb that's going to give me slightly better throttle response and .25HP. This isn't a budget buildup, but I'm not p!ssing money away either.

1) piston?
To address my longevity concerns I was considering the ceramic coated 10.5:1 657cc piston from XRsOnly

2) cam?
To address my longevity concerns I was considering the HRC cam because it's completely hardened, not just surface hardened like the HotCams one.

3) valves?
XRsOnly has some "Black Diamond" nitroneg impregnated valves available. Are they the best ones?

4) valve springs?
I know nothing about this, can anyone make a recommendation?

5) valve guides?
I also know nothing about these, can anyone make a suggestion here?

6) heat wrapped header pipe?
The flanges on the stocker are ground out already. Is a heat wrapped header pipe still a good idea?

7) carb?
XRsOnly has the following ones available. What do you recommend? I should also say that I'm at 3000' elevation and don't have much for carb modding skills.
-Keihin FCR Pumper Carburetor Kit 41mm
-Mikuni Flatslide Carburetor 41mm
-Mikuni Pumper Carburetor 42mm
-Mikuni Pumper Carburetor 45mm

8) oil cooler?
Given that I don't do much serious off-roading, I think I'll just tie in with some random oil cooler from another bike.

9) temp guage?
I think I'll buy an XRsOnly temp guage so I know what's going on in that dept.

10) magnetic oil plug?
To keep particles down after the build up.

11) head work?
I was also considering doing some porting and polishing myself. I've talked to guys on this board who have done it and they have convinced me it's not hard. However, what about a 3 angle valve job?

Any guidance you guys could provide me with would be very much appreciated.

  • rmhrc630

Posted November 01, 2006 - 10:55 AM

#2

Hey guys,

I've spent countless hours on this board searching for "the" answer on how to approach this. I should also say, don't tell me to sell and by an XRR. I don't want to.

I've got a lightly modified (pipe, drilled carb, jets, etc) '93 XRL with 20,000kms on it. My goal is to end up making as much reliable power as possible. However, since I'm not running Baja, I'd like that in the mid-range. I do a couple trips per year but mostly just around town. I'd like to be able to get 30,000kms on these mods before I need to worry.

Additionally, I do have some money to spend, but I'm not willing to spend $200 more for a carb that's going to give me slightly better throttle response and .25HP. This isn't a budget buildup, but I'm not p!ssing money away either.

1) piston?
To address my longevity concerns I was considering the ceramic coated 10.5:1 657cc piston from XRsOnly

2) cam?
To address my longevity concerns I was considering the HRC cam because it's completely hardened, not just surface hardened like the HotCams one.

3) valves?
XRsOnly has some "Black Diamond" nitroneg impregnated valves available. Are they the best ones?

4) valve springs?
I know nothing about this, can anyone make a recommendation?

5) valve guides?
I also know nothing about these, can anyone make a suggestion here?

6) heat wrapped header pipe?
The flanges on the stocker are ground out already. Is a heat wrapped header pipe still a good idea?

7) carb?
XRsOnly has the following ones available. What do you recommend? I should also say that I'm at 3000' elevation and don't have much for carb modding skills.
-Keihin FCR Pumper Carburetor Kit 41mm
-Mikuni Flatslide Carburetor 41mm
-Mikuni Pumper Carburetor 42mm
-Mikuni Pumper Carburetor 45mm

8) oil cooler?
Given that I don't do much serious off-roading, I think I'll just tie in with some random oil cooler from another bike.

9) temp guage?
I think I'll buy an XRsOnly temp guage so I know what's going on in that dept.

10) magnetic oil plug?
To keep particles down after the build up.

11) head work?
I was also considering doing some porting and polishing myself. I've talked to guys on this board who have done it and they have convinced me it's not hard. However, what about a 3 angle valve job?

Any guidance you guys could provide me with would be very much appreciated.




Mate I'm not sure where you've been but XRs make reliable power.

Almost none of the go fast goodies for XRs really hurt the durability.

Mod to your hearts content.

