Call all XR600R!!!

[veetwo _tls]

Originally Posted by mcma111

The XR600 stock bore is 97mm. There are over size pistons available in +97.25mm, +97.5mm, 98.0mm and 100.0mm

go for the JE 630 HI-comp (100.0mm) slug (you will need to deck/bore & hone) if your running pump fuel just use 2 x base gaskets.
i got excellent runs from there pistons better than wiseco as i tried also before hand

[Zombie_Stomp]

Don't they make a 9:1 for use with premium? My wiseco's a 9:1. I'd be more hesitant to double up on base gaskets than have the piston milled a bit while I was having machine work done. The forged pistons are usually well above the minimum safe thickness and so are open to customization (lowering) of compression.

[endocrantz]

I used an HRC 11:1 100mm and had a machine shop help calculate and do a little milling on the top of the piston. I can use pump premium now, and it's been a blast. Someone suggested leaving a crown in the center when milling.

Originally Posted by Zombie_Stomp

Don't they make a 9:1 for use with premium? My wiseco's a 9:1. I'd be more hesitant to double up on base gaskets than have the piston milled a bit while I was having machine work done. The forged pistons are usually well above the minimum safe thickness and so are open to customization (lowering) of compression.

[HeadTrauma]

If it's a flattop piston, then I would prefer to have a shallow dish turned in the center. The only squish these engines have is a thin stripe around the edge of the chamber which is partly why they are so octane sensitive.

A couple FYIs:
1.) The JE 10.5:1 piston does not make 10.5:1. It would if the piston crown was level with the cylinder deck, but it actually sits about 1.0mm below and compression is ~9.8:1.
2.) The HRC Power Up kit included a cylinder assembly that is 0.3mm taller than stock. I don't have any specs on the HRC slug like done volume, compression hight, or actual compression ratio, but using one with an original 600 cylinder will slightly increase compression.
3.) Wiseco is the only source I know of for 9:1 pistons. The rest are ~10.5:1.

[Blakebird]

Originally Posted by HeadTrauma

If it's a flattop piston, then I would prefer to have a shallow dish turned in the center. The only squish these engines have is a thin stripe around the edge of the chamber which is partly why they are so octane sensitive.

A couple FYIs:
1.) The JE 10.5:1 piston does not make 10.5:1. It would if the piston crown was level with the cylinder deck, but it actually sits about 1.0mm below and compression is ~9.8:1.
2.) The HRC Power Up kit included a cylinder assembly that is 0.3mm taller than stock. I don't have any specs on the HRC slug like done volume, compression hight, or actual compression ratio, but using one with an original 600 cylinder will slightly increase compression.
3.) Wiseco is the only source I know of for 9:1 pistons. The rest are ~10.5:1.

I thought (per the TT threads on it ad nauseum) that the Wiseco piston was the one with the compression ratio lower than advertised due to the deck height.
The JE piston has never come up in those discussions to the best of my recollection. I have the JE forged 10.5:1 and it's been great, no knock on premium pump gas, though I used it due to my riding altitude (6k - 13k ft).
It's worked fine from 4,000 ft to over 13,400 ft.

[Assfault]

Originally Posted by Blakebird

I thought (per the TT threads on it ad nauseum) that the Wiseco piston was the one with the compression ratio lower than advertised due to the deck height.
The JE piston has never come up in those discussions to the best of my recollection. I have the JE forged 10.5:1 and it's been great, no knock on premium pump gas, though I used it due to my riding altitude (6k - 13k ft).
It's worked fine from 4,000 ft to over 13,400 ft.

My buddy and I really appreciate all of the info all of you people have given.
He has found a complete XR650L motor for cheaper than he can rebuild the one he has and may go that route. He will have to add all the elect start stuff but that will make it easier to start. lol
He better hurry though and make a decision as we are going to Copper Canyon on the DS the end of March. He needs to make sure that it will be good to go before we go as I dont need any problems down there. I am taking my trusty NX650 instead of my XR due to the elect start and being more comfortable on the road. It will do 95% of what the XR do just a smidge slower. I like the XR better for around here in the mountian trails.
Thanks again,
Assfault

[mcma111]

Well your buddy is in for a heck of a lot of work to get the L engine and it's system in the 600 frame.

[HeadTrauma]

Originally Posted by Blakebird

I thought (per the TT threads on it ad nauseum) that the Wiseco piston was the one with the compression ratio lower than advertised due to the deck height.
The JE piston has never come up in those discussions to the best of my recollection. I have the JE forged 10.5:1 and it's been great, no knock on premium pump gas, though I used it due to my riding altitude (6k - 13k ft).
It's worked fine from 4,000 ft to over 13,400 ft.

