Thumper Racing's XR650L 675CC Big Bore Kit Questions.

[zackm58941]

Hi, I was just on thumper racing's website and found this kit, Thumper racing 675cc BBK. Does anyone else have this kit on their 650L's? If so how do ya like it? Has anyone ever bought anything from these guys, just curious how it all works interms of sending your cylinder away and all to be machined. Oh, this kit would be for my 2004 xr650l. Thanks for any help!

Zack

[zackm58941]

No one? I would have figured someone had bought one of these guys kits, thanks anyways.

[jlpskydive]

It looks cool and pretty affordable. I'd like to know how it performs also. I wonder if they have a Dyno of it?

[zackm58941]

I was thinking about that too, how much of a difference it will make vs stock... I tried to e-mail them but it doesnt seem to want to go through, I think I'll give them a call later today and see what they say about it.

Thanks,

Zack

[jlpskydive]

I think I'll give them a call later today and see what they say about it.

Thanks,

Zack

Let me know what they say. Thanks ?

[EliJoe]

I just did the 660 kit for the 600. I LOVE it. It rocks. I send the cylinder to them, and within about two weeks everything returned ready to install. The rings were even gapped. Tons of low end torque!!! Do it....

[zackm58941]

Awesome!!! Ill have to give them a call tomorrow, didnt get around to it today. Just finished making a custom skip plate for the 650. Thanks everyone!

[zackm58941]

Just an update, I called Thumper Racing about the 675cc BBK and for everything it would be $320! This includes:

-$165 for piston, rings (which they set the gaps on), wrist pin and locks,

-$16 for stronger clutch springs

-$40 for gasket kit

-$35 for valve cover gasket

-$15 for clutch cover gasket

-$49 to bore & hone my cylinder to the new piston.

The guy I talked to said the HotCams Stage 1 cam works great with this kit and seeing that I already have a Uni air filter, he took the K&N out. They also ususally give you a new DynoJet jet kit but I already have that, they will send me new jets to better match the kit and my elivation They no longer do the flywheel service anymore which doesnt bother me but they need to update their website. I'm gonna place the order Monday and send them my cylinder so they can get to work on it, I guess it should take about 8 or 10 days for it to be finished up. Just wanted to let everone know.

[jlpskydive]

Just an update, I called Thumper Racing about the 675cc BBK and for everything it would be $320! This includes:

-$165 for piston, rings (which they set the gaps on), wrist pin and locks,

-$16 for stronger clutch springs

-$40 for gasket kit

-$35 for valve cover gasket

-$15 for clutch cover gasket

-$49 to bore & hone my cylinder to the new piston.

The guy I talked to said the HotCams Stage 1 cam works great with this kit and seeing that I already have a Uni air filter, he took the K&N out. They also ususally give you a new DynoJet jet kit but I already have that, they will send me new jets to better match the kit and my elivation They no longer do the flywheel service anymore which doesnt bother me but they need to update their website. I'm gonna place the order Monday and send them my cylinder so they can get to work on it, I guess it should take about 8 or 10 days for it to be finished up. Just wanted to let everone know.

Please post an update when you're done I might be next. ?

[zackm58941]

Will do! I'll probably start tear down Sunday and call in the order on Monday. I'm also gonna buy the HotCams Stage 1 while I have the thing apart.

Zack

[MrShred]

Yes, please DO let us know how it runs and your opinion of Thumper Racing-after the rings seat!

[Wheels up]

I already have the mods with the cam also. HMMMMMM. More power. Sounds like a plan. The cam alone made a big difference in the overall power with great upper rpm power.

[zackm58941]

Just took the engine out tonight. Took about an hour to get everything out of the way and to get it out of the frame. It was a little heaver than I thought but wasn't too bad at all. Looking in through the intake and exhaust ports, I couldn't believe how good they looked. I figured them to be constrictive and what not but I was pleasantly surprised! Here's a few pic's of it just sitting there, I'm gonna start tear down tomorrow and place my order for the kit too. Hopefully I'll get the cylinder sent out!

Zack

The left overs...

[zackm58941]

One more quick thing, where is the cheapest/best place to buy the HotCams Stage 1 camshaft from? I'll order than one tonight or tomorrow hopfully.

Thanks again everyone,

Zack

[Wheels up]

I have seen them on ebay fairly cheap. I paid 150 U.S. to my door.

[zackm58941]

Thanks, Ill have to check around for the best price.

Update: Just found HotCams Stage 1 for my 650L on ebay for $126.99 HotCams Stage 1 Ebay Link Did you or anyone else ever buy from this guy? Looks like he has a pretty good record going.

Thanks,

Zack

[zackm58941]

Just bought the cam from ebay, will be at my house in 8 days. He was out of stock on that cam so has to order them in and as soon as he gets it, it'll be sent out.

[zackm58941]

Just talked with Gary from thumper racing and he got my cylinder and we went over everything again and totaled to $308 with shipping back to me. This is with the piston kit, gasket kit(minus valvecover gasket), dynojet spec sheet, bore & hone w/ gapped rings, heavy duty clutch springs, clutch cover gasket, new oil filter and spark plug. He says they use the 10.5:1 piston and what gives you the 10:1 final CR is that the 650L cyl head's have larger combustion chambers so 93 octane will work fine with everything. I cant wait to get this thing all back together!! Anyone know how much hp & tq I would be running to the crank after this and what jets does everyone think will work best with this kit? Im right at sea level in upstate new york by the way. Thanks for all the help!!

Zack

[crmc33]

Hi,

Im running a similar set-up;

Hotcam, 10.25:1 102,4mm Wiseco piston, Mikuni VM40 race carb, HRC exhaust system, DIY head porting and I get 50HP at 7000rpm.

Heres the only dyno printout Ive got.....

[XR_Dude]

A piece of the choke plate broke off on my XR600 a couple years ago and it ruined the engine. I removed the engine and sent it to TR. Since they had to do a complete overhaul, I asked them what it would cost for the 660 kit (including the cam) , it was only like a hundred and 50 dollars more, so I had them modify it. The kit gave the bike more power throughout the bottom & mid range. What really made a big difference after the mod was when I installed the FMF silencer. It brought the bike alive. TR has good tech support. Be careful of your valve clearance after you modify the engine. I noticed with the new cam installed, the valve clearance needs to be spot on or the bike will have the cough and stall syndrome. The engine will tend to stall at idle when the engine is hot. Also, as you probably know, you may have to play with jetting, needle position and air screw position on the carb to get the engine to run smooth after the mod installation. Just my opinion. Good luck!