However it will be cheaper and smarter getting a XR650R. The base is superior

  • cleonard

Posted November 01, 2006 - 01:59 PM

#3

Making preformance changes like this does add stress to your engine. There are 3 sources. First is added mechanical stress from higher compression, and a different cam. These put more loads on the crank and valve train. Second is more heat. Third is more torque on the transmission.

Sounds like you mostly ride on the road, and that is much better in the heat department. The heat can get bad on a highly technical fisrt gear trail when it 40C or hotter. Same for riding in the sand. Riding an a road ensures a lot of cooling airflow.

The valve train is usually the first thing to go on the RFVC engines. Using a preformance cam increases the load on the components. A new cam chain and tensioner may be a good idea.

There are a few things that you missed. When you take your engine apart, take a real close look at the transmission gears. Without splitting the cases you can see the gears on the mainshaft. There is a limited view of the driven countershaft gears. If there is pitting on the gear faces they will need to be replaced. You will be increasaing the torque that the transmission needs to deal with so it needs to be perfect. A broken gear can trash the entire engine.

Same goes for the clutch, more torque equals more stress. Heavy duty springs might be a good idea, or at least some new ones. I recently replaced my clutch because it was slipping. I didn't replace the springs and fried the new one in short order. The problem was the springs. The were shot.

1.) Piston - 10.5:1 is about the max that you can run with premium pump gas. With this higher compression there will be almost no margin for poor quality gas, wrong jetting, etc. Since you are at 3000 feet, that will help some as the air is less dense than sea level. You will always need to be vigilant for pinging. A little pinging is OK, a lot will melt your piston. Slightly rich jetting helps prevent pinging. High temperature encourage it.

2.) As stated before the valve train is usually the thing that wears out first. Preformance cams usually open the valves faster and open them higher. This requires greater forces. This is also the problem area for lubrication. Use good oil and change it more often than Honda says.

3.) I have no idea what's "best." I would imagine that those are good. Refreshing your head at this time would be a good idea. Not really sure if you need to replace the valves if they are OK. It sure wouldn't hurt.

4.) If you are not going for higher revs, I don't think that stronger springs are required. Go by what the cam manufacturer says. Stronger springs increase the loads on the rest of the valve train.

5.) Replace them if they are worn. Otherwise I don't know much about them either.

6.) The primary benefit of the head wrap is keeping the engine cooler. Where the headers are in front of the engine they preheat the air before it gets to the engine. The wrap insulates them and the air getting to the engine is a bit cooler. I believe that there is a small benefit for the exhaust system. It's a good plan since higher compression means more heat.

7.) Anything has got to be better than the CV carb on the bike now. The larger carbs will show improvement at wide open. Since that is not what you are looking for I'd go with the smaller ones. The pumpers will help a bit with improved throttle response as they have an acceleration pump to squirt some gas in there. It makes the biggest difference when starting from a stop.

8.) Adding an oil cooler is a great addition. There used to be kits and I think a cooler from a XR400 is a common addition.

9. & 10.) Good ideas.

11.) I thought all "normal" valve grinding is 3 angle.


XRs only is a great resource if you can get a hold of a knowlegable employee. I was also very pleased when I sent them my head for refurb. I had 2 bad valve seats and they replaced them correctly. I got 3 new OEM valves and the 3 angle valve grind. It took them a while, but it's been working great for 3 years.

  • Rideaide

Posted November 01, 2006 - 02:27 PM

#4

Call Xrs Only 760-244-2626 and speak with Chris or Kamell. All of these parts they stock and they will give you what you need. Or email rideaide@hotmail.com for a quote.:mad:

  • wattner

Posted November 02, 2006 - 02:26 AM

#5

I have most of these mods and can comment on most of the items....
1) piston?
To address my longevity concerns I was considering the ceramic coated 10.5:1 657cc piston from XRsOnly

This is what I use...zero problems over 3-4 years, probly 10k miles+

2) cam?
To address my longevity concerns I was considering the HRC cam because it's completely hardened, not just surface hardened like the HotCams one.