The Wiseco 10.25:1 piston is the one that was grossly overstated. If you look on their site or in the most current catalog, it is now listed more accurately as 8.7:1. The 10.5:1 piston they offer now is a different part number.

My bike didn't rattle much around 4000ft either, but it sounded like the head was getting shot-peened down around 2000. I am hoping that the Hot Cam alleviates it when the weather gets hot again. In the cool air it seems happy even at low elevation.

Originally Posted by ASSFAULT

He has found a complete XR650L motor for cheaper than he can rebuild the one he has and may go that route. He will have to add all the elect start stuff but that will make it easier to start. lol
He better hurry though and make a decision as we are going to Copper Canyon on the DS the end of March.

If he's competent and works fast, he might be able to tear both engines (completely) apart and put the XR600 countershaft/kickstart parts in the 650L engine, swap stators, and not have to wire up the e-start right away. That's still going to be a lot of late nights, though.

[flatfender]

Sorry about the off topic question but here it is, "how do you XR600R guys like the split between first and second?" could be closer, wider or about just right.

thanks in advance for any opinions

EDIT: when riding off road, on anything you might consider difficult, how do you like the split between first and second

Greg

[Blakebird]

Originally Posted by ASSFAULT

He better hurry though and make a decision as we are going to Copper Canyon on the DS the end of March. He needs to make sure that it will be good to go before we go as I dont need any problems down there.

I rode a plated XR400 from El Paso to Batopilas and back... anything bigger will be much better since it's mostly paved two lane until you get past Creel.
If you have any doubts about a bike's reliability... bring a tow strap

[Blakebird]

Originally Posted by flatfender

Sorry about the off topic question but here it is, "how do you XR600R guys like the split between first and second?" could be closer, wider or about just right.

thanks in advance for any opinions

EDIT: when riding off road, on anything you might consider difficult, how do you like the split between first and second

Greg

I don't really notice any gaps in the gears I don't like. The motor's grunty enough to not care much either.

[JAB]

Originally Posted by flatfender

Sorry about the off topic question but here it is, "how do you XR600R guys like the split between first and second?" could be closer, wider or about just right.

thanks in advance for any opinions

EDIT: when riding off road, on anything you might consider difficult, how do you like the split between first and second

Greg

Plenty of torque, don't really notice. Start from a dead stop in second if you want/need to. Now since we are talking gears, how about a 6th gear.

[TopDogDave]

3 years ago I found an XR600R by the roadside - "For Sale" it said....hmm, I mused, could be OK to go round town on - do the shopping - save miles on the beemer...so I bought it - kind of a whim...$1500.....never had a dirt bike and it looks like it has 'attitude'...so what the hell!

3 years on....obsession!

These things are like 'The Alien' - a trojan horse or whatever...they are just so compelling it's like getting drawn in....I mean it's got so much stuff to fiddle with....no computer, no fool injection, cheap parts - and most of all - it's got.....(drum roll)......fins! No water bottle radiator and funny blocky barrel as has my mates XR650. Yeah I know they're thumper bothers too but...

Un-apologetic old school and loving it.

So - 3 years later:

- still riding around town
- plus 3 x 4500klm 2 weeks rides across Simpson desert and related areas
- now an XR630 (JE pot and LA sleeve job)
- new bearings everywhere on the chassis
- massive oil cooler (40C days not that uncommon someplaces here)
- WIP - big fin head for even more cooling, building it now
- WIP - hotcams stage 1, ordered
- BMW looking a bit dejected .....

Couple of pics here of how I'm making big fin patterns out of artist card so the aluminium fabricator can copy and weld...and some other stuff showing the oil cooler and etc.

making big fin templates from photos



the goal....



my theory is most engines blow up due overheating - oil cooler



here's my mates 650R - no fins = no fun :)



now....check that handsome 600 on the right, FINS!



my other pet improvement is to wind TWO sets of ignition coils on the stator after being stranded a year ago when the wired broke on it...now we have backup...




welding subframe strengthening bars for luggage



Ok that's my rant for now.

Cheers

TDD

[veetwo _tls]

the reason i ran 2 x base gaskets was to lower the compression to run standard pump fuel. as when the shop built it first up they didn't listen to me & ran 1 x gasket & it lunched the piston in 2 weeks $300aud gone. the bike done 10,000klm on the new replacement JE piston & was still going strong when it was sold.

CLIC ON PICS FOR BIG:






the new replacement:







NX650 starter & casing bolts straight up to the XR600R

oil cooler is the best option compared to the larger cooling fins.


.

[Jeff@TheQuadShop]

Just a bit of info for those that don't already know. Scott Summers won 7 national titles on XR600's in the 90's. 5 GNCC titles and 2 National Hare Scrambles. It truly is the best do it all motorcycle ever made!