I have used many cams over the years, and am most satisfied with the HRC from XR's only...I have had the cams with hardened lobes, used hardened rockers and the cams have failed....HRC zero prob's and the valves rarely if ever need adjustment...If you have to adjust valves, it has been my experience (2-"R"s and 3-"L"s) that the cam is going south....

3) valves?
XRsOnly has some "Black Diamond" nitroneg impregnated valves available. Are they the best ones?

I use the black Diamond with great success...also have the valve springs from XR's only....I had Freddy weld on big fins, had him port the head and install the black diamond valves and springs...Zero problems....


4) valve springs?
I know nothing about this, can anyone make a recommendation?

Same as above...

5) valve guides?
I also know nothing about these, can anyone make a suggestion here?

I believe the stockers are the best, most reliable...Call XR's and talk to Freddy...VERY knowledgeable....

6) heat wrapped header pipe?
The flanges on the stocker are ground out already. Is a heat wrapped header pipe still a good idea?

Don't know...I use the Stainless XR's only...just installed a new one. I used the ceramic coated, but after 4 years, started rusting through the coating...Still works fine, but I like clean and new....I can make a great deal on a slightly rusted, used but in good condition XR's only full system...

7) carb?
XRsOnly has the following ones available. What do you recommend? I should also say that I'm at 3000' elevation and don't have much for carb modding skills.
-Keihin FCR Pumper Carburetor Kit 41mm
-Mikuni Flatslide Carburetor 41mm
-Mikuni Pumper Carburetor 42mm
-Mikuni Pumper Carburetor 45mm

I have used the M-flatslide and now use the FCR pumper...GREAT carb...Zero issues There is no comparison between the 2...FCR far better....No experience with Mikuni pumper, once again ask Freddy...I am on my 3rd 650L....Freddy has done the work on all of them...Always steered me right...

8) oil cooler?
Given that I don't do much serious off-roading, I think I'll just tie in with some random oil cooler from another bike.

I don't have one, I use the Big Fins....Maybe I ought to look at one...I have never had any problem with pinging or overheating with the above set-up...Have ridden thousands of miles through Mexico, through the Copper Canyon to the coast, ferried to the Baja and ridden there...Good to crappy gas...NO issues...

9) temp guage?
I think I'll buy an XRsOnly temp guage so I know what's going on in that dept.

Got one and the plastic lens cover broke off within a week....

10) magnetic oil plug?
To keep particles down after the build up.

Absolute must have....watch the particles with oil change...if you see chunks....Look out....explosion eminent...Best guage of cam wear...If you see an increase in shavings, the bike is hard to start or starts to ping...Probably the cam...Great early detection device

11) head work?
I was also considering doing some porting and polishing myself. I've talked to guys on this board who have done it and they have convinced me it's not hard. However, what about a 3 angle valve job?

Once again, Freddy did the 3- angle..I have had no prob's, so I don't know what to compare to....

Any guidance you guys could provide me with would be very much appreciated.

All of those mods have provided me years and miles of trouble free riding, with a major increase in power. I would have traded for the "R" many years ago, but I still prefer the seat of the "L"...and that button, Gotta have that button....Lastly, you have got to do the suspension....I currently have crf forks and a re-valved stock rear...I have an Ohlins, but it needs a rebuild. I think I am going to sell it and use the revalved stocker....

  • COAL RUN

Posted November 02, 2006 - 07:26 AM

#6

How mutch is involved in swapping in the CRF forks on the 650 L?

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  • wheelnut46

Posted November 02, 2006 - 11:49 AM

#7

BUMP
Awaiting the recipe for the ultimate "L"...
:mad: :mad:

  • cleonard

Posted November 02, 2006 - 11:57 AM

#8

I have most of these mods and can comment on most of the items....
1) piston?
To address my longevity concerns I was considering the ceramic coated 10.5:1 657cc piston from XRsOnly

This is what I use...zero problems over 3-4 years, probly 10k miles+


Does this work with 91 octane premium pump gas? Does it ping much? I've been considering going to a higher compression piston, but don't want to need special fuel. My 600 pings on occasion with it's 9:1 stock piston.

  • dukeryder

Posted November 02, 2006 - 02:15 PM

#9

Does this work with 91 octane premium pump gas? Does it ping much? I've been considering going to a higher compression piston, but don't want to need special fuel. My 600 pings on occasion with it's 9:1 stock piston.


If you're pinging with 9:1 compression and running premium your timing must be too far advanced.

9:1 is relatively low compression for a bike, there's plenty of street bikes that run 11:1 and slightly higher and they do just fine on Premium pump gas.

  • machman

Posted November 03, 2006 - 09:17 PM

#10

Alright, here's what I"m thinking now.

1) Ceramic piston - long term reliability
2) HotCams cam - medium term longevity for budget purposes. Doesn't require hardened rockers. Saves money, not much sacrifice.
3) Valves - Black Diamond for strength and reliability
4) Valve Springs - Where necessary
5) Valve Guides - Where necessary
5.5) Valve Seals - Yes, cheap and easy
6) Heat wrapped Header Pipe - Perhaps, if I can find a good used one
7) Carb - FCR pumper, although the price kills me. Is it possible that it offers twice as much value for twice the price?
8) Oil Cooler - I'm going to wait and see how the tempurature is after the work
9) Temp Guage - see above
10) Magnetic Oil Plug -already ordered
11) Head Work - planning on getting a local engine shop to do the 3 angle valve job and perhaps some porting.

I'm now trying to keep this job close to $1000. The FCR carb certainly doesn't help. What do you think about that?

  • machman

Posted November 04, 2006 - 11:10 AM

#11

Okay, I just got off the phone with Freddy at XRsOnly. Man he is one solid guy. It's Saturday and he spent 15 minutes talking with me telling me straight up what he suggests I should do to get the best value for my money.

Here it is:

cam: Leave the stocker. It's fine for mid-range power.
piston: Go with the 10.5:1 657cc, it makes a huge difference.
Valves: Probably replace intake side, but they'll see when I ship them the head. They'll use the Black Diamond ones they sell.
Carb: He can really get the stock one to hum, and suggested I ship that in as well. However, I'm thinking I'll just buy a new one. He's crazy about the Mikuni 42mm pumper. He says it gives no issues, is easy to tune, and gives great all round power and response. He also says the FCR Keihin is a great carb once it's tuned right, but it can be tough and it doesn't handle altitude changes very well. Given that I'm at 3000' he feels the 42mm Mikuni Pumper is the way to go.
Header: Yes, open up that thing and get the exhaust out. The stock one is super restrictive, even after you grind it out.
Muffler: The IDS2 Supertrapp that I have isn't the best. In fact, he said it's only marginally better than stock. If I keep it he suggests putting at least 12 disks in it. However, he recommends their Stainless Oval pipe. He feels it makes a huge difference.
Head: Send it to them so they can refresh it.
Valve guides: These bikes hardly ever wear out the valve guides. He can almost guarantee mine are fine after 20,000kms
Valve Seals: This is a cheap and easy replacement. Absolutely do it.

Well, now I know what I'm doing thanks to you guys and Freddy. If you guys ever need anything, he's a great guy. Didn't try to sell me a bunch of sh!t I don't need and told me straight what the best bang for my buck was. Gotta like that.

  • crmc33

Posted October 12, 2007 - 03:28 AM

#12

machman,

Ive been using a XRL based road racer for about 8 years now and hope I can help with some guidance for extra midrange.

When having the head tuned ask them for D shaped exhaust port. It will require a very small amount of welding. If they dont know what you mean then they should! This will give you more midrange and top end power as D shaped ports flow better than circular and also stop exhaust gas recirculation (the exhaust gas tumbling back into the exhaust port form the first bend in the pipe). This is also why a small step down into the pipe form the head gives better midrange power.

Bear in mind that if you do ever go with a welded camshaft like I use, if it is stellite welded (ie the best stuff) its not magnetic so any particles wont show on a magnetic drain plug. If you keep with the stock cam as you said you'll be ok. Just make sure you prime the oil system carefully after the rebuild.

The flatslide carb will help a lot with better midrange tuning/repsonse of course.

Feel free to PM me if you have any specific questions.